Add clang-tidy. (#368)

.clang-tidy

@@ -0,0 +1,22 @@
+---
+Checks: "*,
+        -abseil-*,
+        -altera-*,
+        -android-*,
+        -fuchsia-*,
+        -google-*,
+        -llvm*,
+        -modernize-use-trailing-return-type,
+        -zircon-*,
+        -readability-else-after-return,
+        -readability-static-accessed-through-instance,
+        -readability-avoid-const-params-in-decls,
+        -cppcoreguidelines-non-private-member-variables-in-classes,
+        -misc-non-private-member-variables-in-classes,
+        -modernize-use-nodiscard,
+        -misc-no-recursion,
+        -readability-implicit-bool-conversion,
+"
+WarningsAsErrors: ''
+HeaderFilterRegex: ''
+FormatStyle:     none

CMakeLists.txt

@@ -10,6 +10,7 @@ option(FTXUI_BUILD_EXAMPLES "Set to ON to build examples" ON)
 option(FTXUI_BUILD_TESTS "Set to ON to build tests" OFF)
 option(FTXUI_BUILD_TESTS_FUZZER "Set to ON to enable fuzzing" OFF)
 option(FTXUI_ENABLE_INSTALL "Generate the install target" ON)
+option(FTXUI_CLANG_TIDY "Execute clang-tidy" OFF)
 
 set(FTXUI_MICROSOFT_TERMINAL_FALLBACK_HELP_TEXT "On windows, assume the \
 terminal used will be one of Microsoft and use a set of reasonnable fallback \
@@ -22,6 +23,7 @@ else()
     ${FTXUI_MICROSOFT_TERMINAL_FALLBACK_HELP_TEXT} OFF)
 endif()
 
+
 add_library(screen
   include/ftxui/screen/box.hpp
   include/ftxui/screen/color.hpp

cmake/ftxui_set_options.cmake

@@ -1,6 +1,19 @@
+find_program( CLANG_TIDY_EXE NAMES "clang-tidy" DOC "Path to clang-tidy executable" )
+if(NOT CLANG_TIDY_EXE)
+  message(STATUS "clang-tidy not found.")
+else()
+  message(STATUS "clang-tidy found: ${CLANG_TIDY_EXE}")
+endif()
+
+
 function(ftxui_set_options library)
   set_target_properties(${library} PROPERTIES OUTPUT_NAME "ftxui-${library}")
 
+  if(CLANG_TIDY_EXE AND FTXUI_CLANG_TIDY)
+    set_target_properties(${library}
+      PROPERTIES CXX_CLANG_TIDY "${CLANG_TIDY_EXE};-warnings-as-errors=*"
+    )
+  endif()
 
   target_include_directories(${library}
     PUBLIC

examples/CMakeLists.txt

@@ -12,6 +12,9 @@ add_subdirectory(dom)
 if (EMSCRIPTEN)
   # 32MB should be enough to run all the examples, in debug mode.
   target_link_options(component PUBLIC "SHELL: -s TOTAL_MEMORY=33554432")
+  target_link_options(component PUBLIC "SHELL: -s ASSERTIONS=1")
+  #string(APPEND CMAKE_EXE_LINKER_FLAGS " -s ALLOW_MEMORY_GROWTH=1")
+  #target_link_options(component PUBLIC "SHELL: -s ALLOW_MEMORY_GROWTH=1")
 
   get_property(EXAMPLES GLOBAL PROPERTY FTXUI::EXAMPLES)
   foreach(file

examples/component/checkbox_in_frame.cpp

@@ -1,13 +1,12 @@
 #include <array>   // for array
-#include <memory>  // for shared_ptr, __shared_ptr_access, allocator_traits<>::value_type
+#include <memory>  // for shared_ptr, __shared_ptr_access
 #include <string>  // for operator+, to_string
-#include <vector>  // for vector
 
 #include "ftxui/component/captured_mouse.hpp"  // for ftxui
 #include "ftxui/component/component.hpp"  // for Checkbox, Renderer, Vertical
 #include "ftxui/component/component_base.hpp"      // for ComponentBase
 #include "ftxui/component/screen_interactive.hpp"  // for ScreenInteractive
-#include "ftxui/dom/elements.hpp"  // for operator|, Element, size, border, frame, HEIGHT, LESS_THAN
+#include "ftxui/dom/elements.hpp"  // for operator|, Element, size, border, frame, vscroll_indicator, HEIGHT, LESS_THAN
 
 using namespace ftxui;
 

examples/component/menu_entries.cpp

@@ -17,7 +17,7 @@ using namespace ftxui;
 MenuEntryOption Colored(ftxui::Color c) {
   MenuEntryOption option;
   option.transform = [c](EntryState state) {
-    state.label = (state.active? "> " : "  ") + state.label;
+    state.label = (state.active ? "> " : "  ") + state.label;
     Element e = text(state.label) | color(c);
     if (state.focused)
       e = e | inverted;

examples/component/menu_style.cpp

@@ -33,7 +33,7 @@ Component HMenu5(std::vector<std::string>* entries, int* selected);
 int main(int argc, const char* argv[]) {
   auto screen = ScreenInteractive::TerminalOutput();
 
-  std::vector<std::string> entries = {
+  std::vector<std::string> entries{
       "Monkey", "Dog", "Cat", "Bird", "Elephant", "Cat",
   };
   std::array<int, 12> selected = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

examples/dom/border.cpp

@@ -1,3 +1,4 @@
+#include <stdlib.h>                // for EXIT_SUCCESS
 #include <ftxui/dom/elements.hpp>  // for text, operator|, vbox, border, Element, Fit, hbox
 #include <ftxui/screen/screen.hpp>  // for Full, Screen
 #include <memory>                   // for allocator
@@ -5,7 +6,7 @@
 #include "ftxui/dom/node.hpp"      // for Render
 #include "ftxui/screen/color.hpp"  // for ftxui
 
-int main(int argc, const char* argv[]) {
+int main() {
   using namespace ftxui;
   auto document =  //
       hbox({
@@ -30,6 +31,7 @@ int main(int argc, const char* argv[]) {
   auto screen = Screen::Create(Dimension::Full(), Dimension::Fit(document));
   Render(screen, document);
   screen.Print();
+  return EXIT_SUCCESS;
 }
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.

examples/dom/color_gallery.cpp

@@ -12,7 +12,7 @@
 using namespace ftxui;
 #include "./color_info_sorted_2d.ipp"  // for ColorInfoSorted2D
 
-int main(int argc, const char* argv[]) {
+int main() {
   // clang-format off
   auto basic_color_display =
     vbox(
@@ -83,14 +83,18 @@ int main(int argc, const char* argv[]) {
   // True color display.
   auto true_color_display = text("TrueColors: 24bits:");
   {
-    int saturation = 255;
+    const int max_value = 255;
+    const int value_increment = 8;
+    const int hue_increment = 6;
+    int saturation = max_value;
     Elements array;
-    for (int value = 0; value < 255; value += 16) {
+    for (int value = 0; value < max_value; value += 2 * value_increment) {
       Elements line;
-      for (int hue = 0; hue < 255; hue += 6) {
+      for (int hue = 0; hue < max_value; hue += hue_increment) {
-        line.push_back(text("▀")                                    //
+        line.push_back(
+            text("▀")                                    //
             | color(Color::HSV(hue, saturation, value))  //
-                       | bgcolor(Color::HSV(hue, saturation, value + 8)));
+            | bgcolor(Color::HSV(hue, saturation, value + value_increment)));
       }
       array.push_back(hbox(std::move(line)));
     }

examples/dom/graph.cpp

@@ -1,9 +1,10 @@
 #include <chrono>                  // for operator""s, chrono_literals
 #include <cmath>                   // for sin
-#include <ftxui/dom/elements.hpp>  // for operator|, graph, separator, color, Element, vbox, flex, inverted, Fit, hbox, size, border, GREATER_THAN, HEIGHT
+#include <ftxui/dom/elements.hpp>  // for graph, operator|, separator, color, Element, vbox, flex, inverted, operator|=, Fit, hbox, size, border, GREATER_THAN, HEIGHT
 #include <ftxui/screen/screen.hpp>  // for Full, Screen
 #include <functional>               // for ref, reference_wrapper
 #include <iostream>                 // for cout, ostream
+#include <memory>                   // for shared_ptr
 #include <string>                   // for operator<<, string
 #include <thread>                   // for sleep_for
 #include <vector>                   // for vector
@@ -13,15 +14,15 @@
 
 class Graph {
  public:
-  std::vector<int> operator()(int width, int height) {
+  std::vector<int> operator()(int width, int height) const {
     std::vector<int> output(width);
     for (int i = 0; i < width; ++i) {
       float v = 0;
-      v += 0.1f * sin((i + shift) * 0.1f);
+      v += 0.1f * sin((i + shift) * 0.1f);        // NOLINT
-      v += 0.2f * sin((i + shift + 10) * 0.15f);
+      v += 0.2f * sin((i + shift + 10) * 0.15f);  // NOLINT
-      v += 0.1f * sin((i + shift) * 0.03f);
+      v += 0.1f * sin((i + shift) * 0.03f);       // NOLINT
-      v *= height;
+      v *= height;                                // NOLINT
-      v += 0.5f * height;
+      v += 0.5f * height;                         // NOLINT
       output[i] = static_cast<int>(v);
     }
     return output;
@@ -37,7 +38,7 @@ std::vector<int> triangle(int width, int height) {
   return output;
 }
 
-int main(int argc, const char* argv[]) {
+int main() {
   using namespace ftxui;
   using namespace std::chrono_literals;
 
@@ -45,8 +46,7 @@ int main(int argc, const char* argv[]) {
 
   std::string reset_position;
   for (int i = 0;; ++i) {
-    auto document =
+    auto document = hbox({
-        hbox({
         vbox({
             graph(std::ref(my_graph)),
             separator(),
@@ -60,8 +60,12 @@ int main(int argc, const char* argv[]) {
             separator(),
             graph(std::ref(my_graph)) | color(Color::YellowLight),
         }) | flex,
-        }) |
+    });
-        border | size(HEIGHT, GREATER_THAN, 40);
+
+    document |= border;
+
+    const int min_width = 40;
+    document |= size(HEIGHT, GREATER_THAN, min_width);
 
     auto screen = Screen::Create(Dimension::Full(), Dimension::Fit(document));
     Render(screen, document);
@@ -69,7 +73,8 @@ int main(int argc, const char* argv[]) {
     screen.Print();
     reset_position = screen.ResetPosition();
 
-    std::this_thread::sleep_for(0.03s);
+    const auto sleep_time = 0.03s;
+    std::this_thread::sleep_for(sleep_time);
     my_graph.shift++;
   }
 

examples/dom/window.cpp

@@ -1,11 +1,12 @@
-#include <ftxui/dom/elements.hpp>  // for operator|, color, Element, bgcolor, graph, border
+#include <stdlib.h>                // for EXIT_SUCCESS
+#include <ftxui/dom/elements.hpp>  // for operator|=, Element, bgcolor, color, graph, border
 #include <ftxui/screen/screen.hpp>  // for Fixed, Screen
 #include <vector>                   // for vector
 
 #include "ftxui/dom/node.hpp"      // for Render
-#include "ftxui/screen/color.hpp"  // for Color, Color::DarkBlue, Color::Green, Color::Red, ftxui
+#include "ftxui/screen/color.hpp"  // for Color, Color::DarkBlue, Color::Red, ftxui
 
-int main(void) {
+int main() {
   using namespace ftxui;
   Element document = graph([](int x, int y) {
     std::vector<int> result(x, 0);
@@ -13,13 +14,19 @@ int main(void) {
       result[i] = ((3 * i) / 2) % y;
     }
     return result;
-                     }) |
+  });
-                     color(Color::Red) | border | color(Color::Green) |
-                     bgcolor(Color::DarkBlue);
 
-  auto screen = Screen::Create(Dimension::Fixed(80), Dimension::Fixed(10));
+  document |= color(Color::Red);
+  document |= bgcolor(Color::DarkBlue);
+  document |= border;
+
+  const int width = 80;
+  const int height = 10;
+  auto screen =
+      Screen::Create(Dimension::Fixed(width), Dimension::Fixed(height));
   Render(screen, document);
   screen.Print();
+  return EXIT_SUCCESS;
 }
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.

examples/index.html

@@ -44,12 +44,12 @@
     });
 
     let stdin_buffer = [];
-    let stdin = () => {
+    const stdin = () => {
       return stdin_buffer.shift() || 0;
     }
 
-    stdout_buffer = [];
+    let stdout_buffer = [];
-    let stdout = code => {
+    const stdout = code => {
       if (code == 0) {
         term.write(new Uint8Array(stdout_buffer));
         stdout_buffer = [];
@@ -57,7 +57,15 @@
         stdout_buffer.push(code)
       }
     }
-    const stderr = code => console.log(code);
+    let stderrbuffer = [];
+    const stderr = code => {
+      if (code == 0 || code == 10) {
+        console.error(String.fromCodePoint(...stderrbuffer));
+        stderrbuffer = [];
+      } else {
+        stderrbuffer.push(code)
+      }
+    }
     const term = new Terminal();
     term.open(document.querySelector('#terminal'));
     term.resize(140,43);
@@ -69,7 +77,9 @@
     term.onBinary(onBinary);
     term.onData(onBinary)
     window.Module = {
-      preRun: () => { FS.init(stdin, stdout, stderr); },
+      preRun: () => {
+        FS.init(stdin, stdout, stderr);
+      },
       postRun: [],
       onRuntimeInitialized: () => {},
     };

include/ftxui/component/component.hpp

@@ -8,7 +8,7 @@
 #include <vector>      // for vector
 
 #include "ftxui/component/component_base.hpp"     // for Component, Components
-#include "ftxui/component/component_options.hpp"  // for ButtonOption, CheckboxOption (ptr only), InputOption (ptr only), MenuEntryOption (ptr only), MenuOption, RadioboxOption (ptr only)
+#include "ftxui/component/component_options.hpp"  // for ButtonOption, CheckboxOption, InputOption (ptr only), MenuEntryOption (ptr only), MenuOption, RadioboxOption (ptr only)
 #include "ftxui/dom/elements.hpp"                 // for Element
 #include "ftxui/util/ref.hpp"  // for Ref, ConstStringRef, ConstStringListRef, StringRef
 

include/ftxui/component/component_options.hpp

@@ -3,11 +3,11 @@
 
 #include <chrono>                         // for milliseconds
 #include <ftxui/component/animation.hpp>  // for Duration, QuadraticInOut, Function
-#include <ftxui/dom/elements.hpp>  // for Decorator, bold, inverted, operator|, Element, nothing
+#include <ftxui/dom/elements.hpp>         // for Element
 #include <ftxui/util/ref.hpp>             // for Ref
 #include <functional>                     // for function
 #include <optional>                       // for optional
-#include <string>              // for string, allocator
+#include <string>                         // for string
 
 #include "ftxui/screen/color.hpp"  // for Color, Color::GrayDark, Color::White
 
@@ -70,7 +70,7 @@ struct AnimatedColorsOption {
 /// @brief Option for the MenuEntry component.
 /// @ingroup component
 struct MenuEntryOption {
-  std::function<Element(EntryState state)> transform;
+  std::function<Element(const EntryState& state)> transform;
   AnimatedColorsOption animated_colors;
 };
 
@@ -115,7 +115,7 @@ struct ButtonOption {
                                Color foreground_active);
 
   // Style:
-  std::function<Element(EntryState)> transform;
+  std::function<Element(const EntryState&)> transform;
   AnimatedColorsOption animated_colors;
 };
 
@@ -126,7 +126,7 @@ struct CheckboxOption {
   static CheckboxOption Simple();
 
   // Style:
-  std::function<Element(EntryState)> transform;
+  std::function<Element(const EntryState&)> transform;
 
   // Observer:
   /// Called when the user change the state.
@@ -156,7 +156,7 @@ struct RadioboxOption {
   static RadioboxOption Simple();
 
   // Style:
-  std::function<Element(EntryState)> transform;
+  std::function<Element(const EntryState&)> transform;
 
   // Observers:
   /// Called when the selected entry changes.

include/ftxui/component/event.hpp

@@ -54,7 +54,7 @@ struct Event {
   static const Event PageDown;
 
   // --- Custom ---
-  static Event Custom;
+  static const Event Custom;
 
   //--- Method section ---------------------------------------------------------
   bool is_character() const { return type_ == Type::Character; }

include/ftxui/dom/canvas.hpp

@@ -1,7 +1,7 @@
 #ifndef FTXUI_DOM_CANVAS_HPP
 #define FTXUI_DOM_CANVAS_HPP
 
-#include <stddef.h>       // for size_t
+#include <cstddef>        // for size_t
 #include <functional>     // for function
 #include <string>         // for string
 #include <unordered_map>  // for unordered_map
@@ -13,7 +13,7 @@ namespace ftxui {
 
 struct Canvas {
  public:
-  Canvas() {}
+  Canvas() = default;
   Canvas(int width, int height);
 
   // Getters:
@@ -114,7 +114,8 @@ struct Canvas {
 
   struct XYHash {
     size_t operator()(const XY& xy) const {
-      return static_cast<size_t>(xy.x * 1024 + xy.y);
+      constexpr size_t shift = 1024;
+      return size_t(xy.x) * shift + size_t(xy.y);
     }
   };
 

include/ftxui/dom/deprecated.hpp

@@ -1,5 +1,5 @@
-#ifndef FTXUI_DOM_DEPRECRATED_HPP
+#ifndef FTXUI_DOM_DEPRECATED_HPP
-#define FTXUI_DOM_DEPRECRATED_HPP
+#define FTXUI_DOM_DEPRECATED_HPP
 
 #include "ftxui/dom/elements.hpp"
 
@@ -9,7 +9,7 @@ Element vtext(std::wstring text);
 Elements paragraph(std::wstring text);
 }  // namespace ftxui
 
-#endif /* end of include guard: FTXUI_DOM_DEPRECRATED_HPP */
+#endif  // FTXUI_DOM_DEPRECATED_HPP
 
 // Copyright 2021 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

include/ftxui/dom/elements.hpp

@@ -35,7 +35,7 @@ Decorator operator|(Decorator, Decorator);
 // --- Widget ---
 Element text(std::string text);
 Element vtext(std::string text);
-Element separator(void);
+Element separator();
 Element separatorLight();
 Element separatorHeavy();
 Element separatorDouble();
@@ -45,18 +45,18 @@ Element separator(Pixel);
 Element separatorCharacter(std::string);
 Element separatorHSelector(float left,
                            float right,
-                           Color background,
+                           Color unselected_color,
-                           Color foreground);
+                           Color selected_color);
 Element separatorVSelector(float up,
                            float down,
-                           Color background,
+                           Color unselected_color,
-                           Color foreground);
+                           Color selected_color);
-Element gauge(float ratio);
+Element gauge(float progress);
-Element gaugeLeft(float ratio);
+Element gaugeLeft(float progress);
-Element gaugeRight(float ratio);
+Element gaugeRight(float progress);
-Element gaugeUp(float ratio);
+Element gaugeUp(float progress);
-Element gaugeDown(float ratio);
+Element gaugeDown(float progress);
-Element gaugeDirection(float ratio, GaugeDirection);
+Element gaugeDirection(float progress, GaugeDirection);
 Element border(Element);
 Element borderLight(Element);
 Element borderHeavy(Element);
@@ -64,14 +64,14 @@ Element borderDouble(Element);
 Element borderRounded(Element);
 Element borderEmpty(Element);
 Decorator borderStyled(BorderStyle);
-Decorator borderWith(Pixel);
+Decorator borderWith(const Pixel&);
 Element window(Element title, Element content);
 Element spinner(int charset_index, size_t image_index);
-Element paragraph(std::string text);
+Element paragraph(const std::string& text);
-Element paragraphAlignLeft(std::string text);
+Element paragraphAlignLeft(const std::string& text);
-Element paragraphAlignRight(std::string text);
+Element paragraphAlignRight(const std::string& text);
-Element paragraphAlignCenter(std::string text);
+Element paragraphAlignCenter(const std::string& text);
-Element paragraphAlignJustify(std::string text);
+Element paragraphAlignJustify(const std::string& text);
 Element graph(GraphFunction);
 Element emptyElement();
 Element canvas(ConstRef<Canvas>);
@@ -90,7 +90,7 @@ Element color(Color, Element);
 Element bgcolor(Color, Element);
 Decorator focusPosition(int x, int y);
 Decorator focusPositionRelative(float x, float y);
-Element automerge(Element);
+Element automerge(Element child);
 
 // --- Layout is
 // Horizontal, Vertical or stacked set of elements.
@@ -163,7 +163,7 @@ Dimensions Fit(Element&);
 
 // Include old definitions using wstring.
 #include "ftxui/dom/deprecated.hpp"
-#endif /* end of include guard: FTXUI_DOM_ELEMENTS_HPP */
+#endif  // FTXUI_DOM_ELEMENTS_HPP
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

include/ftxui/dom/flexbox_config.hpp

@@ -108,7 +108,7 @@ struct FlexboxConfig {
 
 }  // namespace ftxui
 
-#endif /* end of include guard: FTXUI_DOM_FLEXBOX_CONFIG_HPP */
+#endif  // FTXUI_DOM_FLEXBOX_CONFIG_HPP
 
 // Copyright 2021 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

include/ftxui/dom/node.hpp

@@ -20,6 +20,11 @@ class Node {
  public:
   Node();
   Node(Elements children);
+  Node(const Node&) = delete;
+  Node(const Node&&) = delete;
+  Node& operator=(const Node&) = delete;
+  Node& operator=(const Node&&) = delete;
+
   virtual ~Node();
 
   // Step 1: Compute layout requirement. Tell parent what dimensions this
@@ -50,12 +55,12 @@ class Node {
   Box box_;
 };
 
-void Render(Screen& screen, const Element& node);
+void Render(Screen& screen, const Element& element);
 void Render(Screen& screen, Node* node);
 
 }  // namespace ftxui
 
-#endif /* end of include guard: FTXUI_DOM_NODE_HPP */
+#endif  // FTXUI_DOM_NODE_HPP
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

include/ftxui/dom/requirement.hpp

@@ -28,7 +28,7 @@ struct Requirement {
 
 }  // namespace ftxui
 
-#endif /* end of include guard: FTXUI_DOM_REQUIREMENT_HPP */
+#endif  // FTXUI_DOM_REQUIREMENT_HPP
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

include/ftxui/dom/table.hpp

@@ -52,10 +52,10 @@ class Table {
   void Initialize(std::vector<std::vector<Element>>);
   friend TableSelection;
   std::vector<std::vector<Element>> elements_;
-  int input_dim_x_;
+  int input_dim_x_ = 0;
-  int input_dim_y_;
+  int input_dim_y_ = 0;
-  int dim_x_;
+  int dim_x_ = 0;
-  int dim_y_;
+  int dim_y_ = 0;
 };
 
 class TableSelection {

include/ftxui/dom/take_any_args.hpp

@@ -1,10 +1,13 @@
+#ifndef FTXUI_DOM_TAKE_ANY_ARGS_HPP
+#define FTXUI_DOM_TAKE_ANY_ARGS_HPP
+
 // IWYU pragma: private, include "ftxui/dom/elements.hpp"
 #include <type_traits>
 
 namespace ftxui {
 
 template <class T>
-void Merge(Elements&, T) {}
+void Merge(Elements& /*container*/, T /*element*/) {}
 
 template <>
 inline void Merge(Elements& container, Element element) {
@@ -38,6 +41,8 @@ TAKE_ANY_ARGS(dbox)
 TAKE_ANY_ARGS(hflow)
 }  // namespace ftxui
 
+#endif  // FTXUI_DOM_TAKE_ANY_ARGS_HPP
+
 // Copyright 2020 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in
 // the LICENSE file.

include/ftxui/screen/box.hpp

@@ -9,15 +9,15 @@ struct Box {
   int y_min = 0;
   int y_max = 0;
 
-  static Box Intersection(Box a, Box b);
+  static auto Intersection(Box a, Box b) -> Box;
-  bool Contain(int x, int y);
+  bool Contain(int x, int y) const;
   bool operator==(const Box& other) const;
   bool operator!=(const Box& other) const;
 };
 
 }  // namespace ftxui
 
-#endif /* end of include guard: FTXUI_SCREEN_BOX_HPP */
+#endif  // FTXUI_SCREEN_BOX_HPP
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

include/ftxui/screen/color.hpp

@@ -1,7 +1,7 @@
-#ifndef FTXUI_SCREEN_COLOR
+#ifndef FTXUI_SCREEN_COLOR_HPP
-#define FTXUI_SCREEN_COLOR
+#define FTXUI_SCREEN_COLOR_HPP
 
-#include <stdint.h>  // for uint8_t
+#include <cstdint>  // for uint8_t
 #include <string>   // for wstring
 
 #ifdef RGB
@@ -313,12 +313,8 @@ class Color {
     Palette256,
     TrueColor,
   };
-
+  ColorType type_ = ColorType::Palette1;
-  ColorType type_;
+  uint8_t red_ = 0;
-  union {
-    uint8_t index_ = 0;
-    uint8_t red_;
-  };
   uint8_t green_ = 0;
   uint8_t blue_ = 0;
 };
@@ -333,7 +329,7 @@ Color operator""_rgb(unsigned long long int combined);
 
 }  // namespace ftxui
 
-#endif /* end of include guard: FTXUI_COLOR_H_ */
+#endif  // FTXUI_SCREEN_COLOR_HPP
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

include/ftxui/screen/color_info.hpp

@@ -1,7 +1,7 @@
 #ifndef FTXUI_SCREEN_COLOR_INFO_HPP
 #define FTXUI_SCREEN_COLOR_INFO_HPP
 
-#include <stdint.h>
+#include <cstdint>
 #include <ftxui/screen/color.hpp>
 
 namespace ftxui {
@@ -23,7 +23,7 @@ ColorInfo GetColorInfo(Color::Palette16 index);
 
 }  // namespace ftxui
 
-#endif /* end of include guard: FTXUI_SCREEN_COLOR_INFO_HPP */
+#endif  // FTXUI_SCREEN_COLOR_INFO_HPP
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

include/ftxui/screen/deprecated.hpp

@@ -8,7 +8,7 @@ int wchar_width(wchar_t);
 int wstring_width(const std::wstring&);
 }  // namespace ftxui
 
-#endif /* end of include guard: FTXUI_SCREEN_DEPRECATED_HPP */
+#endif  // FTXUI_SCREEN_DEPRECATED_HPP
 
 // Copyright 2021 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

include/ftxui/screen/screen.hpp

@@ -1,5 +1,5 @@
-#ifndef FTXUI_SCREEN_SCREEN
+#ifndef FTXUI_SCREEN_SCREEN_HPP
-#define FTXUI_SCREEN_SCREEN
+#define FTXUI_SCREEN_SCREEN_HPP
 
 #include <memory>
 #include <string>  // for string, allocator, basic_string
@@ -14,6 +14,8 @@ namespace ftxui {
 /// @brief A unicode character and its associated style.
 /// @ingroup screen
 struct Pixel {
+  bool operator==(const Pixel& other) const;
+
   // The graphemes stored into the pixel. To support combining characters,
   // like: a⃦, this can potentially contains multiple codepoitns.
   std::string character = " ";
@@ -68,13 +70,12 @@ class Screen {
   int dimy() const { return dimy_; }
 
   // Move the terminal cursor n-lines up with n = dimy().
-  std::string ResetPosition(bool clear = false);
+  std::string ResetPosition(bool clear = false) const;
 
   // Fill with space.
   void Clear();
 
   void ApplyShader();
-  Box stencil;
 
   struct Cursor {
     int x = 0;
@@ -83,16 +84,20 @@ class Screen {
   Cursor cursor() const { return cursor_; }
   void SetCursor(Cursor cursor) { cursor_ = cursor; }
 
+  Box stencil;
+
  protected:
   int dimx_;
   int dimy_;
   std::vector<std::vector<Pixel>> pixels_;
   Cursor cursor_;
+
+ private:
 };
 
 }  // namespace ftxui
 
-#endif /* end of include guard: FTXUI_SCREEN_SCREEN */
+#endif  // FTXUI_SCREEN_SCREEN_HPP
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

include/ftxui/screen/terminal.hpp

@@ -1,5 +1,5 @@
-#ifndef FTXUI_CORE_TERMINAL_HPP
+#ifndef FTXUI_SCREEN_TERMINAL_HPP
-#define FTXUI_CORE_TERMINAL_HPP
+#define FTXUI_SCREEN_TERMINAL_HPP
 
 namespace ftxui {
 struct Dimensions {
@@ -22,7 +22,7 @@ Color ColorSupport();
 
 }  // namespace ftxui
 
-#endif /* end of include guard: FTXUI_CORE_TERMINAL_HPP */
+#endif  // FTXUI_SCREEN_TERMINAL_HPP
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

src/ftxui/component/animation.cpp

@@ -1,14 +1,18 @@
-#define _USE_MATH_DEFINES
+#include <cmath>
-#include <cmath>  // for sin, pow, sqrt, M_PI_2, M_PI, cos
+#include <ratio>    // for ratio
+#include <utility>  // for move
 
 #include "ftxui/component/animation.hpp"
 
-#include <ratio>  // for ratio
+namespace ftxui::animation {
-
-namespace ftxui {
-namespace animation {
 
 namespace easing {
+
+namespace {
+constexpr float kPi = 3.14159265358979323846F;
+constexpr float kPi2 = kPi / 2.F;
+}  // namespace
+
 // Easing function have been taken out of:
 // https://github.com/warrenm/AHEasing/blob/master/AHEasing/easing.c
 //
@@ -40,7 +44,7 @@ float QuadraticOut(float p) {
 // y = (1/2)((2x)^2)             ; [0, 0.5)
 // y = -(1/2)((2x-1)*(2x-3) - 1) ; [0.5, 1]
 float QuadraticInOut(float p) {
-  if (p < 0.5) {
+  if (p < 0.5F) {  // NOLINT
     return 2 * p * p;
   } else {
     return (-2 * p * p) + (4 * p) - 1;
@@ -62,11 +66,11 @@ float CubicOut(float p) {
 // y = (1/2)((2x)^3)       ; [0, 0.5)
 // y = (1/2)((2x-2)^3 + 2) ; [0.5, 1]
 float CubicInOut(float p) {
-  if (p < 0.5) {
+  if (p < 0.5F) {  // NOLINT
     return 4 * p * p * p;
   } else {
     float f = ((2 * p) - 2);
-    return 0.5 * f * f * f + 1;
+    return 0.5F * f * f * f + 1;  // NOLINT
   }
 }
 
@@ -85,11 +89,11 @@ float QuarticOut(float p) {
 // y = (1/2)((2x)^4)        ; [0, 0.5)
 // y = -(1/2)((2x-2)^4 - 2) ; [0.5, 1]
 float QuarticInOut(float p) {
-  if (p < 0.5) {
+  if (p < 0.5F) {              // NOLINT
-    return 8 * p * p * p * p;
+    return 8 * p * p * p * p;  // NOLINT
   } else {
     float f = (p - 1);
-    return -8 * f * f * f * f + 1;
+    return -8 * f * f * f * f + 1;  // NOLINT
   }
 }
 
@@ -108,119 +112,122 @@ float QuinticOut(float p) {
 // y = (1/2)((2x)^5)       ; [0, 0.5)
 // y = (1/2)((2x-2)^5 + 2) ; [0.5, 1]
 float QuinticInOut(float p) {
-  if (p < 0.5) {
+  if (p < 0.5F) {                        // NOLINT
-    return 16 * p * p * p * p * p;
+    return 16 * p * p * p * p * p;       // NOLINT
-  } else {
+  } else {                               // NOLINT
-    float f = ((2 * p) - 2);
+    float f = ((2 * p) - 2);             // NOLINT
-    return 0.5 * f * f * f * f * f + 1;
+    return 0.5 * f * f * f * f * f + 1;  // NOLINT
   }
 }
 
 // Modeled after quarter-cycle of sine wave
 float SineIn(float p) {
-  return sin((p - 1) * M_PI_2) + 1;
+  return std::sin((p - 1) * kPi2) + 1;
 }
 
 // Modeled after quarter-cycle of sine wave (different phase)
 float SineOut(float p) {
-  return sin(p * M_PI_2);
+  return std::sin(p * kPi2);
 }
 
 // Modeled after half sine wave
 float SineInOut(float p) {
-  return 0.5 * (1 - cos(p * M_PI));
+  return 0.5F * (1 - std::cos(p * kPi));  // NOLINT
 }
 
 // Modeled after shifted quadrant IV of unit circle
 float CircularIn(float p) {
-  return 1 - sqrt(1 - (p * p));
+  return 1 - std::sqrt(1 - (p * p));
 }
 
 // Modeled after shifted quadrant II of unit circle
 float CircularOut(float p) {
-  return sqrt((2 - p) * p);
+  return std::sqrt((2 - p) * p);
 }
 
 // Modeled after the piecewise circular function
 // y = (1/2)(1 - sqrt(1 - 4x^2))           ; [0, 0.5)
 // y = (1/2)(sqrt(-(2x - 3)*(2x - 1)) + 1) ; [0.5, 1]
 float CircularInOut(float p) {
-  if (p < 0.5) {
+  if (p < 0.5F) {                                    // NOLINT
-    return 0.5 * (1 - sqrt(1 - 4 * (p * p)));
+    return 0.5F * (1 - std::sqrt(1 - 4 * (p * p)));  // NOLINT
   } else {
-    return 0.5 * (sqrt(-((2 * p) - 3) * ((2 * p) - 1)) + 1);
+    return 0.5F * (std::sqrt(-((2 * p) - 3) * ((2 * p) - 1)) + 1);  // NOLINT
   }
 }
 
 // Modeled after the exponential function y = 2^(10(x - 1))
 float ExponentialIn(float p) {
-  return (p == 0.0) ? p : pow(2, 10 * (p - 1));
+  return (p == 0.0) ? p : std::pow(2, 10 * (p - 1));  // NOLINT
 }
 
 // Modeled after the exponential function y = -2^(-10x) + 1
 float ExponentialOut(float p) {
-  return (p == 1.0) ? p : 1 - pow(2, -10 * p);
+  return (p == 1.0) ? p : 1 - std::pow(2, -10 * p);  // NOLINT
 }
 
 // Modeled after the piecewise exponential
 // y = (1/2)2^(10(2x - 1))         ; [0,0.5)
 // y = -(1/2)*2^(-10(2x - 1))) + 1 ; [0.5,1]
 float ExponentialInOut(float p) {
-  if (p == 0.0 || p == 1.0)
+  if (p == 0.0 || p == 1.F) {
     return p;
+  }
 
-  if (p < 0.5) {
+  if (p < 0.5F) {                                   // NOLINT
-    return 0.5 * pow(2, (20 * p) - 10);
+    return 0.5 * std::pow(2, (20 * p) - 10);        // NOLINT
-  } else {
+  } else {                                          // NOLINT
-    return -0.5 * pow(2, (-20 * p) + 10) + 1;
+    return -0.5 * std::pow(2, (-20 * p) + 10) + 1;  // NOLINT
   }
 }
 
 // Modeled after the damped sine wave y = sin(13pi/2*x)*pow(2, 10 * (x - 1))
 float ElasticIn(float p) {
-  return sin(13 * M_PI_2 * p) * pow(2, 10 * (p - 1));
+  return std::sin(13.F * kPi2 * p) * std::pow(2.F, 10.F * (p - 1));  // NOLINT
 }
 
 // Modeled after the damped sine wave y = sin(-13pi/2*(x + 1))*pow(2, -10x) +
 // 1
 float ElasticOut(float p) {
-  return sin(-13 * M_PI_2 * (p + 1)) * pow(2, -10 * p) + 1;
+  return std::sin(-13.F * kPi2 * (p + 1)) * std::pow(2.F, -10.F * p) +
+         1;  // NOLINT
 }
 
 // Modeled after the piecewise exponentially-damped sine wave:
 // y = (1/2)*sin(13pi/2*(2*x))*pow(2, 10 * ((2*x) - 1))      ; [0,0.5)
 // y = (1/2)*(sin(-13pi/2*((2x-1)+1))*pow(2,-10(2*x-1)) + 2) ; [0.5, 1]
 float ElasticInOut(float p) {
-  if (p < 0.5) {
+  if (p < 0.5F) {                                             // NOLINT
-    return 0.5 * sin(13 * M_PI_2 * (2 * p)) * pow(2, 10 * ((2 * p) - 1));
+    return 0.5 * std::sin(13.F * kPi2 * (2 * p)) *              // NOLINT
-  } else {
+           std::pow(2, 10 * ((2 * p) - 1));                   // NOLINT
-    return 0.5 *
+  } else {                                                    // NOLINT
-           (sin(-13 * M_PI_2 * ((2 * p - 1) + 1)) * pow(2, -10 * (2 * p - 1)) +
+    return 0.5 * (std::sin(-13.F * kPi2 * ((2 * p - 1) + 1)) *  // NOLINT
-            2);
+                      std::pow(2, -10 * (2 * p - 1)) +        // NOLINT
+                  2);                                         // NOLINT
   }
 }
 
 // Modeled after the overshooting cubic y = x^3-x*sin(x*pi)
 float BackIn(float p) {
-  return p * p * p - p * sin(p * M_PI);
+  return p * p * p - p * std::sin(p * kPi);
 }
 
 // Modeled after overshooting cubic y = 1-((1-x)^3-(1-x)*sin((1-x)*pi))
 float BackOut(float p) {
   float f = (1 - p);
-  return 1 - (f * f * f - f * sin(f * M_PI));
+  return 1 - (f * f * f - f * std::sin(f * kPi));
 }
 
 // Modeled after the piecewise overshooting cubic function:
 // y = (1/2)*((2x)^3-(2x)*sin(2*x*pi))           ; [0, 0.5)
 // y = (1/2)*(1-((1-x)^3-(1-x)*sin((1-x)*pi))+1) ; [0.5, 1]
 float BackInOut(float p) {
-  if (p < 0.5) {
+  if (p < 0.5F) {  // NOLINT
     float f = 2 * p;
-    return 0.5 * (f * f * f - f * sin(f * M_PI));
+    return 0.5F * (f * f * f - f * std::sin(f * kPi));  // NOLINT
   } else {
-    float f = (1 - (2 * p - 1));
+    float f = (1 - (2 * p - 1));                                    // NOLINT
-    return 0.5 * (1 - (f * f * f - f * sin(f * M_PI))) + 0.5;
+    return 0.5F * (1 - (f * f * f - f * std::sin(f * kPi))) + 0.5;  // NOLINT
   }
 }
 
@@ -229,22 +236,23 @@ float BounceIn(float p) {
 }
 
 float BounceOut(float p) {
-  if (p < 4 / 11.0) {
+  if (p < 4 / 11.0) {                                           // NOLINT
-    return (121 * p * p) / 16.0;
+    return (121 * p * p) / 16.0;                                // NOLINT
-  } else if (p < 8 / 11.0) {
+  } else if (p < 8 / 11.0) {                                    // NOLINT
-    return (363 / 40.0 * p * p) - (99 / 10.0 * p) + 17 / 5.0;
+    return (363 / 40.0 * p * p) - (99 / 10.0 * p) + 17 / 5.0;   // NOLINT
-  } else if (p < 9 / 10.0) {
+  } else if (p < 9 / 10.0) {                                    // NOLINT
-    return (4356 / 361.0 * p * p) - (35442 / 1805.0 * p) + 16061 / 1805.0;
+    return (4356 / 361.0 * p * p) - (35442 / 1805.0 * p) +      // NOLINT
-  } else {
+           16061 / 1805.0;                                      // NOLINT
-    return (54 / 5.0 * p * p) - (513 / 25.0 * p) + 268 / 25.0;
+  } else {                                                      // NOLINT
+    return (54 / 5.0 * p * p) - (513 / 25.0 * p) + 268 / 25.0;  // NOLINT
   }
 }
 
-float BounceInOut(float p) {
+float BounceInOut(float p) {                    // NOLINT
-  if (p < 0.5) {
+  if (p < 0.5F) {                               // NOLINT
-    return 0.5 * BounceIn(p * 2);
+    return 0.5F * BounceIn(p * 2);              // NOLINT
-  } else {
+  } else {                                      // NOLINT
-    return 0.5 * BounceOut(p * 2 - 1) + 0.5;
+    return 0.5F * BounceOut(p * 2 - 1) + 0.5F;  // NOLINT
   }
 }
 
@@ -259,7 +267,7 @@ Animator::Animator(float* from,
       from_(*from),
       to_(to),
       duration_(duration),
-      easing_function_(easing_function),
+      easing_function_(std::move(easing_function)),
       current_(-delay) {
   RequestAnimationFrame();
 }
@@ -275,11 +283,11 @@ void Animator::OnAnimation(Params& params) {
   if (current_ <= Duration()) {
     *value_ = from_;
   } else {
-    *value_ = from_ + (to_ - from_) * easing_function_(current_ / duration_);
+    *value_ = from_ +
+              (to_ - from_) * easing_function_(current_ / duration_);  // NOLINT
   }
 
   RequestAnimationFrame();
 }
 
-}  // namespace animation
+}  // namespace ftxui::animation
-}  // namespace ftxui

src/ftxui/component/button.cpp

@@ -1,17 +1,16 @@
 #include <functional>  // for function
 #include <memory>      // for shared_ptr
-#include <string>      // for string
 #include <utility>     // for move
 
 #include "ftxui/component/animation.hpp"  // for Animator, Params (ptr only)
 #include "ftxui/component/captured_mouse.hpp"  // for CapturedMouse
 #include "ftxui/component/component.hpp"       // for Make, Button
 #include "ftxui/component/component_base.hpp"  // for ComponentBase
-#include "ftxui/component/component_options.hpp"  // for ButtonOption, AnimatedColorOption, AnimatedColorsOption
+#include "ftxui/component/component_options.hpp"  // for ButtonOption, AnimatedColorOption, AnimatedColorsOption, EntryState
 #include "ftxui/component/event.hpp"  // for Event, Event::Return
 #include "ftxui/component/mouse.hpp"  // for Mouse, Mouse::Left, Mouse::Pressed
 #include "ftxui/component/screen_interactive.hpp"  // for Component
-#include "ftxui/dom/elements.hpp"  // for operator|, Decorator, Element, bgcolor, color, operator|=, reflect, text, border, inverted, nothing
+#include "ftxui/dom/elements.hpp"  // for operator|, Decorator, Element, operator|=, bgcolor, color, reflect, text, bold, border, inverted, nothing
 #include "ftxui/screen/box.hpp"    // for Box
 #include "ftxui/screen/color.hpp"  // for Color
 #include "ftxui/util/ref.hpp"      // for Ref, ConstStringRef
@@ -20,12 +19,14 @@ namespace ftxui {
 
 namespace {
 
-Element DefaultTransform(EntryState params) {
+Element DefaultTransform(EntryState params) {  // NOLINT
   auto element = text(params.label) | border;
-  if (params.active)
+  if (params.active) {
     element |= bold;
-  if (params.focused)
+  }
+  if (params.focused) {
     element |= inverted;
+  }
   return element;
 }
 
@@ -62,13 +63,16 @@ Component Button(ConstStringRef label,
     Impl(ConstStringRef label,
          std::function<void()> on_click,
          Ref<ButtonOption> option)
-        : label_(label), on_click_(on_click), option_(std::move(option)) {}
+        : label_(std::move(label)),
+          on_click_(std::move(on_click)),
+          option_(std::move(option)) {}
 
     // Component implementation:
     Element Render() override {
-      float target = Focused() ? 1.0 : 0.f;
+      float target = Focused() ? 1.F : 0.F;  // NOLINT
-      if (target != animator_background_.to())
+      if (target != animator_background_.to()) {
         SetAnimationTarget(target);
+      }
 
       EntryState state = {
           *label_,
@@ -122,14 +126,15 @@ Component Button(ConstStringRef label,
 
     void OnClick() {
       on_click_();
-      animation_background_ = 0.5f;
+      animation_background_ = 0.5F;  // NOLINT
-      animation_foreground_ = 0.5f;
+      animation_foreground_ = 0.5F;  // NOLINT
-      SetAnimationTarget(1.f);
+      SetAnimationTarget(1.F);       // NOLINT
     }
 
     bool OnEvent(Event event) override {
-      if (event.is_mouse())
+      if (event.is_mouse()) {
         return OnMouseEvent(event);
+      }
 
       if (event == Event::Return) {
         OnClick();
@@ -142,8 +147,9 @@ Component Button(ConstStringRef label,
       mouse_hover_ =
           box_.Contain(event.mouse().x, event.mouse().y) && CaptureMouse(event);
 
-      if (!mouse_hover_)
+      if (!mouse_hover_) {
         return false;
+      }
 
       TakeFocus();
 
@@ -172,7 +178,7 @@ Component Button(ConstStringRef label,
         animation::Animator(&animation_foreground_);
   };
 
-  return Make<Impl>(label, std::move(on_click), std::move(option));
+  return Make<Impl>(std::move(label), std::move(on_click), std::move(option));
 }
 
 }  // namespace ftxui

src/ftxui/component/catch_event.cpp

@@ -11,16 +11,17 @@ namespace ftxui {
 class CatchEventBase : public ComponentBase {
  public:
   // Constructor.
-  CatchEventBase(std::function<bool(Event)> on_event)
+  explicit CatchEventBase(std::function<bool(Event)> on_event)
       : on_event_(std::move(on_event)) {}
 
   // Component implementation.
   bool OnEvent(Event event) override {
-    if (on_event_(event))
+    if (on_event_(event)) {
       return true;
-    else
+    } else {
       return ComponentBase::OnEvent(event);
     }
+  }
 
  protected:
   std::function<bool(Event)> on_event_;
@@ -76,8 +77,8 @@ Component CatchEvent(Component child,
 /// ```
 ComponentDecorator CatchEvent(std::function<bool(Event)> on_event) {
   return [on_event = std::move(on_event)](Component child) {
-    return CatchEvent(child, [on_event = std::move(on_event)](Event event) {
+    return CatchEvent(std::move(child), [on_event = on_event](Event event) {
-      return on_event(event);
+      return on_event(std::move(event));
     });
   };
 }

src/ftxui/component/checkbox.cpp

@@ -18,7 +18,7 @@ namespace {
 class CheckboxBase : public ComponentBase {
  public:
   CheckboxBase(ConstStringRef label, bool* state, Ref<CheckboxOption> option)
-      : label_(label), state_(state), option_(std::move(option)) {}
+      : label_(std::move(label)), state_(state), option_(std::move(option)) {}
 
  private:
   // Component implementation.
@@ -32,18 +32,20 @@ class CheckboxBase : public ComponentBase {
         is_active,
         is_focused || hovered_,
     };
-    auto element = (option_->transform
+    auto element =
-                        ? option_->transform
+        (option_->transform ? option_->transform
-                        : CheckboxOption::Simple().transform)(std::move(state));
+                            : CheckboxOption::Simple().transform)(state);
     return element | focus_management | reflect(box_);
   }
 
   bool OnEvent(Event event) override {
-    if (!CaptureMouse(event))
+    if (!CaptureMouse(event)) {
       return false;
+    }
 
-    if (event.is_mouse())
+    if (event.is_mouse()) {
       return OnMouseEvent(event);
+    }
 
     hovered_ = false;
     if (event == Event::Character(' ') || event == Event::Return) {
@@ -58,11 +60,13 @@ class CheckboxBase : public ComponentBase {
   bool OnMouseEvent(Event event) {
     hovered_ = box_.Contain(event.mouse().x, event.mouse().y);
 
-    if (!CaptureMouse(event))
+    if (!CaptureMouse(event)) {
       return false;
+    }
 
-    if (!hovered_)
+    if (!hovered_) {
       return false;
+    }
 
     if (event.mouse().button == Mouse::Left &&
         event.mouse().motion == Mouse::Pressed) {
@@ -109,7 +113,7 @@ class CheckboxBase : public ComponentBase {
 Component Checkbox(ConstStringRef label,
                    bool* checked,
                    Ref<CheckboxOption> option) {
-  return Make<CheckboxBase>(label, checked, std::move(option));
+  return Make<CheckboxBase>(std::move(label), checked, std::move(option));
 }
 
 }  // namespace ftxui

src/ftxui/component/collapsible.cpp

@@ -1,9 +1,11 @@
-#include <string>   // for string
+#include <functional>  // for function
+#include <memory>      // for shared_ptr, allocator
 #include <utility>     // for move
 
 #include "ftxui/component/component.hpp"  // for Checkbox, Maybe, Make, Vertical, Collapsible
 #include "ftxui/component/component_base.hpp"  // for Component, ComponentBase
-#include "ftxui/component/component_options.hpp"  // for CheckboxOption
+#include "ftxui/component/component_options.hpp"  // for CheckboxOption, EntryState
+#include "ftxui/dom/elements.hpp"  // for operator|=, text, hbox, Element, bold, inverted
 #include "ftxui/util/ref.hpp"  // for Ref, ConstStringRef
 
 namespace ftxui {
@@ -28,27 +30,28 @@ namespace ftxui {
 Component Collapsible(ConstStringRef label, Component child, Ref<bool> show) {
   class Impl : public ComponentBase {
    public:
-    Impl(ConstStringRef label, Component child, Ref<bool> show)
+    Impl(ConstStringRef label, Component child, Ref<bool> show) : show_(show) {
-        : show_(std::move(show)) {
       CheckboxOption opt;
-      opt.transform = [](EntryState s) {
+      opt.transform = [](EntryState s) {            // NOLINT
-        auto prefix = text(s.state ? "▼ " : "▶ ");
+        auto prefix = text(s.state ? "▼ " : "▶ ");  // NOLINT
         auto t = text(s.label);
-        if (s.active)
+        if (s.active) {
           t |= bold;
-        if (s.focused)
+        }
+        if (s.focused) {
           t |= inverted;
+        }
         return hbox({prefix, t});
       };
       Add(Container::Vertical({
-          Checkbox(label, show_.operator->(), opt),
+          Checkbox(std::move(label), show_.operator->(), opt),
           Maybe(std::move(child), show_.operator->()),
       }));
     }
     Ref<bool> show_;
   };
 
-  return Make<Impl>(label, std::move(child), std::move(show));
+  return Make<Impl>(std::move(label), std::move(child), show);
 }
 
 }  // namespace ftxui

src/ftxui/component/component.cpp

@@ -1,6 +1,6 @@
-#include <stddef.h>   // for size_t
 #include <algorithm>  // for find_if
 #include <cassert>    // for assert
+#include <cstddef>    // for size_t
 #include <iterator>   // for begin, end
 #include <utility>    // for move
 #include <vector>     // for vector, __alloc_traits<>::value_type
@@ -37,7 +37,7 @@ ComponentBase* ComponentBase::Parent() const {
 /// @brief Access the child at index `i`.
 /// @ingroup component
 Component& ComponentBase::ChildAt(size_t i) {
-  assert(i < ChildCount());
+  assert(i < ChildCount());  // NOLINT
   return children_[i];
 }
 
@@ -61,8 +61,9 @@ void ComponentBase::Add(Component child) {
 /// @see Parent
 /// @ingroup component
 void ComponentBase::Detach() {
-  if (!parent_)
+  if (parent_ == nullptr) {
     return;
+  }
   auto it = std::find_if(std::begin(parent_->children_),  //
                          std::end(parent_->children_),    //
                          [this](const Component& that) {  //
@@ -76,8 +77,9 @@ void ComponentBase::Detach() {
 /// @brief Remove all children.
 /// @ingroup component
 void ComponentBase::DetachAllChildren() {
-  while (!children_.empty())
+  while (!children_.empty()) {
     children_[0]->Detach();
+  }
 }
 
 /// @brief Draw the component.
@@ -85,8 +87,9 @@ void ComponentBase::DetachAllChildren() {
 /// ftxui::ComponentBase.
 /// @ingroup component
 Element ComponentBase::Render() {
-  if (children_.size() == 1)
+  if (children_.size() == 1) {
     return children_.front()->Render();
+  }
 
   return text("Not implemented component");
 }
@@ -97,11 +100,12 @@ Element ComponentBase::Render() {
 /// The default implementation called OnEvent on every child until one return
 /// true. If none returns true, return false.
 /// @ingroup component
-bool ComponentBase::OnEvent(Event event) {
+bool ComponentBase::OnEvent(Event event) {  // NOLINT
-  for (Component& child : children_) {
+  for (Component& child : children_) {      // NOLINT
-    if (child->OnEvent(event))
+    if (child->OnEvent(event)) {
       return true;
     }
+  }
   return false;
 }
 
@@ -110,8 +114,9 @@ bool ComponentBase::OnEvent(Event event) {
 /// The default implementation dispatch the event to every child.
 /// @ingroup component
 void ComponentBase::OnAnimation(animation::Params& params) {
-  for (Component& child : children_)
+  for (Component& child : children_) {
     child->OnAnimation(params);
+  }
 }
 
 /// @brief Return the currently Active child.
@@ -119,9 +124,10 @@ void ComponentBase::OnAnimation(animation::Params& params) {
 /// @ingroup component
 Component ComponentBase::ActiveChild() {
   for (auto& child : children_) {
-    if (child->Focusable())
+    if (child->Focusable()) {
       return child;
     }
+  }
   return nullptr;
 }
 
@@ -130,17 +136,18 @@ Component ComponentBase::ActiveChild() {
 /// keyboard.
 /// @ingroup component
 bool ComponentBase::Focusable() const {
-  for (const Component& child : children_) {
+  for (const Component& child : children_) {  // NOLINT
-    if (child->Focusable())
+    if (child->Focusable()) {
       return true;
     }
+  }
   return false;
 }
 
 /// @brief Returns if the element if the currently active child of its parent.
 /// @ingroup component
 bool ComponentBase::Active() const {
-  return !parent_ || parent_->ActiveChild().get() == this;
+  return parent_ == nullptr || parent_->ActiveChild().get() == this;
 }
 
 /// @brief Returns if the elements if focused by the user.
@@ -149,7 +156,7 @@ bool ComponentBase::Active() const {
 /// Focusable().
 /// @ingroup component
 bool ComponentBase::Focused() const {
-  auto current = this;
+  const auto* current = this;
   while (current && current->Active()) {
     current = current->parent_;
   }
@@ -159,12 +166,12 @@ bool ComponentBase::Focused() const {
 /// @brief Make the |child| to be the "active" one.
 /// @param child the child to become active.
 /// @ingroup component
-void ComponentBase::SetActiveChild(ComponentBase*) {}
+void ComponentBase::SetActiveChild(ComponentBase* /*child*/) {}
 
 /// @brief Make the |child| to be the "active" one.
 /// @param child the child to become active.
 /// @ingroup component
-void ComponentBase::SetActiveChild(Component child) {
+void ComponentBase::SetActiveChild(Component child) {  // NOLINT
   SetActiveChild(child.get());
 }
 
@@ -182,9 +189,10 @@ void ComponentBase::TakeFocus() {
 /// them. It represents a component taking priority over others.
 /// @param event
 /// @ingroup component
-CapturedMouse ComponentBase::CaptureMouse(const Event& event) {
+CapturedMouse ComponentBase::CaptureMouse(const Event& event) {  // NOLINT
-  if (event.screen_)
+  if (event.screen_) {
     return event.screen_->CaptureMouse();
+  }
   return std::make_unique<CaptureMouseImpl>();
 }
 

src/ftxui/component/component_options.cpp

@@ -1,9 +1,10 @@
 #include "ftxui/component/component_options.hpp"
 
-#include <memory>  // for allocator, shared_ptr
+#include <memory>   // for shared_ptr
+#include <utility>  // for move
 
 #include "ftxui/component/animation.hpp"  // for Function, Duration
-#include "ftxui/dom/elements.hpp"  // for Element, operator|, text, bold, dim, inverted, automerge
+#include "ftxui/dom/elements.hpp"  // for operator|=, text, Element, bold, inverted, operator|, dim, hbox, automerge, borderEmpty, borderLight
 
 namespace ftxui {
 
@@ -15,13 +16,13 @@ void AnimatedColorOption::Set(Color a_inactive,
   inactive = a_inactive;
   active = a_active;
   duration = a_duration;
-  function = a_function;
+  function = std::move(a_function);
 }
 
 void UnderlineOption::SetAnimation(animation::Duration d,
                                    animation::easing::Function f) {
   SetAnimationDuration(d);
-  SetAnimationFunction(f);
+  SetAnimationFunction(std::move(f));
 }
 
 void UnderlineOption::SetAnimationDuration(animation::Duration d) {
@@ -31,28 +32,31 @@ void UnderlineOption::SetAnimationDuration(animation::Duration d) {
 
 void UnderlineOption::SetAnimationFunction(animation::easing::Function f) {
   leader_function = f;
-  follower_function = f;
+  follower_function = std::move(f);
 }
 
 void UnderlineOption::SetAnimationFunction(
     animation::easing::Function f_leader,
     animation::easing::Function f_follower) {
-  leader_function = f_leader;
+  leader_function = std::move(f_leader);
-  follower_function = f_follower;
+  follower_function = std::move(f_follower);
 }
 
 // static
 MenuOption MenuOption::Horizontal() {
   MenuOption option;
   option.direction = Direction::Right;
-  option.entries.transform = [](EntryState state) {
+  option.entries.transform = [](const EntryState& state) {
     Element e = text(state.label);
-    if (state.focused)
+    if (state.focused) {
       e |= inverted;
-    if (state.active)
+    }
+    if (state.active) {
       e |= bold;
-    if (!state.focused && !state.active)
+    }
+    if (!state.focused && !state.active) {
       e |= dim;
+    }
     return e;
   };
   option.elements_infix = [] { return text(" "); };
@@ -70,19 +74,17 @@ MenuOption MenuOption::HorizontalAnimated() {
 // static
 MenuOption MenuOption::Vertical() {
   MenuOption option;
-  option.entries.transform = [](EntryState state) {
+  option.entries.transform = [](const EntryState& state) {
-    if (state.active)
+    Element e = text((state.active ? "> " : "  ") + state.label);  // NOLINT
-      state.label = "> " + state.label;
+    if (state.focused) {
-    else
-      state.label = "  " + state.label;
-
-    Element e = text(state.label);
-    if (state.focused)
       e |= inverted;
-    if (state.active)
+    }
+    if (state.active) {
       e |= bold;
-    if (!state.focused && !state.active)
+    }
+    if (!state.focused && !state.active) {
       e |= dim;
+    }
     return e;
   };
   return option;
@@ -91,14 +93,17 @@ MenuOption MenuOption::Vertical() {
 // static
 MenuOption MenuOption::VerticalAnimated() {
   auto option = MenuOption::Vertical();
-  option.entries.transform = [](EntryState state) {
+  option.entries.transform = [](const EntryState& state) {
     Element e = text(state.label);
-    if (state.focused)
+    if (state.focused) {
       e |= inverted;
-    if (state.active)
+    }
+    if (state.active) {
       e |= bold;
-    if (!state.focused && !state.active)
+    }
+    if (!state.focused && !state.active) {
       e |= dim;
+    }
     return e;
   };
   option.underline.enabled = true;
@@ -116,10 +121,10 @@ MenuOption MenuOption::Toggle() {
 // static
 ButtonOption ButtonOption::Ascii() {
   ButtonOption option;
-  option.transform = [](EntryState s) {
+  option.transform = [](const EntryState& s) {
-    s.label = s.focused ? "[" + s.label + "]"  //
+    std::string label = s.focused ? "[" + s.label + "]"  //
                                   : " " + s.label + " ";
-    return text(s.label);
+    return text(label);
   };
   return option;
 }
@@ -128,10 +133,11 @@ ButtonOption ButtonOption::Ascii() {
 // static
 ButtonOption ButtonOption::Simple() {
   ButtonOption option;
-  option.transform = [](EntryState s) {
+  option.transform = [](const EntryState& s) {
     auto element = text(s.label) | borderLight;
-    if (s.focused)
+    if (s.focused) {
       element |= inverted;
+    }
     return element;
   };
   return option;
@@ -147,10 +153,11 @@ ButtonOption ButtonOption::Animated() {
 /// @brief Create a ButtonOption, using animated colors.
 // static
 ButtonOption ButtonOption::Animated(Color color) {
-  return ButtonOption::Animated(Color::Interpolate(0.85f, color, Color::Black),
+  return ButtonOption::Animated(
-                                Color::Interpolate(0.10f, color, Color::White),
+      Color::Interpolate(0.85F, color, Color::Black),   // NOLINT
-                                Color::Interpolate(0.10f, color, Color::Black),
+      Color::Interpolate(0.10F, color, Color::White),   // NOLINT
-                                Color::Interpolate(0.85f, color, Color::White));
+      Color::Interpolate(0.10F, color, Color::Black),   // NOLINT
+      Color::Interpolate(0.85F, color, Color::White));  // NOLINT
 }
 
 /// @brief Create a ButtonOption, using animated colors.
@@ -163,17 +170,18 @@ ButtonOption ButtonOption::Animated(Color background, Color foreground) {
 // static
 ButtonOption ButtonOption::Animated(Color background,
                                     Color foreground,
-                                    Color background_focused,
+                                    Color background_active,
-                                    Color foreground_focused) {
+                                    Color foreground_active) {
   ButtonOption option;
-  option.transform = [](EntryState s) {
+  option.transform = [](const EntryState& s) {
     auto element = text(s.label) | borderEmpty;
-    if (s.focused)
+    if (s.focused) {
       element |= bold;
+    }
     return element;
   };
-  option.animated_colors.foreground.Set(foreground, foreground_focused);
+  option.animated_colors.foreground.Set(foreground, foreground_active);
-  option.animated_colors.background.Set(background, background_focused);
+  option.animated_colors.background.Set(background, background_active);
   return option;
 }
 
@@ -181,19 +189,21 @@ ButtonOption ButtonOption::Animated(Color background,
 // static
 CheckboxOption CheckboxOption::Simple() {
   auto option = CheckboxOption();
-  option.transform = [](EntryState s) {
+  option.transform = [](const EntryState& s) {
 #if defined(FTXUI_MICROSOFT_TERMINAL_FALLBACK)
     // Microsoft terminal do not use fonts able to render properly the default
     // radiobox glyph.
-    auto prefix = text(s.state ? "[X] " : "[ ] ");
+    auto prefix = text(s.state ? "[X] " : "[ ] ");  // NOLINT
 #else
-    auto prefix = text(s.state ? "▣ " : "☐ ");
+    auto prefix = text(s.state ? "▣ " : "☐ ");  // NOLINT
 #endif
     auto t = text(s.label);
-    if (s.active)
+    if (s.active) {
       t |= bold;
-    if (s.focused)
+    }
+    if (s.focused) {
       t |= inverted;
+    }
     return hbox({prefix, t});
   };
   return option;
@@ -203,19 +213,21 @@ CheckboxOption CheckboxOption::Simple() {
 // static
 RadioboxOption RadioboxOption::Simple() {
   auto option = RadioboxOption();
-  option.transform = [](EntryState s) {
+  option.transform = [](const EntryState& s) {
 #if defined(FTXUI_MICROSOFT_TERMINAL_FALLBACK)
     // Microsoft terminal do not use fonts able to render properly the default
     // radiobox glyph.
-    auto prefix = text(s.state ? "(*) " : "( ) ");
+    auto prefix = text(s.state ? "(*) " : "( ) ");  // NOLINT
 #else
-    auto prefix = text(s.state ? "◉ " : "○ ");
+    auto prefix = text(s.state ? "◉ " : "○ ");  // NOLINT
 #endif
     auto t = text(s.label);
-    if (s.active)
+    if (s.active) {
       t |= bold;
-    if (s.focused)
+    }
+    if (s.focused) {
       t |= inverted;
+    }
     return hbox({prefix, t});
   };
   return option;

src/ftxui/component/container.cpp

@@ -1,5 +1,5 @@
-#include <stddef.h>   // for size_t
 #include <algorithm>  // for max, min
+#include <cstddef>    // for size_t
 #include <memory>  // for make_shared, __shared_ptr_access, allocator, shared_ptr, allocator_traits<>::value_type
 #include <utility>  // for move
 #include <vector>   // for vector, __alloc_traits<>::value_type
@@ -17,27 +17,32 @@ class ContainerBase : public ComponentBase {
  public:
   ContainerBase(Components children, int* selector)
       : selector_(selector ? selector : &selected_) {
-    for (Component& child : children)
+    for (Component& child : children) {
       Add(std::move(child));
     }
+  }
 
   // Component override.
   bool OnEvent(Event event) override {
-    if (event.is_mouse())
+    if (event.is_mouse()) {
       return OnMouseEvent(event);
+    }
 
-    if (!Focused())
+    if (!Focused()) {
       return false;
+    }
 
-    if (ActiveChild() && ActiveChild()->OnEvent(event))
+    if (ActiveChild() && ActiveChild()->OnEvent(event)) {
       return true;
+    }
 
     return EventHandler(event);
   }
 
   Component ActiveChild() override {
-    if (children_.size() == 0)
+    if (children_.empty()) {
       return nullptr;
+    }
 
     return children_[*selector_ % children_.size()];
   }
@@ -45,7 +50,7 @@ class ContainerBase : public ComponentBase {
   void SetActiveChild(ComponentBase* child) override {
     for (size_t i = 0; i < children_.size(); ++i) {
       if (children_[i].get() == child) {
-        *selector_ = i;
+        *selector_ = (int)i;
         return;
       }
     }
@@ -53,10 +58,10 @@ class ContainerBase : public ComponentBase {
 
  protected:
   // Handlers
-  virtual bool EventHandler(Event) { return false; }
+  virtual bool EventHandler(Event /*unused*/) { return false; }  // NOLINT
 
   virtual bool OnMouseEvent(Event event) {
-    return ComponentBase::OnEvent(event);
+    return ComponentBase::OnEvent(std::move(event));
   }
 
   int selected_ = 0;
@@ -71,11 +76,16 @@ class ContainerBase : public ComponentBase {
       }
     }
   }
+
   void MoveSelectorWrap(int dir) {
+    if (children_.empty()) {
+      return;
+    }
     for (size_t offset = 1; offset < children_.size(); ++offset) {
-      int i = (*selector_ + offset * dir + children_.size()) % children_.size();
+      size_t i = ((size_t(*selector_ + offset * dir + children_.size())) %
+                  children_.size());
       if (children_[i]->Focusable()) {
-        *selector_ = i;
+        *selector_ = (int)i;
         return;
       }
     }
@@ -88,60 +98,74 @@ class VerticalContainer : public ContainerBase {
 
   Element Render() override {
     Elements elements;
-    for (auto& it : children_)
+    for (auto& it : children_) {
       elements.push_back(it->Render());
-    if (elements.size() == 0)
+    }
+    if (elements.empty()) {
       return text("Empty container") | reflect(box_);
+    }
     return vbox(std::move(elements)) | reflect(box_);
   }
 
   bool EventHandler(Event event) override {
     int old_selected = *selector_;
-    if (event == Event::ArrowUp || event == Event::Character('k'))
+    if (event == Event::ArrowUp || event == Event::Character('k')) {
       MoveSelector(-1);
-    if (event == Event::ArrowDown || event == Event::Character('j'))
+    }
+    if (event == Event::ArrowDown || event == Event::Character('j')) {
       MoveSelector(+1);
+    }
     if (event == Event::PageUp) {
-      for (int i = 0; i < box_.y_max - box_.y_min; ++i)
+      for (int i = 0; i < box_.y_max - box_.y_min; ++i) {
         MoveSelector(-1);
       }
+    }
     if (event == Event::PageDown) {
-      for (int i = 0; i < box_.y_max - box_.y_min; ++i)
+      for (int i = 0; i < box_.y_max - box_.y_min; ++i) {
         MoveSelector(1);
       }
+    }
     if (event == Event::Home) {
-      for (size_t i = 0; i < children_.size(); ++i)
+      for (size_t i = 0; i < children_.size(); ++i) {
         MoveSelector(-1);
       }
+    }
     if (event == Event::End) {
-      for (size_t i = 0; i < children_.size(); ++i)
+      for (size_t i = 0; i < children_.size(); ++i) {
         MoveSelector(1);
       }
-    if (event == Event::Tab && children_.size())
+    }
+    if (event == Event::Tab) {
       MoveSelectorWrap(+1);
-    if (event == Event::TabReverse && children_.size())
+    }
+    if (event == Event::TabReverse) {
       MoveSelectorWrap(-1);
+    }
 
     *selector_ = std::max(0, std::min(int(children_.size()) - 1, *selector_));
     return old_selected != *selector_;
   }
 
   bool OnMouseEvent(Event event) override {
-    if (ContainerBase::OnMouseEvent(event))
+    if (ContainerBase::OnMouseEvent(event)) {
       return true;
+    }
 
     if (event.mouse().button != Mouse::WheelUp &&
         event.mouse().button != Mouse::WheelDown) {
       return false;
     }
 
-    if (!box_.Contain(event.mouse().x, event.mouse().y))
+    if (!box_.Contain(event.mouse().x, event.mouse().y)) {
       return false;
+    }
 
-    if (event.mouse().button == Mouse::WheelUp)
+    if (event.mouse().button == Mouse::WheelUp) {
       MoveSelector(-1);
-    if (event.mouse().button == Mouse::WheelDown)
+    }
+    if (event.mouse().button == Mouse::WheelDown) {
       MoveSelector(+1);
+    }
     *selector_ = std::max(0, std::min(int(children_.size()) - 1, *selector_));
 
     return true;
@@ -156,23 +180,29 @@ class HorizontalContainer : public ContainerBase {
 
   Element Render() override {
     Elements elements;
-    for (auto& it : children_)
+    for (auto& it : children_) {
       elements.push_back(it->Render());
-    if (elements.size() == 0)
+    }
+    if (elements.empty()) {
       return text("Empty container");
+    }
     return hbox(std::move(elements));
   }
 
   bool EventHandler(Event event) override {
     int old_selected = *selector_;
-    if (event == Event::ArrowLeft || event == Event::Character('h'))
+    if (event == Event::ArrowLeft || event == Event::Character('h')) {
       MoveSelector(-1);
-    if (event == Event::ArrowRight || event == Event::Character('l'))
+    }
+    if (event == Event::ArrowRight || event == Event::Character('l')) {
       MoveSelector(+1);
-    if (event == Event::Tab && children_.size())
+    }
+    if (event == Event::Tab) {
       MoveSelectorWrap(+1);
-    if (event == Event::TabReverse && children_.size())
+    }
+    if (event == Event::TabReverse) {
       MoveSelectorWrap(-1);
+    }
 
     *selector_ = std::max(0, std::min(int(children_.size()) - 1, *selector_));
     return old_selected != *selector_;
@@ -185,14 +215,16 @@ class TabContainer : public ContainerBase {
 
   Element Render() override {
     Component active_child = ActiveChild();
-    if (active_child)
+    if (active_child) {
       return active_child->Render();
+    }
     return text("Empty container");
   }
 
   bool Focusable() const override {
-    if (children_.size() == 0)
+    if (children_.empty()) {
       return false;
+    }
     return children_[*selector_ % children_.size()]->Focusable();
   }
 

src/ftxui/component/dropdown.cpp

@@ -1,12 +1,12 @@
 #include <algorithm>   // for max, min
-#include <memory>     // for __shared_ptr_access
+#include <functional>  // for function
+#include <memory>      // for __shared_ptr_access, shared_ptr, allocator
 #include <string>      // for string
-#include <utility>    // for move
 
 #include "ftxui/component/component.hpp"  // for Maybe, Checkbox, Make, Radiobox, Vertical, Dropdown
 #include "ftxui/component/component_base.hpp"  // for Component, ComponentBase
-#include "ftxui/component/component_options.hpp"  // for CheckboxOption
+#include "ftxui/component/component_options.hpp"  // for CheckboxOption, EntryState
-#include "ftxui/dom/elements.hpp"  // for operator|, Element, border, filler, separator, size, vbox, frame, vscroll_indicator, HEIGHT, LESS_THAN
+#include "ftxui/dom/elements.hpp"  // for operator|, Element, border, filler, operator|=, separator, size, text, vbox, frame, vscroll_indicator, hbox, HEIGHT, LESS_THAN, bold, inverted
 #include "ftxui/util/ref.hpp"      // for ConstStringListRef
 
 namespace ftxui {
@@ -15,15 +15,17 @@ Component Dropdown(ConstStringListRef entries, int* selected) {
   class Impl : public ComponentBase {
    public:
     Impl(ConstStringListRef entries, int* selected)
-        : entries_(std::move(entries)), selected_(selected) {
+        : entries_(entries), selected_(selected) {
       CheckboxOption option;
-      option.transform = [](EntryState s) {
+      option.transform = [](const EntryState& s) {
-        auto prefix = text(s.state ? "↓ " : "→ ");
+        auto prefix = text(s.state ? "↓ " : "→ ");  // NOLINT
         auto t = text(s.label);
-        if (s.active)
+        if (s.active) {
           t |= bold;
-        if (s.focused)
+        }
+        if (s.focused) {
           t |= inverted;
+        }
         return hbox({prefix, t});
       };
       checkbox_ = Checkbox(&title_, &show_, option),
@@ -39,11 +41,12 @@ Component Dropdown(ConstStringListRef entries, int* selected) {
       *selected_ = std::min((int)entries_.size() - 1, std::max(0, *selected_));
       title_ = entries_[*selected_];
       if (show_) {
+        const int max_height = 12;
         return vbox({
                    checkbox_->Render(),
                    separator(),
                    radiobox_->Render() | vscroll_indicator | frame |
-                       size(HEIGHT, LESS_THAN, 12),
+                       size(HEIGHT, LESS_THAN, max_height),
                }) |
                border;
       }
@@ -63,7 +66,7 @@ Component Dropdown(ConstStringListRef entries, int* selected) {
     Component radiobox_;
   };
 
-  return Make<Impl>(std::move(entries), selected);
+  return Make<Impl>(entries, selected);
 }
 
 }  // namespace ftxui

src/ftxui/component/event.cpp

@@ -29,7 +29,7 @@ Event Event::Mouse(std::string input, struct Mouse mouse) {
   Event event;
   event.input_ = std::move(input);
   event.type_ = Type::Mouse;
-  event.mouse_ = mouse;
+  event.mouse_ = mouse;  // NOLINT
   return event;
 }
 
@@ -45,40 +45,39 @@ Event Event::CursorReporting(std::string input, int x, int y) {
   Event event;
   event.input_ = std::move(input);
   event.type_ = Type::CursorReporting;
-  event.cursor_.x = x;
+  event.cursor_.x = x;  // NOLINT
-  event.cursor_.y = y;
+  event.cursor_.y = y;  // NOLINT
   return event;
 }
 
 // --- Arrow ---
-const Event Event::ArrowLeft = Event::Special("\x1B[D");
+const Event Event::ArrowLeft = Event::Special("\x1B[D");       // NOLINT
-const Event Event::ArrowRight = Event::Special("\x1B[C");
+const Event Event::ArrowRight = Event::Special("\x1B[C");      // NOLINT
-const Event Event::ArrowUp = Event::Special("\x1B[A");
+const Event Event::ArrowUp = Event::Special("\x1B[A");         // NOLINT
-const Event Event::ArrowDown = Event::Special("\x1B[B");
+const Event Event::ArrowDown = Event::Special("\x1B[B");       // NOLINT
-const Event Event::Backspace = Event::Special({127});
+const Event Event::Backspace = Event::Special({127});          // NOLINT
-const Event Event::Delete = Event::Special("\x1B[3~");
+const Event Event::Delete = Event::Special("\x1B[3~");         // NOLINT
-const Event Event::Escape = Event::Special("\x1B");
+const Event Event::Escape = Event::Special("\x1B");            // NOLINT
-const Event Event::Return = Event::Special({10});
+const Event Event::Return = Event::Special({10});              // NOLINT
-const Event Event::Tab = Event::Special({9});
+const Event Event::Tab = Event::Special({9});                  // NOLINT
-const Event Event::TabReverse = Event::Special({27, 91, 90});
+const Event Event::TabReverse = Event::Special({27, 91, 90});  // NOLINT
-const Event Event::F1 = Event::Special("\x1B[OP");
+const Event Event::F1 = Event::Special("\x1B[OP");             // NOLINT
-const Event Event::F2 = Event::Special("\x1B[OQ");
+const Event Event::F2 = Event::Special("\x1B[OQ");             // NOLINT
-const Event Event::F3 = Event::Special("\x1B[OR");
+const Event Event::F3 = Event::Special("\x1B[OR");             // NOLINT
-const Event Event::F4 = Event::Special("\x1B[OS");
+const Event Event::F4 = Event::Special("\x1B[OS");             // NOLINT
-const Event Event::F5 = Event::Special("\x1B[15~");
+const Event Event::F5 = Event::Special("\x1B[15~");            // NOLINT
-const Event Event::F6 = Event::Special("\x1B[17~");
+const Event Event::F6 = Event::Special("\x1B[17~");            // NOLINT
-const Event Event::F7 = Event::Special("\x1B[18~");
+const Event Event::F7 = Event::Special("\x1B[18~");            // NOLINT
-const Event Event::F8 = Event::Special("\x1B[19~");
+const Event Event::F8 = Event::Special("\x1B[19~");            // NOLINT
-const Event Event::F9 = Event::Special("\x1B[20~");
+const Event Event::F9 = Event::Special("\x1B[20~");            // NOLINT
-const Event Event::F10 = Event::Special("\x1B[21~");
+const Event Event::F10 = Event::Special("\x1B[21~");           // NOLINT
-const Event Event::F11 = Event::Special("\x1B[21~");  // Doesn't exist
+const Event Event::F11 = Event::Special("\x1B[21~");  // Doesn't exist // NOLINT
-const Event Event::F12 = Event::Special("\x1B[24~");
+const Event Event::F12 = Event::Special("\x1B[24~");  // NOLINT
-const Event Event::Home = Event::Special({27, 91, 72});
+const Event Event::Home = Event::Special({27, 91, 72});           // NOLINT
-const Event Event::End = Event::Special({27, 91, 70});
+const Event Event::End = Event::Special({27, 91, 70});            // NOLINT
-const Event Event::PageUp = Event::Special({27, 91, 53, 126});
+const Event Event::PageUp = Event::Special({27, 91, 53, 126});    // NOLINT
-const Event Event::PageDown = Event::Special({27, 91, 54, 126});
+const Event Event::PageDown = Event::Special({27, 91, 54, 126});  // NOLINT
-
+const Event Event::Custom = Event::Special({0});                  // NOLINT
-Event Event::Custom = Event::Special({0});
 
 }  // namespace ftxui
 

src/ftxui/component/input.cpp

@@ -1,5 +1,5 @@
-#include <stddef.h>    // for size_t
 #include <algorithm>   // for max, min
+#include <cstddef>     // for size_t
 #include <functional>  // for function
 #include <memory>      // for shared_ptr, allocator
 #include <string>      // for string, wstring
@@ -24,11 +24,12 @@ namespace ftxui {
 
 namespace {
 
-std::string PasswordField(int size) {
+std::string PasswordField(size_t size) {
   std::string out;
   out.reserve(2 * size);
-  while (size--)
+  while (size--) {
     out += "•";
+  }
   return out;
 }
 
@@ -38,21 +39,25 @@ class InputBase : public ComponentBase {
   InputBase(StringRef content,
             ConstStringRef placeholder,
             Ref<InputOption> option)
-      : content_(content), placeholder_(placeholder), option_(option) {}
+      : content_(std::move(content)),
+        placeholder_(std::move(placeholder)),
+        option_(std::move(option)) {}
 
   int cursor_position_internal_ = 0;
   int& cursor_position() {
     int& opt = option_->cursor_position();
-    if (opt != -1)
+    if (opt != -1) {
       return opt;
+    }
     return cursor_position_internal_;
   }
 
   // Component implementation:
   Element Render() override {
     std::string password_content;
-    if (option_->password())
+    if (option_->password()) {
       password_content = PasswordField(content_->size());
+    }
     std::string& content = option_->password() ? password_content : *content_;
 
     int size = GlyphCount(content);
@@ -65,20 +70,23 @@ class InputBase : public ComponentBase {
     if (size == 0) {
       bool hovered = hovered_;
       Decorator decorator = dim | main_decorator;
-      if (is_focused)
+      if (is_focused) {
         decorator = decorator | focus;
-      if (hovered || is_focused)
+      }
+      if (hovered || is_focused) {
         decorator = decorator | inverted;
+      }
       return text(*placeholder_) | decorator | reflect(box_);
     }
 
     // Not focused.
     if (!is_focused) {
-      if (hovered_)
+      if (hovered_) {
         return text(content) | main_decorator | inverted | reflect(box_);
-      else
+      } else {
         return text(content) | main_decorator | reflect(box_);
       }
+    }
 
     int index_before_cursor = GlyphPosition(content, cursor_position());
     int index_after_cursor = GlyphPosition(content, 1, index_before_cursor);
@@ -100,17 +108,19 @@ class InputBase : public ComponentBase {
 
   bool OnEvent(Event event) override {
     cursor_position() =
-        std::max(0, std::min<int>(content_->size(), cursor_position()));
+        std::max(0, std::min<int>((int)content_->size(), cursor_position()));
 
-    if (event.is_mouse())
+    if (event.is_mouse()) {
       return OnMouseEvent(event);
+    }
 
     std::string c;
 
     // Backspace.
     if (event == Event::Backspace) {
-      if (cursor_position() == 0)
+      if (cursor_position() == 0) {
         return false;
+      }
       size_t start = GlyphPosition(*content_, cursor_position() - 1);
       size_t end = GlyphPosition(*content_, cursor_position());
       content_->erase(start, end - start);
@@ -121,8 +131,9 @@ class InputBase : public ComponentBase {
 
     // Delete
     if (event == Event::Delete) {
-      if (cursor_position() == int(content_->size()))
+      if (cursor_position() == int(content_->size())) {
         return false;
+      }
       size_t start = GlyphPosition(*content_, cursor_position());
       size_t end = GlyphPosition(*content_, cursor_position() + 1);
       content_->erase(start, end - start);
@@ -176,8 +187,9 @@ class InputBase : public ComponentBase {
   bool OnMouseEvent(Event event) {
     hovered_ =
         box_.Contain(event.mouse().x, event.mouse().y) && CaptureMouse(event);
-    if (!hovered_)
+    if (!hovered_) {
       return false;
+    }
 
     if (event.mouse().button != Mouse::Left ||
         event.mouse().motion != Mouse::Pressed) {
@@ -185,22 +197,24 @@ class InputBase : public ComponentBase {
     }
 
     TakeFocus();
-    if (content_->size() == 0)
+    if (content_->empty()) {
       return true;
+    }
 
     auto mapping = CellToGlyphIndex(*content_);
     int original_glyph = cursor_position();
     original_glyph = util::clamp(original_glyph, 0, int(mapping.size()));
-    int original_cell = 0;
+    size_t original_cell = 0;
     for (size_t i = 0; i < mapping.size(); i++) {
       if (mapping[i] == original_glyph) {
-        original_cell = i;
+        original_cell = (int)i;
         break;
       }
     }
-    if (mapping[original_cell] != original_glyph)
+    if (mapping[original_cell] != original_glyph) {
       original_cell = mapping.size();
-    int target_cell = original_cell + event.mouse().x - cursor_box_.x_min;
+    }
+    int target_cell = int(original_cell) + event.mouse().x - cursor_box_.x_min;
     int target_glyph = target_cell < (int)mapping.size() ? mapping[target_cell]
                                                          : (int)mapping.size();
     target_glyph = util::clamp(target_glyph, 0, GlyphCount(*content_));
@@ -279,7 +293,8 @@ class WideInputBase : public InputBase {
 Component Input(StringRef content,
                 ConstStringRef placeholder,
                 Ref<InputOption> option) {
-  return Make<InputBase>(content, placeholder, std::move(option));
+  return Make<InputBase>(std::move(content), std::move(placeholder),
+                         std::move(option));
 }
 
 /// @brief . An input box for editing text.
@@ -307,7 +322,8 @@ Component Input(StringRef content,
 Component Input(WideStringRef content,
                 ConstStringRef placeholder,
                 Ref<InputOption> option) {
-  return Make<WideInputBase>(content, placeholder, std::move(option));
+  return Make<WideInputBase>(std::move(content), std::move(placeholder),
+                             std::move(option));
 }
 
 }  // namespace ftxui

src/ftxui/component/maybe.cpp

@@ -13,7 +13,7 @@ namespace ftxui {
 Component Maybe(Component child, std::function<bool()> show) {
   class Impl : public ComponentBase {
    public:
-    Impl(std::function<bool()> show) : show_(std::move(show)) {}
+    explicit Impl(std::function<bool()> show) : show_(std::move(show)) {}
 
    private:
     Element Render() override {
@@ -48,7 +48,7 @@ Component Maybe(Component child, std::function<bool()> show) {
 /// ```
 ComponentDecorator Maybe(std::function<bool()> show) {
   return [show = std::move(show)](Component child) mutable {
-    return Maybe(child, std::move(show));
+    return Maybe(std::move(child), std::move(show));
   };
 }
 
@@ -64,7 +64,7 @@ ComponentDecorator Maybe(std::function<bool()> show) {
 /// auto maybe_component = Maybe(component, &show);
 /// ```
 Component Maybe(Component child, const bool* show) {
-  return Maybe(child, [show] { return *show; });
+  return Maybe(std::move(child), [show] { return *show; });
 }
 
 /// @brief Decorate a component. It is shown only when |show| is true.
@@ -78,7 +78,7 @@ Component Maybe(Component child, const bool* show) {
 /// auto maybe_component = component | Maybe(&show);
 /// ```
 ComponentDecorator Maybe(const bool* show) {
-  return [show](Component child) { return Maybe(child, show); };
+  return [show](Component child) { return Maybe(std::move(child), show); };
 }
 
 }  // namespace ftxui

src/ftxui/component/menu.cpp

@@ -24,13 +24,15 @@ namespace ftxui {
 
 namespace {
 
-Element DefaultOptionTransform(EntryState state) {
+Element DefaultOptionTransform(const EntryState& state) {
-  state.label = (state.active ? "> " : "  ") + state.label;
+  std::string label = (state.active ? "> " : "  ") + state.label;  // NOLINT
-  Element e = text(state.label);
+  Element e = text(label);
-  if (state.focused)
+  if (state.focused) {
     e = e | inverted;
-  if (state.active)
+  }
+  if (state.active) {
     e = e | bold;
+  }
   return e;
 }
 
@@ -65,18 +67,20 @@ bool IsHorizontal(MenuOption::Direction direction) {
 class MenuBase : public ComponentBase {
  public:
   MenuBase(ConstStringListRef entries, int* selected, Ref<MenuOption> option)
-      : entries_(entries), selected_(selected), option_(option) {}
+      : entries_(entries), selected_(selected), option_(std::move(option)) {}
 
   bool IsHorizontal() { return ftxui::IsHorizontal(option_->direction); }
   void OnChange() {
-    if (option_->on_change)
+    if (option_->on_change) {
       option_->on_change();
     }
+  }
 
   void OnEnter() {
-    if (option_->on_enter)
+    if (option_->on_enter) {
       option_->on_enter();
     }
+  }
 
   void Clamp() {
     boxes_.resize(size());
@@ -87,11 +91,13 @@ class MenuBase : public ComponentBase {
   void OnAnimation(animation::Params& params) override {
     animator_first_.OnAnimation(params);
     animator_second_.OnAnimation(params);
-    for (auto& animator : animator_background_)
+    for (auto& animator : animator_background_) {
       animator.OnAnimation(params);
-    for (auto& animator : animator_foreground_)
+    }
+    for (auto& animator : animator_foreground_) {
       animator.OnAnimation(params);
     }
+  }
 
   Element Render() override {
     Clamp();
@@ -99,11 +105,13 @@ class MenuBase : public ComponentBase {
 
     Elements elements;
     bool is_menu_focused = Focused();
-    if (option_->elements_prefix)
+    if (option_->elements_prefix) {
       elements.push_back(option_->elements_prefix());
+    }
     for (int i = 0; i < size(); ++i) {
-      if (i != 0 && option_->elements_infix)
+      if (i != 0 && option_->elements_infix) {
         elements.push_back(option_->elements_infix());
+      }
       bool is_focused = (focused_entry() == i) && is_menu_focused;
       bool is_selected = (*selected_ == i);
 
@@ -120,21 +128,24 @@ class MenuBase : public ComponentBase {
       Element element =
           (option_->entries.transform ? option_->entries.transform
                                       : DefaultOptionTransform)  //
-          (std::move(state));
+          (state);
       elements.push_back(element | AnimatedColorStyle(i) | reflect(boxes_[i]) |
                          focus_management);
     }
-    if (option_->elements_postfix)
+    if (option_->elements_postfix) {
       elements.push_back(option_->elements_postfix());
+    }
 
-    if (IsInverted(option_->direction))
+    if (IsInverted(option_->direction)) {
       std::reverse(elements.begin(), elements.end());
+    }
 
     Element bar =
         IsHorizontal() ? hbox(std::move(elements)) : vbox(std::move(elements));
 
-    if (!option_->underline.enabled)
+    if (!option_->underline.enabled) {
       return bar | reflect(box_);
+    }
 
     if (IsHorizontal()) {
       return vbox({
@@ -211,36 +222,49 @@ class MenuBase : public ComponentBase {
     }
   }
 
+  // NOLINTNEXTLINE(readability-function-cognitive-complexity)
   bool OnEvent(Event event) override {
     Clamp();
-    if (!CaptureMouse(event))
+    if (!CaptureMouse(event)) {
       return false;
+    }
 
-    if (event.is_mouse())
+    if (event.is_mouse()) {
       return OnMouseEvent(event);
+    }
 
     if (Focused()) {
       int old_selected = *selected_;
-      if (event == Event::ArrowUp || event == Event::Character('k'))
+      if (event == Event::ArrowUp || event == Event::Character('k')) {
         OnUp();
-      if (event == Event::ArrowDown || event == Event::Character('j'))
+      }
+      if (event == Event::ArrowDown || event == Event::Character('j')) {
         OnDown();
-      if (event == Event::ArrowLeft || event == Event::Character('h'))
+      }
+      if (event == Event::ArrowLeft || event == Event::Character('h')) {
         OnLeft();
-      if (event == Event::ArrowRight || event == Event::Character('l'))
+      }
+      if (event == Event::ArrowRight || event == Event::Character('l')) {
         OnRight();
-      if (event == Event::PageUp)
+      }
+      if (event == Event::PageUp) {
         (*selected_) -= box_.y_max - box_.y_min;
-      if (event == Event::PageDown)
+      }
+      if (event == Event::PageDown) {
         (*selected_) += box_.y_max - box_.y_min;
-      if (event == Event::Home)
+      }
+      if (event == Event::Home) {
         (*selected_) = 0;
-      if (event == Event::End)
+      }
+      if (event == Event::End) {
         (*selected_) = size() - 1;
-      if (event == Event::Tab && size())
+      }
+      if (event == Event::Tab && size()) {
         *selected_ = (*selected_ + 1) % size();
-      if (event == Event::TabReverse && size())
+      }
+      if (event == Event::TabReverse && size()) {
         *selected_ = (*selected_ + size() - 1) % size();
+      }
 
       *selected_ = util::clamp(*selected_, 0, size() - 1);
 
@@ -269,11 +293,13 @@ class MenuBase : public ComponentBase {
         event.mouse().button != Mouse::Left) {
       return false;
     }
-    if (!CaptureMouse(event))
+    if (!CaptureMouse(event)) {
       return false;
+    }
     for (int i = 0; i < size(); ++i) {
-      if (!boxes_[i].Contain(event.mouse().x, event.mouse().y))
+      if (!boxes_[i].Contain(event.mouse().x, event.mouse().y)) {
         continue;
+      }
 
       TakeFocus();
       focused_entry() = i;
@@ -290,19 +316,23 @@ class MenuBase : public ComponentBase {
   }
 
   bool OnMouseWheel(Event event) {
-    if (!box_.Contain(event.mouse().x, event.mouse().y))
+    if (!box_.Contain(event.mouse().x, event.mouse().y)) {
       return false;
+    }
     int old_selected = *selected_;
 
-    if (event.mouse().button == Mouse::WheelUp)
+    if (event.mouse().button == Mouse::WheelUp) {
       (*selected_)--;
-    if (event.mouse().button == Mouse::WheelDown)
+    }
+    if (event.mouse().button == Mouse::WheelDown) {
       (*selected_)++;
+    }
 
     *selected_ = util::clamp(*selected_, 0, size() - 1);
 
-    if (*selected_ != old_selected)
+    if (*selected_ != old_selected) {
       OnChange();
+    }
     return true;
   }
 
@@ -319,12 +349,12 @@ class MenuBase : public ComponentBase {
       animator_foreground_.clear();
 
       for (int i = 0; i < size(); ++i) {
-        animation_background_[i] = 0.f;
+        animation_background_[i] = 0.F;
-        animation_foreground_[i] = 0.f;
+        animation_foreground_[i] = 0.F;
-        animator_background_.emplace_back(&animation_background_[i], 0.f,
+        animator_background_.emplace_back(&animation_background_[i], 0.F,
                                           std::chrono::milliseconds(0),
                                           animation::easing::Linear);
-        animator_foreground_.emplace_back(&animation_foreground_[i], 0.f,
+        animator_foreground_.emplace_back(&animation_foreground_[i], 0.F,
                                           std::chrono::milliseconds(0),
                                           animation::easing::Linear);
       }
@@ -334,7 +364,7 @@ class MenuBase : public ComponentBase {
     for (int i = 0; i < size(); ++i) {
       bool is_focused = (focused_entry() == i) && is_menu_focused;
       bool is_selected = (*selected_ == i);
-      float target = is_selected ? 1.f : is_focused ? 0.5f : 0.f;
+      float target = is_selected ? 1.F : is_focused ? 0.5F : 0.F;  // NOLINT
       if (animator_background_[i].to() != target) {
         animator_background_[i] = animation::Animator(
             &animation_background_[i], target,
@@ -367,8 +397,9 @@ class MenuBase : public ComponentBase {
   }
 
   void UpdateUnderlineTarget() {
-    if (!option_->underline.enabled)
+    if (!option_->underline.enabled) {
       return;
+    }
 
     if (FirstTarget() == animator_first_.to() &&
         SecondTarget() == animator_second_.to()) {
@@ -398,32 +429,36 @@ class MenuBase : public ComponentBase {
 
   bool Focusable() const final { return entries_.size(); }
   int& focused_entry() { return option_->focused_entry(); }
-  int size() const { return entries_.size(); }
+  int size() const { return int(entries_.size()); }
-  int FirstTarget() {
+  float FirstTarget() {
-    if (boxes_.size() == 0)
+    if (boxes_.empty()) {
-      return 0;
+      return 0.F;
-    return IsHorizontal() ? boxes_[*selected_].x_min - box_.x_min
-                          : boxes_[*selected_].y_min - box_.y_min;
     }
-  int SecondTarget() {
+    int value = IsHorizontal() ? boxes_[*selected_].x_min - box_.x_min
-    if (boxes_.size() == 0)
+                               : boxes_[*selected_].y_min - box_.y_min;
-      return 0;
+    return float(value);
-    return IsHorizontal() ? boxes_[*selected_].x_max - box_.x_min
+  }
+  float SecondTarget() {
+    if (boxes_.empty()) {
+      return 0.F;
+    }
+    int value = IsHorizontal() ? boxes_[*selected_].x_max - box_.x_min
                                : boxes_[*selected_].y_max - box_.y_min;
+    return float(value);
   }
 
  protected:
   ConstStringListRef entries_;
-  int* selected_ = 0;
+  int* selected_ = nullptr;
   Ref<MenuOption> option_;
 
   std::vector<Box> boxes_;
   Box box_;
 
-  float first_ = 0.f;
+  float first_ = 0.F;
-  float second_ = 0.f;
+  float second_ = 0.F;
-  animation::Animator animator_first_ = animation::Animator(&first_, 0.f);
+  animation::Animator animator_first_ = animation::Animator(&first_, 0.F);
-  animation::Animator animator_second_ = animation::Animator(&second_, 0.f);
+  animation::Animator animator_second_ = animation::Animator(&second_, 0.F);
 
   std::vector<animation::Animator> animator_background_;
   std::vector<animation::Animator> animator_foreground_;
@@ -519,7 +554,7 @@ Component MenuEntry(ConstStringRef label, Ref<MenuEntryOption> option) {
 
       Element element =
           (option_->transform ? option_->transform : DefaultOptionTransform)  //
-          (std::move(state));
+          (state);
 
       auto focus_management = focused ? select : nothing;
       return element | AnimatedColorStyle() | focus_management | reflect(box_);
@@ -527,9 +562,10 @@ Component MenuEntry(ConstStringRef label, Ref<MenuEntryOption> option) {
 
     void UpdateAnimationTarget() {
       bool focused = Focused();
-      float target = focused ? 1.0f : hovered_ ? 0.5f : 0.0f;
+      float target = focused ? 1.F : hovered_ ? 0.5F : 0.F;  // NOLINT
-      if (target == animator_background_.to())
+      if (target == animator_background_.to()) {
         return;
+      }
       animator_background_ =
           animation::Animator(&animation_background_, target,
                               option_->animated_colors.background.duration,
@@ -560,13 +596,15 @@ Component MenuEntry(ConstStringRef label, Ref<MenuEntryOption> option) {
 
     bool Focusable() const override { return true; }
     bool OnEvent(Event event) override {
-      if (!event.is_mouse())
+      if (!event.is_mouse()) {
         return false;
+      }
 
       hovered_ = box_.Contain(event.mouse().x, event.mouse().y);
 
-      if (!hovered_)
+      if (!hovered_) {
         return false;
+      }
 
       if (event.mouse().button == Mouse::Left &&
           event.mouse().motion == Mouse::Released) {
@@ -587,12 +625,12 @@ Component MenuEntry(ConstStringRef label, Ref<MenuEntryOption> option) {
     Box box_;
     bool hovered_ = false;
 
-    float animation_background_ = 0.f;
+    float animation_background_ = 0.F;
-    float animation_foreground_ = 0.f;
+    float animation_foreground_ = 0.F;
     animation::Animator animator_background_ =
-        animation::Animator(&animation_background_, 0.f);
+        animation::Animator(&animation_background_, 0.F);
     animation::Animator animator_foreground_ =
-        animation::Animator(&animation_foreground_, 0.f);
+        animation::Animator(&animation_foreground_, 0.F);
   };
 
   return Make<Impl>(std::move(label), std::move(option));

src/ftxui/component/radiobox.cpp

@@ -1,18 +1,17 @@
 #include <algorithm>   // for max
 #include <functional>  // for function
 #include <memory>      // for shared_ptr, allocator_traits<>::value_type
-#include <string>      // for string
 #include <utility>     // for move
 #include <vector>      // for vector
 
 #include "ftxui/component/captured_mouse.hpp"     // for CapturedMouse
 #include "ftxui/component/component.hpp"          // for Make, Radiobox
 #include "ftxui/component/component_base.hpp"     // for ComponentBase
-#include "ftxui/component/component_options.hpp"  // for RadioboxOption
+#include "ftxui/component/component_options.hpp"  // for RadioboxOption, EntryState
 #include "ftxui/component/event.hpp"  // for Event, Event::ArrowDown, Event::ArrowUp, Event::End, Event::Home, Event::PageDown, Event::PageUp, Event::Return, Event::Tab, Event::TabReverse
 #include "ftxui/component/mouse.hpp"  // for Mouse, Mouse::WheelDown, Mouse::WheelUp, Mouse::Left, Mouse::Released
 #include "ftxui/component/screen_interactive.hpp"  // for Component
-#include "ftxui/dom/elements.hpp"  // for operator|, reflect, text, Element, hbox, vbox, Elements, focus, nothing, select
+#include "ftxui/dom/elements.hpp"  // for operator|, reflect, Element, vbox, Elements, focus, nothing, select
 #include "ftxui/screen/box.hpp"   // for Box
 #include "ftxui/screen/util.hpp"  // for clamp
 #include "ftxui/util/ref.hpp"     // for Ref, ConstStringListRef
@@ -50,41 +49,51 @@ class RadioboxBase : public ComponentBase {
           is_focused,
       };
       auto element =
-          (option_->transform
+          (option_->transform ? option_->transform
-               ? option_->transform
+                              : RadioboxOption::Simple().transform)(state);
-               : RadioboxOption::Simple().transform)(std::move(state));
 
       elements.push_back(element | focus_management | reflect(boxes_[i]));
     }
     return vbox(std::move(elements)) | reflect(box_);
   }
 
+  // NOLINTNEXTLINE(readability-function-cognitive-complexity)
   bool OnEvent(Event event) override {
     Clamp();
-    if (!CaptureMouse(event))
+    if (!CaptureMouse(event)) {
       return false;
+    }
 
-    if (event.is_mouse())
+    if (event.is_mouse()) {
       return OnMouseEvent(event);
+    }
 
     if (Focused()) {
       int old_hovered = hovered_;
-      if (event == Event::ArrowUp || event == Event::Character('k'))
+      if (event == Event::ArrowUp || event == Event::Character('k')) {
         (hovered_)--;
-      if (event == Event::ArrowDown || event == Event::Character('j'))
+      }
+      if (event == Event::ArrowDown || event == Event::Character('j')) {
         (hovered_)++;
-      if (event == Event::PageUp)
+      }
+      if (event == Event::PageUp) {
         (hovered_) -= box_.y_max - box_.y_min;
-      if (event == Event::PageDown)
+      }
+      if (event == Event::PageDown) {
         (hovered_) += box_.y_max - box_.y_min;
-      if (event == Event::Home)
+      }
+      if (event == Event::Home) {
         (hovered_) = 0;
-      if (event == Event::End)
+      }
+      if (event == Event::End) {
         (hovered_) = size() - 1;
-      if (event == Event::Tab && size())
+      }
+      if (event == Event::Tab && size()) {
         hovered_ = (hovered_ + 1) % size();
-      if (event == Event::TabReverse && size())
+      }
+      if (event == Event::TabReverse && size()) {
         hovered_ = (hovered_ + size() - 1) % size();
+      }
 
       hovered_ = util::clamp(hovered_, 0, size() - 1);
 
@@ -111,8 +120,9 @@ class RadioboxBase : public ComponentBase {
     }
 
     for (int i = 0; i < size(); ++i) {
-      if (!boxes_[i].Contain(event.mouse().x, event.mouse().y))
+      if (!boxes_[i].Contain(event.mouse().x, event.mouse().y)) {
         continue;
+      }
 
       TakeFocus();
       focused_entry() = i;
@@ -130,20 +140,24 @@ class RadioboxBase : public ComponentBase {
   }
 
   bool OnMouseWheel(Event event) {
-    if (!box_.Contain(event.mouse().x, event.mouse().y))
+    if (!box_.Contain(event.mouse().x, event.mouse().y)) {
       return false;
+    }
 
     int old_hovered = hovered_;
 
-    if (event.mouse().button == Mouse::WheelUp)
+    if (event.mouse().button == Mouse::WheelUp) {
       (hovered_)--;
-    if (event.mouse().button == Mouse::WheelDown)
+    }
+    if (event.mouse().button == Mouse::WheelDown) {
       (hovered_)++;
+    }
 
     hovered_ = util::clamp(hovered_, 0, size() - 1);
 
-    if (hovered_ != old_hovered)
+    if (hovered_ != old_hovered) {
       option_->on_change();
+    }
 
     return true;
   }
@@ -157,7 +171,7 @@ class RadioboxBase : public ComponentBase {
 
   bool Focusable() const final { return entries_.size(); }
   int& focused_entry() { return option_->focused_entry(); }
-  int size() const { return entries_.size(); }
+  int size() const { return int(entries_.size()); }
 
   ConstStringListRef entries_;
   int* selected_;

src/ftxui/component/renderer.cpp

@@ -28,7 +28,8 @@ namespace ftxui {
 Component Renderer(std::function<Element()> render) {
   class Impl : public ComponentBase {
    public:
-    Impl(std::function<Element()> render) : render_(std::move(render)) {}
+    explicit Impl(std::function<Element()> render)
+        : render_(std::move(render)) {}
     Element Render() override { return render_(); }
     std::function<Element()> render_;
   };
@@ -82,15 +83,17 @@ Component Renderer(Component child, std::function<Element()> render) {
 Component Renderer(std::function<Element(bool)> render) {
   class Impl : public ComponentBase {
    public:
-    Impl(std::function<Element(bool)> render) : render_(std::move(render)) {}
+    explicit Impl(std::function<Element(bool)> render)
+        : render_(std::move(render)) {}
 
    private:
     Element Render() override { return render_(Focused()) | reflect(box_); }
     bool Focusable() const override { return true; }
     bool OnEvent(Event event) override {
       if (event.is_mouse() && box_.Contain(event.mouse().x, event.mouse().y)) {
-        if (!CaptureMouse(event))
+        if (!CaptureMouse(event)) {
           return false;
+        }
 
         TakeFocus();
       }
@@ -118,8 +121,8 @@ Component Renderer(std::function<Element(bool)> render) {
 ///  | Renderer(inverted);
 /// screen.Loop(renderer);
 /// ```
-ComponentDecorator Renderer(ElementDecorator decorator) {
+ComponentDecorator Renderer(ElementDecorator decorator) {  // NOLINT
-  return [decorator](Component component) {
+  return [decorator](Component component) {                // NOLINT
     return Renderer(component, [component, decorator] {
       return component->Render() | decorator;
     });

src/ftxui/component/resizable_split.cpp

@@ -15,16 +15,19 @@ namespace {
 class ResizableSplitLeftBase : public ComponentBase {
  public:
   ResizableSplitLeftBase(Component main, Component child, int* main_size)
-      : main_(main), child_(child), main_size_(main_size) {
+      : main_(std::move(main)),
+        child_(std::move(child)),
+        main_size_(main_size) {
     Add(Container::Horizontal({
-        main,
+        main_,
-        child,
+        child_,
     }));
   }
 
   bool OnEvent(Event event) final {
-    if (event.is_mouse())
+    if (event.is_mouse()) {
       return OnMouseEvent(std::move(event));
+    }
     return ComponentBase::OnEvent(std::move(event));
   }
 
@@ -71,16 +74,19 @@ class ResizableSplitLeftBase : public ComponentBase {
 class ResizableSplitRightBase : public ComponentBase {
  public:
   ResizableSplitRightBase(Component main, Component child, int* main_size)
-      : main_(main), child_(child), main_size_(main_size) {
+      : main_(std::move(main)),
+        child_(std::move(child)),
+        main_size_(main_size) {
     Add(Container::Horizontal({
-        child,
+        child_,
-        main,
+        main_,
     }));
   }
 
   bool OnEvent(Event event) final {
-    if (event.is_mouse())
+    if (event.is_mouse()) {
       return OnMouseEvent(std::move(event));
+    }
     return ComponentBase::OnEvent(std::move(event));
   }
 
@@ -127,16 +133,19 @@ class ResizableSplitRightBase : public ComponentBase {
 class ResizableSplitTopBase : public ComponentBase {
  public:
   ResizableSplitTopBase(Component main, Component child, int* main_size)
-      : main_(main), child_(child), main_size_(main_size) {
+      : main_(std::move(main)),
+        child_(std::move(child)),
+        main_size_(main_size) {
     Add(Container::Vertical({
-        main,
+        main_,
-        child,
+        child_,
     }));
   }
 
   bool OnEvent(Event event) final {
-    if (event.is_mouse())
+    if (event.is_mouse()) {
       return OnMouseEvent(std::move(event));
+    }
     return ComponentBase::OnEvent(std::move(event));
   }
 
@@ -183,16 +192,19 @@ class ResizableSplitTopBase : public ComponentBase {
 class ResizableSplitBottomBase : public ComponentBase {
  public:
   ResizableSplitBottomBase(Component main, Component child, int* main_size)
-      : main_(main), child_(child), main_size_(main_size) {
+      : main_(std::move(main)),
+        child_(std::move(child)),
+        main_size_(main_size) {
     Add(Container::Vertical({
-        child,
+        child_,
-        main,
+        main_,
     }));
   }
 
   bool OnEvent(Event event) final {
-    if (event.is_mouse())
+    if (event.is_mouse()) {
       return OnMouseEvent(std::move(event));
+    }
     return ComponentBase::OnEvent(std::move(event));
   }
 

src/ftxui/component/screen_interactive.cpp

@@ -1,15 +1,15 @@
-#include <stdio.h>    // for fileno, stdin
 #include <algorithm>  // for copy, max, min
-#include <chrono>  // for operator-, duration, operator>=, milliseconds, time_point, common_type<>::type
+#include <array>      // for array
+#include <chrono>  // for operator-, milliseconds, duration, operator>=, time_point, common_type<>::type
 #include <csignal>  // for signal, raise, SIGTSTP, SIGABRT, SIGFPE, SIGILL, SIGINT, SIGSEGV, SIGTERM, SIGWINCH
-#include <cstdlib>  // for NULL
+#include <cstdio>   // for fileno, size_t, stdin
 #include <functional>        // for function
 #include <initializer_list>  // for initializer_list
 #include <iostream>  // for cout, ostream, basic_ostream, operator<<, endl, flush
 #include <stack>     // for stack
 #include <thread>    // for thread, sleep_for
 #include <type_traits>  // for decay_t
-#include <utility>      // for swap, move
+#include <utility>      // for move, swap
 #include <variant>      // for visit
 #include <vector>       // for vector
 
@@ -50,14 +50,15 @@ namespace ftxui {
 namespace animation {
 void RequestAnimationFrame() {
   auto* screen = ScreenInteractive::Active();
-  if (screen)
+  if (screen) {
     screen->RequestAnimationFrame();
+  }
 }
 }  // namespace animation
 
 namespace {
 
-ScreenInteractive* g_active_screen = nullptr;
+ScreenInteractive* g_active_screen = nullptr;  // NOLINT
 
 void Flush() {
   // Emscripten doesn't implement flush. We interpret zero as flush.
@@ -138,16 +139,14 @@ void EventListener(std::atomic<bool>* quit, Sender<Task> out) {
 int CheckStdinReady(int usec_timeout) {
   timeval tv = {0, usec_timeout};
   fd_set fds;
-  FD_ZERO(&fds);
+  FD_ZERO(&fds);                                          // NOLINT
-  FD_SET(STDIN_FILENO, &fds);
+  FD_SET(STDIN_FILENO, &fds);                             // NOLINT
-  select(STDIN_FILENO + 1, &fds, NULL, NULL, &tv);
+  select(STDIN_FILENO + 1, &fds, nullptr, nullptr, &tv);  // NOLINT
-  return FD_ISSET(STDIN_FILENO, &fds);
+  return FD_ISSET(STDIN_FILENO, &fds);                    // NOLINT
 }
 
 // Read char from the terminal.
 void EventListener(std::atomic<bool>* quit, Sender<Task> out) {
-  const int buffer_size = 100;
-
   auto parser = TerminalInputParser(std::move(out));
 
   while (!*quit) {
@@ -156,16 +155,18 @@ void EventListener(std::atomic<bool>* quit, Sender<Task> out) {
       continue;
     }
 
-    char buff[buffer_size];
+    const size_t buffer_size = 100;
-    int l = read(fileno(stdin), buff, buffer_size);
+    std::array<char, buffer_size> buffer;                     // NOLINT;
-    for (int i = 0; i < l; ++i)
+    int l = read(fileno(stdin), buffer.data(), buffer_size);  // NOLINT
-      parser.Add(buff[i]);
+    for (int i = 0; i < l; ++i) {
+      parser.Add(buffer[i]);  // NOLINT
+    }
   }
 }
 
 #endif
 
-const std::string CSI = "\x1b[";
+const std::string CSI = "\x1b[";  // NOLINT
 
 // DEC: Digital Equipment Corporation
 enum class DECMode {
@@ -186,12 +187,13 @@ enum class DSRMode {
   kCursor = 6,
 };
 
-const std::string Serialize(std::vector<DECMode> parameters) {
+std::string Serialize(const std::vector<DECMode>& parameters) {
   bool first = true;
   std::string out;
   for (DECMode parameter : parameters) {
-    if (!first)
+    if (!first) {
       out += ";";
+    }
     out += std::to_string(int(parameter));
     first = false;
   }
@@ -199,22 +201,22 @@ const std::string Serialize(std::vector<DECMode> parameters) {
 }
 
 // DEC Private Mode Set (DECSET)
-const std::string Set(std::vector<DECMode> parameters) {
+std::string Set(const std::vector<DECMode>& parameters) {
   return CSI + "?" + Serialize(parameters) + "h";
 }
 
 // DEC Private Mode Reset (DECRST)
-const std::string Reset(std::vector<DECMode> parameters) {
+std::string Reset(const std::vector<DECMode>& parameters) {
   return CSI + "?" + Serialize(parameters) + "l";
 }
 
 // Device Status Report (DSR)
-const std::string DeviceStatusReport(DSRMode ps) {
+std::string DeviceStatusReport(DSRMode ps) {
   return CSI + std::to_string(int(ps)) + "n";
 }
 
 using SignalHandler = void(int);
-std::stack<Closure> on_exit_functions;
+std::stack<Closure> on_exit_functions;  // NOLINT
 void OnExit(int signal) {
   (void)signal;
   while (!on_exit_functions.empty()) {
@@ -223,14 +225,14 @@ void OnExit(int signal) {
   }
 }
 
-auto install_signal_handler = [](int sig, SignalHandler handler) {
+const auto install_signal_handler = [](int sig, SignalHandler handler) {
   auto old_signal_handler = std::signal(sig, handler);
   on_exit_functions.push([=] { std::signal(sig, old_signal_handler); });
 };
 
-Closure on_resize = [] {};
+Closure g_on_resize = [] {};  // NOLINT
 void OnResize(int /* signal */) {
-  on_resize();
+  g_on_resize();
 }
 
 void OnSigStop(int /*signal*/) {
@@ -239,17 +241,24 @@ void OnSigStop(int /*signal*/) {
 
 class CapturedMouseImpl : public CapturedMouseInterface {
  public:
-  CapturedMouseImpl(std::function<void(void)> callback) : callback_(callback) {}
+  explicit CapturedMouseImpl(std::function<void(void)> callback)
+      : callback_(std::move(callback)) {}
   ~CapturedMouseImpl() override { callback_(); }
+  CapturedMouseImpl(const CapturedMouseImpl&) = delete;
+  CapturedMouseImpl(CapturedMouseImpl&&) = delete;
+  CapturedMouseImpl& operator=(const CapturedMouseImpl&) = delete;
+  CapturedMouseImpl& operator=(CapturedMouseImpl&&) = delete;
 
  private:
   std::function<void(void)> callback_;
 };
 
 void AnimationListener(std::atomic<bool>* quit, Sender<Task> out) {
+  // Animation at around 60fps.
+  const auto time_delta = std::chrono::milliseconds(15);
   while (!*quit) {
     out->Send(AnimationTask());
-    std::this_thread::sleep_for(std::chrono::milliseconds(15));
+    std::this_thread::sleep_for(time_delta);
   }
 }
 
@@ -286,31 +295,36 @@ ScreenInteractive ScreenInteractive::FitComponent() {
 }
 
 void ScreenInteractive::Post(Task task) {
-  if (!quit_)
+  if (!quit_) {
-    task_sender_->Send(task);
+    task_sender_->Send(std::move(task));
+  }
 }
 void ScreenInteractive::PostEvent(Event event) {
   Post(event);
 }
 
 void ScreenInteractive::RequestAnimationFrame() {
-  if (animation_requested_)
+  if (animation_requested_) {
     return;
+  }
   animation_requested_ = true;
   auto now = animation::Clock::now();
-  if (now - previous_animation_time >= std::chrono::milliseconds(33))
+  const auto time_histeresis = std::chrono::milliseconds(33);
+  if (now - previous_animation_time >= time_histeresis) {
     previous_animation_time = now;
+  }
 }
 
 CapturedMouse ScreenInteractive::CaptureMouse() {
-  if (mouse_captured)
+  if (mouse_captured) {
     return nullptr;
+  }
   mouse_captured = true;
   return std::make_unique<CapturedMouseImpl>(
       [this] { mouse_captured = false; });
 }
 
-void ScreenInteractive::Loop(Component component) {
+void ScreenInteractive::Loop(Component component) {  // NOLINT
   // Suspend previously active screen:
   if (g_active_screen) {
     std::swap(suspended_screen_, g_active_screen);
@@ -324,7 +338,7 @@ void ScreenInteractive::Loop(Component component) {
   // This screen is now active:
   g_active_screen = this;
   g_active_screen->Install();
-  g_active_screen->Main(component);
+  g_active_screen->Main(std::move(component));
   g_active_screen->Uninstall();
   g_active_screen = nullptr;
 
@@ -348,7 +362,7 @@ void ScreenInteractive::Loop(Component component) {
 /// @brief Decorate a function. It executes the same way, but with the currently
 /// active screen terminal hooks temporarilly uninstalled during its execution.
 /// @param fn The function to decorate.
-Closure ScreenInteractive::WithRestoredIO(Closure fn) {
+Closure ScreenInteractive::WithRestoredIO(Closure fn) {  // NOLINT
   return [this, fn] {
     Uninstall();
     fn();
@@ -370,8 +384,9 @@ void ScreenInteractive::Install() {
 
   // Install signal handlers to restore the terminal state on exit. The default
   // signal handlers are restored on exit.
-  for (int signal : {SIGTERM, SIGSEGV, SIGINT, SIGILL, SIGABRT, SIGFPE})
+  for (int signal : {SIGTERM, SIGSEGV, SIGINT, SIGILL, SIGABRT, SIGFPE}) {
     install_signal_handler(signal, OnExit);
+  }
 
   // Save the old terminal configuration and restore it on exit.
 #if defined(_WIN32)
@@ -405,12 +420,12 @@ void ScreenInteractive::Install() {
   SetConsoleMode(stdin_handle, in_mode);
   SetConsoleMode(stdout_handle, out_mode);
 #else
-  struct termios terminal;
+  struct termios terminal;  // NOLINT
   tcgetattr(STDIN_FILENO, &terminal);
   on_exit_functions.push([=] { tcsetattr(STDIN_FILENO, TCSANOW, &terminal); });
 
-  terminal.c_lflag &= ~ICANON;  // Non canonique terminal.
+  terminal.c_lflag &= ~ICANON;  // NOLINT Non canonique terminal.
-  terminal.c_lflag &= ~ECHO;    // Do not print after a key press.
+  terminal.c_lflag &= ~ECHO;    // NOLINT Do not print after a key press.
   terminal.c_cc[VMIN] = 0;
   terminal.c_cc[VTIME] = 0;
   // auto oldf = fcntl(STDIN_FILENO, F_GETFL, 0);
@@ -420,19 +435,19 @@ void ScreenInteractive::Install() {
   tcsetattr(STDIN_FILENO, TCSANOW, &terminal);
 
   // Handle resize.
-  on_resize = [&] { task_sender_->Send(Event::Special({0})); };
+  g_on_resize = [&] { task_sender_->Send(Event::Special({0})); };
   install_signal_handler(SIGWINCH, OnResize);
 
   // Handle SIGTSTP/SIGCONT.
   install_signal_handler(SIGTSTP, OnSigStop);
 #endif
 
-  auto enable = [&](std::vector<DECMode> parameters) {
+  auto enable = [&](const std::vector<DECMode>& parameters) {
     std::cout << Set(parameters);
     on_exit_functions.push([=] { std::cout << Reset(parameters); });
   };
 
-  auto disable = [&](std::vector<DECMode> parameters) {
+  auto disable = [&](const std::vector<DECMode>& parameters) {
     std::cout << Reset(parameters);
     on_exit_functions.push([=] { std::cout << Set(parameters); });
   };
@@ -475,6 +490,7 @@ void ScreenInteractive::Uninstall() {
   OnExit(0);
 }
 
+// NOLINTNEXTLINE
 void ScreenInteractive::Main(Component component) {
   previous_animation_time = animation::Clock::now();
 
@@ -493,8 +509,9 @@ void ScreenInteractive::Main(Component component) {
     }
 
     Task task;
-    if (!task_receiver_->Receive(&task))
+    if (!task_receiver_->Receive(&task)) {
       break;
+    }
 
     // clang-format off
     std::visit([&](auto&& arg) {
@@ -527,8 +544,9 @@ void ScreenInteractive::Main(Component component) {
 
       // Handle Animation
       if constexpr (std::is_same_v<T, AnimationTask>) {
-        if (!animation_requested_)
+        if (!animation_requested_) {
           return;
+        }
 
         animation_requested_ = false;
         animation::TimePoint now = animation::Clock::now();
@@ -546,6 +564,7 @@ void ScreenInteractive::Main(Component component) {
   }
 }
 
+// NOLINTNEXTLINE
 void ScreenInteractive::Draw(Component component) {
   auto document = component->Render();
   int dimx = 0;
@@ -596,13 +615,16 @@ void ScreenInteractive::Draw(Component component) {
   // https://github.com/ArthurSonzogni/FTXUI/issues/136
   static int i = -3;
   ++i;
-  if (!use_alternative_screen_ && (i % 150 == 0))
+  if (!use_alternative_screen_ && (i % 150 == 0)) {  // NOLINT
     std::cout << DeviceStatusReport(DSRMode::kCursor);
+  }
 #else
   static int i = -3;
   ++i;
-  if (!use_alternative_screen_ && (previous_frame_resized_ || i % 40 == 0))
+  if (!use_alternative_screen_ &&
+      (previous_frame_resized_ || i % 40 == 0)) {  // NOLINT
     std::cout << DeviceStatusReport(DSRMode::kCursor);
+  }
 #endif
   previous_frame_resized_ = resized;
 

src/ftxui/component/slider.cpp

@@ -18,13 +18,13 @@ template <class T>
 class SliderBase : public ComponentBase {
  public:
   SliderBase(ConstStringRef label, T* value, T min, T max, T increment)
-      : label_(label),
+      : label_(std::move(label)),
         value_(value),
         min_(min),
         max_(max),
         increment_(increment) {}
 
-  Element Render() {
+  Element Render() override {
     auto gauge_color =
         Focused() ? color(Color::GrayLight) : color(Color::GrayDark);
     float percent = float(*value_ - min_) / float(max_ - min_);
@@ -40,8 +40,9 @@ class SliderBase : public ComponentBase {
   }
 
   bool OnEvent(Event event) final {
-    if (event.is_mouse())
+    if (event.is_mouse()) {
       return OnMouseEvent(event);
+    }
 
     if (event == Event::ArrowLeft || event == Event::Character('h')) {
       *value_ -= increment_;

src/ftxui/component/terminal_input_parser.cpp

@@ -14,11 +14,14 @@ TerminalInputParser::TerminalInputParser(Sender<Task> out)
 
 void TerminalInputParser::Timeout(int time) {
   timeout_ += time;
-  if (timeout_ < 50)
+  const int timeout_threshold = 50;
+  if (timeout_ < timeout_threshold) {
     return;
+  }
   timeout_ = 0;
-  if (pending_.size())
+  if (!pending_.empty()) {
     Send(SPECIAL);
+  }
 }
 
 void TerminalInputParser::Add(char c) {
@@ -56,21 +59,23 @@ void TerminalInputParser::Send(TerminalInputParser::Output output) {
       // key. This also happens with linux with the `bind` command:
       // See https://github.com/ArthurSonzogni/FTXUI/issues/337
       // Here, we uniformize the new line character to `\n`.
-      if (pending_ == "\r")
+      if (pending_ == "\r") {
         out_->Send(Event::Special("\n"));
-      else
+      } else {
         out_->Send(Event::Special(std::move(pending_)));
+      }
       pending_.clear();
       return;
 
     case MOUSE:
-      out_->Send(Event::Mouse(std::move(pending_), output.mouse));
+      out_->Send(Event::Mouse(std::move(pending_), output.mouse));  // NOLINT
       pending_.clear();
       return;
 
     case CURSOR_REPORTING:
-      out_->Send(Event::CursorReporting(std::move(pending_), output.cursor.x,
+      out_->Send(Event::CursorReporting(std::move(pending_),  // NOLINT
-                                        output.cursor.y));
+                                        output.cursor.x,      // NOLINT
+                                        output.cursor.y));    // NOLINT
       pending_.clear();
       return;
   }
@@ -78,12 +83,13 @@ void TerminalInputParser::Send(TerminalInputParser::Output output) {
 }
 
 TerminalInputParser::Output TerminalInputParser::Parse() {
-  if (!Eat())
+  if (!Eat()) {
     return UNCOMPLETED;
+  }
 
   switch (Current()) {
-    case 24:  // CAN
+    case 24:  // CAN NOLINT
-    case 26:  // SUB
+    case 26:  // SUB NOLINT
       return DROP;
 
     case '\x1B':
@@ -92,11 +98,13 @@ TerminalInputParser::Output TerminalInputParser::Parse() {
       break;
   }
 
-  if (Current() < 32)  // C0
+  if (Current() < 32) {  // C0 NOLINT
     return SPECIAL;
+  }
 
-  if (Current() == 127)  // Delete
+  if (Current() == 127) {  // Delete // NOLINT
     return SPECIAL;
+  }
 
   return ParseUTF8();
 }
@@ -118,18 +126,18 @@ TerminalInputParser::Output TerminalInputParser::Parse() {
 // Then some sequences are illegal if it exist a shorter representation of the
 // same codepoint.
 TerminalInputParser::Output TerminalInputParser::ParseUTF8() {
-  unsigned char head = static_cast<unsigned char>(Current());
+  auto head = static_cast<unsigned char>(Current());
-  unsigned char selector = 0b1000'0000;
+  unsigned char selector = 0b1000'0000;  // NOLINT
 
   // The non code-point part of the first byte.
   unsigned char mask = selector;
 
   // Find the first zero in the first byte.
-  int first_zero = 8;
+  unsigned int first_zero = 8;            // NOLINT
-  for (int i = 0; i < 8; ++i) {
+  for (unsigned int i = 0; i < 8; ++i) {  // NOLINT
     mask |= selector;
     if (head & selector) {
-      selector >>= 1;
+      selector >>= 1U;
       continue;
     }
     first_zero = i;
@@ -137,48 +145,54 @@ TerminalInputParser::Output TerminalInputParser::ParseUTF8() {
   }
 
   // Accumulate the value of the first byte.
-  uint32_t value = head & ~mask;
+  auto value = uint32_t(head & ~mask);  // NOLINT
 
   // Invalid UTF8, with more than 5 bytes.
-  if (first_zero == 1 || first_zero >= 5)
+  const unsigned int max_utf8_bytes = 5;
+  if (first_zero == 1 || first_zero >= max_utf8_bytes) {
     return DROP;
+  }
 
   // Multi byte UTF-8.
-  for (int i = 2; i <= first_zero; ++i) {
+  for (unsigned int i = 2; i <= first_zero; ++i) {
-    if (!Eat())
+    if (!Eat()) {
       return UNCOMPLETED;
+    }
 
     // Invalid continuation byte.
     head = static_cast<unsigned char>(Current());
-    if ((head & 0b1100'0000) != 0b1000'0000)
+    if ((head & 0b1100'0000) != 0b1000'0000) {  // NOLINT
       return DROP;
-    value <<= 6;
+    }
-    value += head & 0b0011'1111;
+    value <<= 6;                  // NOLINT
+    value += head & 0b0011'1111;  // NOLINT
   }
 
   // Check for overlong UTF8 encoding.
-  int extra_byte;
+  int extra_byte = 0;
-  if (value <= 0b000'0000'0111'1111) {
+  if (value <= 0b000'0000'0111'1111) {                 // NOLINT
-    extra_byte = 0;
+    extra_byte = 0;                                    // NOLINT
-  } else if (value <= 0b000'0111'1111'1111) {
+  } else if (value <= 0b000'0111'1111'1111) {          // NOLINT
-    extra_byte = 1;
+    extra_byte = 1;                                    // NOLINT
-  } else if (value <= 0b1111'1111'1111'1111) {
+  } else if (value <= 0b1111'1111'1111'1111) {         // NOLINT
-    extra_byte = 2;
+    extra_byte = 2;                                    // NOLINT
-  } else if (value <= 0b1'0000'1111'1111'1111'1111) {
+  } else if (value <= 0b1'0000'1111'1111'1111'1111) {  // NOLINT
-    extra_byte = 3;
+    extra_byte = 3;                                    // NOLINT
-  } else {
+  } else {                                             // NOLINT
     return DROP;
   }
 
-  if (extra_byte != position_)
+  if (extra_byte != position_) {
     return DROP;
+  }
 
   return CHARACTER;
 }
 
 TerminalInputParser::Output TerminalInputParser::ParseESC() {
-  if (!Eat())
+  if (!Eat()) {
     return UNCOMPLETED;
+  }
   switch (Current()) {
     case 'P':
       return ParseDCS();
@@ -187,26 +201,32 @@ TerminalInputParser::Output TerminalInputParser::ParseESC() {
     case ']':
       return ParseOSC();
     default:
-      if (!Eat())
+      if (!Eat()) {
         return UNCOMPLETED;
+      } else {
         return SPECIAL;
       }
+  }
 }
 
 TerminalInputParser::Output TerminalInputParser::ParseDCS() {
   // Parse until the string terminator ST.
-  while (1) {
+  while (true) {
-    if (!Eat())
+    if (!Eat()) {
       return UNCOMPLETED;
+    }
 
-    if (Current() != '\x1B')
+    if (Current() != '\x1B') {
       continue;
+    }
 
-    if (!Eat())
+    if (!Eat()) {
       return UNCOMPLETED;
+    }
 
-    if (Current() != '\\')
+    if (Current() != '\\') {
       continue;
+    }
 
     return SPECIAL;
   }
@@ -217,8 +237,9 @@ TerminalInputParser::Output TerminalInputParser::ParseCSI() {
   int argument = 0;
   std::vector<int> arguments;
   while (true) {
-    if (!Eat())
+    if (!Eat()) {
       return UNCOMPLETED;
+    }
 
     if (Current() == '<') {
       altered = true;
@@ -226,7 +247,7 @@ TerminalInputParser::Output TerminalInputParser::ParseCSI() {
     }
 
     if (Current() >= '0' && Current() <= '9') {
-      argument *= 10;
+      argument *= 10;  // NOLINT
       argument += int(Current() - '0');
       continue;
     }
@@ -239,7 +260,7 @@ TerminalInputParser::Output TerminalInputParser::ParseCSI() {
 
     if (Current() >= ' ' && Current() <= '~' && Current() != '<') {
       arguments.push_back(argument);
-      argument = 0;
+      argument = 0;  // NOLINT
       switch (Current()) {
         case 'M':
           return ParseMouse(altered, true, std::move(arguments));
@@ -253,53 +274,61 @@ TerminalInputParser::Output TerminalInputParser::ParseCSI() {
     }
 
     // Invalid ESC in CSI.
-    if (Current() == '\x1B')
+    if (Current() == '\x1B') {
       return SPECIAL;
     }
+  }
 }
 
 TerminalInputParser::Output TerminalInputParser::ParseOSC() {
   // Parse until the string terminator ST.
   while (true) {
-    if (!Eat())
+    if (!Eat()) {
       return UNCOMPLETED;
-    if (Current() != '\x1B')
+    }
+    if (Current() != '\x1B') {
       continue;
-    if (!Eat())
+    }
+    if (!Eat()) {
       return UNCOMPLETED;
-    if (Current() != '\\')
+    }
+    if (Current() != '\\') {
       continue;
+    }
     return SPECIAL;
   }
 }
 
-TerminalInputParser::Output TerminalInputParser::ParseMouse(
+TerminalInputParser::Output TerminalInputParser::ParseMouse(  // NOLINT
     bool altered,
     bool pressed,
     std::vector<int> arguments) {
-  if (arguments.size() != 3)
+  if (arguments.size() != 3) {
     return SPECIAL;
+  }
 
   (void)altered;
 
   Output output(MOUSE);
-  output.mouse.button = Mouse::Button((arguments[0] & 3) +  //
+  output.mouse.button = Mouse::Button((arguments[0] & 3) +          // NOLINT
-                                      ((arguments[0] & 64) >> 4));
+                                      ((arguments[0] & 64) >> 4));  // NOLINT
-  output.mouse.motion = Mouse::Motion(pressed);
+  output.mouse.motion = Mouse::Motion(pressed);                     // NOLINT
-  output.mouse.shift = bool(arguments[0] & 4);
+  output.mouse.shift = bool(arguments[0] & 4);                      // NOLINT
-  output.mouse.meta = bool(arguments[0] & 8);
+  output.mouse.meta = bool(arguments[0] & 8);                       // NOLINT
-  output.mouse.x = arguments[1];
+  output.mouse.x = arguments[1];                                    // NOLINT
-  output.mouse.y = arguments[2];
+  output.mouse.y = arguments[2];                                    // NOLINT
   return output;
 }
 
+// NOLINTNEXTLINE
 TerminalInputParser::Output TerminalInputParser::ParseCursorReporting(
     std::vector<int> arguments) {
-  if (arguments.size() != 2)
+  if (arguments.size() != 2) {
     return SPECIAL;
+  }
   Output output(CURSOR_REPORTING);
-  output.cursor.y = arguments[0];
+  output.cursor.y = arguments[0];  // NOLINT
-  output.cursor.x = arguments[1];
+  output.cursor.x = arguments[1];  // NOLINT
   return output;
 }
 

src/ftxui/component/terminal_input_parser.hpp

@@ -48,7 +48,7 @@ class TerminalInputParser {
     Output(Type t) : type(t) {}
   };
 
-  void Send(Output type);
+  void Send(Output output);
   Output Parse();
   Output ParseUTF8();
   Output ParseESC();

src/ftxui/component/util.cpp

@@ -5,21 +5,25 @@
 
 namespace ftxui {
 
+// NOLINTNEXTLINE
 Component operator|(Component component, ComponentDecorator decorator) {
-  return decorator(component);
+  return decorator(component);  // NOLINT
 }
 
+// NOLINTNEXTLINE
 Component operator|(Component component, ElementDecorator decorator) {
-  return component | Renderer(decorator);
+  return component | Renderer(decorator);  // NOLINT
 }
 
+// NOLINTNEXTLINE
 Component& operator|=(Component& component, ComponentDecorator decorator) {
-  component = component | decorator;
+  component = component | decorator;  // NOLINT
   return component;
 }
 
+// NOLINTNEXTLINE
 Component& operator|=(Component& component, ElementDecorator decorator) {
-  component = component | decorator;
+  component = component | decorator;  // NOLINT
   return component;
 }
 

src/ftxui/dom/border.cpp

@@ -1,9 +1,9 @@
 #include <algorithm>  // for max
-#include <iterator>   // for begin, end
+#include <array>      // for array
 #include <memory>     // for allocator, make_shared, __shared_ptr_access
-#include <string>     // for string, basic_string
+#include <string>     // for basic_string, string
 #include <utility>    // for move
-#include <vector>     // for vector, __alloc_traits<>::value_type
+#include <vector>     // for __alloc_traits<>::value_type
 
 #include "ftxui/dom/elements.hpp"  // for unpack, Element, Decorator, BorderStyle, ROUNDED, Elements, DOUBLE, EMPTY, HEAVY, LIGHT, border, borderDouble, borderEmpty, borderHeavy, borderLight, borderRounded, borderStyled, borderWith, window
 #include "ftxui/dom/node.hpp"      // for Node, Elements
@@ -13,30 +13,25 @@
 
 namespace ftxui {
 
-static std::string simple_border_charset[6][6] = {
+using Charset = std::array<std::string, 6>;  // NOLINT
-    {"┌", "┐", "└", "┘", "─", "│"},  //
+using Charsets = std::array<Charset, 6>;     // NOLINT
-    {"┏", "┓", "┗", "┛", "━", "┃"},  //
+static Charsets simple_border_charset =      // NOLINT
-    {"╔", "╗", "╚", "╝", "═", "║"},  //
+    {
-    {"╭", "╮", "╰", "╯", "─", "│"},  //
+        Charset{"┌", "┐", "└", "┘", "─", "│"},
-    {" ", " ", " ", " ", " ", " "},  //
+        Charset{"┏", "┓", "┗", "┛", "━", "┃"},
+        Charset{"╔", "╗", "╚", "╝", "═", "║"},
+        Charset{"╭", "╮", "╰", "╯", "─", "│"},
+        Charset{" ", " ", " ", " ", " ", " "},
 };
 
 // For reference, here is the charset for normal border:
-// {"┌", "┐", "└", "┘", "─", "│", "┬", "┴", "┤", "├"};
-// TODO(arthursonzogni): Consider adding options to choose the kind of borders
-// to use.
-
 class Border : public Node {
  public:
   Border(Elements children, BorderStyle style)
       : Node(std::move(children)),
-        charset(std::begin(simple_border_charset[style]),
+        charset_(simple_border_charset[style]) {}  // NOLINT
-                std::end(simple_border_charset[style])) {}
-  Border(Elements children, Pixel pixel)
-      : Node(std::move(children)), charset_pixel(10, pixel) {}
 
-  std::vector<Pixel> charset_pixel;
+  const Charset& charset_;  // NOLINT
-  std::vector<std::string> charset;
 
   void ComputeRequirement() override {
     Node::ComputeRequirement();
@@ -75,63 +70,101 @@ class Border : public Node {
     children_[0]->Render(screen);
 
     // Draw the border.
-    if (box_.x_min >= box_.x_max || box_.y_min >= box_.y_max)
+    if (box_.x_min >= box_.x_max || box_.y_min >= box_.y_max) {
       return;
-
-    if (!charset.empty())
-      RenderPixel(screen);
-    else
-      RenderChar(screen);
     }
 
-  void RenderPixel(Screen& screen) {
+    screen.at(box_.x_min, box_.y_min) = charset_[0];  // NOLINT
-    screen.at(box_.x_min, box_.y_min) = charset[0];
+    screen.at(box_.x_max, box_.y_min) = charset_[1];  // NOLINT
-    screen.at(box_.x_max, box_.y_min) = charset[1];
+    screen.at(box_.x_min, box_.y_max) = charset_[2];  // NOLINT
-    screen.at(box_.x_min, box_.y_max) = charset[2];
+    screen.at(box_.x_max, box_.y_max) = charset_[3];  // NOLINT
-    screen.at(box_.x_max, box_.y_max) = charset[3];
 
-    for (float x = box_.x_min + 1; x < box_.x_max; ++x) {
+    for (int x = box_.x_min + 1; x < box_.x_max; ++x) {
       Pixel& p1 = screen.PixelAt(x, box_.y_min);
       Pixel& p2 = screen.PixelAt(x, box_.y_max);
-      p1.character = charset[4];
+      p1.character = charset_[4];  // NOLINT
-      p2.character = charset[4];
+      p2.character = charset_[4];  // NOLINT
       p1.automerge = true;
       p2.automerge = true;
     }
-    for (float y = box_.y_min + 1; y < box_.y_max; ++y) {
+    for (int y = box_.y_min + 1; y < box_.y_max; ++y) {
       Pixel& p3 = screen.PixelAt(box_.x_min, y);
       Pixel& p4 = screen.PixelAt(box_.x_max, y);
-      p3.character = charset[5];
+      p3.character = charset_[5];  // NOLINT
-      p4.character = charset[5];
+      p4.character = charset_[5];  // NOLINT
       p3.automerge = true;
       p4.automerge = true;
     }
 
     // Draw title.
-    if (children_.size() == 2)
+    if (children_.size() == 2) {
       children_[1]->Render(screen);
     }
-
-  void RenderChar(Screen& screen) {
-    screen.PixelAt(box_.x_min, box_.y_min) = charset_pixel[0];
-    screen.PixelAt(box_.x_max, box_.y_min) = charset_pixel[1];
-    screen.PixelAt(box_.x_min, box_.y_max) = charset_pixel[2];
-    screen.PixelAt(box_.x_max, box_.y_max) = charset_pixel[3];
-    for (float x = box_.x_min + 1; x < box_.x_max; ++x) {
-      Pixel& p1 = screen.PixelAt(x, box_.y_min);
-      Pixel& p2 = screen.PixelAt(x, box_.y_max);
-      p1 = charset_pixel[5];
-      p2 = charset_pixel[5];
-      p1.automerge = true;
-      p2.automerge = true;
   }
-    for (float y = box_.y_min + 1; y < box_.y_max; ++y) {
+};
-      Pixel& p3 = screen.PixelAt(box_.x_min, y);
+
-      Pixel& p4 = screen.PixelAt(box_.x_max, y);
+// For reference, here is the charset for normal border:
-      p3 = charset_pixel[5];
+class BorderPixel : public Node {
-      p4 = charset_pixel[5];
+ public:
-      p3.automerge = true;
+  BorderPixel(Elements children, Pixel pixel)
-      p4.automerge = true;
+      : Node(std::move(children)), pixel_(std::move(pixel)) {}
+
+ private:
+  Pixel pixel_;
+
+  void ComputeRequirement() override {
+    Node::ComputeRequirement();
+    requirement_ = children_[0]->requirement();
+    requirement_.min_x += 2;
+    requirement_.min_y += 2;
+    if (children_.size() == 2) {
+      requirement_.min_x =
+          std::max(requirement_.min_x, children_[1]->requirement().min_x + 2);
+    }
+    requirement_.selected_box.x_min++;
+    requirement_.selected_box.x_max++;
+    requirement_.selected_box.y_min++;
+    requirement_.selected_box.y_max++;
+  }
+
+  void SetBox(Box box) override {
+    Node::SetBox(box);
+    if (children_.size() == 2) {
+      Box title_box;
+      title_box.x_min = box.x_min + 1;
+      title_box.x_max = box.x_max - 1;
+      title_box.y_min = box.y_min;
+      title_box.y_max = box.y_min;
+      children_[1]->SetBox(title_box);
+    }
+    box.x_min++;
+    box.x_max--;
+    box.y_min++;
+    box.y_max--;
+    children_[0]->SetBox(box);
+  }
+
+  void Render(Screen& screen) override {
+    // Draw content.
+    children_[0]->Render(screen);
+
+    // Draw the border.
+    if (box_.x_min >= box_.x_max || box_.y_min >= box_.y_max) {
+      return;
+    }
+
+    screen.PixelAt(box_.x_min, box_.y_min) = pixel_;
+    screen.PixelAt(box_.x_max, box_.y_min) = pixel_;
+    screen.PixelAt(box_.x_min, box_.y_max) = pixel_;
+    screen.PixelAt(box_.x_max, box_.y_max) = pixel_;
+
+    for (int x = box_.x_min + 1; x < box_.x_max; ++x) {
+      screen.PixelAt(x, box_.y_min) = pixel_;
+      screen.PixelAt(x, box_.y_max) = pixel_;
+    }
+    for (int y = box_.y_min + 1; y < box_.y_max; ++y) {
+      screen.PixelAt(box_.x_min, y) = pixel_;
+      screen.PixelAt(box_.x_max, y) = pixel_;
     }
   }
 };
@@ -171,9 +204,9 @@ Element border(Element child) {
 /// @brief Same as border but with a constant Pixel around the element.
 /// @ingroup dom
 /// @see border
-Decorator borderWith(Pixel pixel) {
+Decorator borderWith(const Pixel& pixel) {
   return [pixel](Element child) {
-    return std::make_shared<Border>(unpack(std::move(child)), pixel);
+    return std::make_shared<BorderPixel>(unpack(std::move(child)), pixel);
   };
 }
 

src/ftxui/dom/box_helper.cpp

@@ -2,8 +2,7 @@
 
 #include <algorithm>  // for max
 
-namespace ftxui {
+namespace ftxui::box_helper {
-namespace box_helper {
 
 namespace {
 // Called when the size allowed is greater than the requested size. This
@@ -44,7 +43,7 @@ void ComputeShrinkHard(std::vector<Element>* elements,
                        int extra_space,
                        int size) {
   for (Element& element : *elements) {
-    if (element.flex_shrink) {
+    if (element.flex_shrink != 0) {
       element.size = 0;
       continue;
     }
@@ -68,23 +67,25 @@ void Compute(std::vector<Element>* elements, int target_size) {
   for (auto& element : *elements) {
     flex_grow_sum += element.flex_grow;
     flex_shrink_sum += element.min_size * element.flex_shrink;
-    if (element.flex_shrink)
+    if (element.flex_shrink != 0) {
       flex_shrink_size += element.min_size;
+    }
     size += element.min_size;
   }
 
   int extra_space = target_size - size;
-  if (extra_space >= 0)
+  if (extra_space >= 0) {
     ComputeGrow(elements, extra_space, flex_grow_sum);
-  else if (flex_shrink_size + extra_space >= 0)
+  } else if (flex_shrink_size + extra_space >= 0) {
     ComputeShrinkEasy(elements, extra_space, flex_shrink_sum);
-  else
+
+  } else {
     ComputeShrinkHard(elements, extra_space + flex_shrink_size,
                       size - flex_shrink_size);
+  }
 }
 
-}  // namespace box_helper
+}  // namespace ftxui::box_helper
-}  // namespace ftxui
 
 // Copyright 2021 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

src/ftxui/dom/canvas.cpp

@@ -1,8 +1,8 @@
 #include "ftxui/dom/canvas.hpp"
 
-#include <stdlib.h>   // for abs
 #include <algorithm>  // for max, min
 #include <cstdint>    // for uint8_t
+#include <cstdlib>    // for abs
 #include <map>        // for allocator, map
 #include <memory>     // for make_shared
 #include <utility>    // for move, pair
@@ -42,26 +42,29 @@ namespace {
 // 11100010 10100000 10100000 // dot6
 // 11100010 10100010 10000000 // dot0-2
 
+// NOLINTNEXTLINE
 uint8_t g_map_braille[2][4][2] = {
     {
-        {0b00000000, 0b00000001},  // dot1
+        {0b00000000, 0b00000001},  // NOLINT | dot1
-        {0b00000000, 0b00000010},  // dot2
+        {0b00000000, 0b00000010},  // NOLINT | dot2
-        {0b00000000, 0b00000100},  // dot3
+        {0b00000000, 0b00000100},  // NOLINT | dot3
-        {0b00000001, 0b00000000},  // dot0-1
+        {0b00000001, 0b00000000},  // NOLINT | dot0-1
     },
     {
-        {0b00000000, 0b00001000},  // dot4
+        {0b00000000, 0b00001000},  // NOLINT | dot4
-        {0b00000000, 0b00010000},  // dot5
+        {0b00000000, 0b00010000},  // NOLINT | dot5
-        {0b00000000, 0b00100000},  // dot6
+        {0b00000000, 0b00100000},  // NOLINT | dot6
-        {0b00000010, 0b00000000},  // dot0-2
+        {0b00000010, 0b00000000},  // NOLINT | dot0-2
     },
 };
 
+// NOLINTNEXTLINE
 std::vector<std::string> g_map_block = {
     " ", "▘", "▖", "▌", "▝", "▀", "▞", "▛",
     "▗", "▚", "▄", "▙", "▐", "▜", "▟", "█",
 };
 
+// NOLINTNEXTLINE
 const std::map<std::string, uint8_t> g_map_block_inversed = {
     {" ", 0b0000}, {"▘", 0b0001}, {"▖", 0b0010}, {"▌", 0b0011},
     {"▝", 0b0100}, {"▀", 0b0101}, {"▞", 0b0110}, {"▛", 0b0111},
@@ -69,13 +72,17 @@ const std::map<std::string, uint8_t> g_map_block_inversed = {
     {"▐", 0b1100}, {"▜", 0b1101}, {"▟", 0b1110}, {"█", 0b1111},
 };
 
+constexpr auto nostyle = [](Pixel& /*pixel*/) {};
+
 }  // namespace
 
 /// @brief Constructor.
 /// @param width the width of the canvas. A cell is a 2x8 braille dot.
 /// @param height the height of the canvas. A cell is a 2x8 braille dot.
 Canvas::Canvas(int width, int height)
-    : width_(width), height_(height), storage_(width_ * height_ / 8) {}
+    : width_(width),
+      height_(height),
+      storage_(width_ * height_ / 8 /* NOLINT */) {}
 
 /// @brief Get the content of a cell.
 /// @param x the x coordinate of the cell.
@@ -90,7 +97,7 @@ Pixel Canvas::GetPixel(int x, int y) const {
 /// @param y the y coordinate of the dot.
 /// @param value whether the dot is filled or not.
 void Canvas::DrawPoint(int x, int y, bool value) {
-  DrawPoint(x, y, value, [](Pixel&) {});
+  DrawPoint(x, y, value, [](Pixel& /*pixel*/) {});
 }
 
 /// @brief Draw a braille dot.
@@ -109,42 +116,45 @@ void Canvas::DrawPoint(int x, int y, bool value, const Color& color) {
 /// @param style the style of the cell.
 void Canvas::DrawPoint(int x, int y, bool value, const Stylizer& style) {
   Style(x, y, style);
-  if (value)
+  if (value) {
     DrawPointOn(x, y);
-  else
+  } else {
     DrawPointOff(x, y);
+  }
 }
 
 /// @brief Draw a braille dot.
 /// @param x the x coordinate of the dot.
 /// @param y the y coordinate of the dot.
 void Canvas::DrawPointOn(int x, int y) {
-  if (!IsIn(x, y))
+  if (!IsIn(x, y)) {
     return;
+  }
   Cell& cell = storage_[XY{x / 2, y / 4}];
   if (cell.type != CellType::kBraille) {
     cell.content.character = "⠀";  // 3 bytes.
     cell.type = CellType::kBraille;
   }
 
-  cell.content.character[1] |= g_map_braille[x % 2][y % 4][0];
+  cell.content.character[1] |= g_map_braille[x % 2][y % 4][0];  // NOLINT
-  cell.content.character[2] |= g_map_braille[x % 2][y % 4][1];
+  cell.content.character[2] |= g_map_braille[x % 2][y % 4][1];  // NOLINT
 }
 
 /// @brief Erase a braille dot.
 /// @param x the x coordinate of the dot.
 /// @param y the y coordinate of the dot.
 void Canvas::DrawPointOff(int x, int y) {
-  if (!IsIn(x, y))
+  if (!IsIn(x, y)) {
     return;
+  }
   Cell& cell = storage_[XY{x / 2, y / 4}];
   if (cell.type != CellType::kBraille) {
     cell.content.character = "⠀";  // 3 byt
     cell.type = CellType::kBraille;
   }
 
-  cell.content.character[1] &= ~(g_map_braille[x % 2][y % 4][0]);
+  cell.content.character[1] &= ~(g_map_braille[x % 2][y % 4][0]);  // NOLINT
-  cell.content.character[2] &= ~(g_map_braille[x % 2][y % 4][1]);
+  cell.content.character[2] &= ~(g_map_braille[x % 2][y % 4][1]);  // NOLINT
 }
 
 /// @brief Toggle a braille dot. A filled one will be erased, and the other will
@@ -152,16 +162,17 @@ void Canvas::DrawPointOff(int x, int y) {
 /// @param x the x coordinate of the dot.
 /// @param y the y coordinate of the dot.
 void Canvas::DrawPointToggle(int x, int y) {
-  if (!IsIn(x, y))
+  if (!IsIn(x, y)) {
     return;
+  }
   Cell& cell = storage_[XY{x / 2, y / 4}];
   if (cell.type != CellType::kBraille) {
     cell.content.character = "⠀";  // 3 byt
     cell.type = CellType::kBraille;
   }
 
-  cell.content.character[1] ^= g_map_braille[x % 2][y % 4][0];
+  cell.content.character[1] ^= g_map_braille[x % 2][y % 4][0];  // NOLINT
-  cell.content.character[2] ^= g_map_braille[x % 2][y % 4][1];
+  cell.content.character[2] ^= g_map_braille[x % 2][y % 4][1];  // NOLINT
 }
 
 /// @brief Draw a line made of braille dots.
@@ -170,7 +181,7 @@ void Canvas::DrawPointToggle(int x, int y) {
 /// @param x2 the x coordinate of the second dot.
 /// @param y2 the y coordinate of the second dot.
 void Canvas::DrawPointLine(int x1, int y1, int x2, int y2) {
-  DrawPointLine(x1, y1, x2, y2, [](Pixel&) {});
+  DrawPointLine(x1, y1, x2, y2, [](Pixel& /*pixel*/) {});
 }
 
 /// @brief Draw a line made of braille dots.
@@ -201,10 +212,12 @@ void Canvas::DrawPointLine(int x1,
   const int sy = y1 < y2 ? 1 : -1;
   const int length = std::max(dx, dy);
 
-  if (!IsIn(x1, y1) && !IsIn(x2, y2))
+  if (!IsIn(x1, y1) && !IsIn(x2, y2)) {
     return;
-  if (dx + dx > width_ * height_)
+  }
+  if (dx + dx > width_ * height_) {
     return;
+  }
 
   int error = dx - dy;
   for (int i = 0; i < length; ++i) {
@@ -226,7 +239,7 @@ void Canvas::DrawPointLine(int x1,
 /// @param y the y coordinate of the center of the circle.
 /// @param radius the radius of the circle.
 void Canvas::DrawPointCircle(int x, int y, int radius) {
-  DrawPointCircle(x, y, radius, [](Pixel&) {});
+  DrawPointCircle(x, y, radius, [](Pixel& /*pixel*/) {});
 }
 
 /// @brief Draw a circle made of braille dots.
@@ -253,7 +266,7 @@ void Canvas::DrawPointCircle(int x, int y, int radius, const Stylizer& style) {
 /// @param y the y coordinate of the center of the circle.
 /// @param radius the radius of the circle.
 void Canvas::DrawPointCircleFilled(int x, int y, int radius) {
-  DrawPointCircleFilled(x, y, radius, [](Pixel&) {});
+  DrawPointCircleFilled(x, y, radius, [](Pixel& /*pixel*/) {});
 }
 
 /// @brief Draw a filled circle made of braille dots.
@@ -287,7 +300,7 @@ void Canvas::DrawPointCircleFilled(int x,
 /// @param r1 the radius of the ellipse along the x axis.
 /// @param r2 the radius of the ellipse along the y axis.
 void Canvas::DrawPointEllipse(int x, int y, int r1, int r2) {
-  DrawPointEllipse(x, y, r1, r2, [](Pixel&) {});
+  DrawPointEllipse(x, y, r1, r2, [](Pixel& /*pixel*/) {});
 }
 
 /// @brief Draw an ellipse made of braille dots.
@@ -351,7 +364,7 @@ void Canvas::DrawPointEllipse(int x1,
 /// @param r1 the radius of the ellipse along the x axis.
 /// @param r2 the radius of the ellipse along the y axis.
 void Canvas::DrawPointEllipseFilled(int x1, int y1, int r1, int r2) {
-  DrawPointEllipseFilled(x1, y1, r1, r2, [](Pixel&) {});
+  DrawPointEllipseFilled(x1, y1, r1, r2, [](Pixel& /*pixel*/) {});
 }
 
 /// @brief Draw a filled ellipse made of braille dots.
@@ -395,11 +408,11 @@ void Canvas::DrawPointEllipseFilled(int x1,
     e2 = 2 * err;
     if (e2 >= dx) {
       x++;
-      err += dx += 2 * (long)r2 * r2;
+      err += dx += 2 * (long)r2 * r2;  // NOLINT
     }
     if (e2 <= dy) {
       y++;
-      err += dy += 2 * (long)r1 * r1;
+      err += dy += 2 * (long)r1 * r1;  // NOLINT
     }
   } while (x <= 0);
 
@@ -415,7 +428,7 @@ void Canvas::DrawPointEllipseFilled(int x1,
 /// @param y the y coordinate of the block.
 /// @param value whether the block is filled or not.
 void Canvas::DrawBlock(int x, int y, bool value) {
-  DrawBlock(x, y, value, [](Pixel&) {});
+  DrawBlock(x, y, value, [](Pixel& /*pixel*/) {});
 }
 
 /// @brief Draw a block.
@@ -434,18 +447,20 @@ void Canvas::DrawBlock(int x, int y, bool value, const Color& color) {
 /// @param style the style of the block.
 void Canvas::DrawBlock(int x, int y, bool value, const Stylizer& style) {
   Style(x, y, style);
-  if (value)
+  if (value) {
     DrawBlockOn(x, y);
-  else
+  } else {
     DrawBlockOff(x, y);
+  }
 }
 
 /// @brief Draw a block.
 /// @param x the x coordinate of the block.
 /// @param y the y coordinate of the block.
 void Canvas::DrawBlockOn(int x, int y) {
-  if (!IsIn(x, y))
+  if (!IsIn(x, y)) {
     return;
+  }
   y /= 2;
   Cell& cell = storage_[XY{x / 2, y / 2}];
   if (cell.type != CellType::kBlock) {
@@ -453,9 +468,9 @@ void Canvas::DrawBlockOn(int x, int y) {
     cell.type = CellType::kBlock;
   }
 
-  int bit = (x % 2) * 2 + y % 2;
+  uint8_t bit = (x % 2) * 2 + y % 2;
   uint8_t value = g_map_block_inversed.at(cell.content.character);
-  value |= 1 << bit;
+  value |= 1U << bit;
   cell.content.character = g_map_block[value];
 }
 
@@ -463,8 +478,9 @@ void Canvas::DrawBlockOn(int x, int y) {
 /// @param x the x coordinate of the block.
 /// @param y the y coordinate of the block.
 void Canvas::DrawBlockOff(int x, int y) {
-  if (!IsIn(x, y))
+  if (!IsIn(x, y)) {
     return;
+  }
   Cell& cell = storage_[XY{x / 2, y / 4}];
   if (cell.type != CellType::kBlock) {
     cell.content.character = " ";
@@ -472,9 +488,9 @@ void Canvas::DrawBlockOff(int x, int y) {
   }
   y /= 2;
 
-  int bit = (y % 2) * 2 + x % 2;
+  uint8_t bit = (y % 2) * 2 + x % 2;
   uint8_t value = g_map_block_inversed.at(cell.content.character);
-  value &= ~(1 << bit);
+  value &= ~(1U << bit);
   cell.content.character = g_map_block[value];
 }
 
@@ -483,8 +499,9 @@ void Canvas::DrawBlockOff(int x, int y) {
 /// @param x the x coordinate of the block.
 /// @param y the y coordinate of the block.
 void Canvas::DrawBlockToggle(int x, int y) {
-  if (!IsIn(x, y))
+  if (!IsIn(x, y)) {
     return;
+  }
   Cell& cell = storage_[XY{x / 2, y / 4}];
   if (cell.type != CellType::kBlock) {
     cell.content.character = " ";
@@ -492,9 +509,9 @@ void Canvas::DrawBlockToggle(int x, int y) {
   }
   y /= 2;
 
-  int bit = (y % 2) * 2 + x % 2;
+  uint8_t bit = (y % 2) * 2 + x % 2;
   uint8_t value = g_map_block_inversed.at(cell.content.character);
-  value ^= 1 << bit;
+  value ^= 1U << bit;
   cell.content.character = g_map_block[value];
 }
 
@@ -504,7 +521,7 @@ void Canvas::DrawBlockToggle(int x, int y) {
 /// @param x2 the x coordinate of the second point of the line.
 /// @param y2 the y coordinate of the second point of the line.
 void Canvas::DrawBlockLine(int x1, int y1, int x2, int y2) {
-  DrawBlockLine(x1, y1, x2, y2, [](Pixel&) {});
+  DrawBlockLine(x1, y1, x2, y2, [](Pixel& /*pixel*/) {});
 }
 
 /// @brief Draw a line made of block characters.
@@ -538,10 +555,12 @@ void Canvas::DrawBlockLine(int x1,
   const int sy = y1 < y2 ? 1 : -1;
   const int length = std::max(dx, dy);
 
-  if (!IsIn(x1, y1) && !IsIn(x2, y2))
+  if (!IsIn(x1, y1) && !IsIn(x2, y2)) {
     return;
-  if (dx + dx > width_ * height_)
+  }
+  if (dx + dx > width_ * height_) {
     return;
+  }
 
   int error = dx - dy;
   for (int i = 0; i < length; ++i) {
@@ -563,7 +582,7 @@ void Canvas::DrawBlockLine(int x1,
 /// @param y the y coordinate of the center of the circle.
 /// @param radius the radius of the circle.
 void Canvas::DrawBlockCircle(int x, int y, int radius) {
-  DrawBlockCircle(x, y, radius, [](Pixel&) {});
+  DrawBlockCircle(x, y, radius, nostyle);
 }
 
 /// @brief Draw a circle made of block characters.
@@ -590,7 +609,7 @@ void Canvas::DrawBlockCircle(int x, int y, int radius, const Stylizer& style) {
 /// @param y the y coordinate of the center of the circle.
 /// @param radius the radius of the circle.
 void Canvas::DrawBlockCircleFilled(int x, int y, int radius) {
-  DrawBlockCircleFilled(x, y, radius, [](Pixel&) {});
+  DrawBlockCircleFilled(x, y, radius, nostyle);
 }
 
 /// @brief Draw a filled circle made of block characters.
@@ -624,7 +643,7 @@ void Canvas::DrawBlockCircleFilled(int x,
 /// @param r1 the radius of the ellipse along the x axis.
 /// @param r2 the radius of the ellipse along the y axis.
 void Canvas::DrawBlockEllipse(int x, int y, int r1, int r2) {
-  DrawBlockEllipse(x, y, r1, r2, [](Pixel&) {});
+  DrawBlockEllipse(x, y, r1, r2, nostyle);
 }
 
 /// @brief Draw an ellipse made of block characters.
@@ -690,7 +709,7 @@ void Canvas::DrawBlockEllipse(int x1,
 /// @param r1 the radius of the ellipse along the x axis.
 /// @param r2 the radius of the ellipse along the y axis.
 void Canvas::DrawBlockEllipseFilled(int x, int y, int r1, int r2) {
-  DrawBlockEllipseFilled(x, y, r1, r2, [](Pixel&) {});
+  DrawBlockEllipseFilled(x, y, r1, r2, nostyle);
 }
 
 /// @brief Draw a filled ellipse made of block characters.
@@ -756,7 +775,7 @@ void Canvas::DrawBlockEllipseFilled(int x1,
 /// @param y the y coordinate of the text.
 /// @param value the text to draw.
 void Canvas::DrawText(int x, int y, const std::string& value) {
-  DrawText(x, y, value, [](Pixel&) {});
+  DrawText(x, y, value, nostyle);
 }
 
 /// @brief Draw a piece of text.
@@ -781,8 +800,9 @@ void Canvas::DrawText(int x,
                       const std::string& value,
                       const Stylizer& style) {
   for (const auto& it : Utf8ToGlyphs(value)) {
-    if (!IsIn(x, y))
+    if (!IsIn(x, y)) {
       continue;
+    }
     Cell& cell = storage_[XY{x / 2, y / 4}];
     cell.type = CellType::kText;
     cell.content.character = it;
@@ -794,15 +814,16 @@ void Canvas::DrawText(int x,
 /// @brief Modify a pixel at a given location.
 /// @param style a function that modifies the pixel.
 void Canvas::Style(int x, int y, const Stylizer& style) {
-  if (IsIn(x, y))
+  if (IsIn(x, y)) {
     style(storage_[XY{x / 2, y / 4}].content);
+  }
 }
 
 namespace {
 
 class CanvasNodeBase : public Node {
  public:
-  CanvasNodeBase() {}
+  CanvasNodeBase() = default;
 
   void Render(Screen& screen) override {
     const Canvas& c = canvas();
@@ -824,7 +845,7 @@ class CanvasNodeBase : public Node {
 Element canvas(ConstRef<Canvas> canvas) {
   class Impl : public CanvasNodeBase {
    public:
-    Impl(ConstRef<Canvas> canvas) : canvas_(canvas) {
+    explicit Impl(ConstRef<Canvas> canvas) : canvas_(std::move(canvas)) {
       requirement_.min_x = (canvas_->width() + 1) / 2;
       requirement_.min_y = (canvas_->height() + 3) / 4;
     }
@@ -869,7 +890,8 @@ Element canvas(int width, int height, std::function<void(Canvas&)> fn) {
 /// @brief Produce an element drawing a canvas.
 /// @param fn a function drawing the canvas.
 Element canvas(std::function<void(Canvas&)> fn) {
-  return canvas(12, 12, std::move(fn));
+  const int default_dim = 12;
+  return canvas(default_dim, default_dim, std::move(fn));
 }
 
 }  // namespace ftxui

src/ftxui/dom/clear_under.cpp

@@ -29,8 +29,8 @@ class ClearUnder : public NodeDecorator {
 //         combinaison with dbox.
 /// @see ftxui::dbox
 /// @ingroup dom
-Element clear_under(Element child) {
+Element clear_under(Element element) {
-  return std::make_shared<ClearUnder>(std::move(child));
+  return std::make_shared<ClearUnder>(std::move(element));
 }
 
 }  // namespace ftxui

src/ftxui/dom/dbox.cpp

@@ -12,7 +12,7 @@ namespace ftxui {
 
 class DBox : public Node {
  public:
-  DBox(Elements children) : Node(std::move(children)) {}
+  explicit DBox(Elements children) : Node(std::move(children)) {}
 
   void ComputeRequirement() override {
     requirement_.min_x = 0;
@@ -38,9 +38,10 @@ class DBox : public Node {
   void SetBox(Box box) override {
     Node::SetBox(box);
 
-    for (auto& child : children_)
+    for (auto& child : children_) {
       child->SetBox(box);
     }
+  }
 };
 
 /// @brief Stack several element on top of each other.

src/ftxui/dom/flex.cpp

@@ -67,7 +67,7 @@ void function_not_flex(Requirement& r) {
 
 class Flex : public Node {
  public:
-  Flex(FlexFunction f) : f_(f) {}
+  explicit Flex(FlexFunction f) : f_(f) {}
   Flex(FlexFunction f, Element child) : Node(unpack(std::move(child))), f_(f) {}
   void ComputeRequirement() override {
     requirement_.min_x = 0;
@@ -80,8 +80,9 @@ class Flex : public Node {
   }
 
   void SetBox(Box box) override {
-    if (children_.empty())
+    if (children_.empty()) {
       return;
+    }
     children_[0]->SetBox(box);
   }
 

src/ftxui/dom/flexbox.cpp

@@ -1,5 +1,5 @@
-#include <stddef.h>   // for size_t
 #include <algorithm>  // for min, max
+#include <cstddef>    // for size_t
 #include <memory>  // for __shared_ptr_access, shared_ptr, allocator_traits<>::value_type, make_shared
 #include <utility>  // for move, swap
 #include <vector>   // for vector
@@ -56,11 +56,12 @@ class Flexbox : public Node {
     requirement_.flex_grow_x = 1;
     requirement_.flex_grow_y = 0;
 
-    if (IsColumnOriented())
+    if (IsColumnOriented()) {
       std::swap(requirement_.flex_grow_x, requirement_.flex_grow_y);
     }
+  }
 
-  bool IsColumnOriented() {
+  bool IsColumnOriented() const {
     return config_.direction == FlexboxConfig::Direction::Column ||
            config_.direction == FlexboxConfig::Direction::ColumnInversed;
   }
@@ -84,20 +85,21 @@ class Flexbox : public Node {
   }
 
   void ComputeRequirement() override {
-    for (auto& child : children_)
+    for (auto& child : children_) {
       child->ComputeRequirement();
+    }
     flexbox_helper::Global global;
     global.config = config_normalized_;
     if (IsColumnOriented()) {
-      global.size_x = 100000;
+      global.size_x = 100000;  // NOLINT
       global.size_y = asked_;
     } else {
       global.size_x = asked_;
-      global.size_y = 100000;
+      global.size_y = 100000;  // NOLINT
     }
     Layout(global, true);
 
-    if (global.blocks.size() == 0) {
+    if (global.blocks.empty()) {
       requirement_.min_x = 0;
       requirement_.min_y = 0;
       return;
@@ -150,18 +152,19 @@ class Flexbox : public Node {
   }
 
   void Check(Status* status) override {
-    for (auto& child : children_)
+    for (auto& child : children_) {
       child->Check(status);
+    }
 
     if (status->iteration == 0) {
-      asked_ = 6000;
+      asked_ = 6000;  // NOLINT
       need_iteration_ = true;
     }
 
     status->need_iteration |= need_iteration_;
   }
 
-  int asked_ = 6000;
+  int asked_ = 6000;  // NOLINT
   bool need_iteration_ = true;
   const FlexboxConfig config_;
   const FlexboxConfig config_normalized_;
@@ -190,7 +193,7 @@ class Flexbox : public Node {
 //  )
 /// ```
 Element flexbox(Elements children, FlexboxConfig config) {
-  return std::make_shared<Flexbox>(std::move(children), std::move(config));
+  return std::make_shared<Flexbox>(std::move(children), config);
 }
 
 /// @brief A container displaying elements in rows from left to right. When

src/ftxui/dom/flexbox_helper.cpp

@@ -1,14 +1,13 @@
 #include "ftxui/dom/flexbox_helper.hpp"
 
-#include <stddef.h>   // for size_t
 #include <algorithm>  // for min, max
+#include <cstddef>    // for size_t
 #include <memory>     // for allocator_traits<>::value_type
 #include <utility>    // for swap, move
 
 #include "ftxui/dom/box_helper.hpp"  // for Element, Compute
 
-namespace ftxui {
+namespace ftxui::flexbox_helper {
-namespace flexbox_helper {
 
 namespace {
 void SymmetryXY(FlexboxConfig& c) {
@@ -92,15 +91,17 @@ void SetX(Global& global, std::vector<Line> lines) {
       box_helper::Element element;
       element.min_size = block->min_size_x;
       element.flex_grow =
-          block->flex_grow_x || global.config.justify_content ==
+          block->flex_grow_x != 0 || global.config.justify_content ==
-                                    FlexboxConfig::JustifyContent::Stretch;
+                                         FlexboxConfig::JustifyContent::Stretch
+              ? 1
+              : 0;
       element.flex_shrink = block->flex_shrink_x;
       elements.push_back(element);
     }
 
     box_helper::Compute(
         &elements,
-        global.size_x - global.config.gap_x * (line.blocks.size() - 1));
+        global.size_x - global.config.gap_x * (int(line.blocks.size()) - 1));
 
     int x = 0;
     for (size_t i = 0; i < line.blocks.size(); ++i) {
@@ -112,6 +113,7 @@ void SetX(Global& global, std::vector<Line> lines) {
   }
 }
 
+// NOLINTNEXTLINE(readability-function-cognitive-complexity)
 void SetY(Global& g, std::vector<Line> lines) {
   std::vector<box_helper::Element> elements;
   for (auto& line : lines) {
@@ -127,7 +129,7 @@ void SetY(Global& g, std::vector<Line> lines) {
   }
 
   // box_helper::Compute(&elements, g.size_y);
-  box_helper::Compute(&elements, 10000);
+  box_helper::Compute(&elements, 10000);  // NOLINT
 
   // [Align-content]
   std::vector<int> ys(elements.size());
@@ -140,48 +142,57 @@ void SetY(Global& g, std::vector<Line> lines) {
   int remaining_space = std::max(0, g.size_y - y);
   switch (g.config.align_content) {
     case FlexboxConfig::AlignContent::FlexStart: {
-    } break;
+      break;
+    }
 
     case FlexboxConfig::AlignContent::FlexEnd: {
-      for (size_t i = 0; i < ys.size(); ++i)
+      for (size_t i = 0; i < ys.size(); ++i) {  // NOLINT
         ys[i] += remaining_space;
-    } break;
+      }
+      break;
+    }
 
     case FlexboxConfig::AlignContent::Center: {
-      for (size_t i = 0; i < ys.size(); ++i)
+      for (size_t i = 0; i < ys.size(); ++i) {  // NOLINT
         ys[i] += remaining_space / 2;
-    } break;
+      }
+      break;
+    }
 
     case FlexboxConfig::AlignContent::Stretch: {
-      for (int i = ys.size() - 1; i >= 0; --i) {
+      for (int i = ys.size() - 1; i >= 0; --i) {  // NOLINT
         int shifted = remaining_space * (i + 0) / (i + 1);
         ys[i] += shifted;
         int consumed = remaining_space - shifted;
         elements[i].size += consumed;
         remaining_space -= consumed;
       }
-    } break;
+      break;
+    }
 
     case FlexboxConfig::AlignContent::SpaceBetween: {
-      for (int i = ys.size() - 1; i >= 1; --i) {
+      for (int i = ys.size() - 1; i >= 1; --i) {  // NOLINT
         ys[i] += remaining_space;
         remaining_space = remaining_space * (i - 1) / i;
       }
-    } break;
+      break;
+    }
 
     case FlexboxConfig::AlignContent::SpaceAround: {
-      for (int i = ys.size() - 1; i >= 0; --i) {
+      for (int i = ys.size() - 1; i >= 0; --i) {  // NOLINT
         ys[i] += remaining_space * (2 * i + 1) / (2 * i + 2);
         remaining_space = remaining_space * (2 * i) / (2 * i + 2);
       }
-    } break;
+      break;
+    }
 
     case FlexboxConfig::AlignContent::SpaceEvenly: {
-      for (int i = ys.size() - 1; i >= 0; --i) {
+      for (int i = ys.size() - 1; i >= 0; --i) {  // NOLINT
         ys[i] += remaining_space * (i + 1) / (i + 2);
         remaining_space = remaining_space * (i + 1) / (i + 2);
       }
-    } break;
+      break;
+    }
   }
 
   // [Align items]
@@ -189,7 +200,7 @@ void SetY(Global& g, std::vector<Line> lines) {
     auto& element = elements[i];
     for (auto* block : lines[i].blocks) {
       bool stretch =
-          block->flex_grow_y ||
+          block->flex_grow_y != 0 ||
           g.config.align_content == FlexboxConfig::AlignContent::Stretch;
       int size =
           stretch ? element.size : std::min(element.size, block->min_size_y);
@@ -197,22 +208,26 @@ void SetY(Global& g, std::vector<Line> lines) {
         case FlexboxConfig::AlignItems::FlexStart: {
           block->y = ys[i];
           block->dim_y = size;
-        } break;
+          break;
+        }
 
         case FlexboxConfig::AlignItems::Center: {
           block->y = ys[i] + (element.size - size) / 2;
           block->dim_y = size;
-        } break;
+          break;
+        }
 
         case FlexboxConfig::AlignItems::FlexEnd: {
           block->y = ys[i] + element.size - size;
           block->dim_y = size;
-        } break;
+          break;
+        }
 
         case FlexboxConfig::AlignItems::Stretch: {
           block->y = ys[i];
           block->dim_y = element.size;
-        } break;
+          break;
+        }
       }
     }
   }
@@ -228,63 +243,74 @@ void JustifyContent(Global& g, std::vector<Line> lines) {
         break;
 
       case FlexboxConfig::JustifyContent::FlexEnd: {
-        for (auto* block : line.blocks)
+        for (auto* block : line.blocks) {
           block->x += remaining_space;
-      } break;
+        }
+        break;
+      }
 
       case FlexboxConfig::JustifyContent::Center: {
-        for (auto* block : line.blocks)
+        for (auto* block : line.blocks) {
           block->x += remaining_space / 2;
-      } break;
+        }
+        break;
+      }
 
       case FlexboxConfig::JustifyContent::SpaceBetween: {
-        for (int i = line.blocks.size() - 1; i >= 1; --i) {
+        for (int i = (int)line.blocks.size() - 1; i >= 1; --i) {
           line.blocks[i]->x += remaining_space;
           remaining_space = remaining_space * (i - 1) / i;
         }
-      } break;
+        break;
+      }
 
       case FlexboxConfig::JustifyContent::SpaceAround: {
-        for (int i = line.blocks.size() - 1; i >= 0; --i) {
+        for (int i = (int)line.blocks.size() - 1; i >= 0; --i) {
           line.blocks[i]->x += remaining_space * (2 * i + 1) / (2 * i + 2);
           remaining_space = remaining_space * (2 * i) / (2 * i + 2);
         }
-      } break;
+        break;
+      }
 
       case FlexboxConfig::JustifyContent::SpaceEvenly: {
-        for (int i = line.blocks.size() - 1; i >= 0; --i) {
+        for (int i = (int)line.blocks.size() - 1; i >= 0; --i) {
           line.blocks[i]->x += remaining_space * (i + 1) / (i + 2);
           remaining_space = remaining_space * (i + 1) / (i + 2);
         }
-      } break;
+        break;
+      }
     }
   }
 }
 }  // namespace
 
-void Compute(Global& global) {
+namespace {
-  if (global.config.direction == FlexboxConfig::Direction::Column ||
-      global.config.direction == FlexboxConfig::Direction::ColumnInversed) {
-    SymmetryXY(global);
-    Compute(global);
-    SymmetryXY(global);
-    return;
-  }
 
+void Compute1(Global& global);
+void Compute2(Global& global);
+void Compute3(Global& global);
+
+void Compute1(Global& global) {
   if (global.config.direction == FlexboxConfig::Direction::RowInversed) {
     SymmetryX(global);
-    Compute(global);
+    Compute2(global);
     SymmetryX(global);
     return;
   }
+  Compute2(global);
+}
 
+void Compute2(Global& global) {
   if (global.config.wrap == FlexboxConfig::Wrap::WrapInversed) {
     SymmetryY(global);
-    Compute(global);
+    Compute3(global);
     SymmetryY(global);
     return;
   }
+  Compute3(global);
+}
 
+void Compute3(Global& global) {
   // Step 1: Lay out every elements into rows:
   std::vector<Line> lines;
   {
@@ -295,19 +321,21 @@ void Compute(Global& global) {
       // No? Then we need to start a new one:
       if (x + block.min_size_x > global.size_x) {
         x = 0;
-        if (!line.blocks.empty())
+        if (!line.blocks.empty()) {
           lines.push_back(std::move(line));
+        }
         line = Line();
       }
 
-      block.line = lines.size();
+      block.line = (int)lines.size();
-      block.line_position = line.blocks.size();
+      block.line_position = (int)line.blocks.size();
       line.blocks.push_back(&block);
       x += block.min_size_x + global.config.gap_x;
     }
-    if (!line.blocks.empty())
+    if (!line.blocks.empty()) {
       lines.push_back(std::move(line));
     }
+  }
 
   // Step 2: Set positions on the X axis.
   SetX(global, lines);
@@ -317,8 +345,21 @@ void Compute(Global& global) {
   SetY(global, lines);
 }
 
-}  // namespace flexbox_helper
+}  // namespace
-}  // namespace ftxui
+
+void Compute(Global& global) {
+  if (global.config.direction == FlexboxConfig::Direction::Column ||
+      global.config.direction == FlexboxConfig::Direction::ColumnInversed) {
+    SymmetryXY(global);
+    Compute1(global);
+    SymmetryXY(global);
+    return;
+  }
+  Compute1(global);
+}
+
+
+}  // namespace ftxui::flexbox_helper
 
 // Copyright 2021 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in

src/ftxui/dom/focus.cpp

@@ -29,17 +29,17 @@ Decorator focusPositionRelative(float x, float y) {
   class Impl : public NodeDecorator {
    public:
     Impl(Element child, float x, float y)
-        : NodeDecorator(child), x_(x), y_(y) {}
+        : NodeDecorator(std::move(child)), x_(x), y_(y) {}
 
     void ComputeRequirement() override {
       NodeDecorator::ComputeRequirement();
       requirement_.selection = Requirement::Selection::NORMAL;
 
       Box& box = requirement_.selected_box;
-      box.x_min = requirement_.min_x * x_;
+      box.x_min = (int)((float)requirement_.min_x * x_);
-      box.y_min = requirement_.min_y * y_;
+      box.y_min = (int)((float)requirement_.min_y * y_);
-      box.x_max = requirement_.min_x * x_;
+      box.x_max = (int)((float)requirement_.min_x * x_);
-      box.y_max = requirement_.min_y * y_;
+      box.y_max = (int)((float)requirement_.min_y * y_);
     }
 
    private:
@@ -67,8 +67,8 @@ Decorator focusPositionRelative(float x, float y) {
 Decorator focusPosition(int x, int y) {
   class Impl : public NodeDecorator {
    public:
-    Impl(Element child, float x, float y)
+    Impl(Element child, int x, int y)
-        : NodeDecorator(child), x_(x), y_(y) {}
+        : NodeDecorator(std::move(child)), x_(x), y_(y) {}
 
     void ComputeRequirement() override {
       NodeDecorator::ComputeRequirement();

src/ftxui/dom/frame.cpp

@@ -16,7 +16,7 @@ namespace ftxui {
 
 class Select : public Node {
  public:
-  Select(Elements children) : Node(std::move(children)) {}
+  explicit Select(Elements children) : Node(std::move(children)) {}
 
   void ComputeRequirement() override {
     Node::ComputeRequirement();

src/ftxui/dom/gauge.cpp

@@ -1,17 +1,16 @@
-#include <iostream>
-#include <algorithm>  // for max, min
 #include <memory>  // for allocator, make_shared
 #include <string>  // for string
 
-#include "ftxui/dom/elements.hpp"     // for Element, gauge
+#include "ftxui/dom/elements.hpp"  // for GaugeDirection, Element, GaugeDirection::Down, GaugeDirection::Left, GaugeDirection::Right, GaugeDirection::Up, gauge, gaugeDirection, gaugeDown, gaugeLeft, gaugeRight, gaugeUp
 #include "ftxui/dom/node.hpp"      // for Node
 #include "ftxui/dom/requirement.hpp"  // for Requirement
 #include "ftxui/screen/box.hpp"       // for Box
-#include "ftxui/screen/screen.hpp"    // for Screen
+#include "ftxui/screen/screen.hpp"    // for Screen, Pixel
 
 namespace ftxui {
 
-static std::string charset_horizontal[11] = {
+// NOLINTNEXTLINE
+static const std::string charset_horizontal[11] = {
 #if defined(FTXUI_MICROSOFT_TERMINAL_FALLBACK)
     // Microsoft's terminals often use fonts not handling the 8 unicode
     // characters for representing the whole gauge. Fallback with less.
@@ -23,7 +22,8 @@ static std::string charset_horizontal[11] = {
     // int(9 * (limit - limit_int) = 9
     "█"};
 
-static std::string charset_vertical[10] = {
+// NOLINTNEXTLINE
+static const std::string charset_vertical[10] = {
     "█",
     "▇",
     "▆",
@@ -43,10 +43,12 @@ class Gauge : public Node {
   Gauge(float progress, GaugeDirection direction)
       : progress_(progress), direction_(direction) {
     // This handle NAN correctly:
-    if (!(progress_ > 0.f))
+    if (!(progress_ > 0.F)) {
-      progress_ = 0.f;
+      progress_ = 0.F;
-    if (!(progress_ < 1.f))
+    }
-      progress_ = 1.f;
+    if (!(progress_ < 1.F)) {
+      progress_ = 1.F;
+    }
   }
 
   void ComputeRequirement() override {
@@ -89,51 +91,63 @@ class Gauge : public Node {
 
   void RenderHorizontal(Screen& screen, bool invert) {
     int y = box_.y_min;
-    if (y > box_.y_max)
+    if (y > box_.y_max) {
       return;
+    }
 
     // Draw the progress bar horizontally.
     {
-      float progress = invert ? 1.f - progress_ : progress_;
+      float progress = invert ? 1.F - progress_ : progress_;
-      float limit = box_.x_min + progress * (box_.x_max - box_.x_min + 1);
+      float limit =
-      int limit_int = limit;
+          (float)box_.x_min + progress * (float)(box_.x_max - box_.x_min + 1);
+      int limit_int = (int)limit;
       int x = box_.x_min;
-      while (x < limit_int)
+      while (x < limit_int) {
-        screen.at(x++, y) = charset_horizontal[9];
+        screen.at(x++, y) = charset_horizontal[9];  // NOLINT
+      }
+      // NOLINTNEXTLINE
       screen.at(x++, y) = charset_horizontal[int(9 * (limit - limit_int))];
-      while (x <= box_.x_max)
+      while (x <= box_.x_max) {
         screen.at(x++, y) = charset_horizontal[0];
       }
+    }
 
     if (invert) {
-      for (int x = box_.x_min; x <= box_.x_max; x++)
+      for (int x = box_.x_min; x <= box_.x_max; x++) {
         screen.PixelAt(x, y).inverted ^= true;
       }
     }
+  }
 
   void RenderVertical(Screen& screen, bool invert) {
     int x = box_.x_min;
-    if (x > box_.x_max)
+    if (x > box_.x_max) {
       return;
+    }
 
     // Draw the progress bar vertically:
     {
-      float progress = invert ? progress_ : 1.f - progress_;
+      float progress = invert ? progress_ : 1.F - progress_;
-      float limit = box_.y_min + progress * (box_.y_max - box_.y_min + 1);
+      float limit =
-      int limit_int = limit;
+          (float)box_.y_min + progress * (float)(box_.y_max - box_.y_min + 1);
+      int limit_int = (int)limit;
       int y = box_.y_min;
-      while (y < limit_int)
+      while (y < limit_int) {
-        screen.at(x, y++) = charset_vertical[8];
+        screen.at(x, y++) = charset_vertical[8];  // NOLINT
+      }
+      // NOLINTNEXTLINE
       screen.at(x, y++) = charset_vertical[int(8 * (limit - limit_int))];
-      while (y <= box_.y_max)
+      while (y <= box_.y_max) {
         screen.at(x, y++) = charset_vertical[0];
       }
+    }
 
     if (invert) {
-      for (int y = box_.y_min; y <= box_.y_max; y++)
+      for (int y = box_.y_min; y <= box_.y_max; y++) {
         screen.PixelAt(x, y).inverted ^= true;
       }
     }
+  }
 
  private:
   float progress_;

src/ftxui/dom/graph.cpp

@@ -1,6 +1,7 @@
 #include <functional>  // for function
 #include <memory>      // for allocator, make_shared
 #include <string>      // for string
+#include <utility>     // for move
 #include <vector>      // for vector
 
 #include "ftxui/dom/elements.hpp"     // for GraphFunction, Element, graph
@@ -11,6 +12,7 @@
 
 namespace ftxui {
 
+// NOLINTNEXTLINE
 static std::string charset[] =
 #if defined(FTXUI_MICROSOFT_TERMINAL_FALLBACK)
     // Microsoft's terminals often use fonts not handling the 8 unicode
@@ -22,7 +24,8 @@ static std::string charset[] =
 
 class Graph : public Node {
  public:
-  Graph(GraphFunction graph_function) : graph_function_(graph_function) {}
+  explicit Graph(GraphFunction graph_function)
+      : graph_function_(std::move(graph_function)) {}
 
   void ComputeRequirement() override {
     requirement_.flex_grow_x = 1;
@@ -43,9 +46,9 @@ class Graph : public Node {
       int height_2 = 2 * box_.y_max - data[i++];
       for (int y = box_.y_min; y <= box_.y_max; ++y) {
         int yy = 2 * y;
-        int i_1 = yy < height_1 ? 0 : yy == height_1 ? 3 : 6;
+        int i_1 = yy < height_1 ? 0 : yy == height_1 ? 3 : 6;  // NOLINT
-        int i_2 = yy < height_2 ? 0 : yy == height_2 ? 1 : 2;
+        int i_2 = yy < height_2 ? 0 : yy == height_2 ? 1 : 2;  // NOLINT
-        screen.at(x, y) = charset[i_1 + i_2];
+        screen.at(x, y) = charset[i_1 + i_2];                  // NOLINT
       }
     }
   }
@@ -57,7 +60,7 @@ class Graph : public Node {
 /// @brief Draw a graph using a GraphFunction.
 /// @param graph_function the function to be called to get the data.
 Element graph(GraphFunction graph_function) {
-  return std::make_shared<Graph>(graph_function);
+  return std::make_shared<Graph>(std::move(graph_function));
 }
 
 }  // namespace ftxui

src/ftxui/dom/gridbox.cpp

@@ -1,5 +1,5 @@
-#include <stddef.h>   // for size_t
 #include <algorithm>  // for max, min
+#include <cstddef>    // for size_t
 #include <memory>  // for __shared_ptr_access, shared_ptr, make_shared, allocator_traits<>::value_type
 #include <utility>  // for move
 #include <vector>   // for vector, __alloc_traits<>::value_type
@@ -15,10 +15,11 @@ class Screen;
 
 class GridBox : public Node {
  public:
-  GridBox(std::vector<Elements> lines) : Node(), lines_(std::move(lines)) {
+  explicit GridBox(std::vector<Elements> lines) : lines_(std::move(lines)) {
-    y_size = lines_.size();
+    y_size = (int)lines_.size();
-    for (const auto& line : lines_)
+    for (const auto& line : lines_) {
       x_size = std::max(x_size, (int)line.size());
+    }
     for (auto& line : lines_) {
       while (line.size() < (size_t)x_size) {
         line.push_back(filler());
@@ -39,8 +40,9 @@ class GridBox : public Node {
         cell->ComputeRequirement();
 
         // Determine focus based on the focused child.
-        if (requirement_.selection >= cell->requirement().selection)
+        if (requirement_.selection >= cell->requirement().selection) {
           continue;
+        }
         requirement_.selection = cell->requirement().selection;
         requirement_.selected_box = cell->requirement().selected_box;
         requirement_.selected_box.x_min += requirement_.min_x;
@@ -51,16 +53,18 @@ class GridBox : public Node {
     // Work on the x-axis.
     for (int x = 0; x < x_size; ++x) {
       int min_x = 0;
-      for (int y = 0; y < y_size; ++y)
+      for (int y = 0; y < y_size; ++y) {
         min_x = std::max(min_x, lines_[y][x]->requirement().min_x);
+      }
       requirement_.min_x += min_x;
     }
 
     // Work on the y-axis.
     for (int y = 0; y < y_size; ++y) {
       int min_y = 0;
-      for (int x = 0; x < x_size; ++x)
+      for (int x = 0; x < x_size; ++x) {
         min_y = std::max(min_y, lines_[y][x]->requirement().min_y);
+      }
       requirement_.min_y += min_y;
     }
   }
@@ -70,8 +74,8 @@ class GridBox : public Node {
 
     box_helper::Element init;
     init.min_size = 0;
-    init.flex_grow = 1024;
+    init.flex_grow = 1024;    // NOLINT
-    init.flex_shrink = 1024;
+    init.flex_shrink = 1024;  // NOLINT
     std::vector<box_helper::Element> elements_x(x_size, init);
     std::vector<box_helper::Element> elements_y(y_size, init);
 
@@ -115,10 +119,11 @@ class GridBox : public Node {
 
   void Render(Screen& screen) override {
     for (auto& line : lines_) {
-      for (auto& cell : line)
+      for (auto& cell : line) {
         cell->Render(screen);
       }
     }
+  }
 
   int x_size = 0;
   int y_size = 0;

src/ftxui/dom/hbox.cpp

@@ -1,5 +1,5 @@
-#include <stddef.h>   // for size_t
 #include <algorithm>  // for max
+#include <cstddef>    // for size_t
 #include <memory>  // for __shared_ptr_access, shared_ptr, make_shared, allocator_traits<>::value_type
 #include <utility>  // for move
 #include <vector>   // for vector, __alloc_traits<>::value_type
@@ -14,7 +14,7 @@ namespace ftxui {
 
 class HBox : public Node {
  public:
-  HBox(Elements children) : Node(std::move(children)) {}
+  explicit HBox(Elements children) : Node(std::move(children)) {}
 
   void ComputeRequirement() override {
     requirement_.min_x = 0;

src/ftxui/dom/node.cpp

@@ -5,15 +5,16 @@
 
 namespace ftxui {
 
-Node::Node() {}
+Node::Node() = default;
 Node::Node(Elements children) : children_(std::move(children)) {}
-Node::~Node() {}
+Node::~Node() = default;
 
 /// @brief Compute how much space an elements needs.
 /// @ingroup dom
 void Node::ComputeRequirement() {
-  for (auto& child : children_)
+  for (auto& child : children_) {
     child->ComputeRequirement();
+  }
 }
 
 /// @brief Assign a position and a dimension to an element for drawing.
@@ -25,13 +26,15 @@ void Node::SetBox(Box box) {
 /// @brief Display an element on a ftxui::Screen.
 /// @ingroup dom
 void Node::Render(Screen& screen) {
-  for (auto& child : children_)
+  for (auto& child : children_) {
     child->Render(screen);
+  }
 }
 
 void Node::Check(Status* status) {
-  for (auto& child : children_)
+  for (auto& child : children_) {
     child->Check(status);
+  }
   status->need_iteration |= (status->iteration == 0);
 }
 
@@ -52,7 +55,8 @@ void Render(Screen& screen, Node* node) {
 
   Node::Status status;
   node->Check(&status);
-  while (status.need_iteration && status.iteration < 20) {
+  const int max_iterations = 20;
+  while (status.need_iteration && status.iteration < max_iterations) {
     // Step 1: Find what dimension this elements wants to be.
     node->ComputeRequirement();
 

src/ftxui/dom/paragraph.cpp

@@ -8,12 +8,13 @@
 namespace ftxui {
 
 namespace {
-Elements Split(std::string the_text) {
+Elements Split(const std::string& the_text) {
   Elements output;
   std::stringstream ss(the_text);
   std::string word;
-  while (std::getline(ss, word, ' '))
+  while (std::getline(ss, word, ' ')) {
     output.push_back(text(word));
+  }
   return output;
 }
 }  // namespace
@@ -21,37 +22,37 @@ Elements Split(std::string the_text) {
 /// @brief Return an element drawing the paragraph on multiple lines.
 /// @ingroup dom
 /// @see flexbox.
-Element paragraph(std::string the_text) {
+Element paragraph(const std::string& the_text) {
-  return paragraphAlignLeft(std::move(the_text));
+  return paragraphAlignLeft(the_text);
 }
 
 /// @brief Return an element drawing the paragraph on multiple lines, aligned on
 /// the left.
 /// @ingroup dom
 /// @see flexbox.
-Element paragraphAlignLeft(std::string the_text) {
+Element paragraphAlignLeft(const std::string& the_text) {
   static const auto config = FlexboxConfig().SetGap(1, 0);
-  return flexbox(Split(std::move(the_text)), config);
+  return flexbox(Split(the_text), config);
 }
 
 /// @brief Return an element drawing the paragraph on multiple lines, aligned on
 /// the right.
 /// @ingroup dom
 /// @see flexbox.
-Element paragraphAlignRight(std::string the_text) {
+Element paragraphAlignRight(const std::string& the_text) {
   static const auto config =
       FlexboxConfig().SetGap(1, 0).Set(FlexboxConfig::JustifyContent::FlexEnd);
-  return flexbox(Split(std::move(the_text)), config);
+  return flexbox(Split(the_text), config);
 }
 
 /// @brief Return an element drawing the paragraph on multiple lines, aligned on
 /// the center.
 /// @ingroup dom
 /// @see flexbox.
-Element paragraphAlignCenter(std::string the_text) {
+Element paragraphAlignCenter(const std::string& the_text) {
   static const auto config =
       FlexboxConfig().SetGap(1, 0).Set(FlexboxConfig::JustifyContent::Center);
-  return flexbox(Split(std::move(the_text)), config);
+  return flexbox(Split(the_text), config);
 }
 
 /// @brief Return an element drawing the paragraph on multiple lines, aligned
@@ -59,10 +60,10 @@ Element paragraphAlignCenter(std::string the_text) {
 /// the center.
 /// @ingroup dom
 /// @see flexbox.
-Element paragraphAlignJustify(std::string the_text) {
+Element paragraphAlignJustify(const std::string& the_text) {
   static const auto config = FlexboxConfig().SetGap(1, 0).Set(
       FlexboxConfig::JustifyContent::SpaceBetween);
-  Elements words = Split(std::move(the_text));
+  Elements words = Split(the_text);
   words.push_back(text("") | xflex);
   return flexbox(std::move(words), config);
 }

src/ftxui/dom/scroll_indicator.cpp

@@ -21,27 +21,29 @@ Element vscroll_indicator(Element child) {
     using NodeDecorator::NodeDecorator;
 
     void ComputeRequirement() override {
-      Node::ComputeRequirement();
+      NodeDecorator::ComputeRequirement();
       requirement_ = children_[0]->requirement();
       requirement_.min_x++;
     }
 
     void SetBox(Box box) override {
-      Node::SetBox(box);
+      NodeDecorator::SetBox(box);
-      if (box_.x_min > box_.x_max)
+      if (box_.x_min > box_.x_max) {
         box_.x_max--;
+      }
       children_[0]->SetBox(box);
     }
 
     void Render(Screen& screen) final {
-      Node::Render(screen);
+      NodeDecorator::Render(screen);
 
       const Box& stencil = screen.stencil;
 
       int size_inner = box_.y_max - box_.y_min;
       int size_outter = stencil.y_max - stencil.y_min + 1;
-      if (size_outter >= size_inner)
+      if (size_outter >= size_inner) {
         return;
+      }
 
       int size = 2 * size_outter * size_outter / size_inner;
       size = std::max(size, 1);
@@ -56,7 +58,7 @@ Element vscroll_indicator(Element child) {
         bool up = (start_y <= y_up) && (y_up <= start_y + size);
         bool down = (start_y <= y_down) && (y_down <= start_y + size);
 
-        const char* c = up ? (down ? "┃" : "╹") : (down ? "╻" : " ");
+        const char* c = up ? (down ? "┃" : "╹") : (down ? "╻" : " ");  // NOLINT
         screen.PixelAt(x, y) = Pixel();
         screen.PixelAt(x, y).character = c;
       }

src/ftxui/dom/separator.cpp

@@ -1,5 +1,7 @@
+#include <array>    // for array, array<>::value_type
 #include <memory>   // for make_shared, allocator
-#include <string>  // for string
+#include <string>   // for basic_string, string
+#include <utility>  // for move
 
 #include "ftxui/dom/elements.hpp"  // for Element, BorderStyle, LIGHT, separator, DOUBLE, EMPTY, HEAVY, separatorCharacter, separatorDouble, separatorEmpty, separatorHSelector, separatorHeavy, separatorLight, separatorStyled, separatorVSelector
 #include "ftxui/dom/node.hpp"      // for Node
@@ -10,19 +12,25 @@
 
 namespace ftxui {
 
+namespace {
 using ftxui::Screen;
 
-const std::string charset[][2] = {
+using Charset = std::array<std::string, 2>;  // NOLINT
-    {"│", "─"},  //
+using Charsets = std::array<Charset, 5>;     // NOLINT
-    {"┃", "━"},  //
+const Charsets charsets =                    // NOLINT
-    {"║", "═"},  //
+    {
-    {"│", "─"},  //
+        Charset{"│", "─"},  //
-    {" ", " "},  //
+        Charset{"┃", "━"},  //
+        Charset{"║", "═"},  //
+        Charset{"│", "─"},  //
+        Charset{" ", " "},  //
 };
 
+}  // namespace
+
 class Separator : public Node {
  public:
-  Separator(std::string value) : value_(value) {}
+  explicit Separator(std::string value) : value_(std::move(value)) {}
 
   void ComputeRequirement() override {
     requirement_.min_x = 1;
@@ -44,7 +52,7 @@ class Separator : public Node {
 
 class SeparatorAuto : public Node {
  public:
-  SeparatorAuto(BorderStyle style) : style_(style) {}
+  explicit SeparatorAuto(BorderStyle style) : style_(style) {}
 
   void ComputeRequirement() override {
     requirement_.min_x = 1;
@@ -55,7 +63,7 @@ class SeparatorAuto : public Node {
     bool is_column = (box_.x_max == box_.x_min);
     bool is_line = (box_.y_min == box_.y_max);
 
-    const std::string c = charset[style_][is_line && !is_column];
+    const std::string c = charsets[style_][int(is_line && !is_column)];
 
     for (int y = box_.y_min; y <= box_.y_max; ++y) {
       for (int x = box_.x_min; x <= box_.x_max; ++x) {
@@ -71,7 +79,8 @@ class SeparatorAuto : public Node {
 
 class SeparatorWithPixel : public SeparatorAuto {
  public:
-  SeparatorWithPixel(Pixel pixel) : SeparatorAuto(LIGHT), pixel_(pixel) {
+  explicit SeparatorWithPixel(Pixel pixel)
+      : SeparatorAuto(LIGHT), pixel_(std::move(pixel)) {
     pixel_.automerge = true;
   }
   void Render(Screen& screen) override {
@@ -337,7 +346,7 @@ Element separatorEmpty() {
 /// down
 /// ```
 Element separatorCharacter(std::string value) {
-  return std::make_shared<Separator>(value);
+  return std::make_shared<Separator>(std::move(value));
 }
 
 /// @brief Draw a separator in between two element filled with a given pixel.
@@ -367,7 +376,7 @@ Element separatorCharacter(std::string value) {
 /// Down
 /// ```
 Element separator(Pixel pixel) {
-  return std::make_shared<SeparatorWithPixel>(pixel);
+  return std::make_shared<SeparatorWithPixel>(std::move(pixel));
 }
 
 /// @brief Draw an horizontal bar, with the area in between left/right colored
@@ -384,27 +393,28 @@ Element separator(Pixel pixel) {
 /// ```
 Element separatorHSelector(float left,
                            float right,
-                           Color selected_color,
+                           Color unselected_color,
-                           Color unselected_color) {
+                           Color selected_color) {
   class Impl : public Node {
    public:
     Impl(float left, float right, Color selected_color, Color unselected_color)
         : left_(left),
           right_(right),
-          selected_color_(selected_color),
+          unselected_color_(unselected_color),
-          unselected_color_(unselected_color) {}
+          selected_color_(selected_color) {}
     void ComputeRequirement() override {
       requirement_.min_x = 1;
       requirement_.min_y = 1;
     }
 
     void Render(Screen& screen) override {
-      if (box_.y_max < box_.y_min)
+      if (box_.y_max < box_.y_min) {
         return;
+      }
 
       // This are the two location with an empty demi-cell.
-      int demi_cell_left = left_ * 2 - 1;
+      int demi_cell_left = int(left_ * 2.F - 1.F);    // NOLINT
-      int demi_cell_right = right_ * 2 + 2;
+      int demi_cell_right = int(right_ * 2.F + 2.F);  // NOLINT
 
       int y = box_.y_min;
       for (int x = box_.x_min; x <= box_.x_max; ++x) {
@@ -419,23 +429,24 @@ Element separatorHSelector(float left,
           pixel.character = "─";
           pixel.automerge = true;
         } else {
-          pixel.character = a_empty ? "╶" : "╴";
+          pixel.character = a_empty ? "╶" : "╴";  // NOLINT
           pixel.automerge = false;
         }
 
-        if (demi_cell_left <= a && b <= demi_cell_right)
+        if (demi_cell_left <= a && b <= demi_cell_right) {
           pixel.foreground_color = selected_color_;
-        else
+        } else {
           pixel.foreground_color = unselected_color_;
         }
       }
+    }
 
     float left_;
     float right_;
-    Color selected_color_;
     Color unselected_color_;
+    Color selected_color_;
   };
-  return std::make_shared<Impl>(left, right, selected_color, unselected_color);
+  return std::make_shared<Impl>(left, right, unselected_color, selected_color);
 }
 
 /// @brief Draw an vertical bar, with the area in between up/downcolored
@@ -452,27 +463,28 @@ Element separatorHSelector(float left,
 /// ```
 Element separatorVSelector(float up,
                            float down,
-                           Color selected_color,
+                           Color unselected_color,
-                           Color unselected_color) {
+                           Color selected_color) {
   class Impl : public Node {
    public:
-    Impl(float up, float down, Color selected_color, Color unselected_color)
+    Impl(float up, float down, Color unselected_color, Color selected_color)
         : up_(up),
           down_(down),
-          selected_color_(selected_color),
+          unselected_color_(unselected_color),
-          unselected_color_(unselected_color) {}
+          selected_color_(selected_color) {}
     void ComputeRequirement() override {
       requirement_.min_x = 1;
       requirement_.min_y = 1;
     }
 
     void Render(Screen& screen) override {
-      if (box_.x_max < box_.x_min)
+      if (box_.x_max < box_.x_min) {
         return;
+      }
 
       // This are the two location with an empty demi-cell.
-      int demi_cell_up = up_ * 2 - 1;
+      int demi_cell_up = int(up_ * 2 - 1);
-      int demi_cell_down = down_ * 2 + 2;
+      int demi_cell_down = int(down_ * 2 + 2);
 
       int x = box_.x_min;
       for (int y = box_.y_min; y <= box_.y_max; ++y) {
@@ -487,23 +499,24 @@ Element separatorVSelector(float up,
           pixel.character = "│";
           pixel.automerge = true;
         } else {
-          pixel.character = a_empty ? "╷" : "╵";
+          pixel.character = a_empty ? "╷" : "╵";  // NOLINT
           pixel.automerge = false;
         }
 
-        if (demi_cell_up <= a && b <= demi_cell_down)
+        if (demi_cell_up <= a && b <= demi_cell_down) {
           pixel.foreground_color = selected_color_;
-        else
+        } else {
           pixel.foreground_color = unselected_color_;
         }
       }
+    }
 
     float up_;
     float down_;
-    Color selected_color_;
     Color unselected_color_;
+    Color selected_color_;
   };
-  return std::make_shared<Impl>(up, down, selected_color, unselected_color);
+  return std::make_shared<Impl>(up, down, unselected_color, selected_color);
 }
 
 }  // namespace ftxui

src/ftxui/dom/size.cpp

@@ -1,4 +1,3 @@
-#include <stddef.h>   // for size_t
 #include <algorithm>  // for min, max
 #include <memory>     // for make_shared, __shared_ptr_access
 #include <utility>    // for move
@@ -13,7 +12,7 @@ namespace ftxui {
 
 class Size : public Node {
  public:
-  Size(Element child, Direction direction, Constraint constraint, size_t value)
+  Size(Element child, Direction direction, Constraint constraint, int value)
       : Node(unpack(std::move(child))),
         direction_(direction),
         constraint_(constraint),

src/ftxui/dom/spinner.cpp

@@ -1,4 +1,4 @@
-#include <stddef.h>  // for size_t
+#include <cstddef>  // for size_t
 #include <memory>   // for allocator, allocator_traits<>::value_type
 #include <string>   // for basic_string, string
 #include <utility>  // for move
@@ -8,7 +8,9 @@
 
 namespace ftxui {
 
-static const std::vector<std::vector<std::vector<std::string>>> elements = {
+namespace {
+// NOLINTNEXTLINE
+const std::vector<std::vector<std::vector<std::string>>> elements = {
     {
         {"Replaced by the gauge"},
     },
@@ -246,6 +248,8 @@ static const std::vector<std::vector<std::vector<std::string>>> elements = {
          " LOLLOL ",
      }}};
 
+}  // namespace
+
 /// @brief Useful to represent the effect of time and/or events. This display an
 /// ASCII art "video".
 /// @param charset_index The type of "video".
@@ -254,16 +258,19 @@ static const std::vector<std::vector<std::vector<std::string>>> elements = {
 /// @ingroup dom
 Element spinner(int charset_index, size_t image_index) {
   if (charset_index == 0) {
-    image_index %= 40;
+    const int progress_size = 40;
-    if (image_index > 20)
+    image_index %= progress_size;
-      image_index = 40 - image_index;
+    if (image_index > progress_size / 2) {
-    return gauge(image_index * 0.05);
+      image_index = progress_size - image_index;
     }
-  charset_index %= elements.size();
+    return gauge(float(image_index) * 0.05F);  // NOLINT
-  image_index %= elements[charset_index].size();
+  }
+  charset_index %= (int)elements.size();
+  image_index %= (int)elements[charset_index].size();
   std::vector<Element> lines;
-  for (const auto& it : elements[charset_index][image_index])
+  for (const auto& it : elements[charset_index][image_index]) {
     lines.push_back(text(it));
+  }
   return vbox(std::move(lines));
 }
 

src/ftxui/dom/table.cpp

@@ -13,6 +13,7 @@ bool IsCell(int x, int y) {
   return x % 2 == 1 && y % 2 == 1;
 }
 
+// NOLINTNEXTLINE
 static std::string charset[6][6] = {
     {"┌", "┐", "└", "┘", "─", "│"},  //
     {"┏", "┓", "┗", "┛", "━", "┃"},  //
@@ -29,8 +30,9 @@ int Wrap(int input, int modulo) {
 }
 
 void Order(int& a, int& b) {
-  if (a >= b)
+  if (a >= b) {
     std::swap(a, b);
+  }
 }
 
 }  // namespace
@@ -42,10 +44,10 @@ Table::Table() {
 Table::Table(std::vector<std::vector<std::string>> input) {
   std::vector<std::vector<Element>> output;
   for (auto& row : input) {
-    output.push_back({});
+    output.emplace_back();
     auto& output_row = output.back();
     for (auto& cell : row) {
-      output_row.push_back(text(cell));
+      output_row.push_back(text(std::move(cell)));
     }
   }
   Initialize(std::move(output));
@@ -56,18 +58,20 @@ Table::Table(std::vector<std::vector<Element>> input) {
 }
 
 void Table::Initialize(std::vector<std::vector<Element>> input) {
-  input_dim_y_ = input.size();
+  input_dim_y_ = (int)input.size();
   input_dim_x_ = 0;
-  for (auto& row : input)
+  for (auto& row : input) {
     input_dim_x_ = std::max(input_dim_x_, (int)row.size());
+  }
 
   dim_y_ = 2 * input_dim_y_ + 1;
   dim_x_ = 2 * input_dim_x_ + 1;
 
   // Reserve space.
   elements_.resize(dim_y_);
-  for (int y = 0; y < dim_y_; ++y)
+  for (int y = 0; y < dim_y_; ++y) {
     elements_[y].resize(dim_x_);
+  }
 
   // Transfert elements_ from |input| toward |elements_|.
   {
@@ -88,8 +92,9 @@ void Table::Initialize(std::vector<std::vector<Element>> input) {
       auto& element = elements_[y][x];
 
       if (IsCell(x, y)) {
-        if (!element)
+        if (!element) {
           element = emptyElement();
+        }
         continue;
       }
 
@@ -129,7 +134,7 @@ TableSelection Table::SelectRectangle(int column_min,
   row_max = Wrap(row_max, input_dim_y_);
   Order(row_min, row_max);
 
-  TableSelection output;
+  TableSelection output;  // NOLINT
   output.table_ = this;
   output.x_min_ = 2 * column_min;
   output.x_max_ = 2 * column_max + 2;
@@ -139,7 +144,7 @@ TableSelection Table::SelectRectangle(int column_min,
 }
 
 TableSelection Table::SelectAll() {
-  TableSelection output;
+  TableSelection output;  // NOLINT
   output.table_ = this;
   output.x_min_ = 0;
   output.x_max_ = dim_x_ - 1;
@@ -172,6 +177,7 @@ Element Table::Render() {
   return gridbox(std::move(elements_));
 }
 
+// NOLINTNEXTLINE
 void TableSelection::Decorate(Decorator decorator) {
   for (int y = y_min_; y <= y_max_; ++y) {
     for (int x = x_min_; x <= x_max_; ++x) {
@@ -181,10 +187,11 @@ void TableSelection::Decorate(Decorator decorator) {
   }
 }
 
+// NOLINTNEXTLINE
 void TableSelection::DecorateCells(Decorator decorator) {
   for (int y = y_min_; y <= y_max_; ++y) {
     for (int x = x_min_; x <= x_max_; ++x) {
-      if (y % 2 && x % 2) {
+      if (y % 2 == 1 && x % 2 == 1) {
         Element& e = table_->elements_[y][x];
         e = std::move(e) | decorator;
       }
@@ -192,12 +199,13 @@ void TableSelection::DecorateCells(Decorator decorator) {
   }
 }
 
+// NOLINTNEXTLINE
 void TableSelection::DecorateAlternateColumn(Decorator decorator,
                                              int modulo,
                                              int shift) {
   for (int y = y_min_; y <= y_max_; ++y) {
     for (int x = x_min_; x <= x_max_; ++x) {
-      if (y % 2 && (x / 2) % modulo == shift) {
+      if (y % 2 == 1 && (x / 2) % modulo == shift) {
         Element& e = table_->elements_[y][x];
         e = std::move(e) | decorator;
       }
@@ -205,12 +213,13 @@ void TableSelection::DecorateAlternateColumn(Decorator decorator,
   }
 }
 
+// NOLINTNEXTLINE
 void TableSelection::DecorateAlternateRow(Decorator decorator,
                                           int modulo,
                                           int shift) {
   for (int y = y_min_ + 1; y <= y_max_ - 1; ++y) {
     for (int x = x_min_; x <= x_max_; ++x) {
-      if (y % 2 && (y / 2) % modulo == shift) {
+      if (y % 2 == 1 && (y / 2) % modulo == shift) {
         Element& e = table_->elements_[y][x];
         e = std::move(e) | decorator;
       }
@@ -218,12 +227,13 @@ void TableSelection::DecorateAlternateRow(Decorator decorator,
   }
 }
 
+// NOLINTNEXTLINE
 void TableSelection::DecorateCellsAlternateColumn(Decorator decorator,
                                                   int modulo,
                                                   int shift) {
   for (int y = y_min_; y <= y_max_; ++y) {
     for (int x = x_min_; x <= x_max_; ++x) {
-      if (y % 2 && x % 2 && ((x / 2) % modulo == shift)) {
+      if (y % 2 == 1 && x % 2 == 1 && ((x / 2) % modulo == shift)) {
         Element& e = table_->elements_[y][x];
         e = std::move(e) | decorator;
       }
@@ -231,12 +241,13 @@ void TableSelection::DecorateCellsAlternateColumn(Decorator decorator,
   }
 }
 
+// NOLINTNEXTLINE
 void TableSelection::DecorateCellsAlternateRow(Decorator decorator,
                                                int modulo,
                                                int shift) {
   for (int y = y_min_; y <= y_max_; ++y) {
     for (int x = x_min_; x <= x_max_; ++x) {
-      if (y % 2 && x % 2 && ((y / 2) % modulo == shift)) {
+      if (y % 2 == 1 && x % 2 == 1 && ((y / 2) % modulo == shift)) {
         Element& e = table_->elements_[y][x];
         e = std::move(e) | decorator;
       }
@@ -244,77 +255,82 @@ void TableSelection::DecorateCellsAlternateRow(Decorator decorator,
   }
 }
 
-void TableSelection::Border(BorderStyle style) {
+void TableSelection::Border(BorderStyle border) {
-  BorderLeft(style);
+  BorderLeft(border);
-  BorderRight(style);
+  BorderRight(border);
-  BorderTop(style);
+  BorderTop(border);
-  BorderBottom(style);
+  BorderBottom(border);
 
-  table_->elements_[y_min_][x_min_] = text(charset[style][0]) | automerge;
+  // NOLINTNEXTLINE
-  table_->elements_[y_min_][x_max_] = text(charset[style][1]) | automerge;
+  table_->elements_[y_min_][x_min_] = text(charset[border][0]) | automerge;
-  table_->elements_[y_max_][x_min_] = text(charset[style][2]) | automerge;
+  // NOLINTNEXTLINE
-  table_->elements_[y_max_][x_max_] = text(charset[style][3]) | automerge;
+  table_->elements_[y_min_][x_max_] = text(charset[border][1]) | automerge;
+  // NOLINTNEXTLINE
+  table_->elements_[y_max_][x_min_] = text(charset[border][2]) | automerge;
+  // NOLINTNEXTLINE
+  table_->elements_[y_max_][x_max_] = text(charset[border][3]) | automerge;
 }
 
-void TableSelection::Separator(BorderStyle style) {
+void TableSelection::Separator(BorderStyle border) {
   for (int y = y_min_ + 1; y <= y_max_ - 1; ++y) {
     for (int x = x_min_ + 1; x <= x_max_ - 1; ++x) {
       if (y % 2 == 0 || x % 2 == 0) {
         Element& e = table_->elements_[y][x];
-        e = (y % 2) ? separatorCharacter(charset[style][5]) | automerge
+        e = (y % 2 == 1)
-                    : separatorCharacter(charset[style][4]) | automerge;
+                ? separatorCharacter(charset[border][5]) | automerge   // NOLINT
+                : separatorCharacter(charset[border][4]) | automerge;  // NOLINT
       }
     }
   }
 }
 
-void TableSelection::SeparatorVertical(BorderStyle style) {
+void TableSelection::SeparatorVertical(BorderStyle border) {
   for (int y = y_min_ + 1; y <= y_max_ - 1; ++y) {
     for (int x = x_min_ + 1; x <= x_max_ - 1; ++x) {
       if (x % 2 == 0) {
         table_->elements_[y][x] =
-            separatorCharacter(charset[style][5]) | automerge;
+            separatorCharacter(charset[border][5]) | automerge;  // NOLINT
       }
     }
   }
 }
 
-void TableSelection::SeparatorHorizontal(BorderStyle style) {
+void TableSelection::SeparatorHorizontal(BorderStyle border) {
   for (int y = y_min_ + 1; y <= y_max_ - 1; ++y) {
     for (int x = x_min_ + 1; x <= x_max_ - 1; ++x) {
       if (y % 2 == 0) {
         table_->elements_[y][x] =
-            separatorCharacter(charset[style][4]) | automerge;
+            separatorCharacter(charset[border][4]) | automerge;  // NOLINT
       }
     }
   }
 }
 
-void TableSelection::BorderLeft(BorderStyle style) {
+void TableSelection::BorderLeft(BorderStyle border) {
   for (int y = y_min_; y <= y_max_; y++) {
     table_->elements_[y][x_min_] =
-        separatorCharacter(charset[style][5]) | automerge;
+        separatorCharacter(charset[border][5]) | automerge;  // NOLINT
   }
 }
 
-void TableSelection::BorderRight(BorderStyle style) {
+void TableSelection::BorderRight(BorderStyle border) {
   for (int y = y_min_; y <= y_max_; y++) {
     table_->elements_[y][x_max_] =
-        separatorCharacter(charset[style][5]) | automerge;
+        separatorCharacter(charset[border][5]) | automerge;  // NOLINT
   }
 }
 
-void TableSelection::BorderTop(BorderStyle style) {
+void TableSelection::BorderTop(BorderStyle border) {
   for (int x = x_min_; x <= x_max_; x++) {
     table_->elements_[y_min_][x] =
-        separatorCharacter(charset[style][4]) | automerge;
+        separatorCharacter(charset[border][4]) | automerge;  // NOLINT
   }
 }
 
-void TableSelection::BorderBottom(BorderStyle style) {
+void TableSelection::BorderBottom(BorderStyle border) {
   for (int x = x_min_; x <= x_max_; x++) {
     table_->elements_[y_max_][x] =
-        separatorCharacter(charset[style][4]) | automerge;
+        separatorCharacter(charset[border][4]) | automerge;  // NOLINT
   }
 }
 

src/ftxui/dom/text.cpp

@@ -1,6 +1,7 @@
 #include <algorithm>  // for min
 #include <memory>     // for make_shared
 #include <string>     // for string, wstring
+#include <utility>    // for move
 #include <vector>     // for vector
 
 #include "ftxui/dom/deprecated.hpp"   // for text, vtext
@@ -17,7 +18,7 @@ using ftxui::Screen;
 
 class Text : public Node {
  public:
-  Text(std::string text) : text_(text) {}
+  explicit Text(std::string text) : text_(std::move(text)) {}
 
   void ComputeRequirement() override {
     requirement_.min_x = string_width(text_);
@@ -27,11 +28,13 @@ class Text : public Node {
   void Render(Screen& screen) override {
     int x = box_.x_min;
     int y = box_.y_min;
-    if (y > box_.y_max)
+    if (y > box_.y_max) {
       return;
+    }
     for (const auto& cell : Utf8ToGlyphs(text_)) {
-      if (x > box_.x_max)
+      if (x > box_.x_max) {
         return;
+      }
       screen.PixelAt(x, y).character = cell;
       ++x;
     }
@@ -43,8 +46,8 @@ class Text : public Node {
 
 class VText : public Node {
  public:
-  VText(std::string text)
+  explicit VText(std::string text)
-      : text_(text), width_{std::min(string_width(text_), 1)} {}
+      : text_(std::move(text)), width_{std::min(string_width(text_), 1)} {}
 
   void ComputeRequirement() override {
     requirement_.min_x = width_;
@@ -54,11 +57,13 @@ class VText : public Node {
   void Render(Screen& screen) override {
     int x = box_.x_min;
     int y = box_.y_min;
-    if (x + width_ - 1 > box_.x_max)
+    if (x + width_ - 1 > box_.x_max) {
       return;
+    }
     for (const auto& it : Utf8ToGlyphs(text_)) {
-      if (y > box_.y_max)
+      if (y > box_.y_max) {
         return;
+      }
       screen.PixelAt(x, y).character = it;
       y += 1;
     }
@@ -85,7 +90,7 @@ class VText : public Node {
 /// Hello world!
 /// ```
 Element text(std::string text) {
-  return std::make_shared<Text>(text);
+  return std::make_shared<Text>(std::move(text));
 }
 
 /// @brief Display a piece of unicode text.
@@ -103,7 +108,7 @@ Element text(std::string text) {
 /// ```bash
 /// Hello world!
 /// ```
-Element text(std::wstring text) {
+Element text(std::wstring text) {  // NOLINT
   return std::make_shared<Text>(to_string(text));
 }
 
@@ -134,7 +139,7 @@ Element text(std::wstring text) {
 /// !
 /// ```
 Element vtext(std::string text) {
-  return std::make_shared<VText>(text);
+  return std::make_shared<VText>(std::move(text));
 }
 
 /// @brief Display a piece unicode text vertically.
@@ -163,7 +168,7 @@ Element vtext(std::string text) {
 /// d
 /// !
 /// ```
-Element vtext(std::wstring text) {
+Element vtext(std::wstring text) {  // NOLINT
   return std::make_shared<VText>(to_string(text));
 }
 

src/ftxui/dom/util.cpp

@@ -36,16 +36,18 @@ Element nothing(Element element) {
 /// auto decorator = bold | blink;
 /// ```
 Decorator operator|(Decorator a, Decorator b) {
-  return compose(a, b);
+  return compose(std::move(a),  //
+                 std::move(b));
 }
 
 /// @brief From a set of element, apply a decorator to every elements.
 /// @return the set of decorated element.
 /// @ingroup dom
-Elements operator|(Elements elements, Decorator decorator) {
+Elements operator|(Elements elements, Decorator decorator) {  // NOLINT
   Elements output;
-  for (auto& it : elements)
+  for (auto& it : elements) {
     output.push_back(std::move(it) | decorator);
+  }
   return output;
 }
 
@@ -62,7 +64,7 @@ Elements operator|(Elements elements, Decorator decorator) {
 /// ```cpp
 /// text("Hello") | bold;
 /// ```
-Element operator|(Element element, Decorator decorator) {
+Element operator|(Element element, Decorator decorator) {  // NOLINT
   return decorator(std::move(element));
 }
 
@@ -78,7 +80,7 @@ Element operator|(Element element, Decorator decorator) {
 /// element |= bold;
 /// ```
 Element& operator|=(Element& e, Decorator d) {
-  e = e | d;
+  e = e | std::move(d);
   return e;
 }
 
@@ -95,7 +97,8 @@ Dimensions Dimension::Fit(Element& e) {
 
   Node::Status status;
   e->Check(&status);
-  while (status.need_iteration && status.iteration < 20) {
+  const int max_iteration = 20;
+  while (status.need_iteration && status.iteration < max_iteration) {
     e->ComputeRequirement();
 
     // Don't give the element more space than it needs:
@@ -107,8 +110,9 @@ Dimensions Dimension::Fit(Element& e) {
     status.iteration++;
     e->Check(&status);
 
-    if (!status.need_iteration)
+    if (!status.need_iteration) {
       break;
+    }
     // Increase the size of the box until it fits, but not more than the with of
     // the terminal emulator:
     box.x_max = std::min(e->requirement().min_x, fullsize.dimx);

src/ftxui/dom/vbox.cpp

@@ -1,5 +1,5 @@
-#include <stddef.h>   // for size_t
 #include <algorithm>  // for max
+#include <cstddef>    // for size_t
 #include <memory>  // for __shared_ptr_access, shared_ptr, make_shared, allocator_traits<>::value_type
 #include <utility>  // for move
 #include <vector>   // for vector, __alloc_traits<>::value_type
@@ -14,7 +14,7 @@ namespace ftxui {
 
 class VBox : public Node {
  public:
-  VBox(Elements children) : Node(std::move(children)) {}
+  explicit VBox(Elements children) : Node(std::move(children)) {}
 
   void ComputeRequirement() override {
     requirement_.min_x = 0;

src/ftxui/screen/box.cpp

@@ -17,7 +17,7 @@ Box Box::Intersection(Box a, Box b) {
 
 /// @return whether (x,y) is contained inside the box.
 /// @ingroup screen
-bool Box::Contain(int x, int y) {
+bool Box::Contain(int x, int y) const {
   return x_min <= x &&  //
          x_max >= x &&  //
          y_min <= y &&  //

src/ftxui/screen/color.cpp

@@ -1,20 +1,36 @@
 #include "ftxui/screen/color.hpp"
 
-#include <cassert>
+#include <array>        // for array
+#include <string_view>  // for literals
 
 #include "ftxui/screen/color_info.hpp"  // for GetColorInfo, ColorInfo
-#include "ftxui/screen/terminal.hpp"  // for Terminal, Terminal::Color, Terminal::Palette256, Terminal::TrueColor
+#include "ftxui/screen/terminal.hpp"  // for ColorSupport, Color, Palette256, TrueColor
 
 namespace ftxui {
 
+using namespace std::literals;
+
 namespace {
-const char* palette16code[16][2] = {
+const std::array<const char*, 33> palette16code = {
-    {"30", "40"},  {"31", "41"},  {"32", "42"},  {"33", "43"},
+    "30", "40",   //
-    {"34", "44"},  {"35", "45"},  {"36", "46"},  {"37", "47"},
+    "31", "41",   //
-    {"90", "100"}, {"91", "101"}, {"92", "102"}, {"93", "103"},
+    "32", "42",   //
-    {"94", "104"}, {"95", "105"}, {"96", "106"}, {"97", "107"},
+    "33", "43",   //
+    "34", "44",   //
+    "35", "45",   //
+    "36", "46",   //
+    "37", "47",   //
+    "90", "100",  //
+    "91", "101",  //
+    "92", "102",  //
+    "93", "103",  //
+    "94", "104",  //
+    "95", "105",  //
+    "96", "106",  //
+    "97", "107",  //
 };
-}
+
+}  // namespace
 
 bool Color::operator==(const Color& rhs) const {
   return red_ == rhs.red_ && green_ == rhs.green_ && blue_ == rhs.blue_ &&
@@ -28,16 +44,16 @@ bool Color::operator!=(const Color& rhs) const {
 std::string Color::Print(bool is_background_color) const {
   switch (type_) {
     case ColorType::Palette1:
-      return is_background_color ? "49" : "39";
+      return is_background_color ? "49"s : "39"s;
 
     case ColorType::Palette16:
-      return palette16code[index_][is_background_color];
+      return palette16code[2 * red_ + is_background_color];  // NOLINT;
 
     case ColorType::Palette256:
-      return (is_background_color ? "48;5;" : "38;5;") + std::to_string(index_);
+      return (is_background_color ? "48;5;"s : "38;5;"s) + std::to_string(red_);
 
     case ColorType::TrueColor:
-      return (is_background_color ? "48;2;" : "38;2;")  //
+      return (is_background_color ? "48;2;"s : "38;2;"s)  //
              + std::to_string(red_) + ";"                 //
              + std::to_string(green_) + ";"               //
              + std::to_string(blue_);                     //
@@ -47,23 +63,24 @@ std::string Color::Print(bool is_background_color) const {
 
 /// @brief Build a transparent color.
 /// @ingroup screen
-Color::Color() : type_(ColorType::Palette1) {}
+Color::Color() = default;
 
 /// @brief Build a transparent color.
 /// @ingroup screen
-Color::Color(Palette1) : type_(ColorType::Palette1) {}
+Color::Color(Palette1 /*value*/) : Color() {}
 
 /// @brief Build a transparent using Palette16 colors.
 /// @ingroup screen
-Color::Color(Palette16 index) : type_(ColorType::Palette16), index_(index) {}
+Color::Color(Palette16 index) : type_(ColorType::Palette16), red_(index) {}
 
 /// @brief Build a transparent using Palette256 colors.
 /// @ingroup screen
-Color::Color(Palette256 index) : type_(ColorType::Palette256), index_(index) {
+Color::Color(Palette256 index) : type_(ColorType::Palette256), red_(index) {
-  if (Terminal::ColorSupport() >= Terminal::Color::Palette256)
+  if (Terminal::ColorSupport() >= Terminal::Color::Palette256) {
     return;
+  }
   type_ = ColorType::Palette16;
-  index_ = GetColorInfo(Color::Palette256(index_)).index_16;
+  red_ = GetColorInfo(Color::Palette256(red_)).index_16;
 }
 
 /// @brief Build a Color from its RGB representation.
@@ -75,12 +92,17 @@ Color::Color(Palette256 index) : type_(ColorType::Palette256), index_(index) {
 /// @ingroup screen
 Color::Color(uint8_t red, uint8_t green, uint8_t blue)
     : type_(ColorType::TrueColor), red_(red), green_(green), blue_(blue) {
-  if (Terminal::ColorSupport() == Terminal::Color::TrueColor)
+  if (Terminal::ColorSupport() == Terminal::Color::TrueColor) {
     return;
+  }
 
-  int closest = 256 * 256 * 3;
+  // Find the closest coor from the database:
+  const int max_distance = 256 * 256 * 3;
+  int closest = max_distance;
   int best = 0;
-  for (int i = 16; i < 256; ++i) {
+  const int database_begin = 16;
+  const int database_end = 256;
+  for (int i = database_begin; i < database_end; ++i) {
     ColorInfo color_info = GetColorInfo(Color::Palette256(i));
     int dr = color_info.red - red;
     int dg = color_info.green - green;
@@ -94,10 +116,10 @@ Color::Color(uint8_t red, uint8_t green, uint8_t blue)
 
   if (Terminal::ColorSupport() == Terminal::Color::Palette256) {
     type_ = ColorType::Palette256;
-    index_ = best;
+    red_ = best;
   } else {
     type_ = ColorType::Palette16;
-    index_ = GetColorInfo(Color::Palette256(best)).index_16;
+    red_ = GetColorInfo(Color::Palette256(best)).index_16;
   }
 }
 
@@ -122,24 +144,25 @@ Color Color::RGB(uint8_t red, uint8_t green, uint8_t blue) {
 /// @ingroup screen
 // static
 Color Color::HSV(uint8_t h, uint8_t s, uint8_t v) {
-  if (s == 0)
+  if (s == 0) {
     return Color(v, v, v);
+  }
 
-  uint8_t region = h / 43;
+  uint8_t region = h / 43;                                        // NOLINT
-  uint8_t remainder = (h - (region * 43)) * 6;
+  uint8_t remainder = (h - (region * 43)) * 6;                    // NOLINT
-  uint8_t p = (v * (255 - s)) >> 8;
+  uint8_t p = (v * (255 - s)) >> 8;                               // NOLINT
-  uint8_t q = (v * (255 - ((s * remainder) >> 8))) >> 8;
+  uint8_t q = (v * (255 - ((s * remainder) >> 8))) >> 8;          // NOLINT
-  uint8_t t = (v * (255 - ((s * (255 - remainder)) >> 8))) >> 8;
+  uint8_t t = (v * (255 - ((s * (255 - remainder)) >> 8))) >> 8;  // NOLINT
 
   // clang-format off
-  switch (region) {
+  switch (region) {              // NOLINT
-    case 0: return Color(v,t,p);
+    case 0: return Color(v,t,p); // NOLINT
-    case 1: return Color(q,v,p);
+    case 1: return Color(q,v,p); // NOLINT
-    case 2: return Color(p,v,t);
+    case 2: return Color(p,v,t); // NOLINT
-    case 3: return Color(p,q,v);
+    case 3: return Color(p,q,v); // NOLINT
-    case 4: return Color(t,p,v);
+    case 4: return Color(t,p,v); // NOLINT
-    case 5: return Color(v,p,q);
+    case 5: return Color(v,p,q); // NOLINT
-  }
+  }                              // NOLINT
   // clang-format on
 
   return Color(0, 0, 0);
@@ -147,81 +170,77 @@ Color Color::HSV(uint8_t h, uint8_t s, uint8_t v) {
 
 // static
 Color Color::Interpolate(float t, const Color& a, const Color& b) {
-  float red = 0.f;
+  if (a.type_ == ColorType::Palette1) {
-  float green = 0.f;
+    if (t < 0.5F) {  // NOLINT
-  float blue = 0.f;
-  switch (a.type_) {
-    case ColorType::Palette1: {
-      if (t < 0.5)
       return a;
-      else
+    } else {
       return b;
     }
+  }
+
+  if (b.type_ == ColorType::Palette1) {
+    if (t > 0.5F) {  // NOLINT
+      return a;
+    } else {
+      return b;
+    }
+  }
+
+  auto get_color = [](const Color& color,  //
+                      uint8_t* red, uint8_t* green, uint8_t* blue) {
+    switch (color.type_) {
+      case ColorType::Palette1: {
+        return;
+      }
 
       case ColorType::Palette16: {
-      ColorInfo info = GetColorInfo(Color::Palette16(a.index_));
+        ColorInfo info = GetColorInfo(Color::Palette16(color.red_));
-      red = info.red * (1 - t);
+        *red = info.red;
-      green = info.green * (1 - t);
+        *green = info.green;
-      blue = info.blue * (1 - t);
+        *blue = info.blue;
-      break;
+        return;
       }
 
       case ColorType::Palette256: {
-      ColorInfo info = GetColorInfo(Color::Palette256(a.index_));
+        ColorInfo info = GetColorInfo(Color::Palette256(color.red_));
-      red = info.red * (1 - t);
+        *red = info.red;
-      green = info.green * (1 - t);
+        *green = info.green;
-      blue = info.blue * (1 - t);
+        *blue = info.blue;
-      break;
+        return;
       }
 
       case ColorType::TrueColor: {
-      red = a.red_ * (1 - t);
+        *red = color.red_;
-      green = a.green_ * (1 - t);
+        *green = color.green_;
-      blue = a.blue_ * (1 - t);
+        *blue = color.blue_;
-      break;
+        return;
       }
     }
+  };
 
-  switch (b.type_) {
+  uint8_t red_a = 0;
-    case ColorType::Palette1: {
+  uint8_t green_a = 0;
-      if (t > 0.5)
+  uint8_t blue_a = 0;
-        return a;
+  uint8_t red_b = 0;
-      else
+  uint8_t green_b = 0;
-        return b;
+  uint8_t blue_b = 0;
-    }
+  get_color(a, &red_a, &green_a, &blue_a);
+  get_color(b, &red_b, &green_b, &blue_b);
 
-    case ColorType::Palette16: {
+  return Color::RGB(static_cast<uint8_t>(static_cast<float>(red_a) * (1 - t) +
-      ColorInfo info = GetColorInfo(Color::Palette16(b.index_));
+                                         static_cast<float>(red_b) * t),
-      red += info.red * t;
+                    static_cast<uint8_t>(static_cast<float>(green_a) * (1 - t) +
-      green += info.green * t;
+                                         static_cast<float>(green_b) * t),
-      blue += info.blue * t;
+                    static_cast<uint8_t>(static_cast<float>(blue_a) * (1 - t) +
-      break;
+                                         static_cast<float>(blue_b) * t));
-    }
-
-    case ColorType::Palette256: {
-      ColorInfo info = GetColorInfo(Color::Palette256(b.index_));
-      red += info.red * t;
-      green += info.green * t;
-      blue += info.blue * t;
-      break;
-    }
-
-    case ColorType::TrueColor: {
-      red += b.red_ * t;
-      green += b.green_ * t;
-      blue += b.blue_ * t;
-      break;
-    }
-  }
-  return Color::RGB(red, green, blue);
 }
 
 inline namespace literals {
 
 Color operator""_rgb(unsigned long long int combined) {
-  assert(combined <= 0xffffffU);
+  // assert(combined <= 0xffffffU);
-  auto const red = static_cast<uint8_t>(combined >> 16);
+  auto const red = static_cast<uint8_t>(combined >> 16U);
-  auto const green = static_cast<uint8_t>(combined >> 8);
+  auto const green = static_cast<uint8_t>(combined >> 8U);
   auto const blue = static_cast<uint8_t>(combined);
   return Color(red, green, blue);
 }

src/ftxui/screen/color_info.cpp

@@ -1,10 +1,13 @@
 #include "ftxui/screen/color_info.hpp"
+
+#include <array>
+
 #include "ftxui/screen/color.hpp"  // for Color, Color::Palette16, Color::Palette256
 
 namespace ftxui {
 
 // clang-format off
-const ColorInfo palette256[] = {
+const std::array<ColorInfo, 256> palette256 = {{
      {"Black"              , 0   , 0  , 0   , 0   , 0   , 0   , 0   , 0   } ,
      {"Red"                , 1   , 1  , 128 , 0   , 0   , 0   , 255 , 128 } ,
      {"Green"              , 2   , 2  , 0   , 128 , 0   , 85  , 255 , 128 } ,
@@ -261,14 +264,14 @@ const ColorInfo palette256[] = {
      {"Grey85"             , 253 , 7  , 218 , 218 , 218 , 0   , 0   , 218 } ,
      {"Grey89"             , 254 , 15 , 228 , 228 , 228 , 0   , 0   , 228 } ,
      {"Grey93"             , 255 , 15 , 238 , 238 , 238 , 0   , 0   , 238 } ,
-} ;
+}};
 
 ColorInfo GetColorInfo(Color::Palette256 index) {
-  return palette256[int(index)];
+  return palette256[index]; // NOLINT;
 }
 
 ColorInfo GetColorInfo(Color::Palette16 index) {
-  return palette256[int(index)];
+  return palette256[index]; // NOLINT;
 }
 // clang-format off
 

src/ftxui/screen/screen.cpp

@@ -1,6 +1,7 @@
+#include <stdint.h>  // for uint8_t
 #include <iostream>  // for operator<<, stringstream, basic_ostream, flush, cout, ostream
 #include <map>      // for _Rb_tree_const_iterator, map, operator!=, operator==
-#include <memory>   // for allocator, allocator_traits<>::value_type
+#include <memory>   // for allocator
 #include <sstream>  // IWYU pragma: keep
 #include <utility>  // for pair
 
@@ -19,26 +20,11 @@
 namespace ftxui {
 
 namespace {
-static const char BOLD_SET[] = "\x1B[1m";
-static const char BOLD_RESET[] = "\x1B[22m";  // Can't use 21 here.
 
-static const char DIM_SET[] = "\x1B[2m";
+Pixel& dev_null_pixel() {
-static const char DIM_RESET[] = "\x1B[22m";
+  static Pixel pixel;
-
+  return pixel;
-static const char UNDERLINED_SET[] = "\x1B[4m";
+}
-static const char UNDERLINED_RESET[] = "\x1B[24m";
-
-static const char BLINK_SET[] = "\x1B[5m";
-static const char BLINK_RESET[] = "\x1B[25m";
-
-static const char INVERTED_SET[] = "\x1B[7m";
-static const char INVERTED_RESET[] = "\x1B[27m";
-
-static const char MOVE_LEFT[] = "\r";
-static const char MOVE_UP[] = "\x1B[1A";
-static const char CLEAR_LINE[] = "\x1B[2K";
-
-Pixel dev_null_pixel;
 
 #if defined(_WIN32)
 void WindowsEmulateVT100Terminal() {
@@ -66,20 +52,49 @@ void WindowsEmulateVT100Terminal() {
 void UpdatePixelStyle(std::stringstream& ss,
                       Pixel& previous,
                       const Pixel& next) {
-  if (next.bold != previous.bold)
+  if (next == previous) {
-    ss << (next.bold ? BOLD_SET : BOLD_RESET);
+    return;
+  }
 
-  if (next.dim != previous.dim)
+  if (next.bold && !previous.bold) {
-    ss << (next.dim ? DIM_SET : DIM_RESET);
+    ss << "\x1B[1m";  // BOLD_SET
+  }
 
-  if (next.underlined != previous.underlined)
+  if (!next.bold && previous.bold) {
-    ss << (next.underlined ? UNDERLINED_SET : UNDERLINED_RESET);
+    ss << "\x1B[22m";  // BOLD_RESET
+  }
 
-  if (next.blink != previous.blink)
+  if (next.dim && !previous.dim) {
-    ss << (next.blink ? BLINK_SET : BLINK_RESET);
+    ss << "\x1B[2m";  // DIM_SET
+  }
 
-  if (next.inverted != previous.inverted)
+  if (!next.dim && previous.dim) {
-    ss << (next.inverted ? INVERTED_SET : INVERTED_RESET);
+    ss << "\x1B[22m";  // DIM_RESET
+  }
+
+  if (next.underlined && !previous.underlined) {
+    ss << "\x1B[4m";  // UNDERLINED_SET
+  }
+
+  if (!next.underlined && previous.underlined) {
+    ss << "\x1B[24m";  // UNDERLINED_RESET
+  }
+
+  if (next.blink && !previous.blink) {
+    ss << "\x1B[5m";  // BLINK_SET
+  }
+
+  if (!next.blink && previous.blink) {
+    ss << "\x1B[25m";  // BLINK_RESET
+  }
+
+  if (next.inverted && !previous.inverted) {
+    ss << "\x1B[7m";  // INVERTED_SET
+  }
+
+  if (!next.inverted && previous.inverted) {
+    ss << "\x1B[27m";  // INVERTED_RESET
+  }
 
   if (next.foreground_color != previous.foreground_color ||
       next.background_color != previous.background_color) {
@@ -91,31 +106,31 @@ void UpdatePixelStyle(std::stringstream& ss,
 }
 
 struct TileEncoding {
-  unsigned int left : 2;
+  uint8_t left : 2;
-  unsigned int top : 2;
+  uint8_t top : 2;
-  unsigned int right : 2;
+  uint8_t right : 2;
-  unsigned int down : 2;
+  uint8_t down : 2;
-  unsigned int round : 1;
+  uint8_t round : 1;
 
   // clang-format off
   bool operator<(const TileEncoding& other) const {
-    if (left < other.left) return true;
+    if (left < other.left)   { return  true;  }
-    if (left > other.left) return false;
+    if (left > other.left)   { return  false; }
-    if (top < other.top) return true;
+    if (top < other.top)     { return  true;  }
-    if (top > other.top) return false;
+    if (top > other.top)     { return  false; }
-    if (right < other.right) return true;
+    if (right < other.right) { return  true;  }
-    if (right > other.right) return false;
+    if (right > other.right) { return  false; }
-    if (down < other.down) return true;
+    if (down < other.down)   { return  true;  }
-    if (down > other.down) return false;
+    if (down > other.down)   { return  false; }
-    if (round < other.round) return true;
+    if (round < other.round) { return  true;  }
-    if (round > other.round) return false;
+    if (round > other.round) { return  false; }
       return false;
   }
   // clang-format on
 };
 
 // clang-format off
-const std::map<std::string, TileEncoding> tile_encoding = {
+const std::map<std::string, TileEncoding> tile_encoding = { // NOLINT
     {"─", {1, 0, 1, 0, 0}},
     {"━", {2, 0, 2, 0, 0}},
 
@@ -257,64 +272,73 @@ const std::map<std::string, TileEncoding> tile_encoding = {
 // clang-format on
 
 template <class A, class B>
-const std::map<B, A> InvertMap(const std::map<A, B> input) {
+std::map<B, A> InvertMap(const std::map<A, B> input) {
   std::map<B, A> output;
-  for (const auto& it : input)
+  for (const auto& it : input) {
     output[it.second] = it.first;
+  }
   return output;
 }
 
-const std::map<TileEncoding, std::string> tile_encoding_inverse =
+const std::map<TileEncoding, std::string> tile_encoding_inverse =  // NOLINT
     InvertMap(tile_encoding);
 
 void UpgradeLeftRight(std::string& left, std::string& right) {
   const auto it_left = tile_encoding.find(left);
-  if (it_left == tile_encoding.end())
+  if (it_left == tile_encoding.end()) {
     return;
+  }
   const auto it_right = tile_encoding.find(right);
-  if (it_right == tile_encoding.end())
+  if (it_right == tile_encoding.end()) {
     return;
+  }
 
   if (it_left->second.right == 0 && it_right->second.left != 0) {
     TileEncoding encoding_left = it_left->second;
     encoding_left.right = it_right->second.left;
     const auto it_left_upgrade = tile_encoding_inverse.find(encoding_left);
-    if (it_left_upgrade != tile_encoding_inverse.end())
+    if (it_left_upgrade != tile_encoding_inverse.end()) {
       left = it_left_upgrade->second;
     }
+  }
 
   if (it_right->second.left == 0 && it_left->second.right != 0) {
     TileEncoding encoding_right = it_right->second;
     encoding_right.left = it_left->second.right;
     const auto it_right_upgrade = tile_encoding_inverse.find(encoding_right);
-    if (it_right_upgrade != tile_encoding_inverse.end())
+    if (it_right_upgrade != tile_encoding_inverse.end()) {
       right = it_right_upgrade->second;
     }
+  }
 }
 
 void UpgradeTopDown(std::string& top, std::string& down) {
   const auto it_top = tile_encoding.find(top);
-  if (it_top == tile_encoding.end())
+  if (it_top == tile_encoding.end()) {
     return;
+  }
   const auto it_down = tile_encoding.find(down);
-  if (it_down == tile_encoding.end())
+  if (it_down == tile_encoding.end()) {
     return;
+  }
 
   if (it_top->second.down == 0 && it_down->second.top != 0) {
     TileEncoding encoding_top = it_top->second;
     encoding_top.down = it_down->second.top;
     const auto it_top_down = tile_encoding_inverse.find(encoding_top);
-    if (it_top_down != tile_encoding_inverse.end())
+    if (it_top_down != tile_encoding_inverse.end()) {
       top = it_top_down->second;
     }
+  }
 
   if (it_down->second.top == 0 && it_top->second.down != 0) {
     TileEncoding encoding_down = it_down->second;
     encoding_down.top = it_top->second.down;
     const auto it_down_top = tile_encoding_inverse.find(encoding_down);
-    if (it_down_top != tile_encoding_inverse.end())
+    if (it_down_top != tile_encoding_inverse.end()) {
       down = it_down_top->second;
     }
+  }
 }
 
 bool ShouldAttemptAutoMerge(Pixel& pixel) {
@@ -323,6 +347,18 @@ bool ShouldAttemptAutoMerge(Pixel& pixel) {
 
 }  // namespace
 
+bool Pixel::operator==(const Pixel& other) const {
+  return character == other.character &&                //
+         background_color == other.background_color &&  //
+         foreground_color == other.foreground_color &&  //
+         blink == other.blink &&                        //
+         bold == other.bold &&                          //
+         dim == other.dim &&                            //
+         inverted == other.inverted &&                  //
+         underlined == other.underlined &&              //
+         automerge == other.automerge;                  //
+}
+
 /// A fixed dimension.
 /// @see Fit
 /// @see Full
@@ -409,7 +445,7 @@ std::string& Screen::at(int x, int y) {
 /// @param x The pixel position along the x-axis.
 /// @param y The pixel position along the y-axis.
 Pixel& Screen::PixelAt(int x, int y) {
-  return stencil.Contain(x, y) ? pixels_[y][x] : dev_null_pixel;
+  return stencil.Contain(x, y) ? pixels_[y][x] : dev_null_pixel();
 }
 
 /// @brief Return a string to be printed in order to reset the cursor position
@@ -431,17 +467,19 @@ Pixel& Screen::PixelAt(int x, int y) {
 ///
 /// @return The string to print in order to reset the cursor position to the
 ///         beginning.
-std::string Screen::ResetPosition(bool clear) {
+std::string Screen::ResetPosition(bool clear) const {
   std::stringstream ss;
   if (clear) {
-    ss << MOVE_LEFT << CLEAR_LINE;
+    ss << "\r";       // MOVE_LEFT;
+    ss << "\x1b[2K";  // CLEAR_SCREEN;
     for (int y = 1; y < dimy_; ++y) {
-      ss << MOVE_UP << CLEAR_LINE;
+      ss << "\x1B[1A";  // MOVE_UP;
+      ss << "\x1B[2K";  // CLEAR_LINE;
     }
   } else {
-    ss << MOVE_LEFT;
+    ss << "\r";  // MOVE_LEFT;
     for (int y = 1; y < dimy_; ++y) {
-      ss << MOVE_UP;
+      ss << "\x1B[1A";  // MOVE_UP;
     }
   }
   return ss.str();
@@ -462,18 +500,21 @@ void Screen::ApplyShader() {
     for (int x = 1; x < dimx_; ++x) {
       // Box drawing character uses exactly 3 byte.
       Pixel& cur = pixels_[y][x];
-      if (!ShouldAttemptAutoMerge(cur))
+      if (!ShouldAttemptAutoMerge(cur)) {
         continue;
+      }
 
       Pixel& left = pixels_[y][x-1];
       Pixel& top = pixels_[y-1][x];
 
-      if (ShouldAttemptAutoMerge(left))
+      if (ShouldAttemptAutoMerge(left)) {
         UpgradeLeftRight(left.character, cur.character);
-      if (ShouldAttemptAutoMerge(top))
+      }
+      if (ShouldAttemptAutoMerge(top)) {
         UpgradeTopDown(top.character, cur.character);
       }
     }
+  }
 }
 
 // clang-format on

src/ftxui/screen/string.cpp

@@ -7,11 +7,11 @@
 
 #include "ftxui/screen/string.hpp"
 
-#include <stddef.h>  // for size_t
+#include <array>    // for array
-#include <stdint.h>  // for uint32_t, uint8_t
 #include <codecvt>  // for codecvt_utf8_utf16
+#include <cstdint>  // for uint32_t, uint8_t
 #include <locale>   // for wstring_convert
-#include <string>    // for string, basic_string, wstring, allocator
+#include <string>   // for string, basic_string, wstring
 
 #include "ftxui/screen/deprecated.hpp"  // for wchar_width, wstring_width
 
@@ -24,115 +24,149 @@ struct Interval {
 
 // Sorted list of non-overlapping intervals of non-spacing characters
 // generated by "uniset +cat=Me +cat=Mn +cat=Cf -00AD +1160-11FF +200B c"
-static const Interval g_combining_characters[] = {
+const std::array<Interval, 142> g_combining_characters = {
-    {0x0300, 0x036F},   {0x0483, 0x0486},   {0x0488, 0x0489},
+    Interval{0x0300, 0x036F},   Interval{0x0483, 0x0486},
-    {0x0591, 0x05BD},   {0x05BF, 0x05BF},   {0x05C1, 0x05C2},
+    Interval{0x0488, 0x0489},   Interval{0x0591, 0x05BD},
-    {0x05C4, 0x05C5},   {0x05C7, 0x05C7},   {0x0600, 0x0603},
+    Interval{0x05BF, 0x05BF},   Interval{0x05C1, 0x05C2},
-    {0x0610, 0x0615},   {0x064B, 0x065E},   {0x0670, 0x0670},
+    Interval{0x05C4, 0x05C5},   Interval{0x05C7, 0x05C7},
-    {0x06D6, 0x06E4},   {0x06E7, 0x06E8},   {0x06EA, 0x06ED},
+    Interval{0x0600, 0x0603},   Interval{0x0610, 0x0615},
-    {0x070F, 0x070F},   {0x0711, 0x0711},   {0x0730, 0x074A},
+    Interval{0x064B, 0x065E},   Interval{0x0670, 0x0670},
-    {0x07A6, 0x07B0},   {0x07EB, 0x07F3},   {0x0901, 0x0902},
+    Interval{0x06D6, 0x06E4},   Interval{0x06E7, 0x06E8},
-    {0x093C, 0x093C},   {0x0941, 0x0948},   {0x094D, 0x094D},
+    Interval{0x06EA, 0x06ED},   Interval{0x070F, 0x070F},
-    {0x0951, 0x0954},   {0x0962, 0x0963},   {0x0981, 0x0981},
+    Interval{0x0711, 0x0711},   Interval{0x0730, 0x074A},
-    {0x09BC, 0x09BC},   {0x09C1, 0x09C4},   {0x09CD, 0x09CD},
+    Interval{0x07A6, 0x07B0},   Interval{0x07EB, 0x07F3},
-    {0x09E2, 0x09E3},   {0x0A01, 0x0A02},   {0x0A3C, 0x0A3C},
+    Interval{0x0901, 0x0902},   Interval{0x093C, 0x093C},
-    {0x0A41, 0x0A42},   {0x0A47, 0x0A48},   {0x0A4B, 0x0A4D},
+    Interval{0x0941, 0x0948},   Interval{0x094D, 0x094D},
-    {0x0A70, 0x0A71},   {0x0A81, 0x0A82},   {0x0ABC, 0x0ABC},
+    Interval{0x0951, 0x0954},   Interval{0x0962, 0x0963},
-    {0x0AC1, 0x0AC5},   {0x0AC7, 0x0AC8},   {0x0ACD, 0x0ACD},
+    Interval{0x0981, 0x0981},   Interval{0x09BC, 0x09BC},
-    {0x0AE2, 0x0AE3},   {0x0B01, 0x0B01},   {0x0B3C, 0x0B3C},
+    Interval{0x09C1, 0x09C4},   Interval{0x09CD, 0x09CD},
-    {0x0B3F, 0x0B3F},   {0x0B41, 0x0B43},   {0x0B4D, 0x0B4D},
+    Interval{0x09E2, 0x09E3},   Interval{0x0A01, 0x0A02},
-    {0x0B56, 0x0B56},   {0x0B82, 0x0B82},   {0x0BC0, 0x0BC0},
+    Interval{0x0A3C, 0x0A3C},   Interval{0x0A41, 0x0A42},
-    {0x0BCD, 0x0BCD},   {0x0C3E, 0x0C40},   {0x0C46, 0x0C48},
+    Interval{0x0A47, 0x0A48},   Interval{0x0A4B, 0x0A4D},
-    {0x0C4A, 0x0C4D},   {0x0C55, 0x0C56},   {0x0CBC, 0x0CBC},
+    Interval{0x0A70, 0x0A71},   Interval{0x0A81, 0x0A82},
-    {0x0CBF, 0x0CBF},   {0x0CC6, 0x0CC6},   {0x0CCC, 0x0CCD},
+    Interval{0x0ABC, 0x0ABC},   Interval{0x0AC1, 0x0AC5},
-    {0x0CE2, 0x0CE3},   {0x0D41, 0x0D43},   {0x0D4D, 0x0D4D},
+    Interval{0x0AC7, 0x0AC8},   Interval{0x0ACD, 0x0ACD},
-    {0x0DCA, 0x0DCA},   {0x0DD2, 0x0DD4},   {0x0DD6, 0x0DD6},
+    Interval{0x0AE2, 0x0AE3},   Interval{0x0B01, 0x0B01},
-    {0x0E31, 0x0E31},   {0x0E34, 0x0E3A},   {0x0E47, 0x0E4E},
+    Interval{0x0B3C, 0x0B3C},   Interval{0x0B3F, 0x0B3F},
-    {0x0EB1, 0x0EB1},   {0x0EB4, 0x0EB9},   {0x0EBB, 0x0EBC},
+    Interval{0x0B41, 0x0B43},   Interval{0x0B4D, 0x0B4D},
-    {0x0EC8, 0x0ECD},   {0x0F18, 0x0F19},   {0x0F35, 0x0F35},
+    Interval{0x0B56, 0x0B56},   Interval{0x0B82, 0x0B82},
-    {0x0F37, 0x0F37},   {0x0F39, 0x0F39},   {0x0F71, 0x0F7E},
+    Interval{0x0BC0, 0x0BC0},   Interval{0x0BCD, 0x0BCD},
-    {0x0F80, 0x0F84},   {0x0F86, 0x0F87},   {0x0F90, 0x0F97},
+    Interval{0x0C3E, 0x0C40},   Interval{0x0C46, 0x0C48},
-    {0x0F99, 0x0FBC},   {0x0FC6, 0x0FC6},   {0x102D, 0x1030},
+    Interval{0x0C4A, 0x0C4D},   Interval{0x0C55, 0x0C56},
-    {0x1032, 0x1032},   {0x1036, 0x1037},   {0x1039, 0x1039},
+    Interval{0x0CBC, 0x0CBC},   Interval{0x0CBF, 0x0CBF},
-    {0x1058, 0x1059},   {0x1160, 0x11FF},   {0x135F, 0x135F},
+    Interval{0x0CC6, 0x0CC6},   Interval{0x0CCC, 0x0CCD},
-    {0x1712, 0x1714},   {0x1732, 0x1734},   {0x1752, 0x1753},
+    Interval{0x0CE2, 0x0CE3},   Interval{0x0D41, 0x0D43},
-    {0x1772, 0x1773},   {0x17B4, 0x17B5},   {0x17B7, 0x17BD},
+    Interval{0x0D4D, 0x0D4D},   Interval{0x0DCA, 0x0DCA},
-    {0x17C6, 0x17C6},   {0x17C9, 0x17D3},   {0x17DD, 0x17DD},
+    Interval{0x0DD2, 0x0DD4},   Interval{0x0DD6, 0x0DD6},
-    {0x180B, 0x180D},   {0x18A9, 0x18A9},   {0x1920, 0x1922},
+    Interval{0x0E31, 0x0E31},   Interval{0x0E34, 0x0E3A},
-    {0x1927, 0x1928},   {0x1932, 0x1932},   {0x1939, 0x193B},
+    Interval{0x0E47, 0x0E4E},   Interval{0x0EB1, 0x0EB1},
-    {0x1A17, 0x1A18},   {0x1B00, 0x1B03},   {0x1B34, 0x1B34},
+    Interval{0x0EB4, 0x0EB9},   Interval{0x0EBB, 0x0EBC},
-    {0x1B36, 0x1B3A},   {0x1B3C, 0x1B3C},   {0x1B42, 0x1B42},
+    Interval{0x0EC8, 0x0ECD},   Interval{0x0F18, 0x0F19},
-    {0x1B6B, 0x1B73},   {0x1DC0, 0x1DCA},   {0x1DFE, 0x1DFF},
+    Interval{0x0F35, 0x0F35},   Interval{0x0F37, 0x0F37},
-    {0x200B, 0x200F},   {0x202A, 0x202E},   {0x2060, 0x2063},
+    Interval{0x0F39, 0x0F39},   Interval{0x0F71, 0x0F7E},
-    {0x206A, 0x206F},   {0x20D0, 0x20EF},   {0x302A, 0x302F},
+    Interval{0x0F80, 0x0F84},   Interval{0x0F86, 0x0F87},
-    {0x3099, 0x309A},   {0xA806, 0xA806},   {0xA80B, 0xA80B},
+    Interval{0x0F90, 0x0F97},   Interval{0x0F99, 0x0FBC},
-    {0xA825, 0xA826},   {0xFB1E, 0xFB1E},   {0xFE00, 0xFE0F},
+    Interval{0x0FC6, 0x0FC6},   Interval{0x102D, 0x1030},
-    {0xFE20, 0xFE23},   {0xFEFF, 0xFEFF},   {0xFFF9, 0xFFFB},
+    Interval{0x1032, 0x1032},   Interval{0x1036, 0x1037},
-    {0x10A01, 0x10A03}, {0x10A05, 0x10A06}, {0x10A0C, 0x10A0F},
+    Interval{0x1039, 0x1039},   Interval{0x1058, 0x1059},
-    {0x10A38, 0x10A3A}, {0x10A3F, 0x10A3F}, {0x1D167, 0x1D169},
+    Interval{0x1160, 0x11FF},   Interval{0x135F, 0x135F},
-    {0x1D173, 0x1D182}, {0x1D185, 0x1D18B}, {0x1D1AA, 0x1D1AD},
+    Interval{0x1712, 0x1714},   Interval{0x1732, 0x1734},
-    {0x1D242, 0x1D244}, {0xE0001, 0xE0001}, {0xE0020, 0xE007F},
+    Interval{0x1752, 0x1753},   Interval{0x1772, 0x1773},
-    {0xE0100, 0xE01EF},
+    Interval{0x17B4, 0x17B5},   Interval{0x17B7, 0x17BD},
+    Interval{0x17C6, 0x17C6},   Interval{0x17C9, 0x17D3},
+    Interval{0x17DD, 0x17DD},   Interval{0x180B, 0x180D},
+    Interval{0x18A9, 0x18A9},   Interval{0x1920, 0x1922},
+    Interval{0x1927, 0x1928},   Interval{0x1932, 0x1932},
+    Interval{0x1939, 0x193B},   Interval{0x1A17, 0x1A18},
+    Interval{0x1B00, 0x1B03},   Interval{0x1B34, 0x1B34},
+    Interval{0x1B36, 0x1B3A},   Interval{0x1B3C, 0x1B3C},
+    Interval{0x1B42, 0x1B42},   Interval{0x1B6B, 0x1B73},
+    Interval{0x1DC0, 0x1DCA},   Interval{0x1DFE, 0x1DFF},
+    Interval{0x200B, 0x200F},   Interval{0x202A, 0x202E},
+    Interval{0x2060, 0x2063},   Interval{0x206A, 0x206F},
+    Interval{0x20D0, 0x20EF},   Interval{0x302A, 0x302F},
+    Interval{0x3099, 0x309A},   Interval{0xA806, 0xA806},
+    Interval{0xA80B, 0xA80B},   Interval{0xA825, 0xA826},
+    Interval{0xFB1E, 0xFB1E},   Interval{0xFE00, 0xFE0F},
+    Interval{0xFE20, 0xFE23},   Interval{0xFEFF, 0xFEFF},
+    Interval{0xFFF9, 0xFFFB},   Interval{0x10A01, 0x10A03},
+    Interval{0x10A05, 0x10A06}, Interval{0x10A0C, 0x10A0F},
+    Interval{0x10A38, 0x10A3A}, Interval{0x10A3F, 0x10A3F},
+    Interval{0x1D167, 0x1D169}, Interval{0x1D173, 0x1D182},
+    Interval{0x1D185, 0x1D18B}, Interval{0x1D1AA, 0x1D1AD},
+    Interval{0x1D242, 0x1D244}, Interval{0xE0001, 0xE0001},
+    Interval{0xE0020, 0xE007F}, Interval{0xE0100, 0xE01EF},
 };
 
-static const Interval g_full_width_characters[] = {
+const std::array<Interval, 13> g_full_width_characters = {
-    {0x1100, 0x115f},   {0x2329, 0x2329}, {0x232a, 0x232a}, {0x2e80, 0x303e},
+    Interval{0x1100, 0x115f},   Interval{0x2329, 0x2329},
-    {0x3040, 0xa4cf},   {0xac00, 0xd7a3}, {0xf900, 0xfaff}, {0xfe10, 0xfe19},
+    Interval{0x232a, 0x232a},   Interval{0x2e80, 0x303e},
-    {0xfe30, 0xfe6f},   {0xff00, 0xff60}, {0xffe0, 0xffe6}, {0x20000, 0x2fffd},
+    Interval{0x3040, 0xa4cf},   Interval{0xac00, 0xd7a3},
-    {0x30000, 0x3fffd},
+    Interval{0xf900, 0xfaff},   Interval{0xfe10, 0xfe19},
+    Interval{0xfe30, 0xfe6f},   Interval{0xff00, 0xff60},
+    Interval{0xffe0, 0xffe6},   Interval{0x20000, 0x2fffd},
+    Interval{0x30000, 0x3fffd},
 };
 
 // Find a codepoint inside a sorted list of Interval.
-int Bisearch(uint32_t ucs, const Interval* table, int max) {
+bool Bisearch(uint32_t ucs, const Interval* table, int max) {
-  if (ucs < table[0].first || ucs > table[max].last)
+  if (ucs < table[0].first || ucs > table[max].last) {  // NOLINT
-    return 0;
+    return false;
+  }
 
   int min = 0;
   while (max >= min) {
     int mid = (min + max) / 2;
-    if (ucs > table[mid].last)
+    if (ucs > table[mid].last) {  // NOLINT
       min = mid + 1;
-    else if (ucs < table[mid].first)
+    } else if (ucs < table[mid].first) {  // NOLINT
       max = mid - 1;
-    else
+    } else {
-      return 1;
+      return true;
+    }
   }
 
-  return 0;
+  return false;
 }
 
 bool IsCombining(uint32_t ucs) {
-  return Bisearch(ucs, g_combining_characters,
+  return Bisearch(ucs, g_combining_characters.data(),
-                  sizeof(g_combining_characters) / sizeof(Interval) - 1);
+                  g_combining_characters.size() - 1);
 }
 
 bool IsFullWidth(uint32_t ucs) {
-  if (ucs < 0x0300)  // Quick path:
+  if (ucs < 0x0300)  // Quick path: // NOLINT
     return false;
 
-  return Bisearch(ucs, g_full_width_characters,
+  return Bisearch(ucs, g_full_width_characters.data(),
-                  sizeof(g_full_width_characters) / sizeof(Interval) - 1);
+                  g_full_width_characters.size() - 1);
 }
 
 bool IsControl(uint32_t ucs) {
-  if (ucs == 0)
+  if (ucs == 0) {
     return true;
-  if (ucs < 32)
+  }
+  if (ucs < 32) {  // NOLINT
     return true;
-  if (ucs >= 0x7f && ucs < 0xa0)
+  }
+  if (ucs >= 0x7f && ucs < 0xa0) {  // NOLINT
     return true;
+  }
   return false;
 }
 
 int codepoint_width(uint32_t ucs) {
-  if (IsControl(ucs))
+  if (IsControl(ucs)) {
     return -1;
+  }
 
-  if (IsCombining(ucs))
+  if (IsCombining(ucs)) {
     return 0;
+  }
 
-  if (IsFullWidth(ucs))
+  if (IsFullWidth(ucs)) {
     return 2;
+  }
 
   return 1;
 }
@@ -152,50 +186,53 @@ bool EatCodePoint(const std::string& input,
   uint8_t byte_1 = input[start];
 
   // 1 byte string.
-  if ((byte_1 & 0b1000'0000) == 0b0000'0000) {
+  if ((byte_1 & 0b1000'0000) == 0b0000'0000) {  // NOLINT
-    *ucs = byte_1 & 0b0111'1111;
+    *ucs = byte_1 & 0b0111'1111;                // NOLINT
     *end = start + 1;
     return true;
   }
 
   // 2 byte string.
-  if ((byte_1 & 0b1110'0000) == 0b1100'0000 && start + 1 < input.size()) {
+  if ((byte_1 & 0b1110'0000) == 0b1100'0000 &&  // NOLINT
+      start + 1 < input.size()) {
     uint8_t byte_2 = input[start + 1];
     *ucs = 0;
-    *ucs += byte_1 & 0b0001'1111;
+    *ucs += byte_1 & 0b0001'1111;  // NOLINT
-    *ucs <<= 6;
+    *ucs <<= 6;                    // NOLINT
-    *ucs += byte_2 & 0b0011'1111;
+    *ucs += byte_2 & 0b0011'1111;  // NOLINT
     *end = start + 2;
     return true;
   }
 
   // 3 byte string.
-  if ((byte_1 & 0b1111'0000) == 0b1110'0000 && start + 2 < input.size()) {
+  if ((byte_1 & 0b1111'0000) == 0b1110'0000 &&  // NOLINT
+      start + 2 < input.size()) {
     uint8_t byte_2 = input[start + 1];
     uint8_t byte_3 = input[start + 2];
     *ucs = 0;
-    *ucs += byte_1 & 0b0000'1111;
+    *ucs += byte_1 & 0b0000'1111;  // NOLINT
-    *ucs <<= 6;
+    *ucs <<= 6;                    // NOLINT
-    *ucs += byte_2 & 0b0011'1111;
+    *ucs += byte_2 & 0b0011'1111;  // NOLINT
-    *ucs <<= 6;
+    *ucs <<= 6;                    // NOLINT
-    *ucs += byte_3 & 0b0011'1111;
+    *ucs += byte_3 & 0b0011'1111;  // NOLINT
     *end = start + 3;
     return true;
   }
 
   // 4 byte string.
-  if ((byte_1 & 0b1111'1000) == 0b1111'0000 && start + 3 < input.size()) {
+  if ((byte_1 & 0b1111'1000) == 0b1111'0000 &&  // NOLINT
+      start + 3 < input.size()) {
     uint8_t byte_2 = input[start + 1];
     uint8_t byte_3 = input[start + 2];
     uint8_t byte_4 = input[start + 3];
     *ucs = 0;
-    *ucs += byte_1 & 0b0000'0111;
+    *ucs += byte_1 & 0b0000'0111;  // NOLINT
-    *ucs <<= 6;
+    *ucs <<= 6;                    // NOLINT
-    *ucs += byte_2 & 0b0011'1111;
+    *ucs += byte_2 & 0b0011'1111;  // NOLINT
-    *ucs <<= 6;
+    *ucs <<= 6;                    // NOLINT
-    *ucs += byte_3 & 0b0011'1111;
+    *ucs += byte_3 & 0b0011'1111;  // NOLINT
-    *ucs <<= 6;
+    *ucs <<= 6;                    // NOLINT
-    *ucs += byte_4 & 0b0011'1111;
+    *ucs += byte_4 & 0b0011'1111;  // NOLINT
     *end = start + 4;
     return true;
   }
@@ -216,8 +253,9 @@ int wstring_width(const std::wstring& text) {
 
   for (const wchar_t& it : text) {
     int w = wchar_width(it);
-    if (w < 0)
+    if (w < 0) {
       return -1;
+    }
     width += w;
   }
   return width;
@@ -228,14 +266,17 @@ int string_width(const std::string& input) {
   size_t start = 0;
   while (start < input.size()) {
     uint32_t codepoint = 0;
-    if (!EatCodePoint(input, start, &start, &codepoint))
+    if (!EatCodePoint(input, start, &start, &codepoint)) {
       continue;
+    }
 
-    if (IsControl(codepoint))
+    if (IsControl(codepoint)) {
       continue;
+    }
 
-    if (IsCombining(codepoint))
+    if (IsCombining(codepoint)) {
       continue;
+    }
 
     if (IsFullWidth(codepoint)) {
       width += 2;
@@ -254,7 +295,7 @@ std::vector<std::string> Utf8ToGlyphs(const std::string& input) {
   size_t start = 0;
   size_t end = 0;
   while (start < input.size()) {
-    uint32_t codepoint;
+    uint32_t codepoint = 0;
     if (!EatCodePoint(input, start, &end, &codepoint)) {
       start = end;
       continue;
@@ -264,13 +305,15 @@ std::vector<std::string> Utf8ToGlyphs(const std::string& input) {
     start = end;
 
     // Ignore control characters.
-    if (IsControl(codepoint))
+    if (IsControl(codepoint)) {
       continue;
+    }
 
     // Combining characters are put with the previous glyph they are modifying.
     if (IsCombining(codepoint)) {
-      if (out.size() != 0)
+      if (!out.empty()) {
         out.back() += append;
+      }
       continue;
     }
 
@@ -278,7 +321,7 @@ std::vector<std::string> Utf8ToGlyphs(const std::string& input) {
     // string to reserve the space the first is taking.
     if (IsFullWidth(codepoint)) {
       out.push_back(append);
-      out.push_back("");
+      out.emplace_back("");
       continue;
     }
 
@@ -288,14 +331,13 @@ std::vector<std::string> Utf8ToGlyphs(const std::string& input) {
   return out;
 }
 
-int GlyphPosition(const std::string& input,
+int GlyphPosition(const std::string& input, size_t glyph_index, size_t start) {
-                  size_t glyph_to_skip,
+  if (glyph_index <= 0) {
-                  size_t start) {
-  if (glyph_to_skip <= 0)
     return 0;
+  }
   size_t end = 0;
   while (start < input.size()) {
-    uint32_t codepoint;
+    uint32_t codepoint = 0;
     bool eaten = EatCodePoint(input, start, &end, &codepoint);
 
     // Ignore invalid, control characters and combining characters.
@@ -306,14 +348,15 @@ int GlyphPosition(const std::string& input,
 
     // We eat the beginning of the next glyph. If we are eating the one
     // requested, return its start position immediately.
-    if (glyph_to_skip == 0)
+    if (glyph_index == 0) {
-      return start;
+      return static_cast<int>(start);
+    }
 
     // Otherwise, skip this glyph and iterate:
-    glyph_to_skip--;
+    glyph_index--;
     start = end;
   }
-  return input.size();
+  return static_cast<int>(input.size());
 }
 
 std::vector<int> CellToGlyphIndex(const std::string& input) {
@@ -323,13 +366,14 @@ std::vector<int> CellToGlyphIndex(const std::string& input) {
   size_t start = 0;
   size_t end = 0;
   while (start < input.size()) {
-    uint32_t codepoint;
+    uint32_t codepoint = 0;
     bool eaten = EatCodePoint(input, start, &end, &codepoint);
     start = end;
 
     // Ignore invalid / control characters.
-    if (!eaten || IsControl(codepoint))
+    if (!eaten || IsControl(codepoint)) {
       continue;
+    }
 
     // Combining characters are put with the previous glyph they are modifying.
     if (IsCombining(codepoint)) {
@@ -361,19 +405,21 @@ int GlyphCount(const std::string& input) {
   size_t start = 0;
   size_t end = 0;
   while (start < input.size()) {
-    uint32_t codepoint;
+    uint32_t codepoint = 0;
     bool eaten = EatCodePoint(input, start, &end, &codepoint);
     start = end;
 
     // Ignore invalid characters:
-    if (!eaten || IsControl(codepoint))
+    if (!eaten || IsControl(codepoint)) {
       continue;
+    }
 
     // Ignore combining characters, except when they don't have a preceding to
     // combine with.
     if (IsCombining(codepoint)) {
-      if (size == 0)
+      if (size == 0) {
         size++;
+      }
       continue;
     }
 

src/ftxui/screen/terminal.cpp

@@ -18,89 +18,57 @@
 
 namespace ftxui {
 
-#if defined(__EMSCRIPTEN__)
-// This dimension was chosen arbitrarily to be able to display:
-// https://arthursonzogni.com/FTXUI/examples
-// This will have to be improved when someone has time to implement and need
-// it.
-static Dimensions fallback_size{140, 43};
-Dimensions Terminal::Size() {
-  return fallback_size;
-}
-
-#elif defined(_WIN32)
-
-// The terminal size in VT100 was 80x24. It is still used nowadays by
-// default in many terminal emulator. That's a good choice for a fallback
-// value.
-static Dimensions fallback_size{80, 24};
-Dimensions Terminal::Size() {
-  CONSOLE_SCREEN_BUFFER_INFO csbi;
-
-  if (GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi)) {
-    return Dimensions{csbi.srWindow.Right - csbi.srWindow.Left + 1,
-                      csbi.srWindow.Bottom - csbi.srWindow.Top + 1};
-  }
-
-  return fallback_size;
-}
-
-#else
-// The terminal size in VT100 was 80x24. It is still used nowadays by
-// default in many terminal emulator. That's a good choice for a fallback
-// value.
-static Dimensions fallback_size{80, 24};
-Dimensions Terminal::Size() {
-  winsize w{};
-  const int status = ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
-  // The ioctl return value result should be checked. Some operating systems
-  // don't support TIOCGWINSZ.
-  if (w.ws_col == 0 || w.ws_row == 0 || status < 0) {
-    return fallback_size;
-  }
-  return Dimensions{w.ws_col, w.ws_row};
-}
-
-#endif
-
-/// @brief Override terminal size in case auto-detection fails
-/// @param fallbackSize Terminal dimensions to fallback to
-void Terminal::SetFallbackSize(const Dimensions& fallbackSize) {
-  fallback_size = fallbackSize;
-}
-
 namespace {
+Dimensions& FallbackSize() {
+#if defined(__EMSCRIPTEN__)
+  // This dimension was chosen arbitrarily to be able to display:
+  // https://arthursonzogni.com/FTXUI/examples
+  // This will have to be improved when someone has time to implement and need
+  // it.
+  constexpr int fallback_width = 140;
+  constexpr int fallback_height = 43;
+#else
+  // The terminal size in VT100 was 80x24. It is still used nowadays by
+  // default in many terminal emulator. That's a good choice for a fallback
+  // value.
+  constexpr int fallback_width = 80;
+  constexpr int fallback_height = 24;
+#endif
+  static Dimensions g_fallback_size{fallback_width, fallback_height};
+  return g_fallback_size;
+}
 
 const char* Safe(const char* c) {
-  return c ? c : "";
+  return (c != nullptr) ? c : "";
 }
 
 bool Contains(const std::string& s, const char* key) {
   return s.find(key) != std::string::npos;
 }
 
-static bool cached = false;
-Terminal::Color cached_supported_color;
 Terminal::Color ComputeColorSupport() {
 #if defined(__EMSCRIPTEN__)
   return Terminal::Color::TrueColor;
 #endif
 
-  std::string COLORTERM = Safe(std::getenv("COLORTERM"));
+  std::string COLORTERM = Safe(std::getenv("COLORTERM"));  // NOLINT
-  if (Contains(COLORTERM, "24bit") || Contains(COLORTERM, "truecolor"))
+  if (Contains(COLORTERM, "24bit") || Contains(COLORTERM, "truecolor")) {
     return Terminal::Color::TrueColor;
+  }
 
-  std::string TERM = Safe(std::getenv("TERM"));
+  std::string TERM = Safe(std::getenv("TERM"));  // NOLINT
-  if (Contains(COLORTERM, "256") || Contains(TERM, "256"))
+  if (Contains(COLORTERM, "256") || Contains(TERM, "256")) {
     return Terminal::Color::Palette256;
+  }
 
 #if defined(FTXUI_MICROSOFT_TERMINAL_FALLBACK)
   // Microsoft terminals do not properly declare themselve supporting true
   // colors: https://github.com/microsoft/terminal/issues/1040
   // As a fallback, assume microsoft terminal are the ones not setting those
   // variables, and enable true colors.
-  if (TERM == "" && COLORTERM == "")
+  if (TERM == "" && COLORTERM == "") {
     return Terminal::Color::TrueColor;
+  }
 #endif
 
   return Terminal::Color::Palette16;
@@ -108,7 +76,43 @@ Terminal::Color ComputeColorSupport() {
 
 }  // namespace
 
+Dimensions Terminal::Size() {
+#if defined(__EMSCRIPTEN__)
+  // This dimension was chosen arbitrarily to be able to display:
+  // https://arthursonzogni.com/FTXUI/examples
+  // This will have to be improved when someone has time to implement and need
+  // it.
+  return FallbackSize();
+#elif defined(_WIN32)
+  CONSOLE_SCREEN_BUFFER_INFO csbi;
+
+  if (GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi)) {
+    return Dimensions{csbi.srWindow.Right - csbi.srWindow.Left + 1,
+                      csbi.srWindow.Bottom - csbi.srWindow.Top + 1};
+  }
+
+  return FallbackSize();
+#else
+  winsize w{};
+  const int status = ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);  // NOLINT
+  // The ioctl return value result should be checked. Some operating systems
+  // don't support TIOCGWINSZ.
+  if (w.ws_col == 0 || w.ws_row == 0 || status < 0) {
+    return FallbackSize();
+  }
+  return Dimensions{w.ws_col, w.ws_row};
+#endif
+}
+
+/// @brief Override terminal size in case auto-detection fails
+/// @param fallbackSize Terminal dimensions to fallback to
+void Terminal::SetFallbackSize(const Dimensions& fallbackSize) {
+  FallbackSize() = fallbackSize;
+}
+
 Terminal::Color Terminal::ColorSupport() {
+  static bool cached = false;
+  static Terminal::Color cached_supported_color;
   if (!cached) {
     cached = true;
     cached_supported_color = ComputeColorSupport();