Feature: Add multi-line input. (#630)

CHANGELOG.md

@@ -5,6 +5,8 @@ current (development)
 ---------------------
 
 ### Component
+- Feature: `input` is now multi-line.
+- Feature: `input` style can now be customized.
 - Feature: Support `ResizableSplit` with customizable separator.
 - Breaking: MenuDirection enum is renamed Direction
 - Fix: Remove useless new line when using an alternative screen.
@@ -12,9 +14,7 @@ current (development)
 ### Dom
 - Feature: Add the dashed style for border and separator.
 - Feature: Add colored borders.
-- Feature: Customize with gradient color effect. Add the following decorators:
+- Feature: Add `LinearGradient`!
-  - `colorgrad`
-  - `bgcolorgrad`
 - Improvement: Color::Interpolate() uses gamma correction.
 
 ###

cmake/ftxui_test.cmake

@@ -71,3 +71,5 @@ include(GoogleTest)
 gtest_discover_tests(ftxui-tests
   DISCOVERY_TIMEOUT 600
 )
+
+set(CMAKE_CTEST_ARGUMENTS "--rerun-failed --output-on-failure")

examples/component/CMakeLists.txt

@@ -17,6 +17,7 @@ example(focus_cursor)
 example(gallery)
 example(homescreen)
 example(input)
+example(input_style)
 example(linear_gradient_gallery)
 example(maybe)
 example(menu)
@@ -40,5 +41,6 @@ example(slider_direction)
 example(slider_rgb)
 example(tab_horizontal)
 example(tab_vertical)
+example(textarea)
 example(toggle)
 example(with_restored_io)

examples/component/input_style.cpp

@@ -0,0 +1,98 @@
+#include <ftxui/dom/linear_gradient.hpp>  // for LinearGradient
+#include <ftxui/screen/color.hpp>  // for Color, Color::White, Color::Red, Color::Blue, Color::Black, Color::GrayDark, ftxui
+#include <functional>              // for function
+#include <string>                  // for allocator, string
+#include <utility>                 // for move
+
+#include "ftxui/component/component.hpp"  // for Input, Horizontal, Vertical, operator|
+#include "ftxui/component/component_base.hpp"     // for Component
+#include "ftxui/component/component_options.hpp"  // for InputState, InputOption
+#include "ftxui/component/screen_interactive.hpp"  // for ScreenInteractive
+#include "ftxui/dom/elements.hpp"  // for operator|=, Element, bgcolor, operator|, separatorEmpty, color, borderEmpty, separator, text, center, dim, hbox, vbox, border, borderDouble, borderRounded
+
+int main(int argc, const char* argv[]) {
+  using namespace ftxui;
+
+  InputOption style_1 = InputOption::Default();
+
+  InputOption style_2 = InputOption::Spacious();
+
+  InputOption style_3 = InputOption::Spacious();
+  style_3.transform = [](InputState state) {
+    state.element |= borderEmpty;
+
+    if (state.is_placeholder) {
+      state.element |= dim;
+    }
+
+    if (state.focused) {
+      state.element |= borderDouble;
+      state.element |= bgcolor(Color::White);
+      state.element |= color(Color::Black);
+    } else if (state.hovered) {
+      state.element |= borderRounded;
+      state.element |= bgcolor(LinearGradient(90, Color::Blue, Color::Red));
+      state.element |= color(Color::White);
+    } else {
+      state.element |= border;
+      state.element |= bgcolor(LinearGradient(0, Color::Blue, Color::Red));
+      state.element |= color(Color::White);
+    }
+
+    return state.element;
+  };
+
+  InputOption style_4 = InputOption::Spacious();
+  style_4.transform = [](InputState state) {
+    state.element = hbox({
+        text("Theorem") | center | borderEmpty | bgcolor(Color::Red),
+        separatorEmpty(),
+        separator() | color(Color::White),
+        separatorEmpty(),
+        std::move(state.element),
+    });
+
+    state.element |= borderEmpty;
+    if (state.is_placeholder) {
+      state.element |= dim;
+    }
+
+    if (state.focused) {
+      state.element |= bgcolor(Color::Black);
+    } else {
+      state.element |= bgcolor(Color::Blue);
+    }
+
+    if (state.hovered) {
+      state.element |= bgcolor(Color::GrayDark);
+    }
+
+    return vbox({state.element, separatorEmpty()});
+  };
+
+  auto generateUiFromStyle = [&](InputOption style) {
+    auto first_name = new std::string();   // Leaked
+    auto middle_name = new std::string();  // Leaked
+    auto last_name = new std::string();    // Leaked
+    return Container::Vertical({
+               Input(first_name, "first name", style),
+               Input(middle_name, "middle name", style),
+               Input(last_name, "last name", style),
+           }) |
+           borderEmpty;
+  };
+
+  auto ui = Container::Horizontal({
+      generateUiFromStyle(style_1),
+      generateUiFromStyle(style_2),
+      generateUiFromStyle(style_3),
+      generateUiFromStyle(style_4),
+  });
+
+  auto screen = ScreenInteractive::TerminalOutput();
+  screen.Loop(ui);
+}
+
+// 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.

examples/component/textarea.cpp

@@ -0,0 +1,35 @@
+#include <memory>  // for allocator, __shared_ptr_access, shared_ptr
+#include <string>  // for string
+
+#include "ftxui/component/captured_mouse.hpp"  // for ftxui
+#include "ftxui/component/component.hpp"  // for Input, Renderer, ResizableSplitLeft
+#include "ftxui/component/component_base.hpp"  // for ComponentBase, Component
+#include "ftxui/component/screen_interactive.hpp"  // for ScreenInteractive
+#include "ftxui/dom/elements.hpp"  // for operator|, separator, text, Element, flex, vbox, border
+
+int main(int argc, const char* argv[]) {
+  using namespace ftxui;
+
+  std::string content_1;
+  std::string content_2;
+  auto textarea_1 = Input(&content_1);
+  auto textarea_2 = Input(&content_2);
+  int size = 50;
+  auto layout = ResizableSplitLeft(textarea_1, textarea_2, &size);
+
+  auto component = Renderer(layout, [&] {
+    return vbox({
+               text("Input:"),
+               separator(),
+               layout->Render() | flex,
+           }) |
+           border;
+  });
+
+  auto screen = ScreenInteractive::Fullscreen();
+  screen.Loop(component);
+}
+
+// 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/component/component.hpp

@@ -51,8 +51,9 @@ Component Checkbox(ConstStringRef label,
                    bool* checked,
                    Ref<CheckboxOption> option = CheckboxOption::Simple());
 
+Component Input(StringRef content, Ref<InputOption> option = {});
 Component Input(StringRef content,
-                ConstStringRef placeholder,
+                StringRef placeholder,
                 Ref<InputOption> option = {});
 
 Component Menu(ConstStringListRef entries,

include/ftxui/component/component_options.hpp

@@ -5,7 +5,7 @@
 #include <ftxui/component/animation.hpp>  // for Duration, QuadraticInOut, Function
 #include <ftxui/dom/direction.hpp>  // for Direction, Direction::Left, Direction::Right, Direction::Down
 #include <ftxui/dom/elements.hpp>  // for Element, separator
-#include <ftxui/util/ref.hpp>      // for Ref, ConstRef
+#include <ftxui/util/ref.hpp>      // for Ref, ConstRef, StringRef
 #include <functional>              // for function
 #include <optional>                // for optional
 #include <string>                  // for string
@@ -134,20 +134,42 @@ struct CheckboxOption {
   std::function<void()> on_change = [] {};
 };
 
+/// @brief Used to define style for the Input component.
+struct InputState {
+  Element element;
+  bool hovered;         /// < Whether the input is hovered by the mouse.
+  bool focused;         /// < Whether the input is focused by the user.
+  bool is_placeholder;  /// < Whether the input is empty and displaying the
+                        /// < placeholder.
+};
+
 /// @brief Option for the Input component.
 /// @ingroup component
 struct InputOption {
+  // A set of predefined styles:
+
+  /// @brief Create the default input style:
+  static InputOption Default();
+  /// @brief A white on black style with high margins:
+  static InputOption Spacious();
+  /// @brief A style with a border:
+  static InputOption Arthur();
+
+  /// The content of the input when it's empty.
+  StringRef placeholder = "";
+
+  // Style:
+  std::function<Element(InputState)> transform;
+  Ref<bool> password = false;  /// < Obscure the input content using '*'.
+  Ref<bool> multiline = true;  /// < Whether the input can be multiline.
+
   /// Called when the content changes.
   std::function<void()> on_change = [] {};
   /// Called when the user presses enter.
   std::function<void()> on_enter = [] {};
 
-  /// Obscure the input content using '*'.
+  // The char position of the cursor:
-  Ref<bool> password = false;
+  Ref<int> cursor_position = 0;
-
-  /// When set different from -1, this attributes is used to store the cursor
-  /// position.
-  Ref<int> cursor_position = -1;
 };
 
 /// @brief Option for the Radiobox component.

include/ftxui/component/receiver.hpp

@@ -1,7 +1,7 @@
 #ifndef FTXUI_COMPONENT_RECEIVER_HPP_
 #define FTXUI_COMPONENT_RECEIVER_HPP_
 
-#include <algorithm>           // for copy
+#include <algorithm>           // for copy, max
 #include <atomic>              // for atomic, __atomic_base
 #include <condition_variable>  // for condition_variable
 #include <functional>

include/ftxui/screen/string.hpp

@@ -15,44 +15,10 @@ std::wstring to_wstring(T s) {
 }
 
 int string_width(const std::string&);
+
 // Split the string into a its glyphs. An empty one is inserted ater fullwidth
 // ones.
 std::vector<std::string> Utf8ToGlyphs(const std::string& input);
-// If |input| was an array of glyphs, this returns the number of char to eat
-// before reaching the glyph at index |glyph_index|.
-int GlyphPosition(const std::string& input,
-                  size_t glyph_index,
-                  size_t start = 0);
-// Returns the number of glyphs in |input|.
-int GlyphCount(const std::string& input);
-
-// Properties from:
-// https://www.unicode.org/Public/UCD/latest/ucd/auxiliary/WordBreakProperty.txt
-enum class WordBreakProperty {
-  ALetter,
-  CR,
-  Double_Quote,
-  Extend,
-  ExtendNumLet,
-  Format,
-  Hebrew_Letter,
-  Katakana,
-  LF,
-  MidLetter,
-  MidNum,
-  MidNumLet,
-  Newline,
-  Numeric,
-  Regional_Indicator,
-  Single_Quote,
-  WSegSpace,
-  ZWJ,
-};
-WordBreakProperty CodepointToWordBreakProperty(uint32_t codepoint);
-std::vector<WordBreakProperty> Utf8ToWordBreakProperty(
-    const std::string& input);
-
-bool IsWordBreakingCharacter(const std::string& input, size_t glyph_index);
 
 // Map every cells drawn by |input| to their corresponding Glyphs. Half-size
 // Glyphs takes one cell, full-size Glyphs take two cells.

include/ftxui/util/ref.hpp

@@ -48,6 +48,7 @@ class StringRef {
   StringRef(const wchar_t* ref) : StringRef(to_string(std::wstring(ref))) {}
   StringRef(const char* ref) : StringRef(std::string(ref)) {}
   std::string& operator*() { return address_ ? *address_ : owned_; }
+  std::string& operator()() { return address_ ? *address_ : owned_; }
   std::string* operator->() { return address_ ? address_ : &owned_; }
 
  private:

src/ftxui/component/button_test.cpp

@@ -1,4 +1,3 @@
-#include <gtest/gtest.h>  // for AssertionResult, Message, TestPartResult, EXPECT_EQ, Test, EXPECT_FALSE, EXPECT_TRUE, TestInfo (ptr only), TEST
 #include <chrono>  // for operator""s, chrono_literals
 #include <memory>  // for __shared_ptr_access, shared_ptr, allocator
 #include <string>  // for string
@@ -12,6 +11,7 @@
 #include "ftxui/dom/node.hpp"         // for Render
 #include "ftxui/screen/screen.hpp"    // for Screen
 #include "ftxui/screen/terminal.hpp"  // for SetColorSupport, Color, TrueColor
+#include "gtest/gtest.h"  // for AssertionResult, Message, TestPartResult, EXPECT_EQ, Test, EXPECT_FALSE, EXPECT_TRUE, TEST
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/component/collapsible_test.cpp

@@ -1,12 +1,13 @@
-#include <gtest/gtest.h>
 #include <memory>  // for __shared_ptr_access, shared_ptr, allocator
+#include <string>  // for string
 
 #include "ftxui/component/component.hpp"       // for Collapsible, Renderer
 #include "ftxui/component/component_base.hpp"  // for ComponentBase
 #include "ftxui/component/event.hpp"  // for Event, Event::Return, Event::ArrowDown
-#include "ftxui/dom/elements.hpp"     // for text, Element
+#include "ftxui/dom/elements.hpp"     // for Element, text
 #include "ftxui/dom/node.hpp"         // for Render
 #include "ftxui/screen/screen.hpp"  // for Screen
+#include "gtest/gtest.h"  // for AssertionResult, Message, Test, TestPartResult, EXPECT_EQ, EXPECT_FALSE, EXPECT_TRUE, TEST
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/component/component_options.cpp

@@ -1,11 +1,12 @@
 #include "ftxui/component/component_options.hpp"
 
-#include <ftxui/screen/color.hpp>  // for Color, Color::Black, Color::White, Color::GrayDark, Color::GrayLight
+#include <ftxui/dom/linear_gradient.hpp>  // for LinearGradient
+#include <ftxui/screen/color.hpp>  // for Color, Color::White, Color::Black, Color::GrayDark, Color::Blue, Color::GrayLight, Color::Red
 #include <memory>                  // for shared_ptr
 #include <utility>                 // for move
 
 #include "ftxui/component/animation.hpp"  // for Function, Duration
-#include "ftxui/dom/elements.hpp"  // for operator|=, text, Element, bold, inverted, operator|, dim, hbox, automerge, borderEmpty, borderLight
+#include "ftxui/dom/elements.hpp"  // for operator|=, Element, text, bgcolor, inverted, bold, dim, operator|, color, borderEmpty, hbox, automerge, border, borderLight
 
 namespace ftxui {
 
@@ -257,6 +258,77 @@ RadioboxOption RadioboxOption::Simple() {
   return option;
 }
 
+// static
+InputOption InputOption::Default() {
+  InputOption option;
+  option.transform = [](InputState state) {
+    state.element |= color(Color::White);
+
+    if (state.is_placeholder) {
+      state.element |= dim;
+    }
+
+    if (state.focused) {
+      state.element |= inverted;
+    } else if (state.hovered) {
+      state.element |= bgcolor(Color::GrayDark);
+    }
+
+    return state.element;
+  };
+  return option;
+}
+
+// static
+InputOption InputOption::Spacious() {
+  InputOption option;
+  option.transform = [](InputState state) {
+    state.element |= borderEmpty;
+    state.element |= color(Color::White);
+
+    if (state.is_placeholder) {
+      state.element |= dim;
+    }
+
+    if (state.focused) {
+      state.element |= bgcolor(Color::Black);
+    }
+
+    if (state.hovered) {
+      state.element |= bgcolor(Color::GrayDark);
+    }
+
+    return state.element;
+  };
+  return option;
+}
+
+// static
+InputOption InputOption::Arthur() {
+  InputOption option;
+  option.transform = [](InputState state) {
+    state.element |= borderEmpty;
+    state.element |= color(Color::White);
+
+    if (state.is_placeholder) {
+      state.element |= dim;
+    }
+
+    if (state.focused) {
+      state.element |= bgcolor(Color::Black);
+    } else {
+      state.element |= bgcolor(LinearGradient(0, Color::Blue, Color::Red));
+    }
+
+    if (state.hovered) {
+      state.element |= bgcolor(Color::GrayDark);
+    }
+
+    return state.element;
+  };
+  return option;
+}
+
 }  // namespace ftxui
 
 // Copyright 2022 Arthur Sonzogni. All rights reserved.

src/ftxui/component/component_test.cpp

@@ -1,8 +1,9 @@
-#include <gtest/gtest.h>
 #include <memory>  // for shared_ptr, __shared_ptr_access, allocator, __shared_ptr_access<>::element_type, make_shared
+#include <string>  // for string
 
 #include "ftxui/component/component.hpp"       // for Make
 #include "ftxui/component/component_base.hpp"  // for ComponentBase, Component
+#include "gtest/gtest.h"  // for Message, TestPartResult, EXPECT_EQ, Test, AssertionResult, TEST, EXPECT_FALSE
 
 namespace ftxui {
 

src/ftxui/component/container_test.cpp

@@ -1,9 +1,10 @@
-#include <gtest/gtest.h>
 #include <memory>  // for __shared_ptr_access, shared_ptr, allocator
+#include <string>  // for string
 
 #include "ftxui/component/component.hpp"  // for Horizontal, Vertical, Button, Tab
 #include "ftxui/component/component_base.hpp"  // for ComponentBase, Component
 #include "ftxui/component/event.hpp"  // for Event, Event::Tab, Event::TabReverse, Event::ArrowDown, Event::ArrowLeft, Event::ArrowRight, Event::ArrowUp
+#include "gtest/gtest.h"  // for AssertionResult, Message, TestPartResult, EXPECT_EQ, EXPECT_FALSE, Test, EXPECT_TRUE, TEST
 
 namespace ftxui {
 

src/ftxui/component/hoverable_test.cpp

@@ -1,6 +1,6 @@
-#include <gtest/gtest.h>  // for AssertionResult, Message, TestPartResult, EXPECT_FALSE, EXPECT_EQ, Test, EXPECT_TRUE, TestInfo (ptr only), TEST
 #include <ftxui/dom/elements.hpp>  // for Element, text
 #include <memory>  // for shared_ptr, __shared_ptr_access, allocator
+#include <string>  // for string
 
 #include "ftxui/component/component.hpp"  // for Hoverable, Horizontal, operator|=, Renderer
 #include "ftxui/component/component_base.hpp"  // for ComponentBase, Component
@@ -8,6 +8,7 @@
 #include "ftxui/component/mouse.hpp"  // for Mouse, Mouse::Left, Mouse::Released
 #include "ftxui/dom/node.hpp"         // for Render
 #include "ftxui/screen/screen.hpp"    // for Screen
+#include "gtest/gtest.h"  // for AssertionResult, Message, TestPartResult, EXPECT_FALSE, EXPECT_EQ, Test, EXPECT_TRUE, TEST
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/component/input.cpp

@@ -1,8 +1,10 @@
+#include <stdint.h>    // for uint32_t
 #include <algorithm>   // for max, min
 #include <cstddef>     // for size_t
 #include <functional>  // for function
-#include <memory>      // for shared_ptr
+#include <memory>   // for allocator, shared_ptr, allocator_traits<>::value_type
-#include <string>      // for string, allocator
+#include <sstream>  // for basic_istream, stringstream
+#include <string>   // for string, basic_string, operator==, getline
 #include <utility>  // for move
 #include <vector>   // for vector
 
@@ -10,23 +12,44 @@
 #include "ftxui/component/component.hpp"          // for Make, Input
 #include "ftxui/component/component_base.hpp"     // for ComponentBase
 #include "ftxui/component/component_options.hpp"  // for InputOption
-#include "ftxui/component/event.hpp"  // for Event, Event::ArrowLeft, Event::ArrowLeftCtrl, Event::ArrowRight, Event::ArrowRightCtrl, Event::Backspace, Event::Custom, Event::Delete, Event::End, Event::Home, Event::Return
+#include "ftxui/component/event.hpp"  // for Event, Event::ArrowDown, Event::ArrowLeft, Event::ArrowLeftCtrl, Event::ArrowRight, Event::ArrowRightCtrl, Event::ArrowUp, Event::Backspace, Event::Delete, Event::End, Event::Home, 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|, text, Element, reflect, operator|=, flex, inverted, hbox, size, bold, dim, focus, focusCursorBarBlinking, frame, select, Decorator, EQUAL, HEIGHT
+#include "ftxui/dom/elements.hpp"  // for operator|, reflect, text, Element, xflex, hbox, Elements, frame, operator|=, vbox, focus, focusCursorBarBlinking, select
 #include "ftxui/screen/box.hpp"    // for Box
-#include "ftxui/screen/string.hpp"  // for GlyphPosition, WordBreakProperty, GlyphCount, Utf8ToWordBreakProperty, CellToGlyphIndex, WordBreakProperty::ALetter, WordBreakProperty::CR, WordBreakProperty::Double_Quote, WordBreakProperty::Extend, WordBreakProperty::ExtendNumLet, WordBreakProperty::Format, WordBreakProperty::Hebrew_Letter, WordBreakProperty::Katakana, WordBreakProperty::LF, WordBreakProperty::MidLetter, WordBreakProperty::MidNum, WordBreakProperty::MidNumLet, WordBreakProperty::Newline, WordBreakProperty::Numeric, WordBreakProperty::Regional_Indicator, WordBreakProperty::Single_Quote, WordBreakProperty::WSegSpace, WordBreakProperty::ZWJ
+#include "ftxui/screen/string.hpp"           // for string_width
+#include "ftxui/screen/string_internal.hpp"  // for GlyphNext, GlyphPrevious, WordBreakProperty, EatCodePoint, CodepointToWordBreakProperty, IsFullWidth, WordBreakProperty::ALetter, WordBreakProperty::CR, WordBreakProperty::Double_Quote, WordBreakProperty::Extend, WordBreakProperty::ExtendNumLet, WordBreakProperty::Format, WordBreakProperty::Hebrew_Letter, WordBreakProperty::Katakana, WordBreakProperty::LF, WordBreakProperty::MidLetter, WordBreakProperty::MidNum, WordBreakProperty::MidNumLet, WordBreakProperty::Newline, WordBreakProperty::Numeric, WordBreakProperty::Regional_Indicator, WordBreakProperty::Single_Quote, WordBreakProperty::WSegSpace, WordBreakProperty::ZWJ
 #include "ftxui/screen/util.hpp"             // for clamp
-#include "ftxui/util/ref.hpp"       // for StringRef, Ref, ConstStringRef
+#include "ftxui/util/ref.hpp"                // for StringRef, Ref
 
 namespace ftxui {
 
 namespace {
 
-// Group together several propertiej so they appear to form a similar group.
+std::vector<std::string> Split(const std::string& input) {
-// For instance, letters are grouped with number and form a single word.
+  std::vector<std::string> output;
-bool IsWordCharacter(WordBreakProperty property) {
+  std::stringstream ss(input);
-  switch (property) {
+  std::string line;
+  while (std::getline(ss, line)) {
+    output.push_back(line);
+  }
+  if (input.back() == '\n') {
+    output.push_back("");
+  }
+  return output;
+}
+
+size_t GlyphWidth(const std::string& input, size_t iter) {
+  uint32_t ucs = 0;
+  if (!EatCodePoint(input, iter, &iter, &ucs))
+    return 0;
+  if (IsFullWidth(ucs))
+    return 2;
+  return 1;
+}
+
+bool IsWordCodePoint(uint32_t codepoint) {
+  switch (CodepointToWordBreakProperty(codepoint)) {
     case WordBreakProperty::ALetter:
     case WordBreakProperty::Hebrew_Letter:
     case WordBreakProperty::Katakana:
@@ -42,7 +65,7 @@ bool IsWordCharacter(WordBreakProperty property) {
     case WordBreakProperty::Newline:
     case WordBreakProperty::Single_Quote:
     case WordBreakProperty::WSegSpace:
-    // Unsure:
+    // Unexpected/Unsure
     case WordBreakProperty::Extend:
     case WordBreakProperty::ExtendNumLet:
     case WordBreakProperty::Format:
@@ -50,216 +73,398 @@ bool IsWordCharacter(WordBreakProperty property) {
     case WordBreakProperty::ZWJ:
       return false;
   }
-  return true;  // NOT_REACHED();
+  return false;  // NOT_REACHED();
 }
 
-std::string PasswordField(size_t size) {
+bool IsWordCharacter(const std::string& input, size_t iter) {
-  std::string out;
+  uint32_t ucs = 0;
-  out.reserve(2 * size);
+  if (!EatCodePoint(input, iter, &iter, &ucs)) {
-  while (size--) {
+    return false;
-    out += "•";
   }
-  return out;
+
+  return IsWordCodePoint(ucs);
 }
 
 // An input box. The user can type text into it.
 class InputBase : public ComponentBase {
  public:
-  InputBase(StringRef content,
+  // NOLINTNEXTLINE
-            ConstStringRef placeholder,
+  InputBase(StringRef content, Ref<InputOption> option)
-            Ref<InputOption> option)
+      : content_(std::move(content)), option_(std::move(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) {
-      return opt;
-    }
-    return cursor_position_internal_;
-  }
 
+ private:
   // Component implementation:
   Element Render() override {
-    std::string password_content;
-    if (option_->password()) {
-      password_content = PasswordField(content_->size());
-    }
-    const std::string& content =
-        option_->password() ? password_content : *content_;
-
-    const int size = GlyphCount(content);
-
-    cursor_position() = std::max(0, std::min<int>(size, cursor_position()));
-    auto main_decorator = flex | ftxui::size(HEIGHT, EQUAL, 1);
     const bool is_focused = Focused();
+    const auto focused =
+        (is_focused || hovered_) ? focusCursorBarBlinking : select;
+
+    auto transform = option_->transform ? option_->transform
+                                        : InputOption::Default().transform;
 
     // placeholder.
-    if (size == 0) {
+    if (content_->empty()) {
-      auto element = text(*placeholder_) | dim | main_decorator | reflect(box_);
+      auto element = text(option_->placeholder()) | xflex | frame;
       if (is_focused) {
         element |= focus;
       }
-      if (hovered_ || is_focused) {
-        element |= inverted;
-      }
-      return element;
-    }
 
-    // Not focused.
+      return transform({
-    if (!is_focused) {
+                 std::move(element), hovered_, is_focused,
-      auto element = text(content) | main_decorator | reflect(box_);
+                 true  // placeholder
-      if (hovered_) {
-        element |= inverted;
-      }
-      return element;
-    }
-
-    const int index_before_cursor = GlyphPosition(content, cursor_position());
-    const int index_after_cursor =
-        GlyphPosition(content, 1, index_before_cursor);
-    const std::string part_before_cursor =
-        content.substr(0, index_before_cursor);
-    std::string part_at_cursor = " ";
-    if (cursor_position() < size) {
-      part_at_cursor = content.substr(index_before_cursor,
-                                      index_after_cursor - index_before_cursor);
-    }
-    const std::string part_after_cursor = content.substr(index_after_cursor);
-    auto focused = (is_focused || hovered_) ? focusCursorBarBlinking : select;
-    return hbox({
-               text(part_before_cursor),
-               text(part_at_cursor) | focused | reflect(cursor_box_),
-               text(part_after_cursor),
              }) |
-           flex | frame | bold | main_decorator | reflect(box_);
+             reflect(box_);
+    }
+
+    Elements elements;
+    std::vector<std::string> lines = Split(*content_);
+
+    int& cursor_position = option_->cursor_position();
+    cursor_position = util::clamp(cursor_position, 0, (int)content_->size());
+
+    // Find the line and index of the cursor.
+    int cursor_line = 0;
+    int cursor_char_index = cursor_position;
+    for (const auto& line : lines) {
+      if (cursor_char_index <= (int)line.size()) {
+        break;
+      }
+
+      cursor_char_index -= line.size() + 1;
+      cursor_line++;
+    }
+
+    if (lines.empty()) {
+      elements.push_back(text("") | focused);
+    }
+
+    for (size_t i = 0; i < lines.size(); ++i) {
+      const std::string& line = lines[i];
+
+      // This is not the cursor line.
+      if (int(i) != cursor_line) {
+        elements.push_back(Text(line));
+        continue;
+      }
+
+      // The cursor is at the end of the line.
+      if (cursor_char_index >= (int)line.size()) {
+        elements.push_back(hbox({
+                               Text(line),
+                               text(" ") | focused | reflect(cursor_box_),
+                           }) |
+                           xflex);
+        continue;
+      }
+
+      // The cursor is on this line.
+      const int glyph_start = cursor_char_index;
+      const int glyph_end = GlyphNext(line, glyph_start);
+      const std::string part_before_cursor = line.substr(0, glyph_start);
+      const std::string part_at_cursor =
+          line.substr(glyph_start, glyph_end - glyph_start);
+      const std::string part_after_cursor = line.substr(glyph_end);
+      auto element = hbox({
+                         Text(part_before_cursor),
+                         Text(part_at_cursor) | focused | reflect(cursor_box_),
+                         Text(part_after_cursor),
+                     }) |
+                     xflex;
+      elements.push_back(element);
+    }
+
+    auto element = vbox(std::move(elements)) | frame;
+    return transform({
+               std::move(element), hovered_, is_focused,
+               false  // placeholder
+           }) |
+           xflex | reflect(box_);
+  }
+
+  Element Text(const std::string& input) {
+    if (!option_->password()) {
+      return text(input);
+    }
+
+    std::string out;
+    out.reserve(10 + input.size() * 3 / 2);
+    for (size_t i = 0; i < input.size(); ++i) {
+      out += "•";
+    }
+    return text(out);
+  }
+
+  bool HandleBackspace() {
+    int& cursor_position = option_->cursor_position();
+    if (cursor_position == 0) {
+      return false;
+    }
+    const size_t start = GlyphPrevious(content_(), cursor_position);
+    const size_t end = cursor_position;
+    content_->erase(start, end - start);
+    cursor_position = start;
+    return true;
+  }
+
+  bool HandleDelete() {
+    int& cursor_position = option_->cursor_position();
+    if (cursor_position == (int)content_->size()) {
+      return false;
+    }
+    const size_t start = cursor_position;
+    const size_t end = GlyphNext(content_(), cursor_position);
+    content_->erase(start, end - start);
+    return true;
+  }
+
+  bool HandleArrowLeft() {
+    int& cursor_position = option_->cursor_position();
+    if (cursor_position == 0) {
+      return false;
+    }
+
+    cursor_position = GlyphPrevious(content_(), cursor_position);
+    return true;
+  }
+
+  bool HandleArrowRight() {
+    int& cursor_position = option_->cursor_position();
+    if (cursor_position == (int)content_->size()) {
+      return false;
+    }
+
+    cursor_position = GlyphNext(content_(), cursor_position);
+    return true;
+  }
+
+  size_t CursorColumn() {
+    int& cursor_position = option_->cursor_position();
+    size_t iter = cursor_position;
+    int width = 0;
+    while (true) {
+      if (iter == 0) {
+        break;
+      }
+      iter = GlyphPrevious(content_(), iter);
+      if (content_()[iter] == '\n') {
+        break;
+      }
+      width += GlyphWidth(content_(), iter);
+    }
+    return width;
+  }
+
+  // Move the cursor `columns` on the right, if possible.
+  void MoveCursorColumn(int columns) {
+    int& cursor_position = option_->cursor_position();
+    while (columns > 0) {
+      if (cursor_position == (int)content_().size() ||
+          content_()[cursor_position] == '\n') {
+        return;
+      }
+
+      columns -= GlyphWidth(content_(), cursor_position);
+      cursor_position = GlyphNext(content_(), cursor_position);
+    }
+  }
+
+  bool HandleArrowUp() {
+    int& cursor_position = option_->cursor_position();
+    if (cursor_position == 0) {
+      return false;
+    }
+
+    size_t columns = CursorColumn();
+
+    // Move cursor at the beginning of 2 lines above.
+    while (true) {
+      if (cursor_position == 0) {
+        return true;
+      }
+      size_t previous = GlyphPrevious(content_(), cursor_position);
+      if (content_()[previous] == '\n') {
+        break;
+      }
+      cursor_position = previous;
+    }
+    cursor_position = GlyphPrevious(content_(), cursor_position);
+    while (true) {
+      if (cursor_position == 0) {
+        break;
+      }
+      size_t previous = GlyphPrevious(content_(), cursor_position);
+      if (content_()[previous] == '\n') {
+        break;
+      }
+      cursor_position = previous;
+    }
+
+    MoveCursorColumn(columns);
+    return true;
+  }
+
+  bool HandleArrowDown() {
+    int& cursor_position = option_->cursor_position();
+    if (cursor_position == (int)content_->size()) {
+      return false;
+    }
+
+    size_t columns = CursorColumn();
+
+    // Move cursor at the beginning of the next line
+    while (true) {
+      if (content_()[cursor_position] == '\n') {
+        break;
+      }
+      cursor_position = GlyphNext(content_(), cursor_position);
+      if (cursor_position == (int)content_().size()) {
+        return true;
+      }
+    }
+    cursor_position = GlyphNext(content_(), cursor_position);
+
+    MoveCursorColumn(columns);
+    return true;
+  }
+
+  bool HandleHome() {
+    int& cursor_position = option_->cursor_position();
+    cursor_position = 0;
+    return true;
+  }
+
+  bool HandleEnd() {
+    int& cursor_position = option_->cursor_position();
+    cursor_position = content_->size();
+    return true;
+  }
+
+  bool HandleReturn() {
+    int& cursor_position = option_->cursor_position();
+    content_->insert(cursor_position, "\n");
+    cursor_position++;
+    option_->on_change();
+    return true;
+  }
+
+  bool HandleCharacter(const std::string& character) {
+    if (character == "\n" && !option_->multiline()) {
+      option_->on_enter();
+      return false;
+    }
+
+    int& cursor_position = option_->cursor_position();
+    content_->insert(cursor_position, character);
+    cursor_position += character.size();
+    option_->on_change();
+
+    if (character == "\n") {
+      option_->on_enter();
+    }
+    return true;
   }
 
   bool OnEvent(Event event) override {
-    cursor_position() =
+    int& cursor_position = option_->cursor_position();
-        std::max(0, std::min<int>((int)content_->size(), cursor_position()));
+    cursor_position = util::clamp(cursor_position, 0, (int)content_->size());
 
+    if (event.is_character()) {
+      return HandleCharacter(event.character());
+    }
     if (event.is_mouse()) {
-      return OnMouseEvent(event);
+      return HandleMouse(event);
     }
-
-    // Backspace.
     if (event == Event::Backspace) {
-      if (cursor_position() == 0) {
+      return HandleBackspace();
-        return false;
     }
-      const size_t start = GlyphPosition(*content_, cursor_position() - 1);
-      const size_t end = GlyphPosition(*content_, cursor_position());
-      content_->erase(start, end - start);
-      cursor_position()--;
-      option_->on_change();
-      return true;
-    }
-
-    // Delete
     if (event == Event::Delete) {
-      if (cursor_position() == int(content_->size())) {
+      return HandleDelete();
-        return false;
     }
-      const size_t start = GlyphPosition(*content_, cursor_position());
+    if (event == Event::ArrowLeft) {
-      const size_t end = GlyphPosition(*content_, cursor_position() + 1);
+      return HandleArrowLeft();
-      content_->erase(start, end - start);
-      option_->on_change();
-      return true;
     }
-
+    if (event == Event::ArrowRight) {
-    // Enter.
+      return HandleArrowRight();
-    if (event == Event::Return) {
-      option_->on_enter();
-      return true;
     }
-
+    if (event == Event::ArrowUp) {
-    if (event == Event::Custom) {
+      return HandleArrowUp();
-      return false;
     }
-
+    if (event == Event::ArrowDown) {
-    // Arrow
+      return HandleArrowDown();
-    if (event == Event::ArrowLeft && cursor_position() > 0) {
-      cursor_position()--;
-      return true;
     }
-
+    if (event == Event::Home) {
-    if (event == Event::ArrowRight &&
+      return HandleHome();
-        cursor_position() < static_cast<int>(content_->size())) {
+    }
-      cursor_position()++;
+    if (event == Event::End) {
-      return true;
+      return HandleEnd();
     }
-
-    // CTRL + Arrow:
     if (event == Event::ArrowLeftCtrl) {
-      HandleLeftCtrl();
+      return HandleLeftCtrl();
-      return true;
     }
     if (event == Event::ArrowRightCtrl) {
-      HandleRightCtrl();
+      return HandleRightCtrl();
-      return true;
+    }
+    if (event == Event::Return) {
+      return HandleReturn();
     }
 
-    if (event == Event::Home) {
-      cursor_position() = 0;
-      return true;
-    }
-
-    if (event == Event::End) {
-      cursor_position() = GlyphCount(*content_);
-      return true;
-    }
-
-    // Content
-    if (event.is_character()) {
-      const size_t start = GlyphPosition(*content_, cursor_position());
-      content_->insert(start, event.character());
-      cursor_position()++;
-      option_->on_change();
-      return true;
-    }
     return false;
   }
 
- private:
+  bool HandleLeftCtrl() {
-  void HandleLeftCtrl() {
+    int& cursor_position = option_->cursor_position();
-    auto properties = Utf8ToWordBreakProperty(*content_);
+    if (cursor_position == 0) {
-
+      return false;
-    // Move left, as long as left is not a word character.
-    while (cursor_position() > 0 &&
-           !IsWordCharacter(properties[cursor_position() - 1])) {
-      cursor_position()--;
     }
 
+    // Move left, as long as left it not a word.
+    while (cursor_position) {
+      size_t previous = GlyphPrevious(content_(), cursor_position);
+      if (IsWordCharacter(content_(), previous)) {
+        break;
+      }
+      cursor_position = previous;
+    }
     // Move left, as long as left is a word character:
-    while (cursor_position() > 0 &&
+    while (cursor_position) {
-           IsWordCharacter(properties[cursor_position() - 1])) {
+      size_t previous = GlyphPrevious(content_(), cursor_position);
-      cursor_position()--;
+      if (!IsWordCharacter(content_(), previous)) {
+        break;
       }
+      cursor_position = previous;
+    }
+    return true;
   }
 
-  void HandleRightCtrl() {
+  bool HandleRightCtrl() {
-    auto properties = Utf8ToWordBreakProperty(*content_);
+    int& cursor_position = option_->cursor_position();
-    const int max = properties.size();
+    if (cursor_position == (int)content_().size()) {
-
+      return false;
-    // Move right, as long as right is not a word character.
-    while (cursor_position() < max &&
-           !IsWordCharacter(properties[cursor_position()])) {
-      cursor_position()++;
     }
 
+    // Move right, until entering a word.
+    while (cursor_position < (int)content_().size()) {
+      cursor_position = GlyphNext(content_(), cursor_position);
+      if (IsWordCharacter(content_(), cursor_position)) {
+        break;
+      }
+    }
     // Move right, as long as right is a word character:
-    while (cursor_position() < max &&
+    while (cursor_position < (int)content_().size()) {
-           IsWordCharacter(properties[cursor_position()])) {
+      size_t next = GlyphNext(content_(), cursor_position);
-      cursor_position()++;
+      if (!IsWordCharacter(content_(), cursor_position)) {
+        break;
       }
+      cursor_position = next;
     }
 
-  bool OnMouseEvent(Event event) {
+    return true;
-    hovered_ =
+  }
-        box_.Contain(event.mouse().x, event.mouse().y) && CaptureMouse(event);
+
+  bool HandleMouse(Event event) {
+    hovered_ = box_.Contain(event.mouse().x,  //
+                            event.mouse().y) &&
+               CaptureMouse(event);
     if (!hovered_) {
       return false;
     }
@@ -270,32 +475,56 @@ class InputBase : public ComponentBase {
     }
 
     TakeFocus();
+
     if (content_->empty()) {
+      option_->cursor_position() = 0;
       return true;
     }
 
-    auto mapping = CellToGlyphIndex(*content_);
+    // Find the line and index of the cursor.
-    int original_glyph = cursor_position();
+    std::vector<std::string> lines = Split(*content_);
-    original_glyph = util::clamp(original_glyph, 0, int(mapping.size()));
+    int& cursor_position = option_->cursor_position();
-    size_t original_cell = 0;
+    int cursor_line = 0;
-    for (size_t i = 0; i < mapping.size(); i++) {
+    int cursor_char_index = cursor_position;
-      if (mapping[i] == original_glyph) {
+    for (const auto& line : lines) {
-        original_cell = i;
+      if (cursor_char_index <= (int)line.size()) {
         break;
       }
+
+      cursor_char_index -= line.size() + 1;
+      cursor_line++;
     }
-    if (mapping[original_cell] != original_glyph) {
+    int cursor_column =
-      original_cell = mapping.size();
+        string_width(lines[cursor_line].substr(0, cursor_char_index));
+
+    int new_cursor_column = cursor_column + event.mouse().x - cursor_box_.x_min;
+    int new_cursor_line = cursor_line + event.mouse().y - cursor_box_.y_min;
+
+    // Fix the new cursor position:
+    new_cursor_line = std::max(std::min(new_cursor_line, (int)lines.size()), 0);
+
+    std::string empty_string;
+    const std::string& line = new_cursor_line < (int)lines.size()
+                                  ? lines[new_cursor_line]
+                                  : empty_string;
+    new_cursor_column = util::clamp(new_cursor_column, 0, string_width(line));
+
+    if (new_cursor_column == cursor_column &&  //
+        new_cursor_line == cursor_line) {
+      return false;
     }
-    const int target_cell =
+
-        int(original_cell) + event.mouse().x - cursor_box_.x_min;
+    // Convert back the new_cursor_{line,column} toward cursor_position:
-    int target_glyph = target_cell < int(mapping.size()) ? mapping[target_cell]
+    cursor_position = 0;
-                                                         : int(mapping.size());
+    for (int i = 0; i < new_cursor_line; ++i) {
-    target_glyph = util::clamp(target_glyph, 0, GlyphCount(*content_));
+      cursor_position += lines[i].size() + 1;
-    if (cursor_position() != target_glyph) {
+    }
-      cursor_position() = target_glyph;
+    while (new_cursor_column > 0) {
+      new_cursor_column -= GlyphWidth(content_(), cursor_position);
+      cursor_position = GlyphNext(content_(), cursor_position);
+    }
+
     option_->on_change();
-    }
     return true;
   }
 
@@ -303,7 +532,6 @@ class InputBase : public ComponentBase {
 
   bool hovered_ = false;
   StringRef content_;
-  ConstStringRef placeholder_;
 
   Box box_;
   Box cursor_box_;
@@ -314,7 +542,6 @@ class InputBase : public ComponentBase {
 
 /// @brief An input box for editing text.
 /// @param content The editable content.
-/// @param placeholder The text displayed when content is still empty.
 /// @param option Additional optional parameters.
 /// @ingroup component
 /// @see InputBase
@@ -334,15 +561,19 @@ class InputBase : public ComponentBase {
 /// ```bash
 /// placeholder
 /// ```
+Component Input(StringRef content, Ref<InputOption> option) {
+  return Make<InputBase>(std::move(content), std::move(option));
+}
+
 Component Input(StringRef content,
-                ConstStringRef placeholder,
+                StringRef placeholder,
                 Ref<InputOption> option) {
-  return Make<InputBase>(std::move(content), std::move(placeholder),
+  option->placeholder = placeholder;
-                         std::move(option));
+  return Make<InputBase>(std::move(content), std::move(option));
 }
 
 }  // namespace ftxui
 
-// Copyright 2020 Arthur Sonzogni. All rights reserved.
+// Copyright 2022 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in
 // the LICENSE file.

src/ftxui/component/radiobox_test.cpp

@@ -1,4 +1,3 @@
-#include <gtest/gtest.h>  // for AssertionResult, Message, TestPartResult, EXPECT_EQ, EXPECT_TRUE, Test, TestInfo (ptr only), EXPECT_FALSE, TEST
 #include <ftxui/dom/elements.hpp>   // for yframe
 #include <ftxui/dom/node.hpp>       // for Render
 #include <ftxui/screen/screen.hpp>  // for Screen
@@ -11,6 +10,7 @@
 #include "ftxui/component/component_options.hpp"  // for RadioboxOption
 #include "ftxui/component/event.hpp"  // for Event, Event::Return, Event::ArrowDown, Event::End, Event::Home, Event::Tab, Event::TabReverse, Event::PageDown, Event::PageUp, Event::ArrowUp
 #include "ftxui/util/ref.hpp"         // for Ref
+#include "gtest/gtest.h"  // for AssertionResult, Message, TestPartResult, EXPECT_EQ, EXPECT_TRUE, Test, EXPECT_FALSE, TEST
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/component/receiver_test.cpp

@@ -1,8 +1,9 @@
-#include <gtest/gtest.h>
+#include <string>   // for string
 #include <thread>   // for thread
 #include <utility>  // for move
 
 #include "ftxui/component/receiver.hpp"
+#include "gtest/gtest.h"  // for AssertionResult, Message, Test, TestPartResult, EXPECT_EQ, EXPECT_TRUE, EXPECT_FALSE, TEST
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/component/resizable_split_test.cpp

@@ -1,6 +1,6 @@
-#include <gtest/gtest.h>  // for AssertionResult, Message, TestPartResult, Test, EXPECT_EQ, EXPECT_TRUE, TestInfo (ptr only), TEST
 #include <ftxui/dom/direction.hpp>  // for Direction, Direction::Down, Direction::Left, Direction::Right, Direction::Up
 #include <memory>  // for __shared_ptr_access, shared_ptr, allocator
+#include <string>  // for string
 
 #include "ftxui/component/component.hpp"  // for ResizableSplit, Renderer, ResizableSplitBottom, ResizableSplitLeft, ResizableSplitRight, ResizableSplitTop
 #include "ftxui/component/component_base.hpp"  // for ComponentBase, Component
@@ -9,6 +9,7 @@
 #include "ftxui/dom/elements.hpp"   // for Element, separatorDouble, text
 #include "ftxui/dom/node.hpp"       // for Render
 #include "ftxui/screen/screen.hpp"  // for Screen
+#include "gtest/gtest.h"  // for AssertionResult, Message, TestPartResult, Test, EXPECT_EQ, EXPECT_TRUE, TEST
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/component/slider_test.cpp

@@ -1,17 +1,17 @@
-#include <gtest/gtest.h>  // for AssertionResult, Message, TestPartResult, Test, EXPECT_EQ, EXPECT_TRUE, TestInfo (ptr only), EXPECT_FALSE, TEST
 #include <array>                      // for array
 #include <cstddef>                    // for size_t
 #include <ftxui/component/mouse.hpp>  // for Mouse, Mouse::Left, Mouse::Pressed, Mouse::Released
 #include <ftxui/dom/direction.hpp>  // for Direction, Direction::Down, Direction::Left, Direction::Right, Direction::Up
 #include <ftxui/dom/elements.hpp>   // for frame
 #include <memory>  // for shared_ptr, __shared_ptr_access, allocator
-#include <string>  // for to_string
+#include <string>  // for string, to_string
 
 #include "ftxui/component/component.hpp"  // for Slider, Vertical, operator|=
 #include "ftxui/component/component_base.hpp"  // for ComponentBase
 #include "ftxui/component/event.hpp"           // for Event, Event::ArrowDown
 #include "ftxui/dom/node.hpp"                  // for Render
 #include "ftxui/screen/screen.hpp"             // for Screen
+#include "gtest/gtest.h"  // for AssertionResult, Message, TestPartResult, Test, EXPECT_EQ, EXPECT_TRUE, EXPECT_FALSE, TEST
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/component/terminal_input_parser_test.cpp

@@ -1,13 +1,13 @@
-#include <gtest/gtest.h>  // for AssertionResult, Test, Message, TestPartResult, SuiteApiResolver, TestInfo (ptr only), EXPECT_EQ, EXPECT_TRUE, TEST, TestFactoryImpl, EXPECT_FALSE
 #include <ftxui/component/mouse.hpp>  // for Mouse, Mouse::Left, Mouse::Middle, Mouse::Pressed, Mouse::Released, Mouse::Right
 #include <ftxui/component/task.hpp>   // for Task
 #include <initializer_list>           // for initializer_list
 #include <memory>                     // for allocator, unique_ptr
 #include <variant>                    // for get
 
-#include "ftxui/component/event.hpp"  // for Event, Event::Return, Event::ArrowDown, Event::ArrowLeft, Event::ArrowRight, Event::ArrowUp, Event::Backspace, Event::Custom, Event::Delete, Event::End, Event::F10, Event::F11, Event::F12, Event::F5, Event::F6, Event::F7, Event::F8, Event::F9, Event::Home, Event::PageDown, Event::PageUp, Event::Tab, Event::TabReverse, Event::Escape
+#include "ftxui/component/event.hpp"  // for Event, Event::Return, Event::ArrowDown, Event::ArrowLeft, Event::ArrowRight, Event::ArrowUp, Event::Backspace, Event::End, Event::Home, Event::Custom, Event::Delete, Event::F1, Event::F10, Event::F11, Event::F12, Event::F2, Event::F3, Event::F4, Event::F5, Event::F6, Event::F7, Event::F8, Event::F9, Event::PageDown, Event::PageUp, Event::Tab, Event::TabReverse, Event::Escape
 #include "ftxui/component/receiver.hpp"  // for MakeReceiver, ReceiverImpl
 #include "ftxui/component/terminal_input_parser.hpp"
+#include "gtest/gtest.h"  // for AssertionResult, Test, Message, TestPartResult, EXPECT_EQ, EXPECT_TRUE, TEST, EXPECT_FALSE
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/component/toggle_test.cpp

@@ -1,4 +1,3 @@
-#include <gtest/gtest.h>  // for AssertionResult, Message, TestPartResult, EXPECT_EQ, Test, EXPECT_TRUE, TestInfo (ptr only), EXPECT_FALSE, TEST
 #include <functional>  // for function
 #include <memory>      // for __shared_ptr_access, shared_ptr, allocator
 #include <string>      // for string, basic_string
@@ -9,6 +8,7 @@
 #include "ftxui/component/component_options.hpp"  // for MenuOption
 #include "ftxui/component/event.hpp"  // for Event, Event::ArrowLeft, Event::ArrowRight, Event::Return, Event::Tab, Event::TabReverse
 #include "ftxui/util/ref.hpp"         // for Ref
+#include "gtest/gtest.h"  // for AssertionResult, Message, TestPartResult, EXPECT_EQ, Test, EXPECT_TRUE, EXPECT_FALSE, TEST
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/dom/blink_test.cpp

@@ -1,9 +1,9 @@
-#include <gtest/gtest.h>
+#include <string>  // for allocator, string
-#include <string>  // for allocator
 
 #include "ftxui/dom/elements.hpp"   // for operator|, text, blink, Element
 #include "ftxui/dom/node.hpp"       // for Render
 #include "ftxui/screen/screen.hpp"  // for Screen, Pixel
+#include "gtest/gtest.h"  // for Test, AssertionResult, EXPECT_TRUE, Message, TEST, TestPartResult
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/dom/bold_test.cpp

@@ -1,9 +1,9 @@
-#include <gtest/gtest.h>
+#include <string>  // for allocator, string
-#include <string>  // for allocator
 
 #include "ftxui/dom/elements.hpp"   // for operator|, text, bold, Element
 #include "ftxui/dom/node.hpp"       // for Render
 #include "ftxui/screen/screen.hpp"  // for Screen, Pixel
+#include "gtest/gtest.h"  // for Test, AssertionResult, EXPECT_TRUE, Message, TEST, TestPartResult
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/dom/dim_test.cpp

@@ -1,9 +1,9 @@
-#include <gtest/gtest.h>
+#include <string>  // for allocator, string
-#include <string>  // for allocator
 
 #include "ftxui/dom/elements.hpp"   // for operator|, text, dim, Element
 #include "ftxui/dom/node.hpp"       // for Render
 #include "ftxui/screen/screen.hpp"  // for Screen, Pixel
+#include "gtest/gtest.h"  // for Test, AssertionResult, EXPECT_TRUE, Message, TEST, TestPartResult
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/dom/text.cpp

@@ -35,6 +35,9 @@ class Text : public Node {
       if (x > box_.x_max) {
         return;
       }
+      if (cell == "\n") {
+        continue;
+      }
       screen.PixelAt(x, y).character = cell;
       ++x;
     }

src/ftxui/dom/underlined_test.cpp

@@ -1,9 +1,9 @@
-#include <gtest/gtest.h>
+#include <string>  // for allocator, string
-#include <string>  // for allocator
 
 #include "ftxui/dom/elements.hpp"   // for operator|, text, underlined, Element
 #include "ftxui/dom/node.hpp"       // for Render
 #include "ftxui/screen/screen.hpp"  // for Screen, Pixel
+#include "gtest/gtest.h"  // for Test, AssertionResult, EXPECT_TRUE, Message, TEST, TestPartResult
 
 // NOLINTBEGIN
 namespace ftxui {

src/ftxui/screen/string.cpp

@@ -7,15 +7,22 @@
 
 #include "ftxui/screen/string.hpp"
 
+#include <stddef.h>  // for size_t
 #include <array>     // for array
 #include <cstdint>   // for uint32_t, uint8_t, uint16_t, int32_t
 #include <string>    // for string, basic_string, wstring
 #include <tuple>     // for _Swallow_assign, ignore
 
 #include "ftxui/screen/deprecated.hpp"       // for wchar_width, wstring_width
+#include "ftxui/screen/string_internal.hpp"  // for WordBreakProperty, EatCodePoint, CodepointToWordBreakProperty, GlyphCount, GlyphIterate, GlyphNext, GlyphPrevious, IsCombining, IsControl, IsFullWidth, Utf8ToWordBreakProperty
 
 namespace {
 
+using ftxui::EatCodePoint;
+using ftxui::IsCombining;
+using ftxui::IsControl;
+using ftxui::IsFullWidth;
+
 struct Interval {
   uint32_t first;
   uint32_t last;
@@ -1411,46 +1418,26 @@ bool Bisearch(uint32_t ucs, const std::array<C, N> table, C* out) {
   return false;
 }
 
-bool IsCombining(uint32_t ucs) {
-  return ftxui::CodepointToWordBreakProperty(ucs) == WBP::Extend;
-}
-
-bool IsFullWidth(uint32_t ucs) {
-  if (ucs < 0x0300)  // Quick path: // NOLINT
-    return false;
-
-  return Bisearch(ucs, g_full_width_characters);
-}
-
-bool IsControl(uint32_t ucs) {
-  if (ucs == 0) {
-    return true;
-  }
-  if (ucs < 32) {  // NOLINT
-    return true;
-  }
-  if (ucs >= 0x7f && ucs < 0xa0) {  // NOLINT
-    return true;
-  }
-  return false;
-}
-
 int codepoint_width(uint32_t ucs) {
-  if (IsControl(ucs)) {
+  if (ftxui::IsControl(ucs)) {
     return -1;
   }
 
-  if (IsCombining(ucs)) {
+  if (ftxui::IsCombining(ucs)) {
     return 0;
   }
 
-  if (IsFullWidth(ucs)) {
+  if (ftxui::IsFullWidth(ucs)) {
     return 2;
   }
 
   return 1;
 }
 
+}  // namespace
+
+namespace ftxui {
+
 // From UTF8 encoded string |input|, eat in between 1 and 4 byte representing
 // one codepoint. Put the codepoint into |ucs|. Start at |start| and update
 // |end| to represent the beginning of the next byte to eat for consecutive
@@ -1563,9 +1550,29 @@ bool EatCodePoint(const std::wstring& input,
   return true;
 }
 
-}  // namespace
+bool IsCombining(uint32_t ucs) {
+  return ftxui::CodepointToWordBreakProperty(ucs) == WBP::Extend;
+}
 
-namespace ftxui {
+bool IsFullWidth(uint32_t ucs) {
+  if (ucs < 0x0300)  // Quick path: // NOLINT
+    return false;
+
+  return Bisearch(ucs, g_full_width_characters);
+}
+
+bool IsControl(uint32_t ucs) {
+  if (ucs == 0) {
+    return true;
+  }
+  if (ucs < 32) {      // NOLINT
+    return ucs != 10;  // 10 => Line feed.
+  }
+  if (ucs >= 0x7f && ucs < 0xa0) {  // NOLINT
+    return true;
+  }
+  return false;
+}
 
 WordBreakProperty CodepointToWordBreakProperty(uint32_t codepoint) {
   WordBreakPropertyInterval interval = {0, 0, WBP::ALetter};
@@ -1660,12 +1667,35 @@ std::vector<std::string> Utf8ToGlyphs(const std::string& input) {
   return out;
 }
 
-int GlyphPosition(const std::string& input, size_t glyph_index, size_t start) {
+size_t GlyphPrevious(const std::string& input, size_t start) {
-  if (glyph_index <= 0) {
+  while (true) {
+    if (start == 0) {
       return 0;
     }
+    start--;
+
+    // Skip the UTF8 continuation bytes.
+    if ((input[start] & 0b1100'0000) == 0b1000'0000) {
+      continue;
+    }
+
+    uint32_t codepoint = 0;
     size_t end = 0;
+    const bool eaten = EatCodePoint(input, start, &end, &codepoint);
+
+    // Ignore invalid, control characters and combining characters.
+    if (!eaten || IsControl(codepoint) || IsCombining(codepoint)) {
+      continue;
+    }
+
+    return start;
+  }
+}
+
+size_t GlyphNext(const std::string& input, size_t start) {
+  bool glyph_found = false;
   while (start < input.size()) {
+    size_t end = 0;
     uint32_t codepoint = 0;
     const bool eaten = EatCodePoint(input, start, &end, &codepoint);
 
@@ -1677,17 +1707,31 @@ int GlyphPosition(const std::string& input, size_t glyph_index, size_t start) {
 
     // We eat the beginning of the next glyph. If we are eating the one
     // requested, return its start position immediately.
-    if (glyph_index == 0) {
+    if (glyph_found) {
       return static_cast<int>(start);
     }
 
     // Otherwise, skip this glyph and iterate:
-    glyph_index--;
+    glyph_found = true;
     start = end;
   }
   return static_cast<int>(input.size());
 }
 
+size_t GlyphIterate(const std::string& input, int glyph_offset, size_t start) {
+  if (glyph_offset >= 0) {
+    for (int i = 0; i < glyph_offset; ++i) {
+      start = GlyphNext(input, start);
+    }
+    return start;
+  } else {
+    for (int i = 0; i < -glyph_offset; ++i) {
+      start = GlyphPrevious(input, start);
+    }
+    return start;
+  }
+}
+
 std::vector<int> CellToGlyphIndex(const std::string& input) {
   int x = -1;
   std::vector<int> out;

src/ftxui/screen/string_internal.hpp

@@ -0,0 +1,64 @@
+#ifndef FTXUI_SCREEN_STRING_INTERNAL_HPP
+#define FTXUI_SCREEN_STRING_INTERNAL_HPP
+
+namespace ftxui {
+
+bool EatCodePoint(const std::string& input,
+                  size_t start,
+                  size_t* end,
+                  uint32_t* ucs);
+bool EatCodePoint(const std::wstring& input,
+                  size_t start,
+                  size_t* end,
+                  uint32_t* ucs);
+
+bool IsCombining(uint32_t ucs);
+bool IsFullWidth(uint32_t ucs);
+bool IsControl(uint32_t ucs);
+
+size_t GlyphPrevious(const std::string& input, size_t start);
+size_t GlyphNext(const std::string& input, size_t start);
+
+// Return the index in the |input| string of the glyph at |glyph_offset|,
+// starting at |start|
+size_t GlyphIterate(const std::string& input,
+                    int glyph_offset,
+                    size_t start = 0);
+
+// Returns the number of glyphs in |input|.
+int GlyphCount(const std::string& input);
+
+// Properties from:
+// https://www.unicode.org/Public/UCD/latest/ucd/auxiliary/WordBreakProperty.txt
+enum class WordBreakProperty {
+  ALetter,
+  CR,
+  Double_Quote,
+  Extend,
+  ExtendNumLet,
+  Format,
+  Hebrew_Letter,
+  Katakana,
+  LF,
+  MidLetter,
+  MidNum,
+  MidNumLet,
+  Newline,
+  Numeric,
+  Regional_Indicator,
+  Single_Quote,
+  WSegSpace,
+  ZWJ,
+};
+WordBreakProperty CodepointToWordBreakProperty(uint32_t codepoint);
+std::vector<WordBreakProperty> Utf8ToWordBreakProperty(
+    const std::string& input);
+
+bool IsWordBreakingCharacter(const std::string& input, size_t glyph_index);
+}  // namespace ftxui
+
+#endif /* end of include guard: FTXUI_SCREEN_STRING_INTERNAL_HPP */
+
+// Copyright 2023 Arthur Sonzogni. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.

src/ftxui/screen/string_test.cpp

@@ -1,6 +1,7 @@
 #include "ftxui/screen/string.hpp"
 #include <gtest/gtest.h>
 #include <string>  // for allocator, string
+#include "ftxui/screen/string_internal.hpp"
 
 namespace ftxui {
 
@@ -61,41 +62,41 @@ TEST(StringTest, GlyphCount) {
   EXPECT_EQ(GlyphCount("a\1a"), 2);
 }
 
-TEST(StringTest, GlyphPosition) {
+TEST(StringTest, GlyphIterate) {
   // Basic:
-  EXPECT_EQ(GlyphPosition("", -1), 0);
+  EXPECT_EQ(GlyphIterate("", -1), 0);
-  EXPECT_EQ(GlyphPosition("", 0), 0);
+  EXPECT_EQ(GlyphIterate("", 0), 0);
-  EXPECT_EQ(GlyphPosition("", 1), 0);
+  EXPECT_EQ(GlyphIterate("", 1), 0);
-  EXPECT_EQ(GlyphPosition("a", 0), 0);
+  EXPECT_EQ(GlyphIterate("a", 0), 0);
-  EXPECT_EQ(GlyphPosition("a", 1), 1);
+  EXPECT_EQ(GlyphIterate("a", 1), 1);
-  EXPECT_EQ(GlyphPosition("ab", 0), 0);
+  EXPECT_EQ(GlyphIterate("ab", 0), 0);
-  EXPECT_EQ(GlyphPosition("ab", 1), 1);
+  EXPECT_EQ(GlyphIterate("ab", 1), 1);
-  EXPECT_EQ(GlyphPosition("ab", 2), 2);
+  EXPECT_EQ(GlyphIterate("ab", 2), 2);
-  EXPECT_EQ(GlyphPosition("abc", 0), 0);
+  EXPECT_EQ(GlyphIterate("abc", 0), 0);
-  EXPECT_EQ(GlyphPosition("abc", 1), 1);
+  EXPECT_EQ(GlyphIterate("abc", 1), 1);
-  EXPECT_EQ(GlyphPosition("abc", 2), 2);
+  EXPECT_EQ(GlyphIterate("abc", 2), 2);
-  EXPECT_EQ(GlyphPosition("abc", 3), 3);
+  EXPECT_EQ(GlyphIterate("abc", 3), 3);
   // Fullwidth glyphs:
-  EXPECT_EQ(GlyphPosition("测", 0), 0);
+  EXPECT_EQ(GlyphIterate("测", 0), 0);
-  EXPECT_EQ(GlyphPosition("测", 1), 3);
+  EXPECT_EQ(GlyphIterate("测", 1), 3);
-  EXPECT_EQ(GlyphPosition("测试", 0), 0);
+  EXPECT_EQ(GlyphIterate("测试", 0), 0);
-  EXPECT_EQ(GlyphPosition("测试", 1), 3);
+  EXPECT_EQ(GlyphIterate("测试", 1), 3);
-  EXPECT_EQ(GlyphPosition("测试", 2), 6);
+  EXPECT_EQ(GlyphIterate("测试", 2), 6);
-  EXPECT_EQ(GlyphPosition("测试", 1, 3), 6);
+  EXPECT_EQ(GlyphIterate("测试", 1, 3), 6);
-  EXPECT_EQ(GlyphPosition("测试", 1, 0), 3);
+  EXPECT_EQ(GlyphIterate("测试", 1, 0), 3);
   // Combining characters:
-  EXPECT_EQ(GlyphPosition("ā", 0), 0);
+  EXPECT_EQ(GlyphIterate("ā", 0), 0);
-  EXPECT_EQ(GlyphPosition("ā", 1), 3);
+  EXPECT_EQ(GlyphIterate("ā", 1), 3);
-  EXPECT_EQ(GlyphPosition("a⃒a̗ā", 0), 0);
+  EXPECT_EQ(GlyphIterate("a⃒a̗ā", 0), 0);
-  EXPECT_EQ(GlyphPosition("a⃒a̗ā", 1), 4);
+  EXPECT_EQ(GlyphIterate("a⃒a̗ā", 1), 4);
-  EXPECT_EQ(GlyphPosition("a⃒a̗ā", 2), 7);
+  EXPECT_EQ(GlyphIterate("a⃒a̗ā", 2), 7);
-  EXPECT_EQ(GlyphPosition("a⃒a̗ā", 3), 10);
+  EXPECT_EQ(GlyphIterate("a⃒a̗ā", 3), 10);
   // Control characters:
-  EXPECT_EQ(GlyphPosition("\1", 0), 0);
+  EXPECT_EQ(GlyphIterate("\1", 0), 0);
-  EXPECT_EQ(GlyphPosition("\1", 1), 1);
+  EXPECT_EQ(GlyphIterate("\1", 1), 1);
-  EXPECT_EQ(GlyphPosition("a\1a", 0), 0);
+  EXPECT_EQ(GlyphIterate("a\1a", 0), 0);
-  EXPECT_EQ(GlyphPosition("a\1a", 1), 2);
+  EXPECT_EQ(GlyphIterate("a\1a", 1), 2);
-  EXPECT_EQ(GlyphPosition("a\1a", 2), 3);
+  EXPECT_EQ(GlyphIterate("a\1a", 2), 3);
 }
 
 TEST(StringTest, CellToGlyphIndex) {
@@ -135,7 +136,7 @@ TEST(StringTest, Utf8ToWordBreakProperty) {
   EXPECT_EQ(Utf8ToWordBreakProperty(":"), T({P::MidLetter}));
   EXPECT_EQ(Utf8ToWordBreakProperty("."), T({P::MidNumLet}));
   EXPECT_EQ(Utf8ToWordBreakProperty("\r"), T({}));  // FIXME
-  EXPECT_EQ(Utf8ToWordBreakProperty("\n"), T({}));  // FIXME
+  EXPECT_EQ(Utf8ToWordBreakProperty("\n"), T({P::LF}));
 }
 
 TEST(StringTest, to_string) {