Support for inverted selections.

CMakeLists.txt

@@ -56,11 +56,11 @@ add_library(dom
   include/ftxui/dom/flexbox_config.hpp
   include/ftxui/dom/node.hpp
   include/ftxui/dom/requirement.hpp
+  include/ftxui/dom/selection.hpp
   include/ftxui/dom/take_any_args.hpp
   src/ftxui/dom/automerge.cpp
   src/ftxui/dom/blink.cpp
   src/ftxui/dom/bold.cpp
-  src/ftxui/dom/hyperlink.cpp
   src/ftxui/dom/border.cpp
   src/ftxui/dom/box_helper.cpp
   src/ftxui/dom/box_helper.hpp
@@ -81,6 +81,7 @@ add_library(dom
   src/ftxui/dom/graph.cpp
   src/ftxui/dom/gridbox.cpp
   src/ftxui/dom/hbox.cpp
+  src/ftxui/dom/hyperlink.cpp
   src/ftxui/dom/inverted.cpp
   src/ftxui/dom/linear_gradient.cpp
   src/ftxui/dom/node.cpp
@@ -89,6 +90,7 @@ add_library(dom
   src/ftxui/dom/reflect.cpp
   src/ftxui/dom/scroll_indicator.cpp
   src/ftxui/dom/selectable.cpp
+  src/ftxui/dom/selection.cpp
   src/ftxui/dom/separator.cpp
   src/ftxui/dom/size.cpp
   src/ftxui/dom/spinner.cpp

include/ftxui/component/screen_interactive.hpp

@@ -138,7 +138,10 @@ class ScreenInteractive : public Screen {
   // Selection API:
   bool selection_enabled_ = false;
   CapturedMouse selection_pending_;
-  Box selection_box_;
+  int selection_start_x_ = 0;
+  int selection_start_y_ = 0;
+  int selection_end_x_ = 0;
+  int selection_end_y_ = 0;
 
   friend class Loop;
 

include/ftxui/dom/node.hpp

@@ -9,6 +9,7 @@
 #include <vector>  // for vector
 
 #include "ftxui/dom/requirement.hpp"  // for Requirement
+#include "ftxui/dom/selection.hpp"    // for Selection
 #include "ftxui/screen/box.hpp"       // for Box
 #include "ftxui/screen/screen.hpp"
 
@@ -43,7 +44,7 @@ class Node {
 
   // Step 3: (optional) Selection
   //         Propagated from Parents to Children.
-  virtual void Selection(Box selection, std::vector<Box>* selected);
+  virtual void Select(Selection& selection);
 
   // Step 4: Draw this element.
   virtual void Render(Screen& screen);
@@ -66,7 +67,7 @@ class Node {
 
 void Render(Screen& screen, const Element& element);
 void Render(Screen& screen, Node* node);
-void Render(Screen& screen, Node* node, Box selection);
+void Render(Screen& screen, Node* node, Selection& selection);
 
 }  // namespace ftxui
 

include/ftxui/dom/selection.hpp

@@ -0,0 +1,33 @@
+// Copyright 2024 Arthur Sonzogni. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.
+
+#ifndef FTXUI_DOM_SELECTION_HPP
+#define FTXUI_DOM_SELECTION_HPP
+
+#include "ftxui/screen/box.hpp"  // for Box
+
+namespace ftxui {
+
+/// @brief Represent a selection in the terminal.
+class Selection {
+ public:
+  Selection(int start_x, int start_y, int end_x, int end_y);
+  const Box& GetBox() const;
+
+  Selection SaturateHorizontal(Box box);
+  Selection SaturateVertical(Box box);
+
+
+ private:
+  Selection* const parent_ = nullptr;
+  const int start_x_;
+  const int start_y_;
+  const int end_x_;
+  const int end_y_;
+  const Box box_;
+};
+
+}  // namespace ftxui
+
+#endif /* end of include guard: FTXUI_DOM_SELECTION_HPP */

src/ftxui/component/screen_interactive.cpp

@@ -837,28 +837,29 @@ bool ScreenInteractive::HandleSelection(Event event) {
     return false;
   }
 
-  if(mouse.motion == Mouse::Pressed) {
-      selection_pending_ = CaptureMouse();
-      if (!selection_pending_) {
-        return false;
-      }
-      selection_enabled_ = true;
-      selection_box_.x_min = mouse.x;
-      selection_box_.y_min = mouse.y;
-      selection_box_.x_max = mouse.x;
-      selection_box_.y_max = mouse.y;
-      return true;
+  if (mouse.motion == Mouse::Pressed) {
+    selection_pending_ = CaptureMouse();
+    selection_start_x_ = mouse.x;
+    selection_start_y_ = mouse.y;
+    selection_end_x_ = mouse.x;
+    selection_end_y_ = mouse.y;
   }
-  else if((mouse.motion == Mouse::Moved) && (selection_pending_)) {
-      selection_box_.x_max = mouse.x;
-      selection_box_.y_max = mouse.y;
-      return true;
+
+  if (!selection_pending_) {
+    return false;
   }
-  else if((mouse.motion == Mouse::Released) && (selection_pending_)) {
-      selection_box_.x_max = mouse.x;
-      selection_box_.y_max = mouse.y;
-      selection_pending_ = nullptr;
+
+  if (mouse.motion == Mouse::Moved) {
+      selection_end_x_ = mouse.x;
+      selection_end_y_ = mouse.y;
       return true;
+    }
+
+  if (mouse.motion == Mouse::Released) {
+    selection_pending_ = nullptr;
+    selection_end_x_ = mouse.x;
+    selection_end_y_ = mouse.y;
+    return true;
   }
 
   return false;
@@ -932,7 +933,9 @@ void ScreenInteractive::Draw(Component component) {
 #endif
   previous_frame_resized_ = resized;
 
-  Render(*this, document.get(), selection_box_);
+  Selection selection(selection_start_x_, selection_start_y_,  //
+                      selection_end_x_, selection_end_y_);
+  Render(*this, document.get(), selection);
 
   // Set cursor position for user using tools to insert CJK characters.
   {

src/ftxui/dom/hbox.cpp

@@ -65,27 +65,16 @@ class HBox : public Node {
     }
   }
 
-  void Selection(Box selection, std::vector<Box>* selected) override {
+  void Select(Selection& selection) override {
     // If this Node box_ doesn't intersect with the selection, then no
     // selection.
-    if (Box::Intersection(selection, box_).IsEmpty()) {
+    if (Box::Intersection(selection.GetBox(), box_).IsEmpty()) {
       return;
     }
 
-    const bool xmin_saturated =
-        selection.y_min < box_.y_min || selection.x_min < box_.x_min;
-    const bool xmax_saturated =
-        selection.y_max > box_.y_max || selection.x_max > box_.x_max;
-
-    if (xmin_saturated) {
-      selection.x_min = std::min(box_.x_min, selection.x_min);
-    }
-    if (xmax_saturated) {
-      selection.x_max = std::max(box_.x_max, selection.x_max);
-    }
-
+    Selection selection_saturated = selection.SaturateHorizontal(box_);
     for (auto& child : children_) {
-      child->Selection(selection, selected);
+      child->Select(selection_saturated);
     }
   }
 };

src/ftxui/dom/node.cpp

@@ -30,15 +30,15 @@ void Node::SetBox(Box box) {
 
 /// @brief Compute the selection of an element.
 /// @ingroup dom
-void Node::Selection(Box selection, std::vector<Box>* selected) {
+void Node::Select(Selection& selection) {
   // If this Node box_ doesn't intersect with the selection, then no selection.
-  if (Box::Intersection(selection, box_).IsEmpty()) {
+  if (Box::Intersection(selection.GetBox(), box_).IsEmpty()) {
     return;
   }
 
   // By default we defer the selection to the children.
   for (auto& child : children_) {
-    child->Selection(selection, selected);
+    child->Select(selection);
   }
 }
 
@@ -60,16 +60,18 @@ void Node::Check(Status* status) {
 /// @brief Display an element on a ftxui::Screen.
 /// @ingroup dom
 void Render(Screen& screen, const Element& element) {
-  Render(screen, element.get(), Box{0, 0, -1, -1});
+  Selection selection(0, 0, -1, -1);
+  Render(screen, element.get(), selection);
 }
 
 /// @brief Display an element on a ftxui::Screen.
 /// @ingroup dom
 void Render(Screen& screen, Node* node) {
-  Render(screen, node, Box{0, 0, -1, -1});
+  Selection selection(0, 0, -1, -1);
+  Render(screen, node, selection);
 }
 
-void Render(Screen& screen, Node* node, Box selection) {
+void Render(Screen& screen, Node* node, Selection& selection) {
   Box box;
   box.x_min = 0;
   box.y_min = 0;
@@ -93,22 +95,7 @@ void Render(Screen& screen, Node* node, Box selection) {
   }
 
   // Step 3: Selection
-  std::vector<Box> selected;
-
-  Box selectionCleaned = selection;
-  if(selection.x_min > selection.x_max)
-  {
-    selectionCleaned.x_min = selection.x_max;
-    selectionCleaned.x_max = selection.x_min;
-  }
-  
-  if(selection.y_min > selection.y_max)
-  {
-    selectionCleaned.y_min = selection.y_max;
-    selectionCleaned.y_max = selection.y_min;
-  }
-
-  node->Selection(selectionCleaned, &selected);
+  node->Select(selection);
 
   // Step 4: Draw the element.
   screen.stencil = box;

src/ftxui/dom/selection.cpp

@@ -0,0 +1,106 @@
+// Copyright 2024 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/dom/selection.hpp"  // for Selection
+#include <algorithm>                // for max, min
+
+namespace ftxui {
+
+/// @brief Create a selection.
+/// @param start_x The x coordinate of the start of the selection.
+/// @param start_y The y coordinate of the start of the selection.
+/// @param end_x The x coordinate of the end of the selection.
+/// @param end_y The y coordinate of the end of the selection.
+Selection::Selection(int start_x, int start_y, int end_x, int end_y)
+    : start_x_(start_x),
+      start_y_(start_y),
+      end_x_(end_x),
+      end_y_(end_y),
+      box_{
+          std::min(start_x, end_x),
+          std::max(start_x, end_x),
+          std::min(start_y, end_y),
+          std::max(start_y, end_y),
+      } {}
+
+/// @brief Get the box of the selection.
+/// @return The box of the selection.
+const Box& Selection::GetBox() const {
+  return box_;
+}
+
+/// @brief Saturate the selection to be inside the box.
+/// This is called by `hbox` to propagate the selection to its children.
+/// @param box The box to saturate the selection in.
+/// @return The saturated selection.
+Selection Selection::SaturateHorizontal(Box box) {
+  int start_x = start_x_;
+  int start_y = start_y_;
+  int end_x = end_x_;
+  int end_y = end_y_;
+  
+  const bool start_outside = !box.Contain(start_x, start_y);
+  const bool end_outside = !box.Contain(end_x, end_y);
+  const bool properly_ordered =
+      start_y < end_y || (start_y == end_y && start_x <= end_x);
+  if (properly_ordered) {
+    if (start_outside) {
+      start_x = box.x_min;
+      start_y = box.y_min;
+    }
+    if (end_outside) {
+      end_x = box.x_max;
+      end_y = box.y_max;
+    }
+  } else {
+    if (start_outside) {
+      start_x = box.x_max;
+      start_y = box.y_max;
+    }
+    if (end_outside) {
+      end_x = box.x_min;
+      end_y = box.y_min;
+    }
+  }
+  return Selection(start_x, start_y, end_x, end_y);
+}
+
+/// @brief Saturate the selection to be inside the box.
+/// This is called by `vbox` to propagate the selection to its children.
+/// @param box The box to saturate the selection in.
+/// @return The saturated selection.
+Selection Selection::SaturateVertical(Box box) {
+  int start_x = start_x_;
+  int start_y = start_y_;
+  int end_x = end_x_;
+  int end_y = end_y_;
+  
+  const bool start_outside = !box.Contain(start_x, start_y);
+  const bool end_outside = !box.Contain(end_x, end_y);
+  const bool properly_ordered =
+    start_y < end_y || (start_y == end_y && start_x <= end_x);
+
+  if (properly_ordered) {
+    if (start_outside) {
+      start_x = box.x_min;
+      start_y = box.y_min;
+    }
+    if (end_outside) {
+      end_x = box.x_max;
+      end_y = box.y_max;
+    }
+  } else {
+    if (start_outside) {
+      start_x = box.x_max;
+      start_y = box.y_max;
+    }
+    if (end_outside) {
+      end_x = box.x_min;
+      end_y = box.y_min;
+    }
+  }
+  return Selection(start_x, start_y, end_x, end_y);
+}
+
+}  // namespace ftxui

src/ftxui/dom/text.cpp

@@ -26,29 +26,19 @@ class Text : public Node {
   void ComputeRequirement() override {
     requirement_.min_x = string_width(text_);
     requirement_.min_y = 1;
+    has_selection = false;
   }
 
-  void Selection(Box selection, std::vector<Box>* selected) override {
-    if (Box::Intersection(selection, box_).IsEmpty()) {
+  void Select(Selection& selection) override {
+    if (Box::Intersection(selection.GetBox(), box_).IsEmpty()) {
       return;
     }
 
-    const bool xmin_saturated =
-        selection.y_min < box_.y_min || selection.x_min < box_.x_min;
-    const bool xmax_saturated =
-        selection.y_max > box_.y_max || selection.x_max > box_.x_max;
-
-    selection_start_ = xmin_saturated ? box_.x_min : selection.x_min;
-    selection_end_ = xmax_saturated ? box_.x_max : selection.x_max;
+    Selection selection_saturated = selection.SaturateHorizontal(box_);
 
     has_selection = true;
-
-    Box out;
-    out.x_min = selection_start_;
-    out.x_max = selection_end_;
-    out.y_min = box_.y_min;
-    out.y_max = box_.y_max;
-    selected->push_back(out);
+    selection_start_ = selection_saturated.GetBox().x_min;
+    selection_end_ = selection_saturated.GetBox().x_max;
   }
   
   void Render(Screen& screen) override {

src/ftxui/dom/vbox.cpp

@@ -65,27 +65,17 @@ class VBox : public Node {
     }
   }
 
-  void Selection(Box selection, std::vector<Box>* selected) override {
+  void Select(Selection& selection) override {
     // If this Node box_ doesn't intersect with the selection, then no
     // selection.
-    if (Box::Intersection(selection, box_).IsEmpty()) {
+    if (Box::Intersection(selection.GetBox(), box_).IsEmpty()) {
       return;
     }
 
-    const bool ymin_saturated =
-      selection.x_min < box_.x_min || selection.y_min < box_.y_min;
-    const bool ymax_saturated =
-      selection.x_max > box_.x_max || selection.y_max > box_.y_max;
-
-    if (ymin_saturated) {
-      selection.y_min = std::min(box_.y_min, selection.y_min);
-    }
-    if (ymax_saturated) {
-      selection.y_max = std::max(box_.y_max, selection.y_max);
-    }
+    Selection selection_saturated = selection.SaturateVertical(box_);
 
     for (auto& child : children_) {
-      child->Selection(selection, selected);
+      child->Select(selection_saturated);
     }
   }
 };

src/ftxui/screen/screen.cpp

@@ -389,8 +389,7 @@ Screen Screen::Create(Dimensions dimension) {
   return {dimension.dimx, dimension.dimy};
 }
 
-Screen::Screen(int dimx, int dimy) :
-      Image{dimx, dimy} {
+Screen::Screen(int dimx, int dimy) : Image{dimx, dimy} {
 #if defined(_WIN32)
   // The placement of this call is a bit weird, however we can assume that
   // anybody who instantiates a Screen object eventually wants to output