Added a option to set the style of the selection

examples/component/selectable_input.cpp

@@ -73,9 +73,14 @@ int main() {
     });
   });
 
-  screen.onSelectionModified([&] {
-    selectionChangeCounter++;
-    selection = screen.GetSelectedContent(renderer);
+  screen.setSelectionOptions({
+    .transform = [](Pixel& pixel) {
+      pixel.underlined_double = true;
+    },
+    .on_change = [&] {
+      selectionChangeCounter++;
+      selection = screen.GetSelectedContent(renderer);
+    }
   });
 
   screen.Loop(renderer);

include/ftxui/component/screen_interactive.hpp

@@ -15,6 +15,7 @@
 #include "ftxui/component/animation.hpp"       // for TimePoint
 #include "ftxui/component/captured_mouse.hpp"  // for CapturedMouse
 #include "ftxui/component/event.hpp"           // for Event
+#include "ftxui/dom/selection.hpp"             // for SelectionOption
 #include "ftxui/component/task.hpp"            // for Task, Closure
 #include "ftxui/screen/screen.hpp"             // for Screen
 
@@ -70,7 +71,7 @@ class ScreenInteractive : public Screen {
 
   // Selection API.
   std::string GetSelectedContent(Component component);
-  void onSelectionModified(std::function<void(void)> callback);
+  void setSelectionOptions(SelectionOption option);
 
  private:
   void ExitNow();
@@ -143,7 +144,7 @@ class ScreenInteractive : public Screen {
   int selection_end_x_ = 0;
   int selection_end_y_ = 0;
   bool selection_changed = false;
-  std::function<void(void)> selection_changed_callback_ = nullptr;
+  SelectionOption selection_options_ = SelectionOption::Simple();
 
   friend class Loop;
 

include/ftxui/dom/selection.hpp

@@ -5,15 +5,33 @@
 #ifndef FTXUI_DOM_SELECTION_HPP
 #define FTXUI_DOM_SELECTION_HPP
 
+#include <functional>
+
 #include "ftxui/screen/box.hpp"  // for Box
+#include "ftxui/screen/pixel.hpp"  // for Pixel
 
 namespace ftxui {
 
+/// @brief Option for the selection of content.
+/// @ingroup component
+struct SelectionOption {
+  /// @brief Selection is simply inverted:
+  static SelectionOption Simple();
+
+  // Style:
+  std::function<void(Pixel& pixel)> transform ;
+
+  // Observers:
+  /// Called when the selection changed.
+  std::function<void()> on_change = [] {};
+};
+
 /// @brief Represent a selection in the terminal.
 class Selection {
  public:
-  Selection(int start_x, int start_y, int end_x, int end_y);
+  Selection(int start_x, int start_y, int end_x, int end_y, SelectionOption option = SelectionOption::Simple());
   const Box& GetBox() const;
+  const SelectionOption& GetOption() const;
 
   Selection SaturateHorizontal(Box box);
   Selection SaturateVertical(Box box);
@@ -25,6 +43,7 @@ class Selection {
   const int end_x_;
   const int end_y_;
   const Box box_;
+  const SelectionOption option;
 };
 
 }  // namespace ftxui

src/ftxui/component/screen_interactive.cpp

@@ -580,18 +580,14 @@ void ScreenInteractive::ForceHandleCtrlZ(bool force) {
 std::string ScreenInteractive::GetSelectedContent(Component component)
 {
   Selection selection(selection_start_x_, selection_start_y_,  //
-                    selection_end_x_, selection_end_y_);
+                    selection_end_x_, selection_end_y_, selection_options_);
 
   return GetNodeSelectedContent(*this, component->Render().get(), selection);
 }
 
-/// @brief Sets a callback on modifications of the selection
-/// This callback is called when the start of end of the selection moved.
-/// Not when the content/characters inside of the selection change.
-/// @param callback The function to callback on modifications of the selection.
-void ScreenInteractive::onSelectionModified(std::function<void(void)> callback)
+void ScreenInteractive::setSelectionOptions(SelectionOption option)
 {
-  selection_changed_callback_ = std::move(callback);
+  selection_options_ = std::move(option);
 }
 
 /// @brief Return the currently active screen, or null if none.
@@ -970,12 +966,12 @@ void ScreenInteractive::Draw(Component component) {
   previous_frame_resized_ = resized;
 
   Selection selection(selection_start_x_, selection_start_y_,  //
-                      selection_end_x_, selection_end_y_);
+                      selection_end_x_, selection_end_y_, selection_options_);
   Render(*this, document.get(), selection);
 
-  if((selection_changed == true) && (selection_changed_callback_ != nullptr))
+  if(selection_changed == true)
   {
-    selection_changed_callback_();
+    selection_options_.on_change();
   }
 
   // Set cursor position for user using tools to insert CJK characters.

src/ftxui/dom/selection.cpp

@@ -26,11 +26,12 @@ class Unselectable : public NodeDecorator {
 /// @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)
+Selection::Selection(int start_x, int start_y, int end_x, int end_y, SelectionOption option)
     : start_x_(start_x),
       start_y_(start_y),
       end_x_(end_x),
       end_y_(end_y),
+      option(option),
       box_{
           std::min(start_x, end_x),
           std::max(start_x, end_x),
@@ -44,6 +45,12 @@ const Box& Selection::GetBox() const {
   return box_;
 }
 
+/// @brief Get the options of the selection.
+/// @return The options of the selection.
+const SelectionOption& Selection::GetOption() const {
+  return option;
+}
+
 /// @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.
@@ -77,7 +84,7 @@ Selection Selection::SaturateHorizontal(Box box) {
       end_y = box.y_min;
     }
   }
-  return Selection(start_x, start_y, end_x, end_y);
+  return Selection(start_x, start_y, end_x, end_y, option);
 }
 
 /// @brief Saturate the selection to be inside the box.
@@ -114,7 +121,7 @@ Selection Selection::SaturateVertical(Box box) {
       end_y = box.y_min;
     }
   }
-  return Selection(start_x, start_y, end_x, end_y);
+  return Selection(start_x, start_y, end_x, end_y, option);
 }
 
 /// @brief Add a filter that will invert the foreground and the background
@@ -124,4 +131,16 @@ Element unselectable(Element child) {
   return std::make_shared<Unselectable>(std::move(child));
 }
 
+/// @brief Create a SelectionOption, inverting the selection.
+/// @ingroup component
+// static
+SelectionOption SelectionOption::Simple() {
+  SelectionOption option;
+  option.transform = [](Pixel& pixel) {
+
+    pixel.inverted = true;
+  };
+  return option;
+}
+
 }  // namespace ftxui

src/ftxui/dom/text.cpp

@@ -39,6 +39,8 @@ class Text : public Node {
     has_selection = true;
     selection_start_ = selection_saturated.GetBox().x_min;
     selection_end_ = selection_saturated.GetBox().x_max;
+
+    selectionTransform = selection.GetOption().transform;
   }
 
   void Render(Screen& screen) override {
@@ -60,7 +62,7 @@ class Text : public Node {
 
       if (has_selection) {
         if ((x >= selection_start_) && (x <= selection_end_)) {
-          screen.PixelAt(x, y).inverted = true;
+          selectionTransform(screen.PixelAt(x, y));
         }
       }
 
@@ -96,6 +98,7 @@ class Text : public Node {
   bool has_selection = false;
   int selection_start_ = 0;
   int selection_end_ = 10;
+  std::function<void(Pixel& pixel)> selectionTransform;
 };
 
 class VText : public Node {