Fix + support for indpendant styles.

include/ftxui/component/screen_interactive.hpp

@@ -15,8 +15,8 @@
 #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/dom/selection.hpp"             // for SelectionOption
 #include "ftxui/screen/screen.hpp"             // for Screen
 
 namespace ftxui {
@@ -70,7 +70,8 @@ class ScreenInteractive : public Screen {
   void ForceHandleCtrlZ(bool force);
 
   // Selection API.
-  std::string GetSelectedContent(Component component);
+  std::string SelectionAsString();
+  void SelectionOnChange(std::function<void()> callback);
 
  private:
   void ExitNow();
@@ -86,7 +87,7 @@ class ScreenInteractive : public Screen {
   void RunOnceBlocking(Component component);
 
   void HandleTask(Component component, Task& task);
-  bool HandleSelection(Event event);
+  bool HandleSelection(bool handled, Event event);
   void RefreshSelection();
   void Draw(Component component);
   void ResetCursorPosition();
@@ -137,11 +138,19 @@ class ScreenInteractive : public Screen {
 
   // Selection API:
   CapturedMouse selection_pending_;
-  int selection_start_x_ = 0;
-  int selection_start_y_ = 0;
-  int selection_end_x_ = 0;
-  int selection_end_y_ = 0;
-  bool selection_changed = false;
+  struct SelectionData {
+    int start_x = -1;
+    int start_y = -1;
+    int end_x = -2;
+    int end_y = -2;
+    bool empty = true;
+    bool operator==(const SelectionData& other) const;
+    bool operator!=(const SelectionData& other) const;
+  };
+  SelectionData selection_data_;
+  SelectionData selection_data_previous_;
+  std::unique_ptr<Selection> selection_;
+  std::function<void()> selection_on_change_;
 
   friend class Loop;
 

include/ftxui/dom/node.hpp

@@ -68,7 +68,9 @@ class Node {
 void Render(Screen& screen, const Element& element);
 void Render(Screen& screen, Node* node);
 void Render(Screen& screen, Node* node, Selection& selection);
-std::string GetNodeSelectedContent(Screen& screen, Node* node, Selection& selection);
+std::string GetNodeSelectedContent(Screen& screen,
+                                   Node* node,
+                                   Selection& selection);
 
 }  // namespace ftxui
 

include/ftxui/dom/selection.hpp

@@ -7,6 +7,7 @@
 
 #include <functional>
 
+#include <sstream>
 #include "ftxui/screen/box.hpp"    // for Box
 #include "ftxui/screen/pixel.hpp"  // for Pixel
 
@@ -15,19 +16,33 @@ namespace ftxui {
 /// @brief Represent a selection in the terminal.
 class Selection {
  public:
+  Selection();  // Empty selection.
   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);
+  bool IsEmpty() const { return empty_; }
+
+  void AddPart(const std::string& part, int y, int left, int right);
+  std::string GetParts() { return parts_.str(); }
 
  private:
-  Selection* const parent_ = nullptr;
-  const int start_x_;
-  const int start_y_;
-  const int end_x_;
-  const int end_y_;
-  const Box box_;
+  Selection(int start_x, int start_y, int end_x, int end_y, Selection* parent);
+
+  Selection* const parent_ = this;
+  const bool empty_ = true;
+  const int start_x_ = 0;
+  const int start_y_ = 0;
+  const int end_x_ = 0;
+  const int end_y_ = 0;
+  const Box box_ = {};
+  std::stringstream parts_;
+
+  // The position of the last inserted part.
+  int x_ = 0;
+  int y_ = 0;
 };
 
 }  // namespace ftxui