Start the tree-aware selection.

include/ftxui/component/screen_interactive.hpp

@@ -68,7 +68,9 @@ class ScreenInteractive : public Screen {
   void ForceHandleCtrlC(bool force);
   void ForceHandleCtrlZ(bool force);
 
-  std::string GetSelection();
+  // Selection API.
+  //void OnSelectionChange(std::function<void(std::
+  //void ClearSelection();
 
  private:
   void ExitNow();
@@ -133,6 +135,11 @@ class ScreenInteractive : public Screen {
   // The style of the cursor to restore on exit.
   int cursor_reset_shape_ = 1;
 
+  // Selection API:
+  bool selection_enabled_ = false;
+  CapturedMouse selection_pending_;
+  Box selection_box_;
+
   friend class Loop;
 
  public:

include/ftxui/dom/node.hpp

@@ -4,6 +4,7 @@
 #ifndef FTXUI_DOM_NODE_HPP
 #define FTXUI_DOM_NODE_HPP
 
+#include <list>    // for list
 #include <memory>  // for shared_ptr
 #include <vector>  // for vector
 
@@ -40,7 +41,11 @@ class Node {
   //         Propagated from Parents to Children.
   virtual void SetBox(Box box);
 
-  // Step 3: Draw this element.
+  // Step 3: (optional) Selection
+  //         Propagated from Parents to Children.
+  virtual void Selection(Box selection, std::vector<Box>* selected);
+
+  // Step 4: Draw this element.
   virtual void Render(Screen& screen);
 
   // Layout may not resolve within a single iteration for some elements. This
@@ -52,11 +57,6 @@ class Node {
   };
   virtual void Check(Status* status);
 
-  // Selection.
-  // Propagated from Parents to Children.
-  virtual void Select(Box selected_area) {
-    // TODO: Implement this.
-  }
 
  protected:
   Elements children_;
@@ -66,6 +66,7 @@ class Node {
 
 void Render(Screen& screen, const Element& element);
 void Render(Screen& screen, Node* node);
+void Render(Screen& screen, Node* node, Box selection);
 
 }  // namespace ftxui
 

include/ftxui/screen/box.hpp

@@ -11,13 +11,10 @@ struct Box {
   int x_max = 0;
   int y_min = 0;
   int y_max = 0;
-  bool isXInverted = false;  // false means the box box from x_min to x_max (in the case of a selection for example)
-  bool isYInverted = false;  // false means the box box from y_min to y_max (in the case of a selection for example) 
 
   static auto Intersection(Box a, Box b) -> Box;
   static auto Union(Box a, Box b) -> Box;
   bool Contain(int x, int y) const;
-  Box Clean() const;
   bool IsEmpty() const;
   bool operator==(const Box& other) const;
   bool operator!=(const Box& other) const;

include/ftxui/screen/screen.hpp

@@ -63,12 +63,6 @@ class Screen : public Image {
   Cursor cursor() const { return cursor_; }
   void SetCursor(Cursor cursor) { cursor_ = cursor; }
 
-  bool selection_enabled = false;
-  CapturedMouse selection_pending;
-  Box mouse_selection_region;
-  Box selection_region;
-  std::string selection_text;
-
   // Store an hyperlink in the screen. Return the id of the hyperlink. The id is
   // used to identify the hyperlink when the user click on it.
   uint8_t RegisterHyperlink(const std::string& link);