Add mouse implementation of most components.

src/ftxui/component/radiobox.cpp

@@ -8,6 +8,7 @@ namespace ftxui {
 Element RadioBox::Render() {
   std::vector<Element> elements;
   bool is_focused = Focused();
+  boxes_.resize(entries.size());
   for (size_t i = 0; i < entries.size(); ++i) {
     auto style =
         (focused == int(i) && is_focused) ? focused_style : unfocused_style;
@@ -16,12 +17,15 @@ Element RadioBox::Render() {
 
     const std::wstring& symbol = selected == int(i) ? checked : unchecked;
     elements.push_back(hbox(text(symbol), text(entries[i]) | style) |
-                       focus_management);
+                       focus_management | reflect(boxes_[i]));
   }
   return vbox(std::move(elements));
 }
 
 bool RadioBox::OnEvent(Event event) {
+  if (event.is_mouse())
+    return OnMouseEvent(event);
+
   if (!Focused())
     return false;
 
@@ -50,6 +54,30 @@ bool RadioBox::OnEvent(Event event) {
   return false;
 }
 
+bool RadioBox::OnMouseEvent(Event event) {
+  for (int i = 0; i < boxes_.size(); ++i) {
+    if (!boxes_[i].Contain(event.mouse_x(), event.mouse_y()))
+      continue;
+
+    if (event.is_mouse_move()) {
+      focused = i;
+      TakeFocus();
+      return true;
+    }
+
+    if (event.is_mouse_left_down()) {
+      cursor_position = i;
+      TakeFocus();
+      if (selected != i) {
+        selected = i;
+        on_change();
+      }
+      return true;
+    }
+  }
+  return false;
+}
+
 }  // namespace ftxui
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.