Remove Ref<XxxOption> and add new interfaces. (#686)

1. Stop taking Ref<XxxOption> in Component constructors. Instead, use
   the XxxOption directly. Passing by copy avoid problems developers had
   where one was shared in between multiple component, causing issues.

2. Add variants of most component constructors taking a struct only.

This replaces:
https://github.com/ArthurSonzogni/FTXUI/pull/670

This fixes:
https://github.com/ArthurSonzogni/FTXUI/issues/426

src/ftxui/component/radiobox.cpp

@@ -21,12 +21,9 @@ namespace {
 /// @brief A list of selectable element. One and only one can be selected at
 /// the same time.
 /// @ingroup component
-class RadioboxBase : public ComponentBase {
+class RadioboxBase : public ComponentBase, public RadioboxOption {
  public:
-  RadioboxBase(ConstStringListRef entries,
-               int* selected,
-               Ref<RadioboxOption> option)
-      : entries_(entries), selected_(selected), option_(std::move(option)) {}
+  explicit RadioboxBase(RadioboxOption option) : RadioboxOption(option) {}
 
  private:
   Element Render() override {
@@ -41,14 +38,13 @@ class RadioboxBase : public ComponentBase {
                               : is_menu_focused ? focus
                                                 : select;
       auto state = EntryState{
-          entries_[i],
-          *selected_ == i,
+          entries[i],
+          selected() == i,
           is_selected,
           is_focused,
       };
       auto element =
-          (option_->transform ? option_->transform
-                              : RadioboxOption::Simple().transform)(state);
+          (transform ? transform : RadioboxOption::Simple().transform)(state);
 
       elements.push_back(element | focus_management | reflect(boxes_[i]));
     }
@@ -97,14 +93,14 @@ class RadioboxBase : public ComponentBase {
 
       if (hovered_ != old_hovered) {
         focused_entry() = hovered_;
-        option_->on_change();
+        on_change();
         return true;
       }
     }
 
     if (event == Event::Character(' ') || event == Event::Return) {
-      *selected_ = hovered_;
-      option_->on_change();
+      selected() = hovered_;
+      on_change();
       return true;
     }
 
@@ -126,9 +122,9 @@ class RadioboxBase : public ComponentBase {
       focused_entry() = i;
       if (event.mouse().button == Mouse::Left &&
           event.mouse().motion == Mouse::Released) {
-        if (*selected_ != i) {
-          *selected_ = i;
-          option_->on_change();
+        if (selected() != i) {
+          selected() = i;
+          on_change();
         }
 
         return true;
@@ -154,7 +150,7 @@ class RadioboxBase : public ComponentBase {
     hovered_ = util::clamp(hovered_, 0, size() - 1);
 
     if (hovered_ != old_hovered) {
-      option_->on_change();
+      on_change();
     }
 
     return true;
@@ -162,25 +158,54 @@ class RadioboxBase : public ComponentBase {
 
   void Clamp() {
     boxes_.resize(size());
-    *selected_ = util::clamp(*selected_, 0, size() - 1);
+    selected() = util::clamp(selected(), 0, size() - 1);
     focused_entry() = util::clamp(focused_entry(), 0, size() - 1);
     hovered_ = util::clamp(hovered_, 0, size() - 1);
   }
 
-  bool Focusable() const final { return entries_.size(); }
-  int& focused_entry() { return option_->focused_entry(); }
-  int size() const { return int(entries_.size()); }
+  bool Focusable() const final { return entries.size(); }
+  int size() const { return int(entries.size()); }
 
-  ConstStringListRef entries_;
-  int* selected_;
-  int hovered_ = *selected_;
+  int hovered_ = selected();
   std::vector<Box> boxes_;
   Box box_;
-  Ref<RadioboxOption> option_;
 };
 
 }  // namespace
 
+/// @brief A list of element, where only one can be selected.
+/// @param option The parameters
+/// @ingroup component
+/// @see RadioboxBase
+///
+/// ### Example
+///
+/// ```cpp
+/// auto screen = ScreenInteractive::TerminalOutput();
+/// std::vector<std::string> entries = {
+///     "entry 1",
+///     "entry 2",
+///     "entry 3",
+/// };
+/// int selected = 0;
+/// auto menu = Radiobox({
+///   .entries = entries,
+///   .selected = &selected,
+/// });
+/// screen.Loop(menu);
+/// ```
+///
+/// ### Output
+///
+/// ```bash
+/// ◉ entry 1
+/// ○ entry 2
+/// ○ entry 3
+/// ```
+Component Radiobox(RadioboxOption option) {
+  return Make<RadioboxBase>(std::move(option));
+}
+
 /// @brief A list of element, where only one can be selected.
 /// @param entries The list of entries in the list.
 /// @param selected The index of the currently selected element.
@@ -211,8 +236,10 @@ class RadioboxBase : public ComponentBase {
 /// ```
 Component Radiobox(ConstStringListRef entries,
                    int* selected,
-                   Ref<RadioboxOption> option) {
-  return Make<RadioboxBase>(entries, selected, std::move(option));
+                   RadioboxOption option) {
+  option.entries = entries;
+  option.selected = selected;
+  return Make<RadioboxBase>(std::move(option));
 }
 
 }  // namespace ftxui