Improve documentation (#1058)

* Remove @ingroup from class member definitions
* Add the documentation for every public classes.

include/ftxui/component/animation.hpp

@@ -8,11 +8,21 @@
 #include <functional>  // for function
 
 namespace ftxui::animation {
-// Components who haven't completed their animation can call this function to
-// request a new frame to be drawn later.
-//
-// When there is no new events and no animations to complete, no new frame is
-// drawn.
+/// @brief RequestAnimationFrame is a function that requests a new frame to be
+/// drawn in the next animation cycle.
+///
+/// @note This function is typically called by components that need to
+/// update their state or appearance over time, such as animations or
+/// transitions. This is useful when the change doesn't depend depend on the
+/// events seen by the terminal, but rather on the passage of time.
+///
+/// Components who haven't completed their animation can call this function to
+/// request a new frame to be drawn later.
+///
+/// When there is no new events and no animations to complete, no new frame is
+/// drawn.
+///
+/// @ingroup component
 void RequestAnimationFrame();
 
 using Clock = std::chrono::steady_clock;

include/ftxui/component/captured_mouse.hpp

@@ -7,6 +7,7 @@
 #include <memory>
 
 namespace ftxui {
+
 class CapturedMouseInterface {
  public:
   CapturedMouseInterface() = default;

include/ftxui/component/component_options.hpp

@@ -27,6 +27,8 @@ struct EntryState {
   int index;          ///< Index of the entry when applicable or -1.
 };
 
+/// @brief Option for the underline effect.
+/// @ingroup component
 struct UnderlineOption {
   bool enabled = false;
 
@@ -230,7 +232,8 @@ struct SliderOption {
   std::function<void()> on_change;  ///> Called when `value` is updated.
 };
 
-// Parameter pack used by `WindowOptions::render`.
+/// @brief State passed to the `Window` component's render function.
+/// @ingroup component
 struct WindowRenderState {
   Element inner;             ///< The element wrapped inside this window.
   const std::string& title;  ///< The title of the window.

include/ftxui/component/event.hpp

@@ -24,6 +24,8 @@ class ComponentBase;
 ///
 /// Useful documentation about xterm specification:
 /// https://invisible-island.net/xterm/ctlseqs/ctlseqs.html
+///
+/// @ingroup component
 struct Event {
   // --- Constructor section ---------------------------------------------------
   static Event Character(std::string);

include/ftxui/component/loop.hpp

@@ -14,6 +14,45 @@ class ComponentBase;
 using Component = std::shared_ptr<ComponentBase>;
 class ScreenInteractive;
 
+/// @brief Loop is a class that manages the event loop for a component.
+///
+/// It is responsible for running the component, handling events, and
+/// updating the screen.
+///
+/// The Loop class is designed to be used with a ScreenInteractive object,
+/// which represents the terminal screen.
+///
+/// **Example**
+/// ```cpp
+/// #include <ftxui/component/component.hpp>
+/// #include <ftxui/component/screen_interactive.hpp>
+/// #include <ftxui/component/loop.hpp>
+///
+/// int main() {
+///  auto screen = ftxui::ScreenInteractive::TerminalOutput();
+///  auto component = ftxui::Button("Click me", [] { ... });
+///
+///  ftxui::Loop loop(screen.get(), component);
+///
+///  // Either
+///  loop.Run();  // Blocking until the component quits.
+///
+///  // Or
+///  loop.RunOnce();  // Non-blocking, returns immediately.
+///
+///  // Or
+///  loop.RunOnceBlocking();  // Blocking until handling one event.
+///
+///  // Or in a loop:
+///  while (!loop.HasQuitted()) {
+///    loop.RunOnce();
+///
+///    // Do something else like running a different library loop function.
+///  }
+/// }
+/// ```
+///
+/// @ingroup component
 class Loop {
  public:
   Loop(ScreenInteractive* screen, Component component);

include/ftxui/component/screen_interactive.hpp

@@ -27,6 +27,10 @@ struct Event;
 using Component = std::shared_ptr<ComponentBase>;
 class ScreenInteractivePrivate;
 
+/// @brief ScreenInteractive is a `Screen` that can handle events, run a main
+/// loop, and manage components.
+///
+/// @ingroup component
 class ScreenInteractive : public Screen {
  public:
   // Constructors: