src/ftxui/component/renderer.cpp

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// Copyright 2021 Arthur Sonzogni. All rights reserved.
// Use of this source code is governed by the MIT license that can be found in
// the LICENSE file.
#include <functional>  // for function
#include <utility>     // for move
 
#include "ftxui/component/component.hpp"       // for Make, Renderer
#include "ftxui/component/component_base.hpp"  // for Component, ComponentBase
#include "ftxui/component/event.hpp"           // for Event
#include "ftxui/component/mouse.hpp"           // for Mouse
#include "ftxui/dom/elements.hpp"  // for Element, operator|, reflect
#include "ftxui/screen/box.hpp"    // for Box
 
namespace ftxui {
 
/// @brief Return a component, using |render| to render its interface.
/// @param render The function drawing the interface.
/// @ingroup component
///
/// ### Example
///
/// ```cpp
/// auto screen = ScreenInteractive::TerminalOutput();
/// auto renderer = Renderer([] {
///   return text("My interface");
/// });
/// screen.Loop(renderer);
/// ```
Component Renderer(std::function<Element()> render) {
  class Impl : public ComponentBase {
   public:
    explicit Impl(std::function<Element()> render)
        : render_(std::move(render)) {}
    Element OnRender() override { return render_(); }
    std::function<Element()> render_;
  };
 
  return Make<Impl>(std::move(render));
}
 
/// @brief Return a new Component, similar to |child|, but using |render| as the
/// Component::Render() event.
/// @param child The component to forward events to.
/// @param render The function drawing the interface.
/// @ingroup component
///
/// ### Example
///
/// ```cpp
/// auto screen = ScreenInteractive::TerminalOutput();
/// std::string label = "Click to quit";
/// auto button = Button(&label, screen.ExitLoopClosure());
/// auto renderer = Renderer(button, [&] {
///   return hbox({
///     text("A button:"),
///     button->Render(),
///   });
/// });
/// screen.Loop(renderer);
/// ```
Component Renderer(Component child, std::function<Element()> render) {
  Component renderer = Renderer(std::move(render));
  renderer->Add(std::move(child));
  return renderer;
}
 
/// @brief Return a focusable component, using |render| to render its interface.
/// @param render The function drawing the interface, taking a boolean telling
/// whether the component is focused or not.
/// @ingroup component
///
/// ### Example
///
/// ```cpp
/// auto screen = ScreenInteractive::TerminalOutput();
/// auto renderer = Renderer([] (bool focused) {
///   if (focused)
///     return text("My interface") | inverted;
///   else
///     return text("My interface");
/// });
/// screen.Loop(renderer);
/// ```
Component Renderer(std::function<Element(bool)> render) {
  class Impl : public ComponentBase {
   public:
    explicit Impl(std::function<Element(bool)> render)
        : render_(std::move(render)) {}
 
   private:
    Element OnRender() override { return render_(Focused()) | reflect(box_); }
    bool Focusable() const override { return true; }
    bool OnEvent(Event event) override {
      if (event.is_mouse() && box_.Contain(event.mouse().x, event.mouse().y)) {
        if (!CaptureMouse(event)) {
          return false;
        }
 
        TakeFocus();
      }
 
      return false;
    }
    Box box_;
 
    std::function<Element(bool)> render_;
  };
  return Make<Impl>(std::move(render));
}
 
/// @brief Decorate a component, by decorating what it renders.
/// @param decorator the function modifying the element it renders.
/// @ingroup component
///
/// ### Example
///
/// ```cpp
/// auto screen = ScreenInteractive::TerminalOutput();
/// auto renderer =
//     Renderer([] { return text("Hello");)
///  | Renderer(bold)
///  | Renderer(inverted);
/// screen.Loop(renderer);
/// ```
ComponentDecorator Renderer(ElementDecorator decorator) {  // NOLINT
  return [decorator](Component component) {                // NOLINT
    return Renderer(component, [component, decorator] {
      return component->Render() | decorator;
    });
  };
}
 
}  // namespace ftxui