BehaviorNode.h

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#pragma once
 
#include "Core/Event.h"
#include "UI/Behavior/IBehavior.h"
#include "UI/Layout/BaseNode.h"
 
#include <memory>
#include <type_traits>
#include <utility>
#include <vector>
 
namespace z8::ui {
 
class BehaviorNode : public BaseNode, public EventTarget {
public:
  // 非视觉交互容器必须显式开启；根 DockSpace 不应吞掉整个窗口的场景输入。
  bool HitTestVisible = false;
  bool Hovered = false;
  bool Pressed = false;
  bool Focusable = false;
  bool Focused = false;
  std::vector<std::unique_ptr<IBehavior>> Behaviors;
  IBehavior *CapturedBehavior = nullptr;
 
  ~BehaviorNode() override;
  bool SetProperty(const std::string &name, const std::string &value) override;
 
  EventReply DispatchMouseDown(const MouseMovArgs &args);
  bool DispatchMouseMove(const MouseMovArgs &args);
  bool DispatchMouseDrag(const MouseMovArgs &args);
  bool DispatchMouseUp(const MouseMovArgs &args);
  bool DispatchMouseWheel(MouseWheelArgs args);
  MouseCursor QueryMouseCursor(const MouseMovArgs &args) const;
  void DispatchAfterLayout() override;
  void DispatchBeforeLayout(float width, float height) const;
  void DispatchDragStarted(const MouseMovArgs &args) const;
  void DispatchDragCompleted(const MouseMovArgs &args) const;
  void CancelPointerCapture();
 
  IBehavior *AddBehavior(std::unique_ptr<IBehavior> behavior);
  bool RemoveBehavior(IBehavior *behavior);
  void SetHovered(bool hovered);
  void SetPressed(bool pressed);
  void SetFocused(bool focused);
 
  template <typename T, typename... Args> T *AddBehavior(Args &&...args) {
    static_assert(std::is_base_of_v<IBehavior, T>);
    auto behavior = std::make_unique<T>(std::forward<Args>(args)...);
    auto *observer = behavior.get();
    AddBehavior(std::move(behavior));
    return observer;
  }
 
  template <typename T> T *GetBehavior() {
    static_assert(std::is_base_of_v<IBehavior, T>);
    for (auto &behavior : Behaviors)
      if (auto *result = dynamic_cast<T *>(behavior.get()))
        return result;
    return nullptr;
  }
 
  template <typename T> const T *GetBehavior() const {
    static_assert(std::is_base_of_v<IBehavior, T>);
    for (const auto &behavior : Behaviors)
      if (auto *result = dynamic_cast<const T *>(behavior.get()))
        return result;
    return nullptr;
  }
 
protected:
  virtual void OnVisualStateChanged() {}
  void ReleaseBehaviors();
};
 
} // namespace z8::ui