ScrollBehavior.h

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#pragma once
 
#include "UI/Behavior/IBehavior.h"
 
namespace z8::ui {
 
class BaseNode;
class ScrollBarNode;
 
enum class ScrollBarVisibility {
  Hidden,
  Auto,
  Visible
};
 
struct ScrollProperty {
  bool Enabled = true;
  bool Horizontal = false;
  bool Vertical = true;
  ScrollBarVisibility HorizontalScrollBar = ScrollBarVisibility::Hidden;
  ScrollBarVisibility VerticalScrollBar = ScrollBarVisibility::Auto;
  float WheelStep = 40.0f;
};
 
class ScrollBehavior final : public IBehavior {
  BaseNode *Viewport = nullptr;
  BaseNode *Content = nullptr;
  ScrollBarNode *VerticalScrollBar = nullptr;
  float OffsetY = 0.0f;
  float MaximumOffsetY = 0.0f;
public:
  ScrollProperty Properties;
  ScrollBehavior() = default;
 
  void BindVertical(BaseNode *viewport, BaseNode *content, ScrollBarNode *scrollBar);
  void SetProperties(const ScrollProperty &properties);
  bool SetProperty(const std::string &name, const std::string &value) override;
  void SetOffsetY(float offset);
  float GetOffsetY() const { return OffsetY; }
  float GetMaximumOffsetY() const { return MaximumOffsetY; }
;
  EventReply OnMouseWheel(MouseWheelArgs args) override;
  void OnAfterLayout() override;
  void OnDetached() override;
 
private:
  void ApplyProperties();
  void SynchronizeVisuals() const;
  void UpdateRange();
};
 
} // namespace z8::ui