DragHandler.hpp

#ifndef DRAGHANDLER_HPP
#define DRAGHANDLER_HPP

#include "Export.hpp"

#include <MultiWidgets/Widget.hpp>

namespace Showcase {

  struct DropEvent
  {
    enum Type
    {
      TYPE_NONE,
      TYPE_HOVER_BEGIN,
      TYPE_HOVER,
      TYPE_HOVER_END,
      TYPE_DROP
    };

    MultiWidgets::WidgetPtr dragged;
    Nimble::Vector2f location{0, 0};
    Type type{TYPE_NONE};
  };

  class SHOWCASE_API DropListener
  {
  public:
    DropListener(bool multiHover) : m_multiHover(multiHover) {}

    virtual bool dropEvent(const DropEvent &) = 0;

    bool multiHover() const { return m_multiHover; }

    float maximumRelativeDropSize() const { return m_maxRelativeDropSize; }
    void setMaximumRelativeDropSize(float maxRelativeDropSize) { m_maxRelativeDropSize = maxRelativeDropSize; }

  private:
    float m_maxRelativeDropSize{std::numeric_limits<float>::infinity()};
    const bool m_multiHover;
  };

  class SHOWCASE_API DragHandler : public MultiWidgets::Operator
  {
  public:
    static void startDrag(MultiWidgets::WidgetPtr widget);

    virtual ~DragHandler();

  private:
    DragHandler(DropEvent event, bool removeWidgetAtEnd);

    virtual void update(MultiWidgets::Widget & dragged, const MultiWidgets::FrameInfo & frameInfo) override;
    virtual void interactionEnd(MultiWidgets::Widget & dragged, MultiWidgets::GrabManager & gm) override;
    virtual void added(MultiWidgets::Widget & dragged) override;

    bool hoverBegin(MultiWidgets::Widget & dragged, MultiWidgets::WidgetPtr target,
                    const Nimble::Vector2f & location);
    bool checkMaximumDropSize(MultiWidgets::Widget & dragged, const MultiWidgets::WidgetPtr & target,
                              float maximumRelativeDropSize) const;
    void hoverEnd(MultiWidgets::WidgetPtr dragged);

  private:
    MultiWidgets::WidgetPtr m_dragged;
    MultiWidgets::WidgetPtr m_target;
    DropEvent m_event;
    bool m_removeWidgetAtEnd;

    Nimble::Vector2f m_originalLocation{0, 0};
    float m_originalScale{1};
  };

  class SHOWCASE_API DragStarterOperator : public MultiWidgets::Operator
  {
  public:
    DragStarterOperator();

    virtual void added(MultiWidgets::Widget & widget) override;
    virtual void removed(MultiWidgets::Widget & widget) override;

  private:
    long m_dragEventListener;
  };
}

#endif // DRAGHANDLER_HPP