CableDragAutoScroller.hpp

#pragma once
#include <QObject>
#include <QPoint>
#include <QPointer>
#include <QSize>
#include <QTimer>
 
#include <score_lib_process_export.h>
 
#include <functional>
 
class QGraphicsView;
class QWidget;
 
namespace Dataflow
{
class SCORE_LIB_PROCESS_EXPORT CableDragAutoScroller final : public QObject
{
public:
  static constexpr int margin = 32;
  static constexpr int maxStep = 24;
  static constexpr int outsideLimit = 200;
  static constexpr int intervalMs = 16;
 
  using CursorProvider = std::function<QPoint(QWidget& viewport)>;
 
  explicit CableDragAutoScroller(
      std::function<void(QPointF scenePos)> onScrolled, CursorProvider cursor = {});
  ~CableDragAutoScroller();
 
  static QPoint scrollStep(QPoint viewportPos, QSize sz) noexcept;
 
  void track(QWidget* viewport, QPointF scenePos);
 
  void continueFromCursor();
 
  void stop();
 
  bool active() const noexcept { return m_timer.isActive(); }
  QGraphicsView* view() const noexcept;
 
  static bool scrollViewBy(QGraphicsView& view, QPoint delta);
  static bool scrollBarsBy(QGraphicsView& view, QPoint delta);
 
private:
  void tick();
  QPoint cursorInViewport() const;
 
  std::function<void(QPointF)> m_onScrolled;
  CursorProvider m_cursor;
  QPointer<QGraphicsView> m_view{};
  QTimer m_timer;
};
}