qgsscrollarea.h

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/***************************************************************************
    qgsscrollarea.h
    ---------------
    begin                : March 2017
    copyright            : (C) 2017 by Nyall Dawson
    email                : nyall dot dawson at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef QGSSCROLLAREA_H
#define QGSSCROLLAREA_H
 
#include "qgis_gui.h"
#include "qgis_sip.h"
 
#include <QElapsedTimer>
#include <QScrollArea>
 
class ScrollAreaFilter;

class GUI_EXPORT QgsScrollArea : public QScrollArea
{
    Q_OBJECT
 
  public:
    explicit QgsScrollArea( QWidget *parent SIP_TRANSFERTHIS = nullptr );

    void scrollOccurred();

    bool hasScrolled() const;

    void resetHasScrolled() SIP_SKIP;

    void setVerticalOnly( bool verticalOnly );
 
  protected:
    void wheelEvent( QWheelEvent *event ) override;
    void resizeEvent( QResizeEvent *event ) override;
 
  private:
    bool mTimerActive = false;
    QElapsedTimer mTimer;
    ScrollAreaFilter *mFilter = nullptr;
    bool mVerticalOnly = false;
};
 
#ifndef SIP_RUN


class ScrollAreaFilter : public QObject
{
    Q_OBJECT
  public:
    ScrollAreaFilter( QgsScrollArea *parent = nullptr, QWidget *viewPort = nullptr );
 
  protected:
    bool eventFilter( QObject *obj, QEvent *event ) override;
 
  private:
    QgsScrollArea *mScrollAreaWidget = nullptr;
    QWidget *mViewPort = nullptr;
    QPoint mPreviousViewportCursorPos;
    int mMoveDistanceThreshold = 0;
 
    void addChild( QObject *child );
    void removeChild( QObject *child );
};

 
#endif
 
#endif // QGSSCROLLAREA_H