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/*
* SPDX-FileCopyrightText: 2011 Peter Penz <[email protected]>
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#ifndef KITEMLISTSMOOTHSCROLLER_H
#define KITEMLISTSMOOTHSCROLLER_H
#include "dolphin_export.h"
#include <QAbstractAnimation>
#include <QObject>
class QPropertyAnimation;
class QScrollBar;
class QWheelEvent;
/**
* @brief Helper class for KItemListContainer to have a smooth
* scrolling when adjusting the scrollbars.
*/
class DOLPHIN_EXPORT KItemListSmoothScroller : public QObject
{
Q_OBJECT
public:
explicit KItemListSmoothScroller(QScrollBar *scrollBar, QObject *parent = nullptr);
~KItemListSmoothScroller() override;
void setScrollBar(QScrollBar *scrollBar);
QScrollBar *scrollBar() const;
void setTargetObject(QObject *target);
QObject *targetObject() const;
void setPropertyName(const QByteArray &propertyName);
QByteArray propertyName() const;
/**
* Adjusts the position of the target by \p distance
* pixels. Is invoked in the context of QAbstractScrollArea::scrollContentsBy()
* where the scrollbars already have the new position but the content
* has not been scrolled yet.
*/
void scrollContentsBy(qreal distance);
/**
* Does a smooth-scrolling to the position \p position
* on the target and also adjusts the corresponding scrollbar
* to the new position.
*/
void scrollTo(qreal position);
/**
* Must be invoked before the scrollbar should get updated to have a new
* maximum. True is returned if the new maximum can be applied. If false
* is returned the maximum has already been reached and the value will
* be reached at the end of the animation.
*/
// TODO: This interface is tricky to understand. Try to make this more
// generic/readable if the corresponding code in KItemListContainer got
// stable.
bool requestScrollBarUpdate(int newMaximum);
/**
* Forwards wheel events to the scrollbar, ensuring smooth and proper scrolling
*/
void handleWheelEvent(QWheelEvent *event);
bool isAnimating();
Q_SIGNALS:
/**
* Emitted when the scrolling animation has finished
*/
void scrollingStopped();
protected:
bool eventFilter(QObject *obj, QEvent *event) override;
private Q_SLOTS:
void slotAnimationStateChanged(QAbstractAnimation::State newState, QAbstractAnimation::State oldState);
/**
* Calculates the duration of the smooth scrolling animation.
* If \p isSmoothScrollingEnabled is true, the duration will be calculated
* using the widget animation duration from the current style. Otherwise,
* the animation will be instantaneous.
*/
void updateAnimationDuration(bool isSmoothScrollingEnabled);
private:
bool m_scrollBarPressed;
bool m_smoothScrolling;
QScrollBar *m_scrollBar;
QPropertyAnimation *m_animation;
};
#endif
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