- Qt 5.5
- Qt Widgets
- Easing Curves Example
- animation.h Example File
- Qt 5.5.1 Reference Documentation

# animation.h Example File

animation/easing/animation.h

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the QtCore module of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** You may use this file under the terms of the BSD license as follows:
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    #ifndef ANIMATION_H
    #define ANIMATION_H

    #include <QtWidgets>

    #include <QtCore/qpropertyanimation.h>

    class Animation : public QPropertyAnimation {
    public:
        enum PathType {
            LinearPath,
            CirclePath,
            NPathTypes
        };
        Animation(QObject *target, const QByteArray &prop)
            : QPropertyAnimation(target, prop)
        {
            setPathType(LinearPath);
        }

        void setPathType(PathType pathType)
        {
            if (pathType >= NPathTypes)
                qWarning("Unknown pathType %d", pathType);

            m_pathType = pathType;
            m_path = QPainterPath();
        }

        void updateCurrentTime(int currentTime) Q_DECL_OVERRIDE
        {
            if (m_pathType == CirclePath) {
                if (m_path.isEmpty()) {
                    QPointF to = endValue().toPointF();
                    QPointF from = startValue().toPointF();
                    m_path.moveTo(from);
                    m_path.addEllipse(QRectF(from, to));
                }
                int dura = duration();
                const qreal progress = ((dura == 0) ? 1 : ((((currentTime - 1) % dura) + 1) / qreal(dura)));

                qreal easedProgress = easingCurve().valueForProgress(progress);
                if (easedProgress > 1.0) {
                    easedProgress -= 1.0;
                } else if (easedProgress < 0) {
                    easedProgress += 1.0;
                }
                QPointF pt = m_path.pointAtPercent(easedProgress);
                updateCurrentValue(pt);
                emit valueChanged(pt);
            } else {
                QPropertyAnimation::updateCurrentTime(currentTime);
            }
        }

        QPainterPath m_path;
        PathType m_pathType;
    };

    #endif // ANIMATION_H