Qt Reference Documentation

# animation.h Example File

animation/easing/animation.h

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     #ifndef ANIMATION_H
     #define ANIMATION_H

     #include <QtGui>

     #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)
         {
             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