Added bouncing effect for Rotation animation

svn path=/trunk/KDE/kdelibs/; revision=1112192

animations/rotation.cpp

@@ -26,9 +26,13 @@
 namespace Plasma
 {
 
-RotationAnimation::RotationAnimation(QObject *parent, qint8 reference, Qt::Axis axis, qreal angle)
-    : Animation(parent)
+const int RotationAnimation::s_bounceSteps = 10;
+
+RotationAnimation::RotationAnimation(QObject *parent, bool isBounceable, qint8 reference, Qt::Axis axis, qreal angle)
+    : Animation(parent),
+      m_bounceStep(0)
 {
+    setBounceable(isBounceable);
     setAngle(angle);
     setAxis(axis);
     setReference(reference);
@@ -40,6 +44,16 @@ RotationAnimation::~RotationAnimation()
 {
 }
 
+bool RotationAnimation::isBounceable() const
+{
+    return m_isBounceable;
+}
+
+void RotationAnimation::setBounceable(const bool isBounceable)
+{
+    m_isBounceable = isBounceable;
+}
+
 Qt::Axis RotationAnimation::axis() const
 {
     return m_axis;
@@ -154,7 +168,18 @@ void RotationAnimation::updateState(QAbstractAnimation::State newState, QAbstrac
     if ((oldState == Stopped) && (newState == Running)) {
         m_rotation->setAngle(direction() == Forward ? 0 : angle());
     } else if (newState == Stopped) {
-        m_rotation->setAngle(direction() == Forward ? angle() : 0);
+        // Do not bounce if animation is part of a group
+        if (!m_isBounceable || group()) {
+            m_rotation->setAngle(direction() == Forward ? angle() : 0);
+        } else {
+            setDirection(direction() == Forward ? Backward : Forward);
+            if (++m_bounceStep < s_bounceSteps) {
+                start();
+            } else {
+                m_rotation->setAngle(direction() == Forward ? 0 : angle());
+                m_bounceStep = 0;
+            }
+        }
     }
 }
 
@@ -164,7 +189,18 @@ void RotationAnimation::updateCurrentTime(int currentTime)
     if (w) {
         qreal delta = Animation::easingCurve().valueForProgress(
             currentTime / qreal(duration()));
-        delta = angle() * delta;
+        const qreal currentAngle = angle();
+        if (m_isBounceable) {
+            const qreal percentage = 1 - qBound(0.0, qreal(m_bounceStep) / qreal(s_bounceSteps), 1.0);
+            if (m_bounceStep == 0) { // initial bounce
+                delta = qBound(0.0, currentAngle * percentage * delta * 0.5, (currentAngle / 2.0));
+            } else {
+                delta -= 0.5;
+                delta = qBound(-(currentAngle / 2.0), currentAngle * percentage * delta, (currentAngle / 2.0));
+            }
+        } else {
+            delta = qBound(0.0, currentAngle * delta, currentAngle);
+        }
         m_rotation->setAngle(delta);
     }
 }

animations/rotation_p.h

@@ -33,16 +33,17 @@ class QGraphicsRotation;
 namespace Plasma {
 /**
  * @class RotationAnimation plasma/animations/rotation_p.h
- * @short 2D rotation animation.
+ * @short 3D rotation animation.
  *
- * This animation rotates a QGraphicsWidget in a axis (reference and
- * axis can be defined using properties). See also
+ * This animation rotates a QGraphicsWidget in a axis (bounce, reference, axis
+ * and angle can be defined using properties). See also
  * \ref StackedRotationAnimation.
  */
 class RotationAnimation : public Animation
 {
 
     Q_OBJECT
+    Q_PROPERTY(bool isBounceable READ isBounceable WRITE setBounceable)
     Q_PROPERTY(Qt::Axis axis READ axis WRITE setAxis)
     Q_PROPERTY(qint8 reference READ reference WRITE setReference)
     Q_PROPERTY(qreal angle READ angle WRITE setAngle)
@@ -51,12 +52,14 @@ public:
     /** Default constructor
      *
      * @param parent Animation object parent.
+     * @param isBounceable Animation bounce behavior.
      * @param reference See \ref Animation::Reference.
      * @param axis Which axis to rotate (XAxis, YAxis, ZAxis).
      * @param angle Rotation angle (0 to 360)
      *
      */
     explicit RotationAnimation(QObject *parent = 0,
+                               bool isBounceable = false,
                                qint8 reference = Center,
                                Qt::Axis axis = Qt::ZAxis,
                                qreal angle = 180);
@@ -64,6 +67,18 @@ public:
     /** Destructor */
     ~RotationAnimation();
 
+    /**
+     * get animation bounce behavior
+     */
+    bool isBounceable() const;
+
+    /**
+     * set animation bounce behavior (it can be bounceable only if not part of
+     * an animation group)
+     * @arg isBounceable
+     */
+    void setBounceable(const bool isBounceable);
+
     /**
      * get animation rotation axis (e.g. YAxis, ZAxis, XAxis)
      */
@@ -106,6 +121,12 @@ protected:
 private:
     /** Rotation transform object */
     QGraphicsRotation *m_rotation;
+    /** Actual number of bounce steps */
+    int m_bounceStep;
+    /** Number of bounce steps */
+    static const int s_bounceSteps;
+    /** Animation bounce behavior */
+    bool m_isBounceable;
     /** Rotation angle */
     qreal m_angle;
     /** Axis where to perform the rotation */