2 files changed, 38 insertions, 10 deletions

diff --git a/demos/composition/composition.cpp b/demos/composition/composition.cpp
index e03f3e6..deca5dc 100644
--- a/demos/composition/composition.cpp
+++ b/demos/composition/composition.cpp
@@ -48,6 +48,8 @@
 #include <QMouseEvent>
 #include <qmath.h>
 
+const int animationInterval = 15; // update every 16 ms = ~60FPS
+
 CompositionWidget::CompositionWidget(QWidget *parent)
     : QWidget(parent)
 {
@@ -236,6 +238,7 @@ CompositionRenderer::CompositionRenderer(QWidget *parent)
     : ArthurFrame(parent)
 {
     m_animation_enabled = true;
+    m_animationTimer = startTimer(animationInterval);
 #ifdef Q_WS_QWS
     m_image = QPixmap(":res/composition/flower.jpg");
     m_image.setAlphaChannel(QPixmap(":res/composition/flower_alpha.jpg"));
@@ -264,6 +267,20 @@ QRectF rectangle_around(const QPointF &p, const QSizeF &size = QSize(250, 200))
     return rect;
 }
 
+void CompositionRenderer::setAnimationEnabled(bool enabled)
+{
+    if (m_animation_enabled == enabled)
+        return;
+    m_animation_enabled = enabled;
+    if (enabled) {
+        Q_ASSERT(!m_animationTimer);
+        m_animationTimer = startTimer(animationInterval);
+    } else {
+        killTimer(m_animationTimer);
+        m_animationTimer = 0;
+    }
+}
+
 void CompositionRenderer::updateCirclePos()
 {
     if (m_current_object != NoObject)
@@ -471,10 +488,6 @@ void CompositionRenderer::paint(QPainter *painter)
         painter->drawImage(0, 0, m_buffer);
 #endif
     }
-
-    if (m_animation_enabled && m_current_object == NoObject) {
-        updateCirclePos();
-    }
 }
 
 void CompositionRenderer::mousePressEvent(QMouseEvent *e)
@@ -489,6 +502,10 @@ void CompositionRenderer::mousePressEvent(QMouseEvent *e)
     } else {
         m_current_object = NoObject;
     }
+    if (m_animation_enabled) {
+        killTimer(m_animationTimer);
+        m_animationTimer = 0;
+    }
 }
 
 void CompositionRenderer::mouseMoveEvent(QMouseEvent *e)
@@ -500,7 +517,15 @@ void CompositionRenderer::mouseReleaseEvent(QMouseEvent *)
 {
     m_current_object = NoObject;
 
-    if (m_animation_enabled)
+    if (m_animation_enabled) {
+        Q_ASSERT(!m_animationTimer);
+        m_animationTimer = startTimer(animationInterval);
+    }
+}
+
+void CompositionRenderer::timerEvent(QTimerEvent *event)
+{
+    if (event->timerId() == m_animationTimer)
         updateCirclePos();
 }
 
diff --git a/demos/composition/composition.h b/demos/composition/composition.h
index 1123531..f5a9fc3 100644
--- a/demos/composition/composition.h
+++ b/demos/composition/composition.h
@@ -109,10 +109,6 @@ public:
 
     void paint(QPainter *);
 
-    void mousePressEvent(QMouseEvent *);
-    void mouseMoveEvent(QMouseEvent *);
-    void mouseReleaseEvent(QMouseEvent *);
-
     void setCirclePos(const QPointF &pos);
 
     QSize sizeHint() const { return QSize(500, 400); }
@@ -121,6 +117,12 @@ public:
     int circleColor() const { return m_circle_hue; }
     int circleAlpha() const { return m_circle_alpha; }
 
+protected:
+    void mousePressEvent(QMouseEvent *);
+    void mouseMoveEvent(QMouseEvent *);
+    void mouseReleaseEvent(QMouseEvent *);
+    void timerEvent(QTimerEvent *);
+
 public slots:
     void setClearMode() { m_composition_mode = QPainter::CompositionMode_Clear; update(); }
     void setSourceMode() { m_composition_mode = QPainter::CompositionMode_Source; update(); }
@@ -150,7 +152,7 @@ public slots:
 
     void setCircleAlpha(int alpha) { m_circle_alpha = alpha; update(); }
     void setCircleColor(int hue) { m_circle_hue = hue; update(); }
-    void setAnimationEnabled(bool enabled) { m_animation_enabled = enabled; update(); }
+    void setAnimationEnabled(bool enabled);
 
 private:
     void updateCirclePos();
@@ -177,6 +179,7 @@ private:
 
     ObjectType m_current_object;
     bool m_animation_enabled;
+    int m_animationTimer;
 
 #ifdef QT_OPENGL_SUPPORT
     QGLPixelBuffer *m_pbuffer;