Fixes: Improving speed of taking screenshot for rotation animation.

RevBy: Marcin, Dominik
Details: Rendering scene to an image and drawing this image in the
rotation animation is quite slow. In some cases the fadeout animation
of the snapshot could have finished before we were ready to display it.

3 files changed, 9 insertions, 24 deletions

diff --git a/src/corelib/animation/scene/mcrossfadedorientationanimation.cpp b/src/corelib/animation/scene/mcrossfadedorientationanimation.cpp
index 3ef83853..66a7bf91 100644
--- a/src/corelib/animation/scene/mcrossfadedorientationanimation.cpp
+++ b/src/corelib/animation/scene/mcrossfadedorientationanimation.cpp
@@ -74,7 +74,7 @@ void MCrossFadedOrientationAnimationPrivate::createRootElementSnapshot()
     // temporarily hide the scene background.
 
     // hide scene background
-    snapshot = new MSnapshotItem(scene, visibleSceneRect);
+    snapshot = new MSnapshotItem(visibleSceneRect);
     // show scene background
 
     scene->addItem(snapshot);
diff --git a/src/corelib/animation/scene/msnapshotitem.cpp b/src/corelib/animation/scene/msnapshotitem.cpp
index 86ee395a..fb04ac18 100644
--- a/src/corelib/animation/scene/msnapshotitem.cpp
+++ b/src/corelib/animation/scene/msnapshotitem.cpp
@@ -3,31 +3,17 @@
 #include <QGraphicsScene>
 #include <QImage>
 #include <QPainter>
+#include <QApplication>
+#include <QDesktopWidget>
 
-MSnapshotItem::MSnapshotItem(QGraphicsScene *scene, const QRectF &sceneTargetRect, QGraphicsItem *parent)
+MSnapshotItem::MSnapshotItem(const QRectF &sceneTargetRect, QGraphicsItem *parent)
     : QGraphicsObject(parent), m_boundingRect(sceneTargetRect)
 {
-    // Assumes that the resolution is one scene unit per pixel
-    image = new QImage(sceneTargetRect.width(), sceneTargetRect.height(),
-            QImage::Format_ARGB32_Premultiplied);
-
-    QRectF targetRect;
-    targetRect.setX(0.0f);
-    targetRect.setY(0.0f);
-    targetRect.setWidth(sceneTargetRect.width());
-    targetRect.setHeight(sceneTargetRect.height());
-
-    QRectF sourceRect;
-    sourceRect = sceneTargetRect;
-
-    QPainter painter(image);
-    scene->render(&painter, targetRect, sourceRect);
+    pixmap = QPixmap::grabWindow(QApplication::desktop()->winId());
 }
 
 MSnapshotItem::~MSnapshotItem()
 {
-    delete image;
-    image = 0;
 }
 
 QRectF MSnapshotItem::boundingRect() const
@@ -41,7 +27,5 @@ void MSnapshotItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *opt
     Q_UNUSED(option);
     Q_UNUSED(widget);
 
-    painter->setRenderHint(QPainter::Antialiasing, true);
-    painter->setRenderHint(QPainter::SmoothPixmapTransform, true);
-    painter->drawImage(0, 0, *image);
+    painter->drawPixmap(0,0, pixmap);
 }
diff --git a/src/corelib/animation/scene/msnapshotitem.h b/src/corelib/animation/scene/msnapshotitem.h
index 1a92ff10..82eaeb78 100644
--- a/src/corelib/animation/scene/msnapshotitem.h
+++ b/src/corelib/animation/scene/msnapshotitem.h
@@ -6,12 +6,13 @@
 class QGraphicsScene;
 class QRectF;
 class QImage;
+class QPixmap;
 
 class MSnapshotItem : public QGraphicsObject
 {
     Q_OBJECT
 public:
-    MSnapshotItem(QGraphicsScene *scene, const QRectF &targetRect,
+    MSnapshotItem(const QRectF &targetRect,
             QGraphicsItem *parent = 0);
 
     virtual ~MSnapshotItem();
@@ -23,7 +24,7 @@ public:
 
 private:
     QRectF m_boundingRect;
-    QImage *image;
+    QPixmap pixmap;
 };
 
 #endif