1 files changed, 20 insertions, 18 deletions

diff --git a/src/quick/items/context2d/qquickcanvasitem.cpp b/src/quick/items/context2d/qquickcanvasitem.cpp
index e7546535a1..9c4cef1fe1 100644
--- a/src/quick/items/context2d/qquickcanvasitem.cpp
+++ b/src/quick/items/context2d/qquickcanvasitem.cpp
@@ -175,7 +175,6 @@ public:
     uint hasTileSize :1;
     uint hasCanvasWindow :1;
     uint available :1;
-    uint contextInitialized :1;
     QQuickCanvasItem::RenderTarget renderTarget;
     QQuickCanvasItem::RenderStrategy renderStrategy;
     QString contextType;
@@ -193,7 +192,6 @@ QQuickCanvasItemPrivate::QQuickCanvasItemPrivate()
     , hasTileSize(false)
     , hasCanvasWindow(false)
     , available(false)
-    , contextInitialized(false)
     , renderTarget(QQuickCanvasItem::Image)
     , renderStrategy(QQuickCanvasItem::Cooperative)
 {
@@ -272,7 +270,7 @@ QQuickCanvasItemPrivate::~QQuickCanvasItemPrivate()
     requires the pixel data to be exchanged between the system memory and the
     graphic card, which is significantly more expensive.  Rendering may also be
     synchronized with the V-sync signal (to avoid
-    \l{en.wikipedia.org/wiki/Screen_tearing}{screen tearing}) which will further
+    \l{http://en.wikipedia.org/wiki/Screen_tearing}{screen tearing}) which will further
     impact pixel operations with \c Canvas.FrambufferObject render target.
 
     \section1 Tips for Porting Existing HTML5 Canvas applications
@@ -343,7 +341,7 @@ void QQuickCanvasItem::setContextType(const QString &contextType)
     if (contextType.compare(d->contextType, Qt::CaseInsensitive) == 0)
         return;
 
-    if (d->contextInitialized) {
+    if (d->context) {
         qmlInfo(this) << "Canvas already initialized with a different context type";
         return;
     }
@@ -368,7 +366,7 @@ void QQuickCanvasItem::setContextType(const QString &contextType)
 QQmlV4Handle QQuickCanvasItem::context() const
 {
     Q_D(const QQuickCanvasItem);
-    if (d->contextInitialized)
+    if (d->context)
         return QQmlV4Handle(d->context->v4value());
 
     return QQmlV4Handle(QV4::Value::nullValue());
@@ -402,7 +400,7 @@ void QQuickCanvasItem::setCanvasSize(const QSizeF & size)
         d->canvasSize = size;
         emit canvasSizeChanged();
 
-        if (d->contextInitialized)
+        if (d->context)
             polish();
     }
 }
@@ -437,7 +435,7 @@ void QQuickCanvasItem::setTileSize(const QSize & size)
 
         emit tileSizeChanged();
 
-        if (d->contextInitialized)
+        if (d->context)
             polish();
     }
 }
@@ -470,7 +468,7 @@ void QQuickCanvasItem::setCanvasWindow(const QRectF& rect)
         d->hasCanvasWindow = true;
         emit canvasWindowChanged();
 
-        if (d->contextInitialized)
+        if (d->context)
             polish();
     }
 }
@@ -502,7 +500,7 @@ void QQuickCanvasItem::setRenderTarget(QQuickCanvasItem::RenderTarget target)
 {
     Q_D(QQuickCanvasItem);
     if (d->renderTarget != target) {
-        if (d->contextInitialized) {
+        if (d->context) {
             qmlInfo(this) << "Canvas:renderTarget not changeble once context is active.";
             return;
         }
@@ -546,7 +544,7 @@ void QQuickCanvasItem::setRenderStrategy(QQuickCanvasItem::RenderStrategy strate
 {
     Q_D(QQuickCanvasItem);
     if (d->renderStrategy != strategy) {
-        if (d->contextInitialized) {
+        if (d->context) {
             qmlInfo(this) << "Canvas:renderStrategy not changeable once context is active.";
             return;
         }
@@ -651,7 +649,7 @@ void QQuickCanvasItem::updatePolish()
 
     Q_D(QQuickCanvasItem);
 
-    if (d->contextInitialized)
+    if (d->context && d->renderStrategy != QQuickCanvasItem::Cooperative)
         d->context->prepare(d->canvasSize.toSize(), d->tileSize, d->canvasWindow.toRect(), d->dirtyRect.toRect(), d->smooth, d->antialiasing);
 
     if (d->animationCallbacks.size() > 0 && isVisible()) {
@@ -676,7 +674,7 @@ void QQuickCanvasItem::updatePolish()
         }
     }
 
-    if (d->contextInitialized) {
+    if (d->context) {
         if (d->renderStrategy == QQuickCanvasItem::Cooperative)
             update();
         else
@@ -688,8 +686,10 @@ QSGNode *QQuickCanvasItem::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData
 {
     Q_D(QQuickCanvasItem);
 
-    if (!d->contextInitialized)
+    if (!d->context || d->canvasWindow.size().isEmpty()) {
+        delete oldNode;
         return 0;
+    }
 
     QSGSimpleTextureNode *node = static_cast<QSGSimpleTextureNode*>(oldNode);
     if (!node)
@@ -700,10 +700,13 @@ QSGNode *QQuickCanvasItem::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData
     else
         node->setFiltering(QSGTexture::Nearest);
 
-    if (d->renderStrategy == QQuickCanvasItem::Cooperative)
+    if (d->renderStrategy == QQuickCanvasItem::Cooperative) {
+        d->context->prepare(d->canvasSize.toSize(), d->tileSize, d->canvasWindow.toRect(), d->dirtyRect.toRect(), d->smooth, d->antialiasing);
         d->context->flush();
+    }
 
     node->setTexture(d->context->texture());
+    node->markDirty(QSGNode::DirtyMaterial);
     node->setRect(QRectF(QPoint(0, 0), d->canvasWindow.size()));
     return node;
 }
@@ -763,7 +766,7 @@ void QQuickCanvasItem::getContext(QQmlV4Function *args)
 /*!
     \qmlmethod long QtQuick2::Canvas::requestAnimationFrame(callback)
 
-    This function schedules callback to be invoked before composing the QtQuick
+    This function schedules callback to be invoked before composing the Qt Quick
     scene.
 */
 
@@ -970,7 +973,7 @@ bool QQuickCanvasItem::isImageLoaded(const QUrl& url) const
 QImage QQuickCanvasItem::toImage(const QRectF& rect) const
 {
     Q_D(const QQuickCanvasItem);
-    if (d->contextInitialized) {
+    if (d->context) {
         if (rect.isEmpty())
             return d->context->toImage(canvasWindow());
         else
@@ -1026,7 +1029,7 @@ void QQuickCanvasItem::delayedCreate()
 {
     Q_D(QQuickCanvasItem);
 
-    if (!d->contextInitialized && !d->contextType.isNull())
+    if (!d->context && !d->contextType.isNull())
         createContext(d->contextType);
 
     requestPaint();
@@ -1055,7 +1058,6 @@ void QQuickCanvasItem::initializeContext(QQuickCanvasContext *context, const QVa
     d->context = context;
     d->context->init(this, args);
     d->context->setV8Engine(QQmlEnginePrivate::getV8Engine(qmlEngine(this)));
-    d->contextInitialized = true;
     connect(d->context, SIGNAL(textureChanged()), SLOT(update()));
     connect(d->context, SIGNAL(textureChanged()), SIGNAL(painted()));
     emit contextChanged();