2 files changed, 21 insertions, 1 deletions
diff --git a/src/quick/items/context2d/qquickcanvasitem.cpp b/src/quick/items/context2d/qquickcanvasitem.cpp
index b772ed97d2..1167f408f5 100644
--- a/src/quick/items/context2d/qquickcanvasitem.cpp
+++ b/src/quick/items/context2d/qquickcanvasitem.cpp
@@ -640,6 +640,17 @@ void QQuickCanvasItem::releaseResources()
     }
 }
 
+bool QQuickCanvasItem::event(QEvent *event)
+{
+    switch (event->type()) {
+    case QEvent::PolishRequest:
+        polish();
+        return true;
+    default:
+        return QQuickItem::event(event);
+    }
+}
+
 void QQuickCanvasItem::invalidateSceneGraph()
 {
     Q_D(QQuickCanvasItem);
@@ -651,6 +662,12 @@ void QQuickCanvasItem::invalidateSceneGraph()
     d->textureProvider = 0;
 }
 
+void QQuickCanvasItem::schedulePolish()
+{
+    auto polishRequestEvent = new QEvent(QEvent::PolishRequest);
+    QCoreApplication::postEvent(this, polishRequestEvent);
+}
+
 void QQuickCanvasItem::componentComplete()
 {
     QQuickItem::componentComplete();
@@ -892,8 +909,9 @@ void QQuickCanvasItem::requestAnimationFrame(QQmlV4Function *args)
 
     d->animationCallbacks.insert(++id, QV4::PersistentValue(scope.engine, f->asReturnedValue()));
 
+    // QTBUG-55778: Calling polish directly here can lead to a polish loop
     if (isVisible())
-        polish();
+        schedulePolish();
 
     args->setReturnValue(QV4::Encode(id));
 }
diff --git a/src/quick/items/context2d/qquickcanvasitem_p.h b/src/quick/items/context2d/qquickcanvasitem_p.h
index 8af84d0e7c..217ae9bb69 100644
--- a/src/quick/items/context2d/qquickcanvasitem_p.h
+++ b/src/quick/items/context2d/qquickcanvasitem_p.h
@@ -182,6 +182,7 @@ private Q_SLOTS:
     void sceneGraphInitialized();
     void checkAnimationCallbacks();
     void invalidateSceneGraph();
+    void schedulePolish();
 
 protected:
     void componentComplete() Q_DECL_OVERRIDE;
@@ -190,6 +191,7 @@ protected:
     QSGNode *updatePaintNode(QSGNode *, UpdatePaintNodeData *) Q_DECL_OVERRIDE;
     void geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry) Q_DECL_OVERRIDE;
     void releaseResources() Q_DECL_OVERRIDE;
+    bool event(QEvent *event) Q_DECL_OVERRIDE;
 private:
     Q_DECLARE_PRIVATE(QQuickCanvasItem)
     Q_INVOKABLE void delayedCreate();