Fix CPU usage from out of frame animated images

src/ui/MxcAnimatedImage.cpp

@@ -102,10 +102,12 @@ MxcAnimatedImage::startDownload()
             if (buffer.bytesAvailable() <
                 4LL * 1024 * 1024 * 1024) // cache images smaller than 4MB in RAM
                 movie.setCacheMode(QMovie::CacheAll);
-            if (play_)
+            if (play_ && movie.frameCount() > 1)
                 movie.start();
-            else
+            else {
                 movie.jumpToFrame(0);
+                movie.setPaused(true);
+            }
             emit loadedChanged();
             update();
         });
@@ -173,6 +175,9 @@ MxcAnimatedImage::updatePaintNode(QSGNode *oldNode, QQuickItem::UpdatePaintNodeD
     if (!imageDirty)
         return oldNode;
 
+    if (clipRect().isEmpty())
+        return oldNode;
+
     imageDirty      = false;
     QSGImageNode *n = static_cast<QSGImageNode *>(oldNode);
     if (!n) {

src/ui/MxcAnimatedImage.h

@@ -29,6 +29,7 @@ public:
         connect(this, &MxcAnimatedImage::roomChanged, &MxcAnimatedImage::startDownload);
         connect(&movie, &QMovie::frameChanged, this, &MxcAnimatedImage::newFrame);
         setFlag(QQuickItem::ItemHasContents);
+        setFlag(QQuickItem::ItemObservesViewport);
         // setAcceptHoverEvents(true);
     }
 
@@ -55,7 +56,12 @@ public:
     {
         if (play_ != newPlay) {
             play_ = newPlay;
+            if (movie.frameCount() > 1)
                 movie.setPaused(!play_);
+            else {
+                movie.jumpToFrame(0);
+                movie.setPaused(true);
+            }
             emit playChanged();
         }
     }
@@ -77,6 +83,7 @@ private slots:
     {
         currentFrame = frame;
         imageDirty   = true;
+        if (!clipRect().isEmpty())
             update();
     }