Bug 1243589 - Use SingleTiledContentClient even for scrollable layers if the layer is smaller than a single tile. r=mattwoodrow

MozReview-Commit-ID: LHIrrtFfRgm

gfx/layers/client/ClientTiledPaintedLayer.cpp

@@ -28,6 +28,7 @@ ClientTiledPaintedLayer::ClientTiledPaintedLayer(ClientLayerManager* const aMana
                                                ClientLayerManager::PaintedLayerCreationHint aCreationHint)
   : PaintedLayer(aManager, static_cast<ClientLayer*>(this), aCreationHint)
   , mContentClient()
+  , mHaveSingleTiledContentClient(false)
 {
   MOZ_COUNT_CTOR(ClientTiledPaintedLayer);
   mPaintData.mLastScrollOffset = ParentLayerPoint(0, 0);
@@ -411,18 +412,26 @@ ClientTiledPaintedLayer::RenderLayer()
   void *data = ClientManager()->GetPaintedLayerCallbackData();
 
   IntSize layerSize = mVisibleRegion.ToUnknownRegion().GetBounds().Size();
-  if (mContentClient && !mContentClient->SupportsLayerSize(layerSize, ClientManager())) {
+  IntSize tileSize(gfxPlatform::GetPlatform()->GetTileWidth(),
+                   gfxPlatform::GetPlatform()->GetTileHeight());
+
+  bool wantSingleTiledContentClient =
+      (mCreationHint == LayerManager::NONE || layerSize <= tileSize) &&
+      SingleTiledContentClient::ClientSupportsLayerSize(layerSize, ClientManager()) &&
+      gfxPrefs::LayersSingleTileEnabled();
+
+  if (mContentClient && mHaveSingleTiledContentClient && !wantSingleTiledContentClient) {
     mContentClient = nullptr;
     mValidRegion.SetEmpty();
   }
 
   if (!mContentClient) {
-    if (mCreationHint == LayerManager::NONE &&
-        SingleTiledContentClient::ClientSupportsLayerSize(layerSize, ClientManager()) &&
-        gfxPrefs::LayersSingleTileEnabled()) {
+    if (wantSingleTiledContentClient) {
       mContentClient = new SingleTiledContentClient(this, ClientManager());
+      mHaveSingleTiledContentClient = true;
     } else {
       mContentClient = new MultiTiledContentClient(this, ClientManager());
+      mHaveSingleTiledContentClient = false;
     }
 
     mContentClient->Connect();

gfx/layers/client/ClientTiledPaintedLayer.h

@@ -133,6 +133,9 @@ private:
   void EndPaint();
 
   RefPtr<TiledContentClient> mContentClient;
+  // Flag to indicate if mContentClient is a SingleTiledContentClient. This is
+  // only valid when mContentClient is non-null.
+  bool mHaveSingleTiledContentClient;
   nsIntRegion mLowPrecisionValidRegion;
   BasicTiledLayerPaintData mPaintData;
 };

gfx/layers/client/SingleTiledContentClient.cpp

@@ -46,12 +46,6 @@ SingleTiledContentClient::ClientSupportsLayerSize(const gfx::IntSize& aSize, Cli
   return aSize.width <= maxTextureSize && aSize.height <= maxTextureSize;
 }
 
-bool
-SingleTiledContentClient::SupportsLayerSize(const gfx::IntSize& aSize, ClientLayerManager* aManager) const
-{
-  return ClientSupportsLayerSize(aSize, aManager);
-}
-
 ClientSingleTiledLayerBuffer::ClientSingleTiledLayerBuffer(ClientTiledPaintedLayer* aPaintedLayer,
                                                            CompositableClient* aCompositableClient,
                                                            ClientLayerManager* aManager)

gfx/layers/client/SingleTiledContentClient.h

@@ -127,8 +127,6 @@ public:
   virtual ClientTiledLayerBuffer* GetTiledBuffer() override { return mTiledBuffer; }
   virtual ClientTiledLayerBuffer* GetLowPrecisionTiledBuffer() override { return nullptr; }
 
-  virtual bool SupportsLayerSize(const gfx::IntSize& aSize, ClientLayerManager* aManager) const override;
-
 private:
   RefPtr<ClientSingleTiledLayerBuffer> mTiledBuffer;
 };

gfx/layers/client/TiledContentClient.h

@@ -628,9 +628,6 @@ public:
   };
   virtual void UpdatedBuffer(TiledBufferType aType) = 0;
 
-  virtual bool SupportsLayerSize(const gfx::IntSize& aSize, ClientLayerManager* aManager) const
-  { return true; }
-
 private:
   const char* mName;
 };

layout/reftests/invalidation/reftest.list

@@ -51,7 +51,7 @@ pref(layout.animated-image-layers.enabled,true) skip-if(Android||gtkWidget) == t
 != clipped-animated-transform-1.html about:blank
 != paintedlayer-recycling-1.html about:blank
 != paintedlayer-recycling-2.html about:blank
-!= paintedlayer-recycling-3.html about:blank
+pref(layers.single-tile.enabled,false) != paintedlayer-recycling-3.html about:blank
 != paintedlayer-recycling-4.html about:blank
 != paintedlayer-recycling-5.html about:blank
 != paintedlayer-recycling-6.html about:blank
@@ -67,7 +67,7 @@ pref(layout.animated-image-layers.enabled,true) skip-if(Android||gtkWidget) == t
 != layer-splitting-7.html about:blank
 fuzzy-if(gtkWidget,2,4) fuzzy-if(asyncPan,2,3955) fuzzy-if(OSX,179,30) == image-scrolling-zoom-1.html image-scrolling-zoom-1-ref.html
 != image-scrolling-zoom-1-ref.html image-scrolling-zoom-1-notref.html
-!= fast-scrolling.html about:blank
+pref(layers.single-tile.enabled,false) != fast-scrolling.html about:blank
 != fractional-transform-1.html about:blank
 != fractional-transform-2.html about:blank
 != fractional-transform-3.html about:blank

modules/libpref/init/all.js

@@ -4379,6 +4379,7 @@ pref("layers.draw-tile-borders", false);
 pref("layers.draw-bigimage-borders", false);
 pref("layers.frame-counter", false);
 pref("layers.enable-tiles", false);
+pref("layers.single-tile.enabled", true);
 pref("layers.tiled-drawtarget.enabled", false);
 pref("layers.low-precision-buffer", false);
 pref("layers.progressive-paint", false);