Bug 1426386 - Split the transform sent to webrender back into the transform and positioning components. r=mstange

MozReview-Commit-ID: XHqgYPwjZ0

--HG--
extra : rebase_source : 4d04ec882147368733854b9322e00a6030a73b2c

layout/painting/nsDisplayList.cpp

@@ -610,7 +610,8 @@ AddAnimationForProperty(nsIFrame* aFrame, const AnimationProperty& aProperty,
 static void
 AddAnimationsForProperty(nsIFrame* aFrame, nsDisplayListBuilder* aBuilder,
                          nsDisplayItem* aItem, nsCSSPropertyID aProperty,
-                         AnimationInfo& aAnimationInfo, bool aPending)
+                         AnimationInfo& aAnimationInfo, bool aPending,
+                         bool aIsForWebRender)
 {
   if (aPending) {
     aAnimationInfo.ClearAnimationsForNextTransaction();
@@ -667,7 +668,11 @@ AddAnimationsForProperty(nsIFrame* aFrame, nsDisplayListBuilder* aBuilder,
     float scaleX = 1.0f;
     float scaleY = 1.0f;
     bool hasPerspectiveParent = false;
-    if (aItem) {
+    if (aIsForWebRender) {
+      // leave origin empty, because we are sending it separately on the stacking
+      // context that we are pushing to WR, and WR will automatically include
+      // it when picking up the animated transform values
+    } else if (aItem) {
       // This branch is for display items to leverage the cache of
       // nsDisplayListBuilder.
       origin = aItem->ToReferenceFrame();
@@ -845,7 +850,7 @@ nsDisplayListBuilder::AddAnimationsAndTransitionsToLayer(Layer* aLayer,
   bool pending = !aBuilder;
   AnimationInfo& animationInfo = aLayer->GetAnimationInfo();
   AddAnimationsForProperty(aFrame, aBuilder, aItem, aProperty,
-                           animationInfo, pending);
+                           animationInfo, pending, false);
   animationInfo.TransferMutatedFlagToLayer(aLayer);
 }
 
@@ -6671,7 +6676,7 @@ nsDisplayOpacity::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder& aBuil
   AnimationInfo& animationInfo = animationData->GetAnimationInfo();
   AddAnimationsForProperty(Frame(), aDisplayListBuilder,
                            this, eCSSProperty_opacity,
-                           animationInfo, false);
+                           animationInfo, false, true);
   animationInfo.StartPendingAnimations(aManager->GetAnimationReadyTime());
 
   // Note that animationsId can be 0 (uninitialized in AnimationInfo) if there
@@ -8422,9 +8427,18 @@ nsDisplayTransform::GetTransform() const
 }
 
 Matrix4x4
-nsDisplayTransform::GetTransformForRendering()
+nsDisplayTransform::GetTransformForRendering(LayoutDevicePoint* aOutOrigin)
 {
   if (!mFrame->HasPerspective() || mTransformGetter || mIsTransformSeparator) {
+    if (!mTransformGetter && !mIsTransformSeparator && aOutOrigin) {
+      // If aOutOrigin is provided, put the offset to origin into it, because
+      // we need to keep it separate for webrender. The combination of
+      // *aOutOrigin and the returned matrix here should always be equivalent
+      // to what GetTransform() would have returned.
+      float scale = mFrame->PresContext()->AppUnitsPerDevPixel();
+      *aOutOrigin = LayoutDevicePoint::FromAppUnits(ToReferenceFrame(), scale);
+      return GetResultingTransformMatrix(mFrame, nsPoint(0, 0), scale, INCLUDE_PERSPECTIVE);
+    }
     return GetTransform();
   }
   MOZ_ASSERT(!mTransformGetter);
@@ -8480,7 +8494,14 @@ nsDisplayTransform::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder& aBu
                                             WebRenderLayerManager* aManager,
                                             nsDisplayListBuilder* aDisplayListBuilder)
 {
-  Matrix4x4 newTransformMatrix = GetTransformForRendering();
+  // We want to make sure we don't pollute the transform property in the WR
+  // stacking context by including the position of this frame (relative to the
+  // parent reference frame). We need to keep those separate; the position of
+  // this frame goes into the stacking context bounds while the transform goes
+  // into the transform.
+  LayoutDevicePoint position;
+  Matrix4x4 newTransformMatrix = GetTransformForRendering(&position);
+
   gfx::Matrix4x4* transformForSC = &newTransformMatrix;
   if (newTransformMatrix.IsIdentity()) {
     // If the transform is an identity transform, strip it out so that WR
@@ -8494,7 +8515,7 @@ nsDisplayTransform::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder& aBu
   AnimationInfo& animationInfo = animationData->GetAnimationInfo();
   AddAnimationsForProperty(Frame(), aDisplayListBuilder,
                            this, eCSSProperty_transform,
-                           animationInfo, false);
+                           animationInfo, false, true);
   animationInfo.StartPendingAnimations(aManager->GetAnimationReadyTime());
 
   // Note that animationsId can be 0 (uninitialized in AnimationInfo) if there
@@ -8528,7 +8549,7 @@ nsDisplayTransform::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder& aBu
   StackingContextHelper sc(aSc,
                            aBuilder,
                            filters,
-                           LayoutDeviceRect(),
+                           LayoutDeviceRect(position, LayoutDeviceSize()),
                            &newTransformMatrix,
                            animationsId ? &prop : nullptr,
                            nullptr,

layout/painting/nsDisplayList.h

@@ -6155,7 +6155,7 @@ public:
    * nsDisplayPerspective created for that.
    */
   const Matrix4x4& GetTransform() const;
-  Matrix4x4 GetTransformForRendering();
+  Matrix4x4 GetTransformForRendering(mozilla::LayoutDevicePoint* aOutOrigin = nullptr);
 
   /**
    * Return the transform that is aggregation of all transform on the

layout/reftests/bugs/reftest.list

@@ -1861,7 +1861,7 @@ pref(layout.css.moz-document.content.enabled,false) == 1035091-2.html 1035091-re
 == 1062963-floatmanager-reflow.html 1062963-floatmanager-reflow-ref.html
 test-pref(dom.webcomponents.shadowdom.enabled,true) == 1066554-1.html 1066554-1-ref.html
 == 1069716-1.html 1069716-1-ref.html
-fails-if(webrender) == 1078262-1.html about:blank
+== 1078262-1.html about:blank
 test-pref(layout.testing.overlay-scrollbars.always-visible,false) == 1081072-1.html 1081072-1-ref.html
 == 1081185-1.html 1081185-1-ref.html
 == 1097437-1.html 1097437-1-ref.html