Bug 1250718 - Don't flatten opacity to an intermediate surface when used in the middle of preserve-3d. r=thinker

--HG--
extra : rebase_source : 867bab1b5369c88db3a845478f73d3a58845938c

gfx/layers/Layers.cpp

@@ -1387,10 +1387,17 @@ ContainerLayer::DefaultComputeEffectiveTransforms(const Matrix4x4& aTransformToS
     useIntermediateSurface = true;
 #endif
   } else {
+    /* Don't use an intermediate surface for opacity when it's within a 3d
+     * context, since we'd rather keep the 3d effects. This matches the
+     * WebKit/blink behaviour, but is changing in the latest spec.
+     */
     float opacity = GetEffectiveOpacity();
     CompositionOp blendMode = GetEffectiveMixBlendMode();
-    if (((opacity != 1.0f || blendMode != CompositionOp::OP_OVER) && (HasMultipleChildren() || Creates3DContextWithExtendingChildren())) ||
-        (!idealTransform.Is2D() && Creates3DContextWithExtendingChildren())) {
+    if ((HasMultipleChildren() || Creates3DContextWithExtendingChildren()) &&
+        ((opacity != 1.0f && !Extend3DContext()) ||
+         (blendMode != CompositionOp::OP_OVER))) {
+      useIntermediateSurface = true;
+    } else if (!idealTransform.Is2D() && Creates3DContextWithExtendingChildren()) {
       useIntermediateSurface = true;
     } else {
       useIntermediateSurface = false;

gfx/layers/basic/BasicContainerLayer.cpp

@@ -83,7 +83,7 @@ BasicContainerLayer::ComputeEffectiveTransforms(const Matrix4x4& aTransformToSur
     GetMaskLayer() ||
     GetForceIsolatedGroup() ||
     (GetMixBlendMode() != CompositionOp::OP_OVER && HasMultipleChildren()) ||
-    (GetEffectiveOpacity() != 1.0 && (HasMultipleChildren() || hasSingleBlendingChild));
+    (GetEffectiveOpacity() != 1.0 && ((HasMultipleChildren() && !Extend3DContext()) || hasSingleBlendingChild));
 
   if (!Extend3DContext()) {
     idealTransform.ProjectTo2D();

layout/base/nsDisplayList.cpp

@@ -2003,7 +2003,8 @@ void nsDisplayList::HitTest(nsDisplayListBuilder* aBuilder, const nsRect& aRect,
     bool same3DContext =
       (itemType == nsDisplayItem::TYPE_TRANSFORM &&
        static_cast<nsDisplayTransform*>(item)->IsParticipating3DContext()) ||
-      (itemType == nsDisplayItem::TYPE_PERSPECTIVE &&
+      ((itemType == nsDisplayItem::TYPE_PERSPECTIVE ||
+        itemType == nsDisplayItem::TYPE_OPACITY) &&
        static_cast<nsDisplayPerspective*>(item)->Frame()->Extend3DContext());
     if (same3DContext &&
         !static_cast<nsDisplayTransform*>(item)->IsLeafOf3DContext()) {
@@ -4152,6 +4153,7 @@ nsDisplayOpacity::nsDisplayOpacity(nsDisplayListBuilder* aBuilder,
     : nsDisplayWrapList(aBuilder, aFrame, aList, aScrollClip)
     , mOpacity(aFrame->StyleDisplay()->mOpacity)
     , mForEventsOnly(aForEventsOnly)
+    , mParticipatesInPreserve3D(false)
 {
   MOZ_COUNT_CTOR(nsDisplayOpacity);
 }
@@ -4189,6 +4191,12 @@ nsDisplayOpacity::BuildLayer(nsDisplayListBuilder* aBuilder,
   nsDisplayListBuilder::AddAnimationsAndTransitionsToLayer(container, aBuilder,
                                                            this, mFrame,
                                                            eCSSProperty_opacity);
+
+  if (mParticipatesInPreserve3D) {
+    container->SetContentFlags(container->GetContentFlags() | Layer::CONTENT_EXTEND_3D_CONTEXT);
+  } else {
+    container->SetContentFlags(container->GetContentFlags() & ~Layer::CONTENT_EXTEND_3D_CONTEXT);
+  }
   return container.forget();
 }
 

layout/base/nsDisplayList.h

@@ -3375,9 +3375,14 @@ public:
 
   bool CanUseAsyncAnimations(nsDisplayListBuilder* aBuilder) override;
 
+  void SetParticipatesInPreserve3D(bool aParticipatesInPreserve3D)
+  {
+    mParticipatesInPreserve3D = aParticipatesInPreserve3D;
+  }
 private:
   float mOpacity;
   bool mForEventsOnly;
+  bool mParticipatesInPreserve3D;
 };
 
 class nsDisplayBlendMode : public nsDisplayWrapList {

layout/generic/nsFrame.cpp

@@ -1159,12 +1159,6 @@ nsIFrame::Extend3DContext() const
     return false;
   }
 
-  // Opacity can only be only the root or leaves of a preserve-3d context
-  // as it requires flattening.
-  if (HasOpacity() && Combines3DTransformWithAncestors()) {
-    return false;
-  }
-
   nsRect temp;
   return !nsFrame::ShouldApplyOverflowClipping(this, disp) &&
          !GetClipPropClipRect(disp, &temp, GetSize()) &&
@@ -1881,7 +1875,8 @@ static bool
 ItemParticipatesIn3DContext(nsIFrame* aAncestor, nsDisplayItem* aItem)
 {
   nsIFrame* transformFrame;
-  if (aItem->GetType() == nsDisplayItem::TYPE_TRANSFORM) {
+  if (aItem->GetType() == nsDisplayItem::TYPE_TRANSFORM ||
+      aItem->GetType() == nsDisplayItem::TYPE_OPACITY) {
     transformFrame = aItem->Frame();
   } else if (aItem->GetType() == nsDisplayItem::TYPE_PERSPECTIVE) {
     transformFrame = static_cast<nsDisplayPerspective*>(aItem)->TransformFrame();
@@ -1911,16 +1906,21 @@ WrapSeparatorTransform(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
 static void
 CreateOpacityItem(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
                   nsDisplayList& aList, bool aItemForEventsOnly,
-                  const DisplayItemScrollClip* aScrollClip)
+                  const DisplayItemScrollClip* aScrollClip,
+                  bool aParticipatesInPreserve3D)
 {
   // Don't clip nsDisplayOpacity items. We clip their descendants instead.
   // The clip we would set on an element with opacity would clip
   // all descendant content, but some should not be clipped.
   DisplayListClipState::AutoSaveRestore opacityClipState(aBuilder);
   opacityClipState.Clear();
-  aList.AppendNewToTop(
+  nsDisplayOpacity* opacity =
       new (aBuilder) nsDisplayOpacity(aBuilder, aFrame, &aList,
-                                      aScrollClip, aItemForEventsOnly));
+                                      aScrollClip, aItemForEventsOnly);
+  if (opacity) {
+    opacity->SetParticipatesInPreserve3D(aParticipatesInPreserve3D);
+    aList.AppendToTop(opacity);
+  }
 }
 
 void
@@ -2021,7 +2021,7 @@ nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
     aBuilder->EnterSVGEffectsContents(&hoistedScrollInfoItemsStorage);
   }
 
-  bool useOpacity = HasVisualOpacity() && !nsSVGUtils::CanOptimizeOpacity(this);
+  bool useOpacity = HasVisualOpacity() && !nsSVGUtils::CanOptimizeOpacity(this) && !usingSVGEffects;
   bool useBlendMode = disp->mMixBlendMode != NS_STYLE_BLEND_NORMAL;
   bool useStickyPosition = disp->mPosition == NS_STYLE_POSITION_STICKY &&
     IsScrollFrameActive(aBuilder,
@@ -2172,8 +2172,6 @@ nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
     clipState.ExitStackingContextContents(&containerItemScrollClip);
   }
 
-  bool is3DContextRoot = Extend3DContext() && !Combines3DTransformWithAncestors();
-
   /* If there are any SVG effects, wrap the list up in an SVG effects item
    * (which also handles CSS group opacity). Note that we create an SVG effects
    * item even if resultList is empty, since a filter can produce graphical
@@ -2190,18 +2188,6 @@ nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
     aBuilder->ExitSVGEffectsContents();
     resultList.AppendToTop(&hoistedScrollInfoItemsStorage);
   }
-  else if (useOpacity && !resultList.IsEmpty() && !is3DContextRoot) {
-    /* If this element is the root of a preserve-3d context, then we want
-     * to make sure any opacity items are on the outside of the transform
-     * so that they don't interfere with the chain of nsDisplayTransforms.
-     * Opacity on preserve-3d leaves need to be inside the transform for the
-     * same reason, and we do this in the general case as well to preserve
-     * existing behaviour.
-     */
-    CreateOpacityItem(aBuilder, this, resultList, opacityItemForEventsOnly,
-                      containerItemScrollClip);
-    useOpacity = false;
-  }
 
   /* If we're going to apply a transformation and don't have preserve-3d set, wrap
    * everything in an nsDisplayTransform. If there's nothing in the list, don't add
@@ -2214,36 +2200,49 @@ nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
    * We also traverse into sublists created by nsDisplayWrapList or nsDisplayOpacity, so that
    * we find all the correct children.
    */
-  if (isTransformed && !resultList.IsEmpty()) {
-    if (!resultList.IsEmpty() && Extend3DContext()) {
-      // Install dummy nsDisplayTransform as a leaf containing
-      // descendants not participating this 3D rendering context.
-      nsDisplayList nonparticipants;
-      nsDisplayList participants;
-      int index = 1;
+  bool hasPreserve3DChildren = false;
+  if (isTransformed && !resultList.IsEmpty() && Extend3DContext()) {
+    // Install dummy nsDisplayTransform as a leaf containing
+    // descendants not participating this 3D rendering context.
+    nsDisplayList nonparticipants;
+    nsDisplayList participants;
+    int index = 1;
 
-      while (nsDisplayItem* item = resultList.RemoveBottom()) {
-        if (ItemParticipatesIn3DContext(this, item) && !item->GetClip().HasClip()) {
-          // The frame of this item participates the same 3D context.
-          WrapSeparatorTransform(aBuilder, this, dirtyRect,
-                                 &nonparticipants, &participants, index++);
-          participants.AppendToTop(item);
-        } else {
-          // The frame of the item doesn't participate the current
-          // context, or has no transform.
-          //
-          // For items participating but not transformed, they are add
-          // to nonparticipants to get a separator layer for handling
-          // clips, if there is, on an intermediate surface.
-          // \see ContainerLayer::DefaultComputeEffectiveTransforms().
-          nonparticipants.AppendToTop(item);
-        }
+    while (nsDisplayItem* item = resultList.RemoveBottom()) {
+      if (ItemParticipatesIn3DContext(this, item) && !item->GetClip().HasClip()) {
+        // The frame of this item participates the same 3D context.
+        WrapSeparatorTransform(aBuilder, this, dirtyRect,
+                               &nonparticipants, &participants, index++);
+        participants.AppendToTop(item);
+        hasPreserve3DChildren = true;
+      } else {
+        // The frame of the item doesn't participate the current
+        // context, or has no transform.
+        //
+        // For items participating but not transformed, they are add
+        // to nonparticipants to get a separator layer for handling
+        // clips, if there is, on an intermediate surface.
+        // \see ContainerLayer::DefaultComputeEffectiveTransforms().
+        nonparticipants.AppendToTop(item);
       }
-      WrapSeparatorTransform(aBuilder, this, dirtyRect,
-                             &nonparticipants, &participants, index++);
-      resultList.AppendToTop(&participants);
     }
+    WrapSeparatorTransform(aBuilder, this, dirtyRect,
+                           &nonparticipants, &participants, index++);
+    resultList.AppendToTop(&participants);
+  }
 
+  /* We create the opacity outside any transform separators we created,
+   * so that the opacity will be applied to them as groups. When we have
+   * opacity and preserve-3d we break the 'group' nature of opacity in order
+   * to maintain preserve-3d. This matches the behaviour of blink and WebKit,
+   * see bug 1250718.
+   */
+  if (useOpacity && !resultList.IsEmpty()) {
+    CreateOpacityItem(aBuilder, this, resultList,
+                      opacityItemForEventsOnly, containerItemScrollClip, hasPreserve3DChildren);
+  }
+
+  if (isTransformed && !resultList.IsEmpty()) {
     // Restore clip state now so nsDisplayTransform is clipped properly.
     if (!HasPerspective() && !useFixedPosition && !useStickyPosition) {
       clipState.ExitStackingContextContents(&containerItemScrollClip);
@@ -2275,14 +2274,6 @@ nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
           aBuilder, this,
           GetContainingBlock()->GetContent()->GetPrimaryFrame(), &resultList));
     }
-
-    /* If we need an opacity item, but didn't do it earlier, add it now on the
-     * outside of the transform.
-     */
-    if (useOpacity && !usingSVGEffects) {
-      CreateOpacityItem(aBuilder, this, resultList, opacityItemForEventsOnly,
-                        containerItemScrollClip);
-    }
   }
 
   if (useFixedPosition || useStickyPosition) {

layout/reftests/transform-3d/opacity-preserve3d-1-ref.html

@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<html><head>
+<style>
+    .first {
+        transform: translateZ(10px);
+        background-color: red;
+        opacity: 0.5;
+    }
+    .second {
+        transform: translateZ(5px);
+        background-color: yellow;
+        top: 28px;
+    }
+    .third {
+        background-color: green;
+        top: 48px;
+        opacity: 0.5;
+    }
+    .fourth {
+        background-color: blue;
+        top: 68px;
+    }
+    .leaf {
+        width: 100px;
+        height: 100px;
+        position:absolute;
+    }
+</style>
+</head><body>
+
+<div class="leaf first"></div>
+<div class="leaf second"></div>
+<div class="leaf third"></div>
+<div class="leaf fourth"></div>
+
+</body>
+</html>
+

layout/reftests/transform-3d/opacity-preserve3d-1.html

@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<html><head>
+<style>
+    .first {
+        transform: translateZ(10px);
+        background-color: blue;
+        top: 60px;
+    }
+    .second {
+        transform: translateZ(5px);
+        background-color: green;
+        top: 40px;
+    }
+    .third {
+        transform: translateZ(-5px);
+        background-color: yellow;
+        top: 20px;
+    }
+    .fourth {
+        transform: translateZ(-10px);
+        background-color: red;
+    }
+    .preserve {
+        transform-style: preserve-3d;
+    }
+    .leaf {
+        width: 100px;
+        height: 100px;
+        position:absolute;
+    }
+</style>
+</head><body>
+
+<div class="preserve">
+    <div class="leaf first"></div>
+    <div class="preserve" style="opacity:0.5">
+        <div class="leaf second"></div>
+        <div class="leaf fourth"></div>
+    </div>
+    <div class="leaf third"></div>
+</div>
+
+</body>
+</html>
+

layout/reftests/transform-3d/opacity-preserve3d-2-ref.html

@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html><head>
+<style>
+    .first {
+        background-color: green;
+    }
+    .second {
+        background-color: blue;
+        top: 58px;
+    }
+    .leaf {
+        width: 100px;
+        height: 100px;
+        position:absolute;
+        opacity: 0.5;
+    }
+</style>
+</head><body>
+
+<div class="leaf first"></div>
+<div class="leaf second"></div>
+
+</body>
+</html>
+

layout/reftests/transform-3d/opacity-preserve3d-2.html

@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html><head>
+<style>
+    .first {
+        transform: translateZ(10px);
+        background-color: blue;
+        top: 50px;
+    }
+    .second {
+        transform: translateZ(5px);
+        background-color: green;
+    }
+    .preserve {
+        transform-style: preserve-3d;
+    }
+    .leaf {
+        width: 100px;
+        height: 100px;
+        position:absolute;
+    }
+</style>
+</head><body>
+
+<div class="preserve" style="opacity:0.5">
+    <div class="leaf first"></div>
+    <div class="leaf second"></div>
+</div>
+
+</body>
+</html>
+

layout/reftests/transform-3d/opacity-preserve3d-3-ref.html

@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<html><head>
+<style>
+    .first {
+        background-color: green;
+        top: 48px;
+    }
+    .second {
+        top: 88px;
+    }
+    .third {
+        background-color: blue;
+        opacity: 0.5;
+    }
+    .group {
+        opacity: 0.5;
+    }
+    .leaf {
+        width: 100px;
+        height: 100px;
+        position:absolute;
+    }
+</style>
+</head><body>
+
+<div class="group">
+  <div class="leaf first"></div>
+  <canvas class="leaf second" width="100px" height="100px" id="canvas"></canvas>
+</div>
+<div class="leaf third"></div>
+<script>
+    var canvas = document.getElementById("canvas");
+    var ctx = canvas.getContext("2d");
+    ctx.fillStyle = "red";
+    ctx.fillRect(0, 0, 100, 100);
+</script>
+</body>
+</html>
+

layout/reftests/transform-3d/opacity-preserve3d-3.html

@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<html><head>
+<style>
+    .first {
+        transform: translateZ(10px);
+        background-color: blue;
+        top: 0px;
+    }
+    .second {
+        background-color: green;
+        top: 40px;
+    }
+    .third {
+        top: 80px;
+    }
+    .preserve {
+        transform-style: preserve-3d;
+    }
+    .leaf {
+        width: 100px;
+        height: 100px;
+        position:absolute;
+    }
+</style>
+</head><body>
+
+<div class="preserve">
+    <div class="preserve" style="opacity:0.5">
+        <div class="leaf first"></div>
+        <div class="leaf second"></div>
+        <canvas class="leaf third" width="100px" height="100px" id="canvas"></canvas>
+    </div>
+</div>
+<script>
+    var canvas = document.getElementById("canvas");
+    var ctx = canvas.getContext("2d");
+    ctx.fillStyle = "red";
+    ctx.fillRect(0, 0, 100, 100);
+</script>
+</body>
+</html>
+

layout/reftests/transform-3d/opacity-preserve3d-4-ref.html

@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html><head>
+<style>
+    .first {
+        background-color: blue;
+    }
+    .second {
+        background-color: green;
+        top: 48px;
+    }
+    .leaf {
+        width: 100px;
+        height: 100px;
+        position:absolute;
+        opacity: 0.5;
+    }
+</style>
+</head><body>
+
+<canvas class="leaf second" width="100px" height="100px" id="canvas"></canvas>
+<div class="leaf first"></div>
+<script>
+    var canvas = document.getElementById("canvas");
+    var ctx = canvas.getContext("2d");
+    ctx.fillStyle = "red";
+    ctx.fillRect(0, 0, 100, 100);
+</script>
+</body>
+</html>
+

layout/reftests/transform-3d/opacity-preserve3d-4.html

@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<html><head>
+<style>
+    .first {
+        transform: translateZ(10px);
+        background-color: blue;
+        top: 0px;
+    }
+    .second {
+        background-color: green;
+        top: 40px;
+    }
+    .preserve {
+        transform-style: preserve-3d;
+    }
+    .leaf {
+        width: 100px;
+        height: 100px;
+        position:absolute;
+    }
+</style>
+</head><body>
+
+<div class="preserve">
+    <div class="preserve" style="opacity:0.5">
+        <div class="leaf first"></div>
+        <canvas class="leaf second" width="100px" height="100px" id="canvas"></canvas>
+    </div>
+</div>
+<script>
+    var canvas = document.getElementById("canvas");
+    var ctx = canvas.getContext("2d");
+    ctx.fillStyle = "red";
+    ctx.fillRect(0, 0, 100, 100);
+</script>
+</body>
+</html>
+

layout/reftests/transform-3d/reftest.list

@@ -72,3 +72,7 @@ fuzzy-if(cocoaWidget,128,9) == animate-preserve3d-parent.html animate-preserve3d
 fuzzy-if(cocoaWidget,128,9) == animate-preserve3d-child.html animate-preserve3d-ref.html # intermittently fuzzy on Mac
 == animate-backface-hidden.html about:blank
 == 1245450-1.html green-rect.html
+fuzzy(1,2000) == opacity-preserve3d-1.html opacity-preserve3d-1-ref.html
+fuzzy(1,15000) == opacity-preserve3d-2.html opacity-preserve3d-2-ref.html
+fuzzy(1,10000) == opacity-preserve3d-3.html opacity-preserve3d-3-ref.html
+fuzzy(1,10000) == opacity-preserve3d-4.html opacity-preserve3d-4-ref.html