# HG changeset patch
# Parent  0625c68c0abcfe4d10880d15d8fe7d06df3369c9
Bug 1211264. Fallback to rendering dest rect with rotated box shadows. r=mstange

diff --git a/gfx/thebes/gfxBlur.cpp b/gfx/thebes/gfxBlur.cpp
--- a/gfx/thebes/gfxBlur.cpp
+++ b/gfx/thebes/gfxBlur.cpp
@@ -444,28 +444,25 @@ CacheBlur(DrawTarget& aDT,
   BlurCacheData* data = new BlurCacheData(aBoxShadow, aExtendDest, key);
   if (!gBlurCache->RegisterEntry(data)) {
     delete data;
   }
 }
 
 // Blurs a small surface and creates the mask.
 static already_AddRefed<SourceSurface>
-CreateBlurMask(const IntSize& aRectSize,
+CreateBlurMask(const IntSize& aMinSize,
                RectCornerRadii* aCornerRadii,
                IntSize aBlurRadius,
                IntMargin& aExtendDestBy,
                IntMargin& aSliceBorder,
                DrawTarget& aDestDrawTarget)
 {
-  IntMargin slice;
   gfxAlphaBoxBlur blur;
-  IntSize minSize =
-    ComputeMinSizeForShadowShape(aCornerRadii, aBlurRadius, slice, aRectSize);
-  IntRect minRect(IntPoint(), minSize);
+  IntRect minRect(IntPoint(), aMinSize);
 
   gfxContext* blurCtx = blur.Init(ThebesRect(Rect(minRect)), IntSize(),
                                   aBlurRadius, nullptr, nullptr);
 
   if (!blurCtx) {
     return nullptr;
   }
 
@@ -483,17 +480,17 @@ CreateBlurMask(const IntSize& aRectSize,
   IntPoint topLeft;
   RefPtr<SourceSurface> result = blur.DoBlur(&aDestDrawTarget, &topLeft);
   if (!result) {
     return nullptr;
   }
 
   IntRect expandedMinRect(topLeft, result->GetSize());
   aExtendDestBy = expandedMinRect - minRect;
-  aSliceBorder = slice + aExtendDestBy;
+  aSliceBorder += aExtendDestBy;
 
   MOZ_ASSERT(aSliceBorder.LeftRight() <= expandedMinRect.width);
   MOZ_ASSERT(aSliceBorder.TopBottom() <= expandedMinRect.height);
 
   return result.forget();
 }
 
 static already_AddRefed<SourceSurface>
@@ -508,56 +505,71 @@ CreateBoxShadow(SourceSurface* aBlurMask
     return nullptr;
   }
 
   ColorPattern shadowColor(ToDeviceColor(aShadowColor));
   boxShadowDT->MaskSurface(shadowColor, aBlurMask, Point(0, 0));
   return boxShadowDT->Snapshot();
 }
 
-static SourceSurface*
+static already_AddRefed<SourceSurface>
 GetBlur(DrawTarget& aDT,
         const IntSize& aRectSize,
         const IntSize& aBlurRadius,
         RectCornerRadii* aCornerRadii,
         const Color& aShadowColor,
         IntMargin& aExtendDestBy,
-        IntMargin& aSlice)
+        IntMargin& aSlice,
+        gfxContext* aDestinationCtx)
 {
   if (!gBlurCache) {
     gBlurCache = new BlurCache();
   }
 
   IntSize minSize =
     ComputeMinSizeForShadowShape(aCornerRadii, aBlurRadius, aSlice, aRectSize);
 
+  // We can get seams using the min size rect when drawing to the destination rect
+  // If we have a rotation on the destination context. In those cases,
+  // just draw the rotated blur.
+  bool useDestRect = aDestinationCtx->CurrentMatrix().HasNonTranslationOrFlip();
+  if (useDestRect) {
+    minSize = aRectSize;
+  }
+
   BlurCacheData* cached = gBlurCache->Lookup(minSize, aBlurRadius,
                                              aCornerRadii, aShadowColor,
                                              aDT.GetBackendType());
-  if (cached) {
+  if (cached && !useDestRect) {
     // See CreateBlurMask() for these values
     aExtendDestBy = cached->mExtendDest;
     aSlice = aSlice + aExtendDestBy;
-    return cached->mBlur;
+    RefPtr<SourceSurface> blur = cached->mBlur;
+    return blur.forget();
   }
 
   RefPtr<SourceSurface> blurMask =
-    CreateBlurMask(aRectSize, aCornerRadii, aBlurRadius, aExtendDestBy, aSlice, aDT);
+    CreateBlurMask(minSize, aCornerRadii, aBlurRadius, aExtendDestBy, aSlice, aDT);
 
   if (!blurMask) {
     return nullptr;
   }
 
   RefPtr<SourceSurface> boxShadow = CreateBoxShadow(blurMask, aShadowColor);
   if (!boxShadow) {
     return nullptr;
   }
 
-  CacheBlur(aDT, minSize, aBlurRadius, aCornerRadii, aShadowColor, aExtendDestBy, boxShadow);
-  return boxShadow;
+  if (useDestRect) {
+    // Since we're just going to paint the actual rect to the destination
+    aSlice.SizeTo(0, 0, 0, 0);
+  } else {
+    CacheBlur(aDT, minSize, aBlurRadius, aCornerRadii, aShadowColor, aExtendDestBy, boxShadow);
+  }
+  return boxShadow.forget();
 }
 
 void
 gfxAlphaBoxBlur::ShutdownBlurCache()
 {
   delete gBlurCache;
   gBlurCache = nullptr;
 }
@@ -693,17 +705,18 @@ gfxAlphaBoxBlur::BlurRectangle(gfxContex
 
   IntRect rect = RoundedToInt(ToRect(aRect));
   IntMargin extendDestBy;
   IntMargin slice;
 
   RefPtr<SourceSurface> boxShadow = GetBlur(destDrawTarget,
                                             rect.Size(), blurRadius,
                                             aCornerRadii, aShadowColor,
-                                            extendDestBy, slice);
+                                            extendDestBy, slice,
+                                            aDestinationCtx);
   if (!boxShadow) {
     return;
   }
 
   destDrawTarget.PushClipRect(ToRect(aDirtyRect));
 
   // Copy the right parts from boxShadow into destDrawTarget. The middle parts
   // will be stretched, border-image style.
diff --git a/layout/reftests/box-shadow/boxshadow-rotated-ref.html b/layout/reftests/box-shadow/boxshadow-rotated-ref.html
new file mode 100644
--- /dev/null
+++ b/layout/reftests/box-shadow/boxshadow-rotated-ref.html
@@ -0,0 +1,15 @@
+<html>
+<head>
+<style>
+div.second {
+  margin: 35px auto 95px auto; 
+  box-shadow: 0px 0px 15px 0px #808080;
+  width: 100;
+  height: 116.36px;
+}
+</style>
+</head>
+<body>
+<div class="second"></div>
+</body>
+</html>
diff --git a/layout/reftests/box-shadow/boxshadow-rotated.html b/layout/reftests/box-shadow/boxshadow-rotated.html
new file mode 100644
--- /dev/null
+++ b/layout/reftests/box-shadow/boxshadow-rotated.html
@@ -0,0 +1,16 @@
+<html>
+<head>
+<style>
+div.first {
+  margin: 35px auto 95px auto; 
+  box-shadow: 0px 0px 15px 0px #808080;
+  transform: rotate(-180deg);
+  width: 100;
+  height: 116.36px;
+}
+</style>
+</head>
+<body>
+<div class="first"></div>
+</body>
+</html>
diff --git a/layout/reftests/box-shadow/reftest.list b/layout/reftests/box-shadow/reftest.list
--- a/layout/reftests/box-shadow/reftest.list
+++ b/layout/reftests/box-shadow/reftest.list
@@ -19,16 +19,17 @@ random-if(d2d) == boxshadow-onecorner.ht
 random-if(d2d) == boxshadow-twocorners.html boxshadow-twocorners-ref.html
 random-if(d2d) == boxshadow-threecorners.html boxshadow-threecorners-ref.html
 == boxshadow-skiprect.html boxshadow-skiprect-ref.html
 == boxshadow-opacity.html boxshadow-opacity-ref.html
 == boxshadow-color-rounding.html boxshadow-color-rounding-ref.html
 == boxshadow-color-rounding-middle.html boxshadow-color-rounding-middle-ref.html
 fuzzy-if(OSX==1010,1,24) == boxshadow-large-border-radius.html boxshadow-large-border-radius-ref.html # Bug 1209649
 == boxshadow-border-radius-int.html boxshadow-border-radius-int-ref.html
+fuzzy(24,3072) == boxshadow-rotated.html boxshadow-rotated-ref.html # Bug 1211264
 
 == overflow-not-scrollable-1.html overflow-not-scrollable-1-ref.html
 == overflow-not-scrollable-1.html overflow-not-scrollable-1-ref2.html
 == overflow-not-scrollable-2.html overflow-not-scrollable-2-ref.html
 fails-if(B2G||Mulet) == 611574-1.html 611574-1-ref.html # Initial mulet triage: parity with B2G/B2G Desktop
 fails-if(B2G||Mulet) == 611574-2.html 611574-2-ref.html # Initial mulet triage: parity with B2G/B2G Desktop
 fuzzy-if(winWidget,5,30) == fieldset.html fieldset-ref.html # minor anti-aliasing problem on Windows
 fuzzy-if(winWidget,5,30) == fieldset-inset.html fieldset-inset-ref.html # minor anti-aliasing problem on Windows