Bug 779029: Try to respect EXTEND_NONE when masking. r=jrmuizel

--HG--
extra : rebase_source : 0634d90f2c580fd4cc1ad73fb5b3406a6afda964

gfx/thebes/gfxContext.cpp

@@ -1404,7 +1404,48 @@ gfxContext::Mask(gfxPattern *pattern)
   if (mCairo) {
     cairo_mask(mCairo, pattern->CairoPattern());
   } else {
+    bool needsClip = false;
+    if (pattern->Extend() == gfxPattern::EXTEND_NONE) {
+      // In this situation the mask will be fully transparent (i.e. nothing
+      // will be drawn) outside of the bounds of the surface. We can support
+      // that by clipping out drawing to that area.
+      Rect surfaceSourceRect;
+      if (!pattern->IsAzure() &&
+          pattern->GetType() == gfxPattern::PATTERN_SURFACE)
+      {
+        needsClip = true;
+
+        nsRefPtr<gfxASurface> surf = pattern->GetSurface();
+        gfxPoint offset = surf->GetDeviceOffset();
+
+        surfaceSourceRect = Rect(-offset.x, -offset.y, surf->GetSize().width, surf->GetSize().height);
+      } else if (pattern->IsAzure()) {
+        // This is an Azure pattern. i.e. this was the result of a PopGroup and
+        // then the extend mode was changed to EXTEND_NONE.
+        // XXX - We may need some additional magic here in theory to support
+        // device offsets in these patterns, but no problems have been observed
+        // yet because of this. And it would complicate things a little further.
+        needsClip = true;
+
+        RefPtr<SourceSurface> surf = pattern->GetAzureSurface();
+        surfaceSourceRect = Rect(0, 0, surf->GetSize().width, surf->GetSize().height);
+      }
+
+      if (needsClip) {
+        Matrix mat = ToMatrix(pattern->GetMatrix());
+        mat.Invert();
+        mat = mat * GetDTTransform();
+
+        mDT->SetTransform(mat);
+        mDT->PushClipRect(surfaceSourceRect);
+        mDT->SetTransform(GetDTTransform());
+      }
+    }
     mDT->Mask(GeneralPattern(this), *pattern->GetPattern(mDT), DrawOptions(1.0f, CurrentState().op, CurrentState().aaMode));
+
+    if (needsClip) {
+      mDT->PopClip();
+    }
   }
 }
 
@@ -1420,10 +1461,14 @@ gfxContext::Mask(gfxASurface *surface, const gfxPoint& offset)
       gfxPlatform::GetPlatform()->GetSourceSurfaceForSurface(mDT, surface);
 
     gfxPoint pt = surface->GetDeviceOffset();
+
+    // We clip here to bind to the mask surface bounds, see above.
+    mDT->PushClipRect(Rect(offset.x - pt.x, offset.y - pt.y, sourceSurf->GetSize().width, sourceSurf->GetSize().height));
     mDT->Mask(GeneralPattern(this), 
               SurfacePattern(sourceSurf, EXTEND_CLAMP,
                              Matrix(1.0f, 0, 0, 1.0f, Float(offset.x - pt.x), Float(offset.y - pt.y))),
               DrawOptions(1.0f, CurrentState().op, CurrentState().aaMode));
+    mDT->PopClip();
   }
 }
 

gfx/thebes/gfxPattern.h

@@ -101,6 +101,10 @@ public:
 
     already_AddRefed<gfxASurface> GetSurface();
 
+    bool IsAzure() { return !mPattern; }
+
+    mozilla::TemporaryRef<mozilla::gfx::SourceSurface> GetAzureSurface() { return mSourceSurface; }
+
 protected:
     cairo_pattern_t *mPattern;
 

layout/reftests/svg/reftest.list

@@ -186,7 +186,7 @@ fuzzy-if(Android,9,980) == gradient-live-01d.svg gradient-live-01-ref.svg
 == marker-orientation-01.svg marker-orientation-01-ref.svg
 == mask-basic-01.svg pass.svg
 == mask-basic-02.svg mask-basic-02-ref.svg
-#== mask-basic-03.svg pass.svg
+== mask-basic-03.svg pass.svg
 == mask-extref-dataURI-01.svg pass.svg
 == mask-containing-masked-content-01.svg pass.svg
 == mask-transformed-01.svg mask-transformed-01-ref.svg