Bug 928727 - Share code for getting the user-space clip bounds in DrawTargetCairo. r=jrmuizel

gfx/2d/DrawTargetCairo.cpp

@@ -512,13 +512,10 @@ DrawTargetCairo::DrawSurface(SourceSurface *aSurface,
 
   cairo_set_antialias(mContext, GfxAntialiasToCairoAntialias(aOptions.mAntialiasMode));
 
-  double clipX1, clipY1, clipX2, clipY2;
-  cairo_clip_extents(mContext, &clipX1, &clipY1, &clipX2, &clipY2);
-  Rect clip(clipX1, clipY1, clipX2 - clipX1, clipY2 - clipY1); // Narrowing of doubles to floats
   // If the destination rect covers the entire clipped area, then unbounded and bounded
   // operations are identical, and we don't need to push a group.
   bool needsGroup = !IsOperatorBoundByMask(aOptions.mCompositionOp) &&
-                    !aDest.Contains(clip);
+                    !aDest.Contains(GetUserSpaceClip());
 
   cairo_translate(mContext, aDest.X(), aDest.Y());
 
@@ -682,13 +679,7 @@ DrawTargetCairo::FillRect(const Rect &aRect,
 
   bool pathBoundsClip = false;
 
-  double cexts[4];
-  cairo_clip_extents(mContext, &cexts[0], &cexts[1], &cexts[2], &cexts[3]);
-  Rect clipRect(cexts[0], cexts[1], cexts[2] - cexts[0], cexts[3] - cexts[1]);
-  double pexts[4];
-  cairo_path_extents(mContext, &pexts[0], &pexts[1], &pexts[2], &pexts[3]);
-  Rect pathRect(pexts[0], pexts[1], pexts[2] - pexts[0], pexts[3] - pexts[1]);
-  if (pathRect.Contains(clipRect)) {
+  if (aRect.Contains(GetUserSpaceClip())) {
     pathBoundsClip = true;
   }
 
@@ -1192,6 +1183,14 @@ DrawTargetCairo::SetTransform(const Matrix& aTransform)
   cairo_set_matrix(mContext, &mat);
 }
 
+Rect
+DrawTargetCairo::GetUserSpaceClip()
+{
+  double clipX1, clipY1, clipX2, clipY2;
+  cairo_clip_extents(mContext, &clipX1, &clipY1, &clipX2, &clipY2);
+  return Rect(clipX1, clipY1, clipX2 - clipX1, clipY2 - clipY1); // Narrowing of doubles to floats
+}
+
 cairo_t*
 BorrowedCairoContext::BorrowCairoContextFromDrawTarget(DrawTarget* aDT)
 {

gfx/2d/DrawTargetCairo.h

@@ -172,6 +172,8 @@ private: // methods
                            const IntRect& aSource,
                            const IntPoint& aDest);
 
+  Rect GetUserSpaceClip();
+
   // Call before you make any changes to the backing surface with which this
   // context is associated. Pass the path you're going to be using if you have
   // one.