From 1c19e4af27e24e33cc2ef9a4ec309f0422d44b65 Mon Sep 17 00:00:00 2001
From: Lee Salzman <lsalzman@mozilla.com>
Date: Thu, 18 Aug 2016 11:25:38 -0400
Subject: [PATCH] Bug 1296301 - use getClipDeviceBounds instead of
 getClipBounds in DrawTargetSkia. r=jrmuizel

MozReview-Commit-ID: BEIAGS0hLzB
---
 gfx/2d/DrawTargetSkia.cpp | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/gfx/2d/DrawTargetSkia.cpp b/gfx/2d/DrawTargetSkia.cpp
index b9081ab18c4c..ec6ed8fa6598 100644
--- a/gfx/2d/DrawTargetSkia.cpp
+++ b/gfx/2d/DrawTargetSkia.cpp
@@ -398,11 +398,20 @@ SetPaintPattern(SkPaint& aPaint, const Pattern& aPattern, Float aAlpha = 1.0)
 static inline Rect
 GetClipBounds(SkCanvas *aCanvas)
 {
-  SkRect clipBounds;
-  if (!aCanvas->getClipBounds(&clipBounds)) {
+  // Use a manually transformed getClipDeviceBounds instead of
+  // getClipBounds because getClipBounds inflates the the bounds
+  // by a pixel in each direction to compensate for antialiasing.
+  SkIRect deviceBounds;
+  if (!aCanvas->getClipDeviceBounds(&deviceBounds)) {
     return Rect();
   }
-  return SkRectToRect(clipBounds);
+  SkMatrix inverseCTM;
+  if (!aCanvas->getTotalMatrix().invert(&inverseCTM)) {
+    return Rect();
+  }
+  SkRect localBounds;
+  inverseCTM.mapRect(&localBounds, SkRect::Make(deviceBounds));
+  return SkRectToRect(localBounds);
 }
 
 struct AutoPaintSetup {