Tighten SkAAClip Bounds by Path Bounds

src/core/SkAAClip.cpp

Index: src/core/SkAAClip.cpp
diff --git a/src/core/SkAAClip.cpp b/src/core/SkAAClip.cpp
index 1a60754d91370a1888a6b99842bf77de24b88580..16f02ac04d72eb50e4c0ec6fece292d977508f79 100644
--- a/src/core/SkAAClip.cpp
+++ b/src/core/SkAAClip.cpp
@@ -1403,12 +1403,15 @@ bool SkAAClip::setPath(const SkPath& path, const SkRegion* clip, bool doAA) {
         clip = &tmpClip;
     }
 
+    SkRegion realClip(*clip);

[reed1, 2016/11/09 21:27:42]

nit: real doesn't convey much. How about tightClip or snugClip, perhaps with a
comment explaining the value.

+
     if (path.isInverseFillType()) {
         ibounds = clip->getBounds();
     } else {
         if (ibounds.isEmpty() || !ibounds.intersect(clip->getBounds())) {
             return this->setEmpty();
         }
+        realClip.op(ibounds, SkRegion::kIntersect_Op);
     }
 
     Builder        builder(ibounds);
@@ -1416,12 +1419,12 @@ bool SkAAClip::setPath(const SkPath& path, const SkRegion* clip, bool doAA) {
 
     if (doAA) {
         if (gSkUseAnalyticAA.load()) {
-            SkScan::AAAFillPath(path, *clip, &blitter, true);
+            SkScan::AAAFillPath(path, realClip, &blitter, true);
         } else {
-            SkScan::AntiFillPath(path, *clip, &blitter, true);
+            SkScan::AntiFillPath(path, realClip, &blitter, true);
         }
     } else {
-        SkScan::FillPath(path, *clip, &blitter);
+        SkScan::FillPath(path, realClip, &blitter);
     }
 
     blitter.finish();