Tighten SkAAClip Bounds by Path Bounds

src/core/SkAAClip.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAAClip.h"
 #include "SkAtomics.h"
 #include "SkBlitter.h"
@@ skipping 1385 matching lines @@
 
     SkIRect ibounds;
     path.getBounds().roundOut(&ibounds);
 
     SkRegion tmpClip;
     if (nullptr == clip) {
         tmpClip.setRect(ibounds);
         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);
     BuilderBlitter blitter(&builder);
 
     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();
     return builder.finish(this);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 typedef void (*RowProc)(SkAAClip::Builder&, int bottom,
                         const uint8_t* rowA, const SkIRect& rectA,
@@ skipping 797 matching lines @@
             rowMask.fBounds.fBottom = y + 1;
             fBlitter->blitMask(rowMask, rowMask.fBounds);
             src = (const void*)((const char*)src + srcRB);
         } while (++y < localStopY);
     } while (y < stopY);
 }
 
 const SkPixmap* SkAAClipBlitter::justAnOpaqueColor(uint32_t* value) {
     return nullptr;
 }