Fix bug where ovals' AA exceed bounds by .5 pixel

src/gpu/GrOvalRenderer.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrOvalRenderer.h"
 
 #include "GrBatchFlushState.h"
@@ skipping 925 matching lines @@
 
         xRadius += scaledStroke.fX;
         yRadius += scaledStroke.fY;
     }
 
     // We've extended the outer x radius out half a pixel to antialias.
     // This will also expand the rect so all the pixels will be captured.
     // TODO: Consider if we should use sqrt(2)/2 instead
     xRadius += SK_ScalarHalf;
     yRadius += SK_ScalarHalf;
 

[robertphillips, 2016/06/30 14:10:16]

Hmmm ... can we not just remove the above 2 lines ?

[vjiaoblack, 2016/06/30 14:13:35]

Right yeah, sorry. Jim pointed this out while overlooking my commit.

Fixed in Patch Set 2.

+    // fix bug where the ovals are drawn 0.5 pixels too big on each side
+    // (the 0.5 width antialiasing exceeds the rect bounds)
+    xRadius -= 0.5f;
+    yRadius -= 0.5f;
+
     EllipseBatch::Geometry geometry;
     geometry.fColor = color;
     geometry.fXRadius = xRadius;
     geometry.fYRadius = yRadius;
     geometry.fInnerXRadius = innerXRadius;
     geometry.fInnerYRadius = innerYRadius;
     geometry.fDevBounds = SkRect::MakeLTRB(center.fX - xRadius, center.fY - yRadius,
                                            center.fX + xRadius, center.fY + yRadius);
 
     return new EllipseBatch(geometry, viewMatrix,
@@ skipping 760 matching lines @@
 }
 
 DRAW_BATCH_TEST_DEFINE(RRectBatch) {
     SkMatrix viewMatrix = GrTest::TestMatrixRectStaysRect(random);
     GrColor color = GrRandomColor(random);
     const SkRRect& rrect = GrTest::TestRRectSimple(random);
     return create_rrect_batch(color, viewMatrix, rrect, GrTest::TestStrokeRec(random));
 }
 
 #endif