Restrict query bounds for reduce clip to dev bounds

src/gpu/batches/GrTessellatingPathRenderer.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrTessellatingPathRenderer.h"
 
 #include "GrBatchFlushState.h"
@@ skipping 1574 matching lines @@
 
     TessellatingPathBatch(const GrColor& color,
                           const SkPath& path,
                           const GrStrokeInfo& stroke,
                           const SkMatrix& viewMatrix,
                           const SkRect& clipBounds)
       : INHERITED(ClassID())
       , fColor(color)
       , fPath(path)
       , fStroke(stroke)
-      , fViewMatrix(viewMatrix)
-      , fClipBounds(clipBounds) {
-        fBounds = path.getBounds();
+      , fViewMatrix(viewMatrix) {
+        const SkRect& pathBounds = path.getBounds();
+        fClipBounds = clipBounds;
+        // Because the clip bounds are used to add a contour for inverse fills, they must also
+        // include the path bounds.

[robertphillips, 2015/11/23 17:22:55]

// This will increase the size of the resulting geometry but will propagate more
reliable information to the ClipStack (which will need to apply an explicit clip
to the inverse filled geometry).

?

I wonder if adding an extra bit of bloat to the clipBounds (for the inverse fill
case) will make the tesselator happier.

[bsalomon, 2015/11/23 17:59:34]

It's not fundamentally for clipping. The current code is just incorrect even
without changes to the clipping code.
I don't see any artifacts in any of our tests. I can think of cases where it
would simplify things to add pad and cases where it would make it worse (e.g.
the contains a rect where one edge of the rect is along the path bounds.

+        fClipBounds.join(pathBounds);
+        if (path.isInverseFillType()) {
+            fBounds = fClipBounds;
+        } else {
+            fBounds = path.getBounds();
+        }
         if (!stroke.isFillStyle()) {
             SkScalar radius = SkScalarHalf(stroke.getWidth());
             if (stroke.getJoin() == SkPaint::kMiter_Join) {
                 SkScalar scale = stroke.getMiter();
                 if (scale > SK_Scalar1) {
                     radius = SkScalarMul(radius, scale);
                 }
             }
             fBounds.outset(radius, radius);
         }
@@ skipping 46 matching lines @@
     bool result = viewMatrix.invert(&vmi);
     if (!result) {
         SkFAIL("Cannot invert matrix\n");
     }
     vmi.mapRect(&clipBounds);
     GrStrokeInfo strokeInfo = GrTest::TestStrokeInfo(random);
     return TessellatingPathBatch::Create(color, path, strokeInfo, viewMatrix, clipBounds);
 }
 
 #endif