fix the visual difference of raster vs gpu -- inverse_paths

src/core/SkCanvas.cpp

 
 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkCanvas.h"
@@ skipping 1728 matching lines @@
 
     SkRect storage;
     const SkRect* bounds = NULL;
     if (!path.isInverseFillType() && paint.canComputeFastBounds()) {
         const SkRect& pathBounds = path.getBounds();
         bounds = &paint.computeFastBounds(pathBounds, &storage);
         if (this->quickReject(*bounds)) {
             return;
         }
     }
-    if (path.isEmpty()) {
+
+    const SkRect& r = path.getBounds();
+    if (r.width() <= 0 && r.height() <= 0) {

[reed2, 2014/02/21 10:48:49]

Do we have unit-tests added to exercise this?
Does this catch a width > 0 but height < 0 filled path (e.g. horizontal line as
a path)?
Do we perform the same checks on drawRect/drawOval?

[yunchao, 2014/02/24 03:07:20]

Hi Mike,
Do you think we need to add a unit-tests like tests/GpuDrawPathTest.cpp to show
that inverse-filling an empty path will not crash? The previous tests didn't
test this in unit-tests too. If we want to test the images generated by drawPath
for inverse-filled empty path, gm/inversepaths have done this.

a width > 0 but height < 0 filled path is not included in this fix, I think.
because It is not an empty path. It is a hairline, right? Skia can draw it
correctly.

Rects and Ovals have no FillType if they are not added to a path, so they didn't
need to check this. If they are empty, just draw nothing. GM cases have tested
empty rects/ovals too.

         if (path.isInverseFillType()) {
             this->internalDrawPaint(paint);
         }
         return;
     }
 
     LOOPER_BEGIN(paint, SkDrawFilter::kPath_Type, bounds)
 
     while (iter.next()) {
         iter.fDevice->drawPath(iter, path, looper.paint());
@@ skipping 481 matching lines @@
     return *paint;
 }
 
 const SkRegion& SkCanvas::LayerIter::clip() const { return fImpl->getClip(); }
 int SkCanvas::LayerIter::x() const { return fImpl->getX(); }
 int SkCanvas::LayerIter::y() const { return fImpl->getY(); }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkCanvas::ClipVisitor::~ClipVisitor() { }