Image filters: fix filtering of transparent black in CFIF.

gm/imagefilterscropexpand.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "SkCanvas.h"
 #include "SkColorFilter.h"
@@ skipping 31 matching lines @@
     void onDraw(SkCanvas* canvas) override {
         SkImageFilter::CropRect cropRect(
             SkRect::Make(SkIRect::MakeXYWH(10, 10, 44, 44)),
             SkImageFilter::CropRect::kHasAll_CropEdge);
 
         sk_sp<SkImage> gradientCircle(MakeGradientCircle(64, 64));
         SkBitmap checkerboard;
         MakeCheckerboard(&checkerboard);
 
         sk_sp<SkImageFilter> gradientCircleSource(SkImageSource::Make(std::move(gradientCircle)));
         sk_sp<SkImageFilter> noopCropped(SkOffsetImageFilter::Make(0, 0, nullptr, &cropRect));

[robertphillips, 2016/05/18 12:36:00]

// This color matrix saturates the green component but only partly increases the
opacity. 
// For the opaque checkerboard texture the opacity boost doesn't matter but it
does impact the area outside the checkerboard

?

-        SkScalar sk255 = SkIntToScalar(255);
         SkScalar matrix[20] = { 1, 0, 0, 0, 0,
-                                0, 1, 0, 0, sk255,
+                                0, 1, 0, 0, 255,
                                 0, 0, 1, 0, 0,
-                                0, 0, 0, 0, sk255 };
+                                0, 0, 0, 1, 32 };
         sk_sp<SkColorFilter> cfAlphaTrans(SkColorFilter::MakeMatrixFilterRowMajor255(matrix));
 
         SkRect r = SkRect::MakeWH(SkIntToScalar(64), SkIntToScalar(64));
         SkScalar MARGIN = SkIntToScalar(12);
 
         SkPoint3 pointLocation = SkPoint3::Make(0, 0, SkIntToScalar(10));
         SkScalar kd = SkIntToScalar(2);
         SkScalar surfaceScale = SkIntToScalar(1);
         SkIRect bounds;
         r.roundOut(&bounds);
@@ skipping 119 matching lines @@
 
         canvas->translate(SkIntToScalar(80), 0);
     }
 
     typedef GM INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 DEF_GM( return new ImageFiltersCropExpandGM; )