Adding an option to render only the shadow in SkDropShadowImageFilter

tests/ImageFilterTest.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 "SkBitmap.h"
 #include "SkBitmapDevice.h"
 #include "SkBitmapSource.h"
@@ skipping 238 matching lines @@
     };
     SkISize kernelSize = SkISize::Make(3, 3);
     SkScalar gain = SK_Scalar1, bias = 0;
 
     SkImageFilter* filters[] = {
         SkColorFilterImageFilter::Create(cf.get(), input.get(), &cropRect),
         SkDisplacementMapEffect::Create(SkDisplacementMapEffect::kR_ChannelSelectorType,
                                         SkDisplacementMapEffect::kB_ChannelSelectorType,
                                         40.0f, input.get(), input.get(), &cropRect),
         SkBlurImageFilter::Create(SK_Scalar1, SK_Scalar1, input.get(), &cropRect),
-        SkDropShadowImageFilter::Create(SK_Scalar1, SK_Scalar1, SK_Scalar1, SK_Scalar1, SK_ColorGREEN, input.get(), &cropRect),
+        SkDropShadowImageFilter::Create(SK_Scalar1, SK_Scalar1, SK_Scalar1, SK_Scalar1,
+            SK_ColorGREEN, SkDropShadowImageFilter::kDrawShadowAndForeground_ShadowMode,
+            input.get(), &cropRect, 0),
         SkLightingImageFilter::CreatePointLitDiffuse(location, SK_ColorGREEN, 0, 0, input.get(), &cropRect),
         SkLightingImageFilter::CreatePointLitSpecular(location, SK_ColorGREEN, 0, 0, 0, input.get(), &cropRect),
         SkMatrixConvolutionImageFilter::Create(kernelSize, kernel, gain, bias, SkIPoint::Make(1, 1), SkMatrixConvolutionImageFilter::kRepeat_TileMode, false, input.get(), &cropRect),
         SkMergeImageFilter::Create(input.get(), input.get(), SkXfermode::kSrcOver_Mode, &cropRect),
         SkOffsetImageFilter::Create(SK_Scalar1, SK_Scalar1, input.get(), &cropRect),
         SkOffsetImageFilter::Create(SK_Scalar1, SK_Scalar1, input.get(), &cropRect),
         SkDilateImageFilter::Create(3, 2, input.get(), &cropRect),
         SkErodeImageFilter::Create(2, 3, input.get(), &cropRect),
         SkTileImageFilter::Create(inputCropRect.rect(), cropRect.rect(), input.get()),
         SkXfermodeImageFilter::Create(SkXfermode::Create(SkXfermode::kSrcOver_Mode), input.get(), input.get(), &cropRect),
@@ skipping 132 matching lines @@
         const char*    fName;
         SkImageFilter* fFilter;
     } filters[] = {
         { "color filter", SkColorFilterImageFilter::Create(cf.get()) },
         { "displacement map", SkDisplacementMapEffect::Create(
               SkDisplacementMapEffect::kR_ChannelSelectorType,
               SkDisplacementMapEffect::kB_ChannelSelectorType,
               20.0f, gradient_source.get()) },
         { "blur", SkBlurImageFilter::Create(SK_Scalar1, SK_Scalar1) },
         { "drop shadow", SkDropShadowImageFilter::Create(
-              SK_Scalar1, SK_Scalar1, SK_Scalar1, SK_Scalar1, SK_ColorGREEN) },
+              SK_Scalar1, SK_Scalar1, SK_Scalar1, SK_Scalar1, SK_ColorGREEN,
+              SkDropShadowImageFilter::kDrawShadowAndForeground_ShadowMode) },
         { "diffuse lighting", SkLightingImageFilter::CreatePointLitDiffuse(
               location, SK_ColorGREEN, 0, 0) },
         { "specular lighting",
               SkLightingImageFilter::CreatePointLitSpecular(location, SK_ColorGREEN, 0, 0, 0) },
         { "matrix convolution",
               SkMatrixConvolutionImageFilter::Create(
                   kernelSize, kernel, gain, bias, SkIPoint::Make(1, 1),
                   SkMatrixConvolutionImageFilter::kRepeat_TileMode, false) },
         { "merge", SkMergeImageFilter::Create(NULL, NULL, SkXfermode::kSrcOver_Mode) },
         { "offset", SkOffsetImageFilter::Create(SK_Scalar1, SK_Scalar1) },
@@ skipping 107 matching lines @@
 }
 
 static SkImageFilter* makeBlur(SkImageFilter* input = NULL) {
     return SkBlurImageFilter::Create(SK_Scalar1, SK_Scalar1, input);
 }
 
 static SkImageFilter* makeDropShadow(SkImageFilter* input = NULL) {
     return SkDropShadowImageFilter::Create(
         SkIntToScalar(100), SkIntToScalar(100),
         SkIntToScalar(10), SkIntToScalar(10),
-        SK_ColorBLUE, input);
+        SK_ColorBLUE, SkDropShadowImageFilter::kDrawShadowAndForeground_ShadowMode,
+        input, NULL, 0);
 }
 
 DEF_TEST(ImageFilterBlurThenShadowBounds, reporter) {
     SkAutoTUnref<SkImageFilter> filter1(makeBlur());
     SkAutoTUnref<SkImageFilter> filter2(makeDropShadow(filter1.get()));
 
     SkIRect bounds = SkIRect::MakeXYWH(0, 0, 100, 100);
     SkIRect expectedBounds = SkIRect::MakeXYWH(-133, -133, 236, 236);
     filter2->filterBounds(bounds, SkMatrix::I(), &bounds);
 
@@ skipping 534 matching lines @@
 
 DEF_GPUTEST(TestNegativeBlurSigmaGPU, reporter, factory) {
     GrContext* context = factory->get(static_cast<GrContextFactory::GLContextType>(0));
     SkAutoTUnref<SkGpuDevice> device(SkGpuDevice::Create(context,
                                                          SkImageInfo::MakeN32Premul(1, 1),
                                                          gProps,
                                                          0));
     test_negative_blur_sigma(device, reporter);
 }
 #endif