Make SkComposeImageFilter::onFilterImage filter the bounds given to the inner filter.

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"
@@ skipping 1351 matching lines @@
 DEF_TEST(ComposedImageFilterOffset, reporter) {
     run_raster_test(reporter, 100, test_composed_imagefilter_offset);
 }
 
 #if SK_SUPPORT_GPU
 DEF_GPUTEST_FOR_NATIVE_CONTEXT(ComposedImageFilterOffset_Gpu, reporter, context) {
     run_gpu_test(reporter, context, 100, test_composed_imagefilter_offset);
 }
 #endif
 
+static void test_composed_imagefilter_bounds(SkImageFilter::Proxy* proxy,
+                                             skiatest::Reporter* reporter,
+                                             GrContext* context) {
+    // The bounds passed to the inner filter must be filtered by the outer

[reed1, 2016/03/19 14:28:49]

Some version of this comment might be useful in the SkComposeImageFilter class
as well, to clarify why the method does what it does.

[jbroman, 2016/03/20 01:12:12]

Copied the first three lines to SkComposeImageFilter::onFilterImage.

+    // filter, so that the inner filter produces the pixels that the outer
+    // filter requires as input. This matters if the outer filter moves pixels.
+    // Here, accounting for the outer offset is necessary so that the green
+    // pixels of the picture are not clipped.
+
+    SkPictureRecorder recorder;
+    recorder.beginRecording(SkRect::MakeWH(200, 100));

[reed1, 2016/03/19 14:28:49]

btw -- beginRecording returns the canvas, so you don't have to call
getRecordingCanvas...

canvas = recorder.beginRecording(...)

[jbroman, 2016/03/20 01:12:12]

Done.

+    SkCanvas* recordingCanvas = recorder.getRecordingCanvas();
+    recordingCanvas->clipRect(SkRect::MakeXYWH(100, 0, 100, 100));
+    recordingCanvas->clear(SK_ColorGREEN);
+    sk_sp<SkPicture> picture = recorder.finishRecordingAsPicture();
+    sk_sp<SkImageFilter> pictureFilter(
+        SkPictureImageFilter::Create(picture.get()));
+    SkImageFilter::CropRect cropRect(SkRect::MakeWH(100, 100));
+    sk_sp<SkImageFilter> offsetFilter(SkOffsetImageFilter::Create(-100, 0, nullptr, &cropRect));
+    sk_sp<SkImageFilter> composedFilter(
+        SkComposeImageFilter::Create(offsetFilter.get(), pictureFilter.get()));
+
+    sk_sp<SkSpecialImage> sourceImage(create_empty_special_image(context, proxy, 100));
+    SkImageFilter::Context ctx(SkMatrix::I(), SkIRect::MakeWH(100, 100), nullptr);
+    SkIPoint offset;
+    sk_sp<SkSpecialImage> result(composedFilter->filterImage(sourceImage.get(), ctx, &offset));
+    REPORTER_ASSERT(reporter, offset.isZero());
+    REPORTER_ASSERT(reporter, result);
+    REPORTER_ASSERT(reporter, result->subset().size() == SkISize::Make(100, 100));
+
+    SkBitmap resultBM;
+    TestingSpecialImageAccess::GetROPixels(result.get(), &resultBM);
+    SkAutoLockPixels lock(resultBM);
+    REPORTER_ASSERT(reporter, resultBM.getColor(50, 50) == SK_ColorGREEN);
+}
+
+DEF_TEST(ComposedImageFilterBounds, reporter) {
+    run_raster_test(reporter, 100, test_composed_imagefilter_bounds);
+}
+
+#if SK_SUPPORT_GPU
+DEF_GPUTEST_FOR_NATIVE_CONTEXT(ComposedImageFilterBounds_Gpu, reporter, context) {
+    run_gpu_test(reporter, context, 100, test_composed_imagefilter_bounds);
+}
+#endif
+
 static void test_partial_crop_rect(SkImageFilter::Proxy* proxy,
                                    skiatest::Reporter* reporter,
                                    GrContext* context) {
     sk_sp<SkSpecialImage> srcImg(create_empty_special_image(context, proxy, 100));
 
     SkImageFilter::CropRect cropRect(SkRect::MakeXYWH(100, 0, 20, 30),
         SkImageFilter::CropRect::kHasWidth_CropEdge | SkImageFilter::CropRect::kHasHeight_CropEdge);
     SkAutoTUnref<SkImageFilter> filter(make_grayscale(nullptr, &cropRect));
     SkIPoint offset;
     SkImageFilter::Context ctx(SkMatrix::I(), SkIRect::MakeWH(100, 100), nullptr);
@@ skipping 172 matching lines @@
     test_xfermode_cropped_input(&canvas, reporter);
 }
 
 DEF_GPUTEST_FOR_ALL_CONTEXTS(BlurLargeImage_Gpu, reporter, context) {
     SkAutoTUnref<SkSurface> surface(
         SkSurface::NewRenderTarget(context, SkBudgeted::kYes,
                                    SkImageInfo::MakeN32Premul(100, 100)));
     test_large_blur_input(reporter, surface->getCanvas());
 }
 #endif