Implement crop rect for SkImageFilter

tests/ImageFilterTest.cpp

Index: tests/ImageFilterTest.cpp
diff --git a/tests/ImageFilterTest.cpp b/tests/ImageFilterTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..6331020965fe18724b0dc196b8a3fd27639a0e59
--- /dev/null
+++ b/tests/ImageFilterTest.cpp
@@ -0,0 +1,78 @@
+
+/*
+ * 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 "Test.h"
+#include "SkColorMatrixFilter.h"
+#include "SkColorFilterImageFilter.h"
+#include "SkRect.h"
+
+class ImageFilterTest {
+public:
+
+    static SkImageFilter* make_scale(float amount, SkImageFilter* input = NULL) {
+        SkScalar s = SkFloatToScalar(amount);
+        SkScalar matrix[20] = { s, 0, 0, 0, 0,
+                                0, s, 0, 0, 0,
+                                0, 0, s, 0, 0,
+                                0, 0, 0, s, 0 };
+        SkAutoTUnref<SkColorFilter> filter(new SkColorMatrixFilter(matrix));
+        return SkColorFilterImageFilter::Create(filter, input);
+    }
+
+    static SkImageFilter* make_grayscale(SkImageFilter* input = NULL, const SkIRect* cropRect = NULL) {
+        SkScalar matrix[20];
+        memset(matrix, 0, 20 * sizeof(SkScalar));
+        matrix[0] = matrix[5] = matrix[10] = SkFloatToScalar(0.2126f);
+        matrix[1] = matrix[6] = matrix[11] = SkFloatToScalar(0.7152f);
+        matrix[2] = matrix[7] = matrix[12] = SkFloatToScalar(0.0722f);
+        matrix[18] = SkFloatToScalar(1.0f);
+        SkAutoTUnref<SkColorFilter> filter(new SkColorMatrixFilter(matrix));
+        return SkColorFilterImageFilter::Create(filter, input, cropRect);
+    }
+
+    static SkImageFilter* make_mode_blue(SkImageFilter* input = NULL) {
+        SkAutoTUnref<SkColorFilter> filter(
+            SkColorFilter::CreateModeFilter(SK_ColorBLUE, SkXfermode::kSrcIn_Mode));
+        return SkColorFilterImageFilter::Create(filter, input);
+    }
+
+    static void Test(skiatest::Reporter* reporter) {
+        {
+            // Check that two non-clipping color matrices concatenate into a single filter.
+            SkAutoTUnref<SkImageFilter> halfBrightness(make_scale(0.5f));
+            SkAutoTUnref<SkImageFilter> quarterBrightness(make_scale(0.5f, halfBrightness));
+            REPORTER_ASSERT(reporter, NULL == quarterBrightness->getInput(0));
+        }
+        
+        {
+            // Check that a clipping color matrix followed by a grayscale does not concatenate into a single filter.
+            SkAutoTUnref<SkImageFilter> doubleBrightness(make_scale(2.0f));
+            SkAutoTUnref<SkImageFilter> halfBrightness(make_scale(0.5f, doubleBrightness));
+            REPORTER_ASSERT(reporter, NULL != halfBrightness->getInput(0));
+        }
+
+        {
+            // Check that a color filter image filter without a crop rect can be
+            // expressed as a color filter.
+            SkAutoTUnref<SkImageFilter> gray(make_grayscale());
+            REPORTER_ASSERT(reporter, true == gray->asColorFilter(NULL));
+        }
+
+        {
+            // Check that a color filter image filter with a crop rect cannot
+            // be expressed as a color filter.
+            SkIRect cropRect = SkIRect::MakeXYWH(0, 0, 100, 100);
+            SkAutoTUnref<SkImageFilter> grayWithCrop(make_grayscale(NULL, &cropRect));
+            REPORTER_ASSERT(reporter, false == grayWithCrop->asColorFilter(NULL));
+        }
+    }
+};
+
+
+#include "TestClassDef.h"
+DEFINE_TESTCLASS("ImageFilterTest", ImageFilterTestClass, ImageFilterTest::Test)