Fix for SkMatrixConvolutionImageFilter with large borders.

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 "SkBicubicImageFilter.h"
 #include "SkBitmap.h"
 #include "SkBitmapDevice.h"
@@ skipping 380 matching lines @@
     result.allocN32Pixels(width, height);
     SkCanvas canvas(result);
     canvas.clear(0);
 
     SkPaint paint;
     paint.setImageFilter(filter);
     SkRect rect = SkRect::Make(SkIRect::MakeWH(width, height));
     canvas.drawRect(rect, paint);
 }
 
+DEF_TEST(ImageFilterMatrixConvolutionBorder, reporter) {
+    // Check that a filter with borders outside the target bounds
+    // does not crash.
+    SkScalar kernel[3] = {
+        0, 0, 0,
+    };
+    SkISize kernelSize = SkISize::Make(3, 1);
+    SkScalar gain = SK_Scalar1, bias = 0;
+    SkIPoint kernelOffset = SkIPoint::Make(2, 0);
+
+    SkAutoTUnref<SkImageFilter> filter(
+        SkMatrixConvolutionImageFilter::Create(
+            kernelSize, kernel, gain, bias, kernelOffset,
+            SkMatrixConvolutionImageFilter::kClamp_TileMode, true));
+
+    SkBitmap result;
+
+    int width = 10, height = 10;
+    result.allocN32Pixels(width, height);
+    SkCanvas canvas(result);
+    canvas.clear(0);
+
+    SkPaint filterPaint;
+    filterPaint.setImageFilter(filter);
+    SkRect bounds = SkRect::MakeWH(1, 10);
+    SkRect rect = SkRect::Make(SkIRect::MakeWH(width, height));
+    SkPaint rectPaint;
+    canvas.saveLayer(&bounds, &filterPaint);
+    canvas.drawRect(rect, rectPaint);
+    canvas.restore();
+}
+
 DEF_TEST(ImageFilterCropRect, reporter) {
     SkBitmap temp;
     temp.allocN32Pixels(100, 100);
     SkBitmapDevice device(temp);
     test_crop_rects(&device, reporter);
 }
 
 DEF_TEST(ImageFilterMatrixTest, reporter) {
     SkBitmap temp;
     temp.allocN32Pixels(100, 100);
@@ skipping 168 matching lines @@
 }
 
 DEF_GPUTEST(XfermodeImageFilterCroppedInputGPU, reporter, factory) {
     GrContext* context = factory->get(static_cast<GrContextFactory::GLContextType>(0));
     SkAutoTUnref<SkGpuDevice> device(SkGpuDevice::Create(context,
                                                          SkImageInfo::MakeN32Premul(1, 1),
                                                          0));
     test_xfermode_cropped_input(device, reporter);
 }
 #endif