Fix for cropped matrix convolution for BottomLeft render targets.

R=bsalomon@google.com

Review URL: https://codereview.chromium.org/31083002

git-svn-id: http://skia.googlecode.com/svn/trunk@11872 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/matrixconvolution.cpp b/gm/matrixconvolution.cpp
index 5c443da..1863a7f 100644
--- a/gm/matrixconvolution.cpp
+++ b/gm/matrixconvolution.cpp
@@ -93,7 +93,7 @@
             target.fY++;
         }
         target.fY = 1;
-        SkImageFilter::CropRect rect(SkRect::MakeXYWH(10, 10, 60, 60));
+        SkImageFilter::CropRect rect(SkRect::MakeXYWH(10, 5, 60, 60));
         this->draw(canvas, 310, 10, target, MCIF::kClamp_TileMode, true, &rect);
         this->draw(canvas, 310, 110, target, MCIF::kClampToBlack_TileMode, true, &rect);
         this->draw(canvas, 310, 210, target, MCIF::kRepeat_TileMode, true, &rect);
diff --git a/src/effects/SkMatrixConvolutionImageFilter.cpp b/src/effects/SkMatrixConvolutionImageFilter.cpp
index 04326c6..a9dfecc 100644
--- a/src/effects/SkMatrixConvolutionImageFilter.cpp
+++ b/src/effects/SkMatrixConvolutionImageFilter.cpp
@@ -515,11 +515,15 @@
     uman.set1f(fGainUni, conv.gain());
     uman.set1f(fBiasUni, conv.bias());
     const SkIRect& bounds = conv.bounds();
-    uman.set4f(fBoundsUni,
-                (float) bounds.left() / texture.width(),
-                (float) bounds.top() / texture.height(),
-                (float) bounds.right() / texture.width(),
-                (float) bounds.bottom() / texture.height());
+    float left = (float) bounds.left() / texture.width();
+    float top = (float) bounds.top() / texture.height();
+    float right = (float) bounds.right() / texture.width();
+    float bottom = (float) bounds.bottom() / texture.height();
+    if (texture.origin() == kBottomLeft_GrSurfaceOrigin) {
+        uman.set4f(fBoundsUni, left, 1.0f - bottom, right, 1.0f - top);
+    } else {
+        uman.set4f(fBoundsUni, left, top, right, bottom);
+    }
 }
 
 GrMatrixConvolutionEffect::GrMatrixConvolutionEffect(GrTexture* texture,