Implements a matrix convolution filter (raster path only). The filtering loop

is templated on the tiling mode for speed:  interior pixels are unconditionally
fetched; border pixels apply the appropriate tiling mode before fetching.  It
handles target, bias, divisor (as gain), and edge modes (named to be more
skia-like).  It does not handle the "preserveAlpha" semantics of
feConvolveMatrix, nor "kernelUnitLength".



git-svn-id: http://skia.googlecode.com/svn/trunk@5592 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 82 insertions, 0 deletions

diff --git a/gm/matrixconvolution.cpp b/gm/matrixconvolution.cpp
new file mode 100644
index 0000000000..6c69fac485
--- /dev/null
+++ b/gm/matrixconvolution.cpp
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+#include "SkMatrixConvolutionImageFilter.h"
+
+namespace skiagm {
+
+class MatrixConvolutionGM : public GM {
+public:
+    MatrixConvolutionGM() : fInitialized(false) {
+        this->setBGColor(0x00000000);
+    }
+
+protected:
+    virtual SkString onShortName() {
+        return SkString("matrixconvolution");
+    }
+
+    void make_bitmap() {
+        fBitmap.setConfig(SkBitmap::kARGB_8888_Config, 80, 80);
+        fBitmap.allocPixels();
+        SkDevice device(fBitmap);
+        SkCanvas canvas(&device);
+        canvas.clear(0x00000000);
+        SkPaint paint;
+        paint.setAntiAlias(true);
+        paint.setColor(0xFFFFFFFF);
+        paint.setTextSize(SkIntToScalar(180));
+        const char* str = "e";
+        canvas.drawText(str, strlen(str), SkIntToScalar(-10), SkIntToScalar(80), paint);
+    }
+
+    virtual SkISize onISize() {
+        return make_isize(300, 300);
+    }
+
+    void draw(SkCanvas* canvas, int x, int y, const SkIPoint& target, SkMatrixConvolutionImageFilter::TileMode tileMode) {
+        SkScalar kernel[9] = {
+            SkIntToScalar( 1), SkIntToScalar( 1), SkIntToScalar( 1),
+            SkIntToScalar( 1), SkIntToScalar(-7), SkIntToScalar( 1),
+            SkIntToScalar( 1), SkIntToScalar( 1), SkIntToScalar( 1),
+        };
+        SkISize kernelSize = SkISize::Make(3, 3);
+        SkScalar gain = SkFloatToScalar(0.3f), bias = SkIntToScalar(100);
+        SkPaint paint;
+        SkAutoTUnref<SkImageFilter> filter(SkNEW_ARGS(SkMatrixConvolutionImageFilter, (kernelSize, kernel, gain, bias, target, tileMode)));
+        paint.setImageFilter(filter);
+        canvas->drawSprite(fBitmap, x, y, &paint);
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        if (!fInitialized) {
+            make_bitmap();
+            fInitialized = true;
+        }
+        canvas->clear(0x00000000);
+        SkIPoint target = SkIPoint::Make(1, 1);
+        for (target.fY = 0; target.fY < 3; ++target.fY) {
+            int y = target.fY * 100 + 10;
+            draw(canvas, 10, y, target, SkMatrixConvolutionImageFilter::kClamp_TileMode);
+            draw(canvas, 110, y, target, SkMatrixConvolutionImageFilter::kClampToBlack_TileMode);
+            draw(canvas, 210, y, target, SkMatrixConvolutionImageFilter::kRepeat_TileMode);
+        }
+    }
+
+private:
+    typedef GM INHERITED;
+    SkBitmap fBitmap;
+    bool fInitialized;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new MatrixConvolutionGM; }
+static GMRegistry reg(MyFactory);
+
+}