Added a few bench for some image filters

bench/MergeBench.cpp

Index: bench/MergeBench.cpp
===================================================================
--- bench/MergeBench.cpp	(revision 0)
+++ bench/MergeBench.cpp	(revision 0)
@@ -0,0 +1,102 @@
+/*
+ * 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 "SkBenchmark.h"
+#include "SkBitmapSource.h"
+#include "SkBlurImageFilter.h"
+#include "SkCanvas.h"
+#include "SkDevice.h"
+#include "SkMergeImageFilter.h"
+
+#define FILTER_WIDTH_SMALL  SkIntToScalar(32)
+#define FILTER_HEIGHT_SMALL SkIntToScalar(32)
+#define FILTER_WIDTH_LARGE  SkIntToScalar(256)
+#define FILTER_HEIGHT_LARGE SkIntToScalar(256)
+
+class MergeBench : public SkBenchmark {
+public:
+    MergeBench(void* param, bool small) : INHERITED(param), fIsSmall(small), fInitialized(false) {
+    }
+
+protected:
+    virtual const char* onGetName() SK_OVERRIDE {
+        return fIsSmall ? "merge_small" : "merge_large";
+    }
+
+    virtual void onPreDraw() SK_OVERRIDE {
+        if (!fInitialized) {
+            make_bitmap();
+            make_checkerboard();
+            fInitialized = true;
+        }
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        SkRect r = fIsSmall ? SkRect::MakeWH(FILTER_WIDTH_SMALL, FILTER_HEIGHT_SMALL) :
+                              SkRect::MakeWH(FILTER_WIDTH_LARGE, FILTER_HEIGHT_LARGE);
+        SkPaint paint;
+        paint.setImageFilter(mergeBitmaps())->unref();
+        canvas->drawRect(r, paint);
+    }
+
+private:
+    SkImageFilter* mergeBitmaps() {
+        SkImageFilter* first = new SkBitmapSource(fCheckerboard);
+        SkImageFilter* second = new SkBitmapSource(fBitmap);
+        SkAutoUnref aur0(first);
+        SkAutoUnref aur1(second);
+        return new SkMergeImageFilter(first, second);
+    }
+
+    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(0xFF884422);
+        paint.setTextSize(SkIntToScalar(96));
+        const char* str = "g";
+        canvas.drawText(str, strlen(str), SkIntToScalar(15), SkIntToScalar(55), paint);
+    }
+
+    void make_checkerboard() {
+        fCheckerboard.setConfig(SkBitmap::kARGB_8888_Config, 80, 80);
+        fCheckerboard.allocPixels();
+        SkDevice device(fCheckerboard);
+        SkCanvas canvas(&device);
+        canvas.clear(0x00000000);
+        SkPaint darkPaint;
+        darkPaint.setColor(0xFF804020);
+        SkPaint lightPaint;
+        lightPaint.setColor(0xFF244484);
+        for (int y = 0; y < 80; y += 16) {
+            for (int x = 0; x < 80; x += 16) {
+                canvas.save();
+                canvas.translate(SkIntToScalar(x), SkIntToScalar(y));
+                canvas.drawRect(SkRect::MakeXYWH(0, 0, 8, 8), darkPaint);
+                canvas.drawRect(SkRect::MakeXYWH(8, 0, 8, 8), lightPaint);
+                canvas.drawRect(SkRect::MakeXYWH(0, 8, 8, 8), lightPaint);
+                canvas.drawRect(SkRect::MakeXYWH(8, 8, 8, 8), darkPaint);
+                canvas.restore();
+            }
+        }
+    }
+
+    bool fIsSmall;
+    bool fInitialized;
+    SkBitmap fBitmap, fCheckerboard;
+
+    typedef SkBenchmark INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+DEF_BENCH( return new MergeBench(p, true); )
+DEF_BENCH( return new MergeBench(p, false); )
+