Added a few bench for some image filters

bench/MagnifierBench.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 "SkBenchmark.h"
+#include "SkCanvas.h"
+#include "SkMagnifierImageFilter.h"
+
+#define WIDTH 250

[Stephen White, 2013/04/19 18:39:01]

As above, perhaps 32x32 and 512x512.

[sugoi1, 2013/04/22 15:49:47]

Done.

+#define HEIGHT 250
+
+class MagnifierBench : public SkBenchmark {
+public:
+    MagnifierBench(void* param) : INHERITED(param) {
+    }
+
+protected:
+    virtual const char* onGetName() SK_OVERRIDE {
+        return "magnifier";
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        SkPaint paint;
+        paint.setImageFilter(
+            new SkMagnifierImageFilter(
+                SkRect::MakeXYWH(SkIntToScalar(WIDTH / 4),
+                                 SkIntToScalar(HEIGHT / 4),
+                                 SkIntToScalar(WIDTH / 2),
+                                 SkIntToScalar(HEIGHT / 2)), 100))->unref();
+        canvas->saveLayer(NULL, &paint);
+        paint.setAntiAlias(true);
+        const char* str = "The quick brown fox jumped over the lazy dog.";
+        srand(1234);

[jvanverth1, 2013/04/19 19:26:31]

Is there a reason you're using rand()? Can you try SkMWCRandom instead?

[sugoi1, 2013/04/19 20:47:28]

The quality of the randomness isn't really important here. I could also hardcode
some values. I'll change it to SkMWCRandom, it's doesn't make a difference to
me. Note that this part was copied from the GM, so you may want to change the GM
if rand() should not be used in GMs.

[sugoi1, 2013/04/22 15:49:47]

Well, I ended up removing all random number generation from the bench...

+        for (int i = 0; i < 25; ++i) {
+            int x = rand() % WIDTH;
+            int y = rand() % HEIGHT;
+            paint.setColor(rand() % 0x1000000 | 0xFF000000);
+            paint.setTextSize(SkIntToScalar(rand() % 300));
+            canvas->drawText(str, strlen(str), SkIntToScalar(x),

[Stephen White, 2013/04/19 18:39:01]

You should probably preinitialize the input bitmap here, to take text drawing
speed out of the equation.  And I'd take out the 25x loop, since the bench
infrastructure should take care of iterations (I think).

[sugoi1, 2013/04/22 15:49:47]

Done.

+                             SkIntToScalar(y), paint);
+        }
+        canvas->restore();
+    }
+
+private:
+    typedef SkBenchmark INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+DEF_BENCH( return new MagnifierBench(p); )
+