Add a bench for measuring drawBitmap anti-aliasing overhead

bench/DrawBitmapAABench.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "Benchmark.h"
+#include "SkCanvas.h"
+#include "SkMatrix.h"
+#include "SkPaint.h"
+#include "SkString.h"
+
+/**
+ * This bench measures the rendering time of SkCanvas::drawBitmap with different anti-aliasing /
+ * matrix combinations.
+ */
+
+class DrawBitmapAABench : public Benchmark {
+public:
+    DrawBitmapAABench(bool doAA, const SkMatrix& matrix, const char name[])
+        : fMatrix(matrix)
+        , fName("draw_bitmap_") {
+
+        fPaint.setAntiAlias(doAA);
+        fName.appendf("%s_%s", doAA ? "aa" : "noaa", name);
+    }
+
+protected:
+    const char* onGetName() override {
+        return fName.c_str();
+    }
+
+    void onPreDraw() override {
+        fBitmap.allocN32Pixels(200, 200);
+        fBitmap.eraseARGB(255, 0, 255, 0);
+    }
+
+    void onDraw(const int loops, SkCanvas* canvas) override {
+        canvas->concat(fMatrix);
+        for (int i = 0; i < loops; i++) {
+            canvas->drawBitmap(fBitmap, 0, 0, &fPaint);
+        }
+    }
+
+private:
+    SkPaint  fPaint;
+    SkMatrix fMatrix;
+    SkString fName;
+    SkBitmap fBitmap;
+
+    typedef Benchmark INHERITED;
+};
+
+DEF_BENCH( return new DrawBitmapAABench(false, SkMatrix::MakeScale(1), "ident"); )
+
+DEF_BENCH( return new DrawBitmapAABench(false, SkMatrix::MakeScale(1.17f), "scale"); )
+
+DEF_BENCH( return new DrawBitmapAABench(false, SkMatrix::MakeTrans(17.5f, 17.5f), "translate"); )
+
+DEF_BENCH(
+    SkMatrix m;
+    m.reset();
+    m.preRotate(15);
+    return new DrawBitmapAABench(false, m, "rotate");
+)
+
+DEF_BENCH( return new DrawBitmapAABench(true, SkMatrix::MakeScale(1), "ident"); )
+
+DEF_BENCH( return new DrawBitmapAABench(true, SkMatrix::MakeScale(1.17f), "scale"); )
+
+DEF_BENCH( return new DrawBitmapAABench(true, SkMatrix::MakeTrans(17.5f, 17.5f), "translate"); )
+
+DEF_BENCH(
+    SkMatrix m;
+    m.reset();
+    m.preRotate(15);
+    return new DrawBitmapAABench(true, m, "rotate");
+)