Add HardStopGradientBench.cpp

bench/HardStopGradientBench.cpp

Index: bench/HardStopGradientBench.cpp
diff --git a/bench/HardStopGradientBench.cpp b/bench/HardStopGradientBench.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..7ebc51c9ed28cafb8a903c067e1ba8bdb353cc82
--- /dev/null
+++ b/bench/HardStopGradientBench.cpp
@@ -0,0 +1,118 @@
+/*
+ * Copyright 2016 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 "SkShader.h"
+#include "SkGradientShader.h"
+#include "SkString.h"
+#include "SkColor.h"
+#include "SkPaint.h"
+
+static const char* get_tilemode_name(SkShader::TileMode tilemode) {
+    switch (tilemode) {
+        case SkShader::kClamp_TileMode:
+            return "clamp";
+        case SkShader::kRepeat_TileMode:
+            return "repeat";
+        case SkShader::kMirror_TileMode:
+            return "mirror";
+        default:
+            SkDEBUGFAIL("Unknown tilemode");
+            return "error";
+    }
+}
+
+class HardStopGradientBench : public Benchmark {
+public:
+    HardStopGradientBench(SkShader::TileMode tilemode, int count) {
+        fName.printf("hardstop_%s_%03d_colors", get_tilemode_name(tilemode), count);
+
+        fTileMode   = tilemode;
+        fColorCount = count;
+    }
+
+    const char* onGetName() override {
+        return fName.c_str();
+    }
+
+    SkIPoint onGetSize() override {
+        return SkIPoint::Make(kSize, kSize);
+    }
+
+    void onPreDraw(SkCanvas* canvas) override {
+        // Left to right
+        SkPoint points[2] = {
+            SkPoint::Make(0,        kSize/2), 
+            SkPoint::Make(kSize-1,  kSize/2),
+        };
+
+        // "Evenly spaced" colors
+        SkColor  colors[100];

[bsalomon, 2016/07/11 17:40:02]

Why not use a dynamic array?

+        for (int i = 0; i < fColorCount; i++) {
+            colors[i] = i * (0xffffffff / fColorCount);
+        }
+
+        // Create a hard stop
+        SkScalar positions[100];
+        positions[0] = 0.0f;
+        positions[1] = 0.0f;
+        for (int i = 2; i < fColorCount; i++) {
+            // Evenly spaced afterwards
+            positions[i] = i / (fColorCount - 1.0f);
+        }
+
+        fPaint.setShader(SkGradientShader::MakeLinear(points,
+                                                      colors,
+                                                      positions,
+                                                      fColorCount,
+                                                      fTileMode,
+                                                      0,
+                                                      nullptr));
+    }
+
+    /*
+     * Draw simple linear gradient from left to right
+     */
+    void onDraw(int loops, SkCanvas* canvas) override {
+        for (int i = 0; i < loops; i++) {
+            canvas->drawPaint(fPaint);
+        }
+    }
+
+private:
+    static const int kSize = 500;
+
+    SkShader::TileMode  fTileMode;
+    SkString            fName;
+    int                 fColorCount;
+    SkPaint             fPaint;
+
+    typedef Benchmark INHERITED;
+};
+
+// Clamp
+DEF_BENCH(return new HardStopGradientBench(SkShader::kClamp_TileMode,   5);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kClamp_TileMode,  10);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kClamp_TileMode,  25);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kClamp_TileMode,  50);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kClamp_TileMode, 100);)
+
+// Repeat
+DEF_BENCH(return new HardStopGradientBench(SkShader::kRepeat_TileMode,   5);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kRepeat_TileMode,  10);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kRepeat_TileMode,  25);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kRepeat_TileMode,  50);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kRepeat_TileMode, 100);)
+
+// Mirror
+DEF_BENCH(return new HardStopGradientBench(SkShader::kMirror_TileMode,   5);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kMirror_TileMode,  10);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kMirror_TileMode,  25);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kMirror_TileMode,  50);)
+DEF_BENCH(return new HardStopGradientBench(SkShader::kMirror_TileMode, 100);)