Add a bench for comparing complex clip strategies

Clip consisting of a union of |n| circles.

Comparing mask (2x saveLayer + srcIn) vs. clipPath approaches.

MBP numbers:

! -> high variance, ? -> moderate variance
    micros   	bench
    233.05 !	clip_strategy_mask_100	gl
    207.61 !	clip_strategy_mask_10	gl
    210.41 ?	clip_strategy_mask_5	gl
    219.10 ?	clip_strategy_mask_1	gl
    115.56 ?	clip_strategy_path_100	gl
    113.29 !	clip_strategy_path_10	gl
    102.36 ?	clip_strategy_path_5	gl
      6.37 ?	clip_strategy_path_1	gl

    361.06 !	clip_strategy_mask_100	8888
    328.97 !	clip_strategy_mask_10	8888
    316.72 !	clip_strategy_mask_5	8888
    325.84 !	clip_strategy_mask_1	8888
    368.54 !	clip_strategy_path_100	8888
    306.99 !	clip_strategy_path_10	8888
    298.71 !	clip_strategy_path_5	8888
    191.00 !	clip_strategy_path_1	8888

TBR=

Change-Id: I945c12e2e35b9847af06342473e56272e2041e21
Reviewed-on: https://skia-review.googlesource.com/72521
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Florin Malita <fmalita@chromium.org>

1 files changed, 91 insertions, 0 deletions

diff --git a/bench/ClipStrategyBench.cpp b/bench/ClipStrategyBench.cpp
new file mode 100644
index 0000000000..c65cf4b97d
--- /dev/null
+++ b/bench/ClipStrategyBench.cpp
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2017 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 "SkPath.h"
+#include "SkPathOps.h"
+
+class ClipStrategyBench : public Benchmark {
+public:
+    enum class Mode {
+        kClipPath,
+        kMask,
+    };
+
+    ClipStrategyBench(Mode mode, size_t count)
+        : fMode(mode)
+        , fCount(count)
+        , fName("clip_strategy_"){
+
+        if (fMode == Mode::kClipPath) {
+            fName.append("path_");
+            this->forEachClipCircle([&](float x, float y, float r) {
+                fClipPath.addCircle(x, y, r);
+            });
+        } else {
+            fName.append("mask_");
+        }
+        fName.appendf("%zu", count);
+    }
+
+    ~ClipStrategyBench() override = default;
+
+protected:
+    const char* onGetName() override {
+        return fName.c_str();
+    }
+
+    void onDraw(int loops, SkCanvas* canvas) override {
+        SkPaint p, srcIn;
+        p.setAntiAlias(true);
+        srcIn.setBlendMode(SkBlendMode::kSrcIn);
+
+        for (int i = 0; i < loops; ++i) {
+            SkAutoCanvasRestore acr(canvas, false);
+
+            if (fMode == Mode::kClipPath) {
+                canvas->save();
+                canvas->clipPath(fClipPath, true);
+            } else {
+                canvas->saveLayer(nullptr, nullptr);
+                this->forEachClipCircle([&](float x, float y, float r) {
+                    canvas->drawCircle(x, y, r, p);
+                });
+                canvas->saveLayer(nullptr, &srcIn);
+            }
+            canvas->drawColor(SK_ColorGREEN);
+        }
+    }
+
+private:
+    template <typename Func>
+    void forEachClipCircle(Func&& func) {
+        auto q = static_cast<float>(this->getSize().x()) / (fCount + 1);
+        for (size_t i = 1; i <= fCount; ++i) {
+            auto x = q * i;
+            func(x, x, q / 2);
+        }
+    }
+
+    Mode     fMode;
+    size_t   fCount;
+    SkString fName;
+    SkPath   fClipPath;
+
+    typedef Benchmark INHERITED;
+};
+
+DEF_BENCH( return new ClipStrategyBench(ClipStrategyBench::Mode::kClipPath, 1  );)
+DEF_BENCH( return new ClipStrategyBench(ClipStrategyBench::Mode::kClipPath, 5  );)
+DEF_BENCH( return new ClipStrategyBench(ClipStrategyBench::Mode::kClipPath, 10 );)
+DEF_BENCH( return new ClipStrategyBench(ClipStrategyBench::Mode::kClipPath, 100);)
+
+DEF_BENCH( return new ClipStrategyBench(ClipStrategyBench::Mode::kMask, 1  );)
+DEF_BENCH( return new ClipStrategyBench(ClipStrategyBench::Mode::kMask, 5  );)
+DEF_BENCH( return new ClipStrategyBench(ClipStrategyBench::Mode::kMask, 10 );)
+DEF_BENCH( return new ClipStrategyBench(ClipStrategyBench::Mode::kMask, 100);)