skia2/bench/HardStopGradientBench_ScaleNumHardStops.cpp

/*
 * 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"

class HardStopGradientBench_ScaleNumHardStops : public Benchmark {
public:
    HardStopGradientBench_ScaleNumHardStops(int colorCount, int hardStopCount) {
        SkASSERT(hardStopCount <= colorCount/2);

        fName.printf("hardstop_scale_num_hard_stops_%03d_colors_%03d_hard_stops", 
                     colorCount, hardStopCount);

        fColorCount    = colorCount;
        fHardStopCount = hardStopCount;
    }

    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),
        };

        constexpr int kNumColorChoices = 4;
        SkColor color_choices[kNumColorChoices] = {
            SK_ColorRED,
            SK_ColorGREEN,
            SK_ColorBLUE,
            SK_ColorYELLOW,
        };

        // Alternate between different choices
        SkAutoTArray<SkColor> colors(fColorCount);
        for (int i = 0; i < fColorCount; i++) {
            colors[i] = color_choices[i % kNumColorChoices];
        }

        // Create requisite number of hard stops, and evenly
        // space positions after that
        SkAutoTArray<SkScalar> positions(fColorCount);
        int k = 0;
        for (int i = 0; i < fHardStopCount; i++) {
            float val = k/2.0f;
            positions[k++] = val / fColorCount;
            positions[k++] = val / fColorCount;
        }
        for (int i = k; i < fColorCount; i++) {
            positions[i] = i / (fColorCount - 1.0f);
        }

        fPaint.setShader(SkGradientShader::MakeLinear(points,
                                                      colors.get(),
                                                      positions.get(),
                                                      fColorCount,
                                                      SkShader::kClamp_TileMode,
                                                      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;

    SkString fName;
    int      fColorCount;
    int      fHardStopCount;
    SkPaint  fPaint;

    typedef Benchmark INHERITED;
};

DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(10, 1);)
DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(10, 2);)
DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(10, 5);)

DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(20,  1);)
DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(20,  5);)
DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(20, 10);)

DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(50,  1);)
DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(50, 10);)
DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(50, 25);)

DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(100,  1);)
DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(100, 25);)
DEF_BENCH(return new HardStopGradientBench_ScaleNumHardStops(100, 50);)