text: /*
   * 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 "gm.h"
  #include "SkGradientShader.h"
  
  typedef sk_sp<SkShader> (*MakeShaderProc)(const SkColor[], int count, const SkSize&);
  
  static sk_sp<SkShader> shader_linear(const SkColor colors[], int count, const SkSize& size) {
      SkPoint pts[] = { { 0, 0 }, { size.width(), size.height() } };
      return SkGradientShader::MakeLinear(pts, colors, nullptr, count, SkShader::kClamp_TileMode);
  }
  
  static sk_sp<SkShader> shader_radial(const SkColor colors[], int count, const SkSize& size) {
      SkPoint center = { size.width()/2, size.height()/2 };
      return SkGradientShader::MakeRadial(center, size.width()/2, colors, nullptr, count,
                                          SkShader::kClamp_TileMode);
  }
  
  static sk_sp<SkShader> shader_conical(const SkColor colors[], int count, const SkSize& size) {
      SkPoint center = { size.width()/2, size.height()/2 };
      return SkGradientShader::MakeTwoPointConical(center, size.width()/64, center, size.width()/2,
                                                  colors, nullptr, count, SkShader::kClamp_TileMode);
  }
  
  static sk_sp<SkShader> shader_sweep(const SkColor colors[], int count, const SkSize& size) {
      return SkGradientShader::MakeSweep(size.width()/2, size.height()/2, colors, nullptr, count);
  }
  
  class ShallowGradientGM : public skiagm::GM {
  public:
      ShallowGradientGM(MakeShaderProc proc, const char name[], bool dither)
          : fProc(proc)
          , fDither(dither) {
          fName.printf("shallow_gradient_%s", name);
      }
  
  protected:
  
      SkString onShortName() override {
          return fName;
      }
  
      SkISize onISize() override {
          return SkISize::Make(800, 800);
      }
  
      void onDraw(SkCanvas* canvas) override {
          const SkColor colors[] = { 0xFF555555, 0xFF444444 };
          const int colorCount = SK_ARRAY_COUNT(colors);
  
          SkRect r = { 0, 0, this->width(), this->height() };
          SkSize size = SkSize::Make(r.width(), r.height());
  
          SkPaint paint;
          paint.setShader(fProc(colors, colorCount, size));
          paint.setDither(fDither);
          canvas->drawRect(r, paint);
      }
  
  private:
      MakeShaderProc fProc;
      SkString fName;
      bool fDither;
  
      typedef skiagm::GM INHERITED;
  };
  
  ///////////////////////////////////////////////////////////////////////////////
  
  DEF_GM( return new ShallowGradientGM(shader_linear, "linear", true); )
  DEF_GM( return new ShallowGradientGM(shader_radial, "radial", true); )
  DEF_GM( return new ShallowGradientGM(shader_conical, "conical", true); )
  DEF_GM( return new ShallowGradientGM(shader_sweep, "sweep", true); )
  
  DEF_GM( return new ShallowGradientGM(shader_linear, "linear_nodither", false); )
  DEF_GM( return new ShallowGradientGM(shader_radial, "radial_nodither", false); )
  DEF_GM( return new ShallowGradientGM(shader_conical, "conical_nodither", false); )
  DEF_GM( return new ShallowGradientGM(shader_sweep, "sweep_nodither", false); )
  