1 /* 2 * Copyright 2014 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #include "gm/gm.h" 9 #include "include/core/SkCanvas.h" 10 #include "include/core/SkColor.h" 11 #include "include/core/SkImageInfo.h" 12 #include "include/core/SkPaint.h" 13 #include "include/core/SkRefCnt.h" 14 #include "include/core/SkShader.h" 15 #include "include/core/SkSize.h" 16 #include "include/core/SkString.h" 17 #include "include/core/SkSurface.h" 18 #include "include/core/SkTypes.h" 19 #include "include/utils/SkRandom.h" 20 #include "tools/ToolUtils.h" 21 22 class GrContext; 23 class GrRenderTargetContext; 24 25 namespace skiagm { 26 27 /* 28 * This GM exercises SkCanvas::discard() by creating an offscreen SkSurface and repeatedly 29 * discarding it, drawing to it, and then drawing it to the main canvas. 30 */ 31 class DiscardGM : public GpuGM { 32 33 public: DiscardGM()34 DiscardGM() { 35 } 36 37 protected: onShortName()38 SkString onShortName() override { 39 return SkString("discard"); 40 } 41 onISize()42 SkISize onISize() override { 43 return SkISize::Make(100, 100); 44 } 45 onDraw(GrContext * context,GrRenderTargetContext *,SkCanvas * canvas,SkString * errorMsg)46 DrawResult onDraw(GrContext* context, GrRenderTargetContext*, SkCanvas* canvas, 47 SkString* errorMsg) override { 48 SkISize size = this->getISize(); 49 size.fWidth /= 10; 50 size.fHeight /= 10; 51 SkImageInfo info = SkImageInfo::MakeN32Premul(size); 52 auto surface = SkSurface::MakeRenderTarget(context, SkBudgeted::kNo, info); 53 if (nullptr == surface) { 54 *errorMsg = "Could not create render target."; 55 return DrawResult::kFail; 56 } 57 58 canvas->clear(SK_ColorBLACK); 59 60 SkRandom rand; 61 for (int x = 0; x < 10; ++x) { 62 for (int y = 0; y < 10; ++y) { 63 surface->getCanvas()->discard(); 64 // Make something that isn't too close to the background color, black. 65 SkColor color = ToolUtils::color_to_565(rand.nextU() | 0xFF404040); 66 switch (rand.nextULessThan(3)) { 67 case 0: 68 surface->getCanvas()->drawColor(color); 69 break; 70 case 1: 71 surface->getCanvas()->clear(color); 72 break; 73 case 2: 74 SkPaint paint; 75 paint.setShader(SkShaders::Color(color)); 76 surface->getCanvas()->drawPaint(paint); 77 break; 78 } 79 surface->draw(canvas, 10.f*x, 10.f*y, nullptr); 80 } 81 } 82 83 surface->getCanvas()->discard(); 84 return DrawResult::kOk; 85 } 86 87 private: 88 typedef GM INHERITED; 89 }; 90 91 ////////////////////////////////////////////////////////////////////////////// 92 93 DEF_GM(return new DiscardGM;) 94 95 } // end namespace 96