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.h" 9 #include "SkCanvas.h" 10 #include "SkColorShader.h" 11 #include "SkPaint.h" 12 #include "SkRandom.h" 13 #include "SkSurface.h" 14 15 #if SK_SUPPORT_GPU 16 17 namespace skiagm { 18 19 /* 20 * This GM exercises SkCanvas::discard() by creating an offscreen SkSurface and repeatedly 21 * discarding it, drawing to it, and then drawing it to the main canvas. 22 */ 23 class DiscardGM : public GM { 24 25 public: DiscardGM()26 DiscardGM() { 27 } 28 29 protected: onShortName()30 SkString onShortName() override { 31 return SkString("discard"); 32 } 33 onISize()34 SkISize onISize() override { 35 return SkISize::Make(100, 100); 36 } 37 onDraw(SkCanvas * canvas)38 void onDraw(SkCanvas* canvas) override { 39 GrContext* context = canvas->getGrContext(); 40 if (nullptr == context) { 41 return; 42 } 43 44 SkISize size = this->getISize(); 45 size.fWidth /= 10; 46 size.fHeight /= 10; 47 SkImageInfo info = SkImageInfo::MakeN32Premul(size); 48 SkSurface* surface = SkSurface::NewRenderTarget(context, SkBudgeted::kNo, info); 49 50 if (nullptr == surface) { 51 return; 52 } 53 54 canvas->clear(SK_ColorBLACK); 55 56 SkRandom rand; 57 for (int x = 0; x < 10; ++x) { 58 for (int y = 0; y < 10; ++y) { 59 surface->getCanvas()->discard(); 60 // Make something that isn't too close to the background color, black. 61 SkColor color = sk_tool_utils::color_to_565(rand.nextU() | 0xFF404040); 62 switch (rand.nextULessThan(3)) { 63 case 0: 64 surface->getCanvas()->drawColor(color); 65 break; 66 case 1: 67 surface->getCanvas()->clear(color); 68 break; 69 case 2: 70 SkColorShader shader(color); 71 SkPaint paint; 72 paint.setShader(&shader); 73 surface->getCanvas()->drawPaint(paint); 74 break; 75 } 76 surface->draw(canvas, 10.f*x, 10.f*y, nullptr); 77 } 78 } 79 80 surface->getCanvas()->discard(); 81 surface->unref(); 82 } 83 84 private: 85 typedef GM INHERITED; 86 }; 87 88 ////////////////////////////////////////////////////////////////////////////// 89 90 DEF_GM(return new DiscardGM;) 91 92 } // end namespace 93 94 #endif 95