1 /* 2 * Copyright 2013 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/SkPaint.h" 11 #include "include/core/SkPath.h" 12 #include "include/core/SkPoint.h" 13 #include "include/core/SkScalar.h" 14 #include "include/core/SkSize.h" 15 #include "include/core/SkString.h" 16 #include "include/core/SkTypes.h" 17 #include "tools/ToolUtils.h" 18 #include "tools/timer/TimeUtils.h" 19 20 // Reproduces https://code.google.com/p/chromium/issues/detail?id=279014 21 22 constexpr int kWidth = 440; 23 constexpr int kHeight = 440; 24 constexpr SkScalar kAngle = 0.305f; 25 constexpr int kMaxNumSteps = 140; 26 27 // Renders a string art shape. 28 // The particular shape rendered can be controlled by adjusting kAngle, from 0 to 1 29 30 class StringArtGM : public skiagm::GM { 31 public: StringArtGM()32 StringArtGM() : fNumSteps(kMaxNumSteps) {} 33 34 protected: getName() const35 SkString getName() const override { return SkString("stringart"); } 36 getISize()37 SkISize getISize() override { return SkISize::Make(kWidth, kHeight); } 38 onDraw(SkCanvas * canvas)39 void onDraw(SkCanvas* canvas) override { 40 SkScalar angle = kAngle*SK_ScalarPI + SkScalarHalf(SK_ScalarPI); 41 SkScalar size = SkIntToScalar(std::min(kWidth, kHeight)); 42 SkPoint center = SkPoint::Make(SkScalarHalf(kWidth), SkScalarHalf(kHeight)); 43 SkScalar length = 5; 44 SkScalar step = angle; 45 46 SkPath path; 47 path.moveTo(center); 48 49 for (int i = 0; i < fNumSteps && length < (SkScalarHalf(size) - 10.f); ++i) { 50 SkPoint rp = SkPoint::Make(length*SkScalarCos(step) + center.fX, 51 length*SkScalarSin(step) + center.fY); 52 path.lineTo(rp); 53 length += angle / SkScalarHalf(SK_ScalarPI); 54 step += angle; 55 } 56 57 SkPaint paint; 58 paint.setAntiAlias(true); 59 paint.setStyle(SkPaint::kStroke_Style); 60 paint.setColor(ToolUtils::color_to_565(0xFF007700)); 61 62 canvas->drawPath(path, paint); 63 } 64 onAnimate(double nanos)65 bool onAnimate(double nanos) override { 66 constexpr SkScalar kDesiredDurationSecs = 3.0f; 67 68 // Make the animation ping-pong back and forth but start in the fully drawn state 69 SkScalar fraction = 1.0f - TimeUtils::Scaled(1e-9 * nanos, 2.0f/kDesiredDurationSecs, 2.0f); 70 if (fraction <= 0.0f) { 71 fraction = -fraction; 72 } 73 74 SkASSERT(fraction >= 0.0f && fraction <= 1.0f); 75 76 fNumSteps = (int) (fraction * kMaxNumSteps); 77 return true; 78 } 79 80 private: 81 int fNumSteps; 82 83 using INHERITED = GM; 84 }; 85 86 DEF_GM( return new StringArtGM; ) 87