1 /* 2 * Copyright 2019 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/SkFont.h" 12 #include "include/core/SkFontTypes.h" 13 #include "include/core/SkImage.h" 14 #include "include/core/SkM44.h" 15 #include "include/core/SkMatrix.h" 16 #include "include/core/SkPaint.h" 17 #include "include/core/SkRRect.h" 18 #include "include/core/SkRect.h" 19 #include "include/core/SkRefCnt.h" 20 #include "include/core/SkScalar.h" 21 #include "include/core/SkSize.h" 22 #include "include/core/SkString.h" 23 #include "include/core/SkSurface.h" 24 #include "tools/timer/TimeUtils.h" 25 26 // Mimics https://output.jsbin.com/falefice/1/quiet?CC_POSTER_CIRCLE, which can't be captured as 27 // an SKP due to many 3D layers being composited post-SKP capture. 28 // See skbug.com/9028 29 class PosterCircleGM : public skiagm::GM { 30 public: PosterCircleGM()31 PosterCircleGM() : fTime(0.f) {} 32 33 protected: 34 onShortName()35 SkString onShortName() override { 36 return SkString("poster_circle"); 37 } 38 onISize()39 SkISize onISize() override { 40 return SkISize::Make(kStageWidth, kStageHeight + 50); 41 } 42 onAnimate(double nanos)43 bool onAnimate(double nanos) override { 44 fTime = TimeUtils::Scaled(1e-9 * nanos, 0.5f); 45 return true; 46 } 47 onOnceBeforeDraw()48 void onOnceBeforeDraw() override { 49 SkFont font; 50 font.setEdging(SkFont::Edging::kAntiAlias); 51 font.setEmbolden(true); 52 font.setSize(24.f); 53 54 sk_sp<SkSurface> surface = SkSurface::MakeRasterN32Premul(kPosterSize, kPosterSize); 55 for (int i = 0; i < kNumAngles; ++i) { 56 SkCanvas* canvas = surface->getCanvas(); 57 58 SkPaint fillPaint; 59 fillPaint.setAntiAlias(true); 60 fillPaint.setColor(i % 2 == 0 ? SkColorSetRGB(0x99, 0x5C, 0x7F) 61 : SkColorSetRGB(0x83, 0x5A, 0x99)); 62 canvas->drawRRect(SkRRect::MakeRectXY(SkRect::MakeWH(kPosterSize, kPosterSize), 63 10.f, 10.f), fillPaint); 64 65 SkString label; 66 label.printf("%d", i); 67 SkRect labelBounds; 68 font.measureText(label.c_str(), label.size(), SkTextEncoding::kUTF8, &labelBounds); 69 SkScalar labelX = 0.5f * kPosterSize - 0.5f * labelBounds.width(); 70 SkScalar labelY = 0.5f * kPosterSize + 0.5f * labelBounds.height(); 71 72 73 SkPaint labelPaint; 74 labelPaint.setAntiAlias(true); 75 canvas->drawString(label, labelX, labelY, font, labelPaint); 76 77 fPosterImages[i] = surface->makeImageSnapshot(); 78 } 79 } 80 onDraw(SkCanvas * canvas)81 void onDraw(SkCanvas* canvas) override { 82 // See https://developer.mozilla.org/en-US/docs/Web/CSS/transform-function/perspective 83 // for projection matrix when --webkit-perspective: 800px is used. 84 SkM44 proj; 85 proj.setRC(3, 2, -1.f / 800.f); 86 87 for (int pass = 0; pass < 2; ++pass) { 88 // Want to draw 90 to 270 first (the back), then 270 to 90 (the front), but do all 3 89 // rings backsides, then their frontsides since the front projections overlap across 90 // rings. Note: we skip the poster circle's x axis rotation because that complicates the 91 // back-to-front drawing order and it isn't necessary to trigger draws aligned with Z. 92 bool drawFront = pass > 0; 93 94 for (int y = 0; y < 3; ++y) { 95 float ringY = (y - 1) * (kPosterSize + 10.f); 96 for (int i = 0; i < kNumAngles; ++i) { 97 // Add an extra 45 degree rotation, which triggers the bug by aligning some of 98 // the posters with the z axis. 99 SkScalar yDuration = 5.f - y; 100 SkScalar yRotation = SkScalarMod(kAngleStep * i + 101 360.f * SkScalarMod(fTime / yDuration, yDuration), 360.f); 102 // These rotation limits were chosen manually to line up with current projection 103 static constexpr SkScalar kBackMinAngle = 70.f; 104 static constexpr SkScalar kBackMaxAngle = 290.f; 105 if (drawFront) { 106 if (yRotation >= kBackMinAngle && yRotation <= kBackMaxAngle) { 107 // Back portion during a front draw 108 continue; 109 } 110 } else { 111 if (yRotation < kBackMinAngle || yRotation > kBackMaxAngle) { 112 // Front portion during a back draw 113 continue; 114 } 115 } 116 117 canvas->save(); 118 119 // Matrix matches transform: rotateY(<angle>deg) translateZ(200px); nested in an 120 // element with the perspective projection matrix above. 121 SkM44 model = SkM44::Translate(kStageWidth/2, kStageHeight/2 + 25, 0) 122 * proj 123 * SkM44::Translate(0, ringY, 0) 124 * SkM44::Rotate({0,1,0}, SkDegreesToRadians(yRotation)) 125 * SkM44::Translate(0, 0, kRingRadius); 126 canvas->concat(model); 127 128 SkRect poster = SkRect::MakeLTRB(-0.5f * kPosterSize, -0.5f * kPosterSize, 129 0.5f * kPosterSize, 0.5f * kPosterSize); 130 SkPaint fillPaint; 131 fillPaint.setAntiAlias(true); 132 fillPaint.setAlphaf(0.7f); 133 canvas->drawImageRect(fPosterImages[i], poster, 134 SkSamplingOptions(SkFilterMode::kLinear), &fillPaint); 135 136 canvas->restore(); 137 } 138 } 139 } 140 } 141 142 private: 143 static const int kAngleStep = 30; 144 static const int kNumAngles = 12; // 0 through 330 degrees 145 146 static const int kStageWidth = 600; 147 static const int kStageHeight = 400; 148 static const int kRingRadius = 200; 149 static const int kPosterSize = 100; 150 151 sk_sp<SkImage> fPosterImages[kNumAngles]; 152 SkScalar fTime; 153 }; 154 155 DEF_GM(return new PosterCircleGM();) 156