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/fonts/FontToolUtils.h" 25 #include "tools/timer/TimeUtils.h" 26 27 // Mimics https://output.jsbin.com/falefice/1/quiet?CC_POSTER_CIRCLE, which can't be captured as 28 // an SKP due to many 3D layers being composited post-SKP capture. 29 // See skbug.com/9028 30 class PosterCircleGM : public skiagm::GM { 31 public: PosterCircleGM()32 PosterCircleGM() : fTime(0.f) {} 33 34 protected: getName() const35 SkString getName() const override { return SkString("poster_circle"); } 36 getISize()37 SkISize getISize() override { return SkISize::Make(kStageWidth, kStageHeight + 50); } 38 onAnimate(double nanos)39 bool onAnimate(double nanos) override { 40 fTime = TimeUtils::Scaled(1e-9 * nanos, 0.5f); 41 return true; 42 } 43 onOnceBeforeDraw()44 void onOnceBeforeDraw() override { 45 SkFont font = ToolUtils::DefaultPortableFont(); 46 font.setEdging(SkFont::Edging::kAntiAlias); 47 font.setEmbolden(true); 48 font.setSize(24.f); 49 50 sk_sp<SkSurface> surface = 51 SkSurfaces::Raster(SkImageInfo::MakeN32Premul(kPosterSize, kPosterSize)); 52 for (int i = 0; i < kNumAngles; ++i) { 53 SkCanvas* canvas = surface->getCanvas(); 54 55 SkPaint fillPaint; 56 fillPaint.setAntiAlias(true); 57 fillPaint.setColor(i % 2 == 0 ? SkColorSetRGB(0x99, 0x5C, 0x7F) 58 : SkColorSetRGB(0x83, 0x5A, 0x99)); 59 canvas->drawRRect(SkRRect::MakeRectXY(SkRect::MakeWH(kPosterSize, kPosterSize), 60 10.f, 10.f), fillPaint); 61 62 SkString label; 63 label.printf("%d", i); 64 SkRect labelBounds; 65 font.measureText(label.c_str(), label.size(), SkTextEncoding::kUTF8, &labelBounds); 66 SkScalar labelX = 0.5f * kPosterSize - 0.5f * labelBounds.width(); 67 SkScalar labelY = 0.5f * kPosterSize + 0.5f * labelBounds.height(); 68 69 70 SkPaint labelPaint; 71 labelPaint.setAntiAlias(true); 72 canvas->drawString(label, labelX, labelY, font, labelPaint); 73 74 fPosterImages[i] = surface->makeImageSnapshot(); 75 } 76 } 77 onDraw(SkCanvas * canvas)78 void onDraw(SkCanvas* canvas) override { 79 // See https://developer.mozilla.org/en-US/docs/Web/CSS/transform-function/perspective 80 // for projection matrix when --webkit-perspective: 800px is used. 81 SkM44 proj; 82 proj.setRC(3, 2, -1.f / 800.f); 83 84 for (int pass = 0; pass < 2; ++pass) { 85 // Want to draw 90 to 270 first (the back), then 270 to 90 (the front), but do all 3 86 // rings backsides, then their frontsides since the front projections overlap across 87 // rings. Note: we skip the poster circle's x axis rotation because that complicates the 88 // back-to-front drawing order and it isn't necessary to trigger draws aligned with Z. 89 bool drawFront = pass > 0; 90 91 for (int y = 0; y < 3; ++y) { 92 float ringY = (y - 1) * (kPosterSize + 10.f); 93 for (int i = 0; i < kNumAngles; ++i) { 94 // Add an extra 45 degree rotation, which triggers the bug by aligning some of 95 // the posters with the z axis. 96 SkScalar yDuration = 5.f - y; 97 SkScalar yRotation = SkScalarMod(kAngleStep * i + 98 360.f * SkScalarMod(fTime / yDuration, yDuration), 360.f); 99 // These rotation limits were chosen manually to line up with current projection 100 static constexpr SkScalar kBackMinAngle = 70.f; 101 static constexpr SkScalar kBackMaxAngle = 290.f; 102 if (drawFront) { 103 if (yRotation >= kBackMinAngle && yRotation <= kBackMaxAngle) { 104 // Back portion during a front draw 105 continue; 106 } 107 } else { 108 if (yRotation < kBackMinAngle || yRotation > kBackMaxAngle) { 109 // Front portion during a back draw 110 continue; 111 } 112 } 113 114 canvas->save(); 115 116 // Matrix matches transform: rotateY(<angle>deg) translateZ(200px); nested in an 117 // element with the perspective projection matrix above. 118 SkM44 model = SkM44::Translate(kStageWidth/2, kStageHeight/2 + 25, 0) 119 * proj 120 * SkM44::Translate(0, ringY, 0) 121 * SkM44::Rotate({0,1,0}, SkDegreesToRadians(yRotation)) 122 * SkM44::Translate(0, 0, kRingRadius); 123 canvas->concat(model); 124 125 SkRect poster = SkRect::MakeLTRB(-0.5f * kPosterSize, -0.5f * kPosterSize, 126 0.5f * kPosterSize, 0.5f * kPosterSize); 127 SkPaint fillPaint; 128 fillPaint.setAntiAlias(true); 129 fillPaint.setAlphaf(0.7f); 130 canvas->drawImageRect(fPosterImages[i], poster, 131 SkSamplingOptions(SkFilterMode::kLinear), &fillPaint); 132 133 canvas->restore(); 134 } 135 } 136 } 137 } 138 139 private: 140 static const int kAngleStep = 30; 141 static const int kNumAngles = 12; // 0 through 330 degrees 142 143 static const int kStageWidth = 600; 144 static const int kStageHeight = 400; 145 static const int kRingRadius = 200; 146 static const int kPosterSize = 100; 147 148 sk_sp<SkImage> fPosterImages[kNumAngles]; 149 SkScalar fTime; 150 }; 151 152 DEF_GM(return new PosterCircleGM();) 153