/* * Copyright 2019 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #include "gm/gm.h" #include "include/core/SkCanvas.h" #include "include/core/SkColor.h" #include "include/core/SkFilterQuality.h" #include "include/core/SkFont.h" #include "include/core/SkFontTypes.h" #include "include/core/SkImage.h" #include "include/core/SkM44.h" #include "include/core/SkMatrix.h" #include "include/core/SkPaint.h" #include "include/core/SkRRect.h" #include "include/core/SkRect.h" #include "include/core/SkRefCnt.h" #include "include/core/SkScalar.h" #include "include/core/SkSize.h" #include "include/core/SkString.h" #include "include/core/SkSurface.h" #include "tools/timer/TimeUtils.h" // Mimics https://output.jsbin.com/falefice/1/quiet?CC_POSTER_CIRCLE, which can't be captured as // an SKP due to many 3D layers being composited post-SKP capture. // See skbug.com/9028 class PosterCircleGM : public skiagm::GM { public: PosterCircleGM() : fTime(0.f) {} protected: SkString onShortName() override { return SkString("poster_circle"); } SkISize onISize() override { return SkISize::Make(kStageWidth, kStageHeight + 50); } bool onAnimate(double nanos) override { fTime = TimeUtils::Scaled(1e-9 * nanos, 0.5f); return true; } void onOnceBeforeDraw() override { SkFont font; font.setEdging(SkFont::Edging::kAntiAlias); font.setEmbolden(true); font.setSize(24.f); sk_sp<SkSurface> surface = SkSurface::MakeRasterN32Premul(kPosterSize, kPosterSize); for (int i = 0; i < kNumAngles; ++i) { SkCanvas* canvas = surface->getCanvas(); SkPaint fillPaint; fillPaint.setAntiAlias(true); fillPaint.setColor(i % 2 == 0 ? SkColorSetRGB(0x99, 0x5C, 0x7F) : SkColorSetRGB(0x83, 0x5A, 0x99)); canvas->drawRRect(SkRRect::MakeRectXY(SkRect::MakeWH(kPosterSize, kPosterSize), 10.f, 10.f), fillPaint); SkString label; label.printf("%d", i); SkRect labelBounds; font.measureText(label.c_str(), label.size(), SkTextEncoding::kUTF8, &labelBounds); SkScalar labelX = 0.5f * kPosterSize - 0.5f * labelBounds.width(); SkScalar labelY = 0.5f * kPosterSize + 0.5f * labelBounds.height(); SkPaint labelPaint; labelPaint.setAntiAlias(true); canvas->drawString(label, labelX, labelY, font, labelPaint); fPosterImages[i] = surface->makeImageSnapshot(); } } void onDraw(SkCanvas* canvas) override { // See https://developer.mozilla.org/en-US/docs/Web/CSS/transform-function/perspective // for projection matrix when --webkit-perspective: 800px is used. SkM44 proj; proj.setRC(3, 2, -1.f / 800.f); for (int pass = 0; pass < 2; ++pass) { // Want to draw 90 to 270 first (the back), then 270 to 90 (the front), but do all 3 // rings backsides, then their frontsides since the front projections overlap across // rings. Note: we skip the poster circle's x axis rotation because that complicates the // back-to-front drawing order and it isn't necessary to trigger draws aligned with Z. bool drawFront = pass > 0; for (int y = 0; y < 3; ++y) { float ringY = (y - 1) * (kPosterSize + 10.f); for (int i = 0; i < kNumAngles; ++i) { // Add an extra 45 degree rotation, which triggers the bug by aligning some of // the posters with the z axis. SkScalar yDuration = 5.f - y; SkScalar yRotation = SkScalarMod(kAngleStep * i + 360.f * SkScalarMod(fTime / yDuration, yDuration), 360.f); // These rotation limits were chosen manually to line up with current projection static constexpr SkScalar kBackMinAngle = 70.f; static constexpr SkScalar kBackMaxAngle = 290.f; if (drawFront) { if (yRotation >= kBackMinAngle && yRotation <= kBackMaxAngle) { // Back portion during a front draw continue; } } else { if (yRotation < kBackMinAngle || yRotation > kBackMaxAngle) { // Front portion during a back draw continue; } } canvas->save(); // Matrix matches transform: rotateY(<angle>deg) translateZ(200px); nested in an // element with the perspective projection matrix above. SkM44 model = SkM44::Translate(kStageWidth/2, kStageHeight/2 + 25, 0) * proj * SkM44::Translate(0, ringY, 0) * SkM44::Rotate({0,1,0}, SkDegreesToRadians(yRotation)) * SkM44::Translate(0, 0, kRingRadius); canvas->concat(model); SkRect poster = SkRect::MakeLTRB(-0.5f * kPosterSize, -0.5f * kPosterSize, 0.5f * kPosterSize, 0.5f * kPosterSize); SkPaint fillPaint; fillPaint.setAntiAlias(true); fillPaint.setAlphaf(0.7f); fillPaint.setFilterQuality(kLow_SkFilterQuality); canvas->drawImageRect(fPosterImages[i], poster, &fillPaint); canvas->restore(); } } } } private: static const int kAngleStep = 30; static const int kNumAngles = 12; // 0 through 330 degrees static const int kStageWidth = 600; static const int kStageHeight = 400; static const int kRingRadius = 200; static const int kPosterSize = 100; sk_sp<SkImage> fPosterImages[kNumAngles]; SkScalar fTime; }; DEF_GM(return new PosterCircleGM();)