/* * Copyright 2018 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/SkPaint.h" #include "include/core/SkPath.h" #include "include/core/SkPoint.h" #include "include/core/SkScalar.h" #include "include/core/SkSize.h" #include "include/core/SkString.h" #include "include/core/SkTypes.h" #include "include/utils/SkRandom.h" #include "src/core/SkGeometry.h" #include <math.h> namespace skiagm { // Slices paths into sliver-size contours shaped like ice cream cones. class MandolineSlicer { public: static constexpr int kDefaultSubdivisions = 10; MandolineSlicer(SkPoint anchorPt) { fPath.setFillType(SkPath::kEvenOdd_FillType); fPath.setIsVolatile(true); this->reset(anchorPt); } void reset(SkPoint anchorPt) { fPath.reset(); fLastPt = fAnchorPt = anchorPt; } void sliceLine(SkPoint pt, int numSubdivisions = kDefaultSubdivisions) { if (numSubdivisions <= 0) { fPath.moveTo(fAnchorPt); fPath.lineTo(fLastPt); fPath.lineTo(pt); fPath.close(); fLastPt = pt; return; } float T = this->chooseChopT(numSubdivisions); if (0 == T) { return; } SkPoint midpt = fLastPt * (1 - T) + pt * T; this->sliceLine(midpt, numSubdivisions - 1); this->sliceLine(pt, numSubdivisions - 1); } void sliceQuadratic(SkPoint p1, SkPoint p2, int numSubdivisions = kDefaultSubdivisions) { if (numSubdivisions <= 0) { fPath.moveTo(fAnchorPt); fPath.lineTo(fLastPt); fPath.quadTo(p1, p2); fPath.close(); fLastPt = p2; return; } float T = this->chooseChopT(numSubdivisions); if (0 == T) { return; } SkPoint P[3] = {fLastPt, p1, p2}, PP[5]; SkChopQuadAt(P, PP, T); this->sliceQuadratic(PP[1], PP[2], numSubdivisions - 1); this->sliceQuadratic(PP[3], PP[4], numSubdivisions - 1); } void sliceCubic(SkPoint p1, SkPoint p2, SkPoint p3, int numSubdivisions = kDefaultSubdivisions) { if (numSubdivisions <= 0) { fPath.moveTo(fAnchorPt); fPath.lineTo(fLastPt); fPath.cubicTo(p1, p2, p3); fPath.close(); fLastPt = p3; return; } float T = this->chooseChopT(numSubdivisions); if (0 == T) { return; } SkPoint P[4] = {fLastPt, p1, p2, p3}, PP[7]; SkChopCubicAt(P, PP, T); this->sliceCubic(PP[1], PP[2], PP[3], numSubdivisions - 1); this->sliceCubic(PP[4], PP[5], PP[6], numSubdivisions - 1); } void sliceConic(SkPoint p1, SkPoint p2, float w, int numSubdivisions = kDefaultSubdivisions) { if (numSubdivisions <= 0) { fPath.moveTo(fAnchorPt); fPath.lineTo(fLastPt); fPath.conicTo(p1, p2, w); fPath.close(); fLastPt = p2; return; } float T = this->chooseChopT(numSubdivisions); if (0 == T) { return; } SkConic conic(fLastPt, p1, p2, w), halves[2]; if (!conic.chopAt(T, halves)) { SK_ABORT("SkConic::chopAt failed"); } this->sliceConic(halves[0].fPts[1], halves[0].fPts[2], halves[0].fW, numSubdivisions - 1); this->sliceConic(halves[1].fPts[1], halves[1].fPts[2], halves[1].fW, numSubdivisions - 1); } const SkPath& path() const { return fPath; } private: float chooseChopT(int numSubdivisions) { SkASSERT(numSubdivisions > 0); if (numSubdivisions > 1) { return .5f; } float T = (0 == fRand.nextU() % 10) ? 0 : scalbnf(1, -(int)fRand.nextRangeU(10, 149)); SkASSERT(T >= 0 && T < 1); return T; } SkRandom fRand; SkPath fPath; SkPoint fAnchorPt; SkPoint fLastPt; }; class SliverPathsGM : public GM { public: SliverPathsGM() { this->setBGColor(SK_ColorBLACK); } protected: SkString onShortName() override { return SkString("mandoline"); } SkISize onISize() override { return SkISize::Make(560, 475); } void onDraw(SkCanvas* canvas) override { SkPaint paint; paint.setColor(SK_ColorWHITE); paint.setAntiAlias(true); MandolineSlicer mandoline({41, 43}); mandoline.sliceCubic({5, 277}, {381, -74}, {243, 162}); mandoline.sliceLine({41, 43}); canvas->drawPath(mandoline.path(), paint); mandoline.reset({357.049988f, 446.049988f}); mandoline.sliceCubic({472.750000f, -71.950012f}, {639.750000f, 531.950012f}, {309.049988f, 347.950012f}); mandoline.sliceLine({309.049988f, 419}); mandoline.sliceLine({357.049988f, 446.049988f}); canvas->drawPath(mandoline.path(), paint); canvas->save(); canvas->translate(421, 105); canvas->scale(100, 81); mandoline.reset({-cosf(SkDegreesToRadians(-60)), sinf(SkDegreesToRadians(-60))}); mandoline.sliceConic({-2, 0}, {-cosf(SkDegreesToRadians(60)), sinf(SkDegreesToRadians(60))}, .5f); mandoline.sliceConic({-cosf(SkDegreesToRadians(120))*2, sinf(SkDegreesToRadians(120))*2}, {1, 0}, .5f); mandoline.sliceLine({0, 0}); mandoline.sliceLine({-cosf(SkDegreesToRadians(-60)), sinf(SkDegreesToRadians(-60))}); canvas->drawPath(mandoline.path(), paint); canvas->restore(); canvas->save(); canvas->translate(150, 300); canvas->scale(75, 75); mandoline.reset({1, 0}); constexpr int nquads = 5; for (int i = 0; i < nquads; ++i) { float theta1 = 2*SK_ScalarPI/nquads * (i + .5f); float theta2 = 2*SK_ScalarPI/nquads * (i + 1); mandoline.sliceQuadratic({cosf(theta1)*2, sinf(theta1)*2}, {cosf(theta2), sinf(theta2)}); } canvas->drawPath(mandoline.path(), paint); canvas->restore(); } }; DEF_GM(return new SliverPathsGM;) }