| /* |
| * 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 "src/base/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: |
| inline static constexpr int kDefaultSubdivisions = 10; |
| |
| MandolineSlicer(SkPoint anchorPt) { |
| fPath.setFillType(SkPathFillType::kEvenOdd); |
| 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 getName() const override { return SkString("mandoline"); } |
| |
| SkISize getISize() 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;) |
| |
| } // namespace skiagm |