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- /*
- * 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;)
- }
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