src/pathops/SkIntersections.h - skia - Git at Google

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkIntersections_DEFINE
 #define SkIntersections_DEFINE

 #include "SkPathOpsConic.h"
 #include "SkPathOpsCubic.h"
 #include "SkPathOpsLine.h"
 #include "SkPathOpsPoint.h"
 #include "SkPathOpsQuad.h"

 class SkIntersections {
 public:
     SkIntersections(SkDEBUGCODE(SkOpGlobalState* globalState = nullptr))
         : fSwap(0)
 #ifdef SK_DEBUG
         SkDEBUGPARAMS(fDebugGlobalState(globalState))
         , fDepth(0)
 #endif
     {
         sk_bzero(fPt, sizeof(fPt));
         sk_bzero(fPt2, sizeof(fPt2));
         sk_bzero(fT, sizeof(fT));
         sk_bzero(fNearlySame, sizeof(fNearlySame));
 #if DEBUG_T_SECT_LOOP_COUNT
         sk_bzero(fDebugLoopCount, sizeof(fDebugLoopCount));
 #endif
         reset();
         fMax = 0;  // require that the caller set the max
     }

     class TArray {
     public:
         explicit TArray(const double ts[10]) : fTArray(ts) {}
         double operator[](int n) const {
             return fTArray[n];
         }
         const double* fTArray;
     };
     TArray operator[](int n) const { return TArray(fT[n]); }

     void allowNear(bool nearAllowed) {
         fAllowNear = nearAllowed;
     }

     void clearCoincidence(int index) {
         SkASSERT(index >= 0);
         int bit = 1 << index;
         fIsCoincident[0] &= ~bit;
         fIsCoincident[1] &= ~bit;
     }

     int conicHorizontal(const SkPoint a[3], SkScalar weight, SkScalar left, SkScalar right,
                 SkScalar y, bool flipped) {
         SkDConic conic;
         conic.set(a, weight);
         fMax = 2;
         return horizontal(conic, left, right, y, flipped);
     }

     int conicVertical(const SkPoint a[3], SkScalar weight, SkScalar top, SkScalar bottom,
             SkScalar x, bool flipped) {
         SkDConic conic;
         conic.set(a, weight);
         fMax = 2;
         return vertical(conic, top, bottom, x, flipped);
     }

     int conicLine(const SkPoint a[3], SkScalar weight, const SkPoint b[2]) {
         SkDConic conic;
         conic.set(a, weight);
         SkDLine line;
         line.set(b);
         fMax = 3; // 2;  permit small coincident segment + non-coincident intersection
         return intersect(conic, line);
     }

     int cubicHorizontal(const SkPoint a[4], SkScalar left, SkScalar right, SkScalar y,
                         bool flipped) {
         SkDCubic cubic;
         cubic.set(a);
         fMax = 3;
         return horizontal(cubic, left, right, y, flipped);
     }

     int cubicVertical(const SkPoint a[4], SkScalar top, SkScalar bottom, SkScalar x, bool flipped) {
         SkDCubic cubic;
         cubic.set(a);
         fMax = 3;
         return vertical(cubic, top, bottom, x, flipped);
     }

     int cubicLine(const SkPoint a[4], const SkPoint b[2]) {
         SkDCubic cubic;
         cubic.set(a);
         SkDLine line;
         line.set(b);
         fMax = 3;
         return intersect(cubic, line);
     }

 #ifdef SK_DEBUG
     SkOpGlobalState* globalState() const { return fDebugGlobalState; }
 #endif

     bool hasT(double t) const {
         SkASSERT(t == 0 || t == 1);
         return fUsed > 0 && (t == 0 ? fT[0][0] == 0 : fT[0][fUsed - 1] == 1);
     }

     bool hasOppT(double t) const {
         SkASSERT(t == 0 || t == 1);
         return fUsed > 0 && (fT[1][0] == t || fT[1][fUsed - 1] == t);
     }

     int insertSwap(double one, double two, const SkDPoint& pt) {
         if (fSwap) {
             return insert(two, one, pt);
         } else {
             return insert(one, two, pt);
         }
     }

     bool isCoincident(int index) {
         return (fIsCoincident[0] & 1 << index) != 0;
     }

     int lineHorizontal(const SkPoint a[2], SkScalar left, SkScalar right, SkScalar y,
                        bool flipped) {
         SkDLine line;
         line.set(a);
         fMax = 2;
         return horizontal(line, left, right, y, flipped);
     }

     int lineVertical(const SkPoint a[2], SkScalar top, SkScalar bottom, SkScalar x, bool flipped) {
         SkDLine line;
         line.set(a);
         fMax = 2;
         return vertical(line, top, bottom, x, flipped);
     }

     int lineLine(const SkPoint a[2], const SkPoint b[2]) {
         SkDLine aLine, bLine;
         aLine.set(a);
         bLine.set(b);
         fMax = 2;
         return intersect(aLine, bLine);
     }

     bool nearlySame(int index) const {
         SkASSERT(index == 0 || index == 1);
         return fNearlySame[index];
     }

     const SkDPoint& pt(int index) const {
         return fPt[index];
     }

     const SkDPoint& pt2(int index) const {
         return fPt2[index];
     }

     int quadHorizontal(const SkPoint a[3], SkScalar left, SkScalar right, SkScalar y,
                        bool flipped) {
         SkDQuad quad;
         quad.set(a);
         fMax = 2;
         return horizontal(quad, left, right, y, flipped);
     }

     int quadVertical(const SkPoint a[3], SkScalar top, SkScalar bottom, SkScalar x, bool flipped) {
         SkDQuad quad;
         quad.set(a);
         fMax = 2;
         return vertical(quad, top, bottom, x, flipped);
     }

     int quadLine(const SkPoint a[3], const SkPoint b[2]) {
         SkDQuad quad;
         quad.set(a);
         SkDLine line;
         line.set(b);
         return intersect(quad, line);
     }

     // leaves swap, max alone
     void reset() {
         fAllowNear = true;
         fUsed = 0;
         sk_bzero(fIsCoincident, sizeof(fIsCoincident));
     }

     void set(bool swap, int tIndex, double t) {
         fT[(int) swap][tIndex] = t;
     }

     void setMax(int max) {
         SkASSERT(max <= (int) SK_ARRAY_COUNT(fPt));
         fMax = max;
     }

     void swap() {
         fSwap ^= true;
     }

     bool swapped() const {
         return fSwap;
     }

     int used() const {
         return fUsed;
     }

     void downDepth() {
         SkASSERT(--fDepth >= 0);
     }

     bool unBumpT(int index) {
         SkASSERT(fUsed == 1);
         fT[0][index] = fT[0][index] * (1 + BUMP_EPSILON * 2) - BUMP_EPSILON;
         if (!between(0, fT[0][index], 1)) {
             fUsed = 0;
             return false;
         }
         return true;
     }

     void upDepth() {
         SkASSERT(++fDepth < 16);
     }

     void alignQuadPts(const SkPoint a[3], const SkPoint b[3]);
     int cleanUpCoincidence();
     int closestTo(double rangeStart, double rangeEnd, const SkDPoint& testPt, double* dist) const;
     void cubicInsert(double one, double two, const SkDPoint& pt, const SkDCubic& c1,
                      const SkDCubic& c2);
     void flip();
     int horizontal(const SkDLine&, double left, double right, double y, bool flipped);
     int horizontal(const SkDQuad&, double left, double right, double y, bool flipped);
     int horizontal(const SkDQuad&, double left, double right, double y, double tRange[2]);
     int horizontal(const SkDCubic&, double y, double tRange[3]);
     int horizontal(const SkDConic&, double left, double right, double y, bool flipped);
     int horizontal(const SkDCubic&, double left, double right, double y, bool flipped);
     int horizontal(const SkDCubic&, double left, double right, double y, double tRange[3]);
     static double HorizontalIntercept(const SkDLine& line, double y);
     static int HorizontalIntercept(const SkDQuad& quad, SkScalar y, double* roots);
     static int HorizontalIntercept(const SkDConic& conic, SkScalar y, double* roots);
     // FIXME : does not respect swap
     int insert(double one, double two, const SkDPoint& pt);
     void insertNear(double one, double two, const SkDPoint& pt1, const SkDPoint& pt2);
     // start if index == 0 : end if index == 1
     int insertCoincident(double one, double two, const SkDPoint& pt);
     int intersect(const SkDLine&, const SkDLine&);
     int intersect(const SkDQuad&, const SkDLine&);
     int intersect(const SkDQuad&, const SkDQuad&);
     int intersect(const SkDConic&, const SkDLine&);
     int intersect(const SkDConic&, const SkDQuad&);
     int intersect(const SkDConic&, const SkDConic&);
     int intersect(const SkDCubic&, const SkDLine&);
     int intersect(const SkDCubic&, const SkDQuad&);
     int intersect(const SkDCubic&, const SkDConic&);
     int intersect(const SkDCubic&, const SkDCubic&);
     int intersectRay(const SkDLine&, const SkDLine&);
     int intersectRay(const SkDQuad&, const SkDLine&);
     int intersectRay(const SkDConic&, const SkDLine&);
     int intersectRay(const SkDCubic&, const SkDLine&);
     int intersectRay(const SkTCurve& tCurve, const SkDLine& line) {
         return tCurve.intersectRay(this, line);
     }

     void merge(const SkIntersections& , int , const SkIntersections& , int );
     int mostOutside(double rangeStart, double rangeEnd, const SkDPoint& origin) const;
     void removeOne(int index);
     void setCoincident(int index);
     int vertical(const SkDLine&, double top, double bottom, double x, bool flipped);
     int vertical(const SkDQuad&, double top, double bottom, double x, bool flipped);
     int vertical(const SkDConic&, double top, double bottom, double x, bool flipped);
     int vertical(const SkDCubic&, double top, double bottom, double x, bool flipped);
     static double VerticalIntercept(const SkDLine& line, double x);
     static int VerticalIntercept(const SkDQuad& quad, SkScalar x, double* roots);
     static int VerticalIntercept(const SkDConic& conic, SkScalar x, double* roots);

     int depth() const {
 #ifdef SK_DEBUG
         return fDepth;
 #else
         return 0;
 #endif
     }

     enum DebugLoop {
         kIterations_DebugLoop,
         kCoinCheck_DebugLoop,
         kComputePerp_DebugLoop,
     };

     void debugBumpLoopCount(DebugLoop );
     int debugCoincidentUsed() const;
     int debugLoopCount(DebugLoop ) const;
     void debugResetLoopCount();
     void dump() const;  // implemented for testing only

 private:
     bool cubicCheckCoincidence(const SkDCubic& c1, const SkDCubic& c2);
     bool cubicExactEnd(const SkDCubic& cubic1, bool start, const SkDCubic& cubic2);
     void cubicNearEnd(const SkDCubic& cubic1, bool start, const SkDCubic& cubic2, const SkDRect& );
     void cleanUpParallelLines(bool parallel);
     void computePoints(const SkDLine& line, int used);

     SkDPoint fPt[13];  // FIXME: since scans store points as SkPoint, this should also
     SkDPoint fPt2[2];  // used by nearly same to store alternate intersection point
     double fT[2][13];
     uint16_t fIsCoincident[2];  // bit set for each curve's coincident T
     bool fNearlySame[2];  // true if end points nearly match
     unsigned char fUsed;
     unsigned char fMax;
     bool fAllowNear;
     bool fSwap;
 #ifdef SK_DEBUG
     SkOpGlobalState* fDebugGlobalState;
     int fDepth;
 #endif
 #if DEBUG_T_SECT_LOOP_COUNT
     int fDebugLoopCount[3];
 #endif
 };

 #endif
	/*
	* Copyright 2012 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/
	#ifndef SkIntersections_DEFINE
	#define SkIntersections_DEFINE

	#include "SkPathOpsConic.h"
	#include "SkPathOpsCubic.h"
	#include "SkPathOpsLine.h"
	#include "SkPathOpsPoint.h"
	#include "SkPathOpsQuad.h"

	class SkIntersections {
	public:
	SkIntersections(SkDEBUGCODE(SkOpGlobalState* globalState = nullptr))
	: fSwap(0)
	#ifdef SK_DEBUG
	SkDEBUGPARAMS(fDebugGlobalState(globalState))
	, fDepth(0)
	#endif
	{
	sk_bzero(fPt, sizeof(fPt));
	sk_bzero(fPt2, sizeof(fPt2));
	sk_bzero(fT, sizeof(fT));
	sk_bzero(fNearlySame, sizeof(fNearlySame));
	#if DEBUG_T_SECT_LOOP_COUNT
	sk_bzero(fDebugLoopCount, sizeof(fDebugLoopCount));
	#endif
	reset();
	fMax = 0; // require that the caller set the max
	}

	class TArray {
	public:
	explicit TArray(const double ts[10]) : fTArray(ts) {}
	double operator[](int n) const {
	return fTArray[n];
	}
	const double* fTArray;
	};
	TArray operator[](int n) const { return TArray(fT[n]); }

	void allowNear(bool nearAllowed) {
	fAllowNear = nearAllowed;
	}

	void clearCoincidence(int index) {
	SkASSERT(index >= 0);
	int bit = 1 << index;
	fIsCoincident[0] &= ~bit;
	fIsCoincident[1] &= ~bit;
	}

	int conicHorizontal(const SkPoint a[3], SkScalar weight, SkScalar left, SkScalar right,
	SkScalar y, bool flipped) {
	SkDConic conic;
	conic.set(a, weight);
	fMax = 2;
	return horizontal(conic, left, right, y, flipped);
	}

	int conicVertical(const SkPoint a[3], SkScalar weight, SkScalar top, SkScalar bottom,
	SkScalar x, bool flipped) {
	SkDConic conic;
	conic.set(a, weight);
	fMax = 2;
	return vertical(conic, top, bottom, x, flipped);
	}

	int conicLine(const SkPoint a[3], SkScalar weight, const SkPoint b[2]) {
	SkDConic conic;
	conic.set(a, weight);
	SkDLine line;
	line.set(b);
	fMax = 3; // 2; permit small coincident segment + non-coincident intersection
	return intersect(conic, line);
	}

	int cubicHorizontal(const SkPoint a[4], SkScalar left, SkScalar right, SkScalar y,
	bool flipped) {
	SkDCubic cubic;
	cubic.set(a);
	fMax = 3;
	return horizontal(cubic, left, right, y, flipped);
	}

	int cubicVertical(const SkPoint a[4], SkScalar top, SkScalar bottom, SkScalar x, bool flipped) {
	SkDCubic cubic;
	cubic.set(a);
	fMax = 3;
	return vertical(cubic, top, bottom, x, flipped);
	}

	int cubicLine(const SkPoint a[4], const SkPoint b[2]) {
	SkDCubic cubic;
	cubic.set(a);
	SkDLine line;
	line.set(b);
	fMax = 3;
	return intersect(cubic, line);
	}

	#ifdef SK_DEBUG
	SkOpGlobalState* globalState() const { return fDebugGlobalState; }
	#endif

	bool hasT(double t) const {
	SkASSERT(t == 0 \|\| t == 1);
	return fUsed > 0 && (t == 0 ? fT[0][0] == 0 : fT[0][fUsed - 1] == 1);
	}

	bool hasOppT(double t) const {
	SkASSERT(t == 0 \|\| t == 1);
	return fUsed > 0 && (fT[1][0] == t \|\| fT[1][fUsed - 1] == t);
	}

	int insertSwap(double one, double two, const SkDPoint& pt) {
	if (fSwap) {
	return insert(two, one, pt);
	} else {
	return insert(one, two, pt);
	}
	}

	bool isCoincident(int index) {
	return (fIsCoincident[0] & 1 << index) != 0;
	}

	int lineHorizontal(const SkPoint a[2], SkScalar left, SkScalar right, SkScalar y,
	bool flipped) {
	SkDLine line;
	line.set(a);
	fMax = 2;
	return horizontal(line, left, right, y, flipped);
	}

	int lineVertical(const SkPoint a[2], SkScalar top, SkScalar bottom, SkScalar x, bool flipped) {
	SkDLine line;
	line.set(a);
	fMax = 2;
	return vertical(line, top, bottom, x, flipped);
	}

	int lineLine(const SkPoint a[2], const SkPoint b[2]) {
	SkDLine aLine, bLine;
	aLine.set(a);
	bLine.set(b);
	fMax = 2;
	return intersect(aLine, bLine);
	}

	bool nearlySame(int index) const {
	SkASSERT(index == 0 \|\| index == 1);
	return fNearlySame[index];
	}

	const SkDPoint& pt(int index) const {
	return fPt[index];
	}

	const SkDPoint& pt2(int index) const {
	return fPt2[index];
	}

	int quadHorizontal(const SkPoint a[3], SkScalar left, SkScalar right, SkScalar y,
	bool flipped) {
	SkDQuad quad;
	quad.set(a);
	fMax = 2;
	return horizontal(quad, left, right, y, flipped);
	}

	int quadVertical(const SkPoint a[3], SkScalar top, SkScalar bottom, SkScalar x, bool flipped) {
	SkDQuad quad;
	quad.set(a);
	fMax = 2;
	return vertical(quad, top, bottom, x, flipped);
	}

	int quadLine(const SkPoint a[3], const SkPoint b[2]) {
	SkDQuad quad;
	quad.set(a);
	SkDLine line;
	line.set(b);
	return intersect(quad, line);
	}

	// leaves swap, max alone
	void reset() {
	fAllowNear = true;
	fUsed = 0;
	sk_bzero(fIsCoincident, sizeof(fIsCoincident));
	}

	void set(bool swap, int tIndex, double t) {
	fT[(int) swap][tIndex] = t;
	}

	void setMax(int max) {
	SkASSERT(max <= (int) SK_ARRAY_COUNT(fPt));
	fMax = max;
	}

	void swap() {
	fSwap ^= true;
	}

	bool swapped() const {
	return fSwap;
	}

	int used() const {
	return fUsed;
	}

	void downDepth() {
	SkASSERT(--fDepth >= 0);
	}

	bool unBumpT(int index) {
	SkASSERT(fUsed == 1);
	fT[0][index] = fT[0][index] * (1 + BUMP_EPSILON * 2) - BUMP_EPSILON;
	if (!between(0, fT[0][index], 1)) {
	fUsed = 0;
	return false;
	}
	return true;
	}

	void upDepth() {
	SkASSERT(++fDepth < 16);
	}

	void alignQuadPts(const SkPoint a[3], const SkPoint b[3]);
	int cleanUpCoincidence();
	int closestTo(double rangeStart, double rangeEnd, const SkDPoint& testPt, double* dist) const;
	void cubicInsert(double one, double two, const SkDPoint& pt, const SkDCubic& c1,
	const SkDCubic& c2);
	void flip();
	int horizontal(const SkDLine&, double left, double right, double y, bool flipped);
	int horizontal(const SkDQuad&, double left, double right, double y, bool flipped);
	int horizontal(const SkDQuad&, double left, double right, double y, double tRange[2]);
	int horizontal(const SkDCubic&, double y, double tRange[3]);
	int horizontal(const SkDConic&, double left, double right, double y, bool flipped);
	int horizontal(const SkDCubic&, double left, double right, double y, bool flipped);
	int horizontal(const SkDCubic&, double left, double right, double y, double tRange[3]);
	static double HorizontalIntercept(const SkDLine& line, double y);
	static int HorizontalIntercept(const SkDQuad& quad, SkScalar y, double* roots);
	static int HorizontalIntercept(const SkDConic& conic, SkScalar y, double* roots);
	// FIXME : does not respect swap
	int insert(double one, double two, const SkDPoint& pt);
	void insertNear(double one, double two, const SkDPoint& pt1, const SkDPoint& pt2);
	// start if index == 0 : end if index == 1
	int insertCoincident(double one, double two, const SkDPoint& pt);
	int intersect(const SkDLine&, const SkDLine&);
	int intersect(const SkDQuad&, const SkDLine&);
	int intersect(const SkDQuad&, const SkDQuad&);
	int intersect(const SkDConic&, const SkDLine&);
	int intersect(const SkDConic&, const SkDQuad&);
	int intersect(const SkDConic&, const SkDConic&);
	int intersect(const SkDCubic&, const SkDLine&);
	int intersect(const SkDCubic&, const SkDQuad&);
	int intersect(const SkDCubic&, const SkDConic&);
	int intersect(const SkDCubic&, const SkDCubic&);
	int intersectRay(const SkDLine&, const SkDLine&);
	int intersectRay(const SkDQuad&, const SkDLine&);
	int intersectRay(const SkDConic&, const SkDLine&);
	int intersectRay(const SkDCubic&, const SkDLine&);
	int intersectRay(const SkTCurve& tCurve, const SkDLine& line) {
	return tCurve.intersectRay(this, line);
	}

	void merge(const SkIntersections& , int , const SkIntersections& , int );
	int mostOutside(double rangeStart, double rangeEnd, const SkDPoint& origin) const;
	void removeOne(int index);
	void setCoincident(int index);
	int vertical(const SkDLine&, double top, double bottom, double x, bool flipped);
	int vertical(const SkDQuad&, double top, double bottom, double x, bool flipped);
	int vertical(const SkDConic&, double top, double bottom, double x, bool flipped);
	int vertical(const SkDCubic&, double top, double bottom, double x, bool flipped);
	static double VerticalIntercept(const SkDLine& line, double x);
	static int VerticalIntercept(const SkDQuad& quad, SkScalar x, double* roots);
	static int VerticalIntercept(const SkDConic& conic, SkScalar x, double* roots);

	int depth() const {
	#ifdef SK_DEBUG
	return fDepth;
	#else
	return 0;
	#endif
	}

	enum DebugLoop {
	kIterations_DebugLoop,
	kCoinCheck_DebugLoop,
	kComputePerp_DebugLoop,
	};

	void debugBumpLoopCount(DebugLoop );
	int debugCoincidentUsed() const;
	int debugLoopCount(DebugLoop ) const;
	void debugResetLoopCount();
	void dump() const; // implemented for testing only

	private:
	bool cubicCheckCoincidence(const SkDCubic& c1, const SkDCubic& c2);
	bool cubicExactEnd(const SkDCubic& cubic1, bool start, const SkDCubic& cubic2);
	void cubicNearEnd(const SkDCubic& cubic1, bool start, const SkDCubic& cubic2, const SkDRect& );
	void cleanUpParallelLines(bool parallel);
	void computePoints(const SkDLine& line, int used);

	SkDPoint fPt[13]; // FIXME: since scans store points as SkPoint, this should also
	SkDPoint fPt2[2]; // used by nearly same to store alternate intersection point
	double fT[2][13];
	uint16_t fIsCoincident[2]; // bit set for each curve's coincident T
	bool fNearlySame[2]; // true if end points nearly match
	unsigned char fUsed;
	unsigned char fMax;
	bool fAllowNear;
	bool fSwap;
	#ifdef SK_DEBUG
	SkOpGlobalState* fDebugGlobalState;
	int fDepth;
	#endif
	#if DEBUG_T_SECT_LOOP_COUNT
	int fDebugLoopCount[3];
	#endif
	};

	#endif