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assimp/contrib/clipper/clipper.cpp

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/*******************************************************************************
* *
* Author : Angus Johnson *
* Version : 4.8.8 *
* Date : 30 August 2012 *
* Website : http://www.angusj.com *
* Copyright : Angus Johnson 2010-2012 *
* *
* License: *
* Use, modification & distribution is subject to Boost Software License Ver 1. *
* http://www.boost.org/LICENSE_1_0.txt *
* *
* Attributions: *
* The code in this library is an extension of Bala Vatti's clipping algorithm: *
* "A generic solution to polygon clipping" *
* Communications of the ACM, Vol 35, Issue 7 (July 1992) pp 56-63. *
* http://portal.acm.org/citation.cfm?id=129906 *
* *
* Computer graphics and geometric modeling: implementation and algorithms *
* By Max K. Agoston *
* Springer; 1 edition (January 4, 2005) *
* http://books.google.com/books?q=vatti+clipping+agoston *
* *
* See also: *
* "Polygon Offsetting by Computing Winding Numbers" *
* Paper no. DETC2005-85513 pp. 565-575 *
* ASME 2005 International Design Engineering Technical Conferences *
* and Computers and Information in Engineering Conference (IDETC/CIE2005) *
* September 24-28, 2005 , Long Beach, California, USA *
* http://www.me.berkeley.edu/~mcmains/pubs/DAC05OffsetPolygon.pdf *
* *
*******************************************************************************/
/*******************************************************************************
* *
* This is a translation of the Delphi Clipper library and the naming style *
* used has retained a Delphi flavour. *
* *
*******************************************************************************/
#include "clipper.hpp"
#include <cmath>
#include <vector>
#include <algorithm>
#include <stdexcept>
#include <cstring>
#include <cstdlib>
#include <ostream>
namespace ClipperLib {
static long64 const loRange = 0x3FFFFFFF;
static long64 const hiRange = 0x3FFFFFFFFFFFFFFFLL;
static double const pi = 3.141592653589793238;
enum Direction { dRightToLeft, dLeftToRight };
#define HORIZONTAL (-1.0E+40)
#define TOLERANCE (1.0e-20)
#define NEAR_ZERO(val) (((val) > -TOLERANCE) && ((val) < TOLERANCE))
#define NEAR_EQUAL(a, b) NEAR_ZERO((a) - (b))
inline long64 Abs(long64 val)
{
return val < 0 ? -val : val;
}
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
// Int128 class (enables safe math on signed 64bit integers)
// eg Int128 val1((long64)9223372036854775807); //ie 2^63 -1
// Int128 val2((long64)9223372036854775807);
// Int128 val3 = val1 * val2;
// val3.AsString => "85070591730234615847396907784232501249" (8.5e+37)
//------------------------------------------------------------------------------
class Int128
{
public:
Int128(long64 _lo = 0)
{
lo = _lo;
if (lo < 0) hi = -1; else hi = 0;
}
Int128(const Int128 &val): hi(val.hi), lo(val.lo){}
long64 operator = (const long64 &val)
{
lo = val;
if (lo < 0) hi = -1; else hi = 0;
return val;
}
bool operator == (const Int128 &val) const
{return (hi == val.hi && lo == val.lo);}
bool operator != (const Int128 &val) const
{ return !(*this == val);}
bool operator > (const Int128 &val) const
{
if (hi != val.hi)
return hi > val.hi;
else
return lo > val.lo;
}
bool operator < (const Int128 &val) const
{
if (hi != val.hi)
return hi < val.hi;
else
return lo < val.lo;
}
bool operator >= (const Int128 &val) const
{ return !(*this < val);}
bool operator <= (const Int128 &val) const
{ return !(*this > val);}
Int128& operator += (const Int128 &rhs)
{
hi += rhs.hi;
lo += rhs.lo;
if (ulong64(lo) < ulong64(rhs.lo)) hi++;
return *this;
}
Int128 operator + (const Int128 &rhs) const
{
Int128 result(*this);
result+= rhs;
return result;
}
Int128& operator -= (const Int128 &rhs)
{
Int128 tmp(rhs);
Negate(tmp);
*this += tmp;
return *this;
}
//Int128 operator -() const
//{
// Int128 result(*this);
// if (result.lo == 0) {
// if (result.hi != 0) result.hi = -1;
// }
// else {
// result.lo = -result.lo;
// result.hi = ~result.hi;
// }
// return result;
//}
Int128 operator - (const Int128 &rhs) const
{
Int128 result(*this);
result -= rhs;
return result;
}
Int128 operator * (const Int128 &rhs) const
{
if ( !(hi == 0 || hi == -1) || !(rhs.hi == 0 || rhs.hi == -1))
throw "Int128 operator*: overflow error";
bool negate = (hi < 0) != (rhs.hi < 0);
Int128 tmp(*this);
if (tmp.hi < 0) Negate(tmp);
ulong64 int1Hi = ulong64(tmp.lo) >> 32;
ulong64 int1Lo = ulong64(tmp.lo & 0xFFFFFFFF);
tmp = rhs;
if (tmp.hi < 0) Negate(tmp);
ulong64 int2Hi = ulong64(tmp.lo) >> 32;
ulong64 int2Lo = ulong64(tmp.lo & 0xFFFFFFFF);
//nb: see comments in clipper.pas
ulong64 a = int1Hi * int2Hi;
ulong64 b = int1Lo * int2Lo;
ulong64 c = int1Hi * int2Lo + int1Lo * int2Hi;
tmp.hi = long64(a + (c >> 32));
tmp.lo = long64(c << 32);
tmp.lo += long64(b);
if (ulong64(tmp.lo) < b) tmp.hi++;
if (negate) Negate(tmp);
return tmp;
}
Int128 operator/ (const Int128 &rhs) const
{
if (rhs.lo == 0 && rhs.hi == 0)
throw "Int128 operator/: divide by zero";
bool negate = (rhs.hi < 0) != (hi < 0);
Int128 result(*this), denom(rhs);
if (result.hi < 0) Negate(result);
if (denom.hi < 0) Negate(denom);
if (denom > result) return Int128(0); //result is only a fraction of 1
Negate(denom);
Int128 p(0);
for (int i = 0; i < 128; ++i)
{
p.hi = p.hi << 1;
if (p.lo < 0) p.hi++;
p.lo = long64(p.lo) << 1;
if (result.hi < 0) p.lo++;
result.hi = result.hi << 1;
if (result.lo < 0) result.hi++;
result.lo = long64(result.lo) << 1;
Int128 p2(p);
p += denom;
if (p.hi < 0) p = p2;
else result.lo++;
}
if (negate) Negate(result);
return result;
}
double AsDouble() const
{
const double shift64 = 18446744073709551616.0; //2^64
const double bit64 = 9223372036854775808.0;
if (hi < 0)
{
Int128 tmp(*this);
Negate(tmp);
if (tmp.lo < 0)
return (double)tmp.lo - bit64 - tmp.hi * shift64;
else
return -(double)tmp.lo - tmp.hi * shift64;
}
else if (lo < 0)
return -(double)lo + bit64 + hi * shift64;
else
return (double)lo + (double)hi * shift64;
}
//for bug testing ...
//std::string AsString() const
//{
// std::string result;
// unsigned char r = 0;
// Int128 tmp(0), val(*this);
// if (hi < 0) Negate(val);
// result.resize(50);
// std::string::size_type i = result.size() -1;
// while (val.hi != 0 || val.lo != 0)
// {
// Div10(val, tmp, r);
// result[i--] = char('0' + r);
// val = tmp;
// }
// if (hi < 0) result[i--] = '-';
// result.erase(0,i+1);
// if (result.size() == 0) result = "0";
// return result;
//}
private:
long64 hi;
long64 lo;
static void Negate(Int128 &val)
{
if (val.lo == 0) {
if (val.hi != 0) val.hi = -val.hi;;
}
else {
val.lo = -val.lo;
val.hi = ~val.hi;
}
}
//debugging only ...
//void Div10(const Int128 val, Int128& result, unsigned char & remainder) const
//{
// remainder = 0;
// result = 0;
// for (int i = 63; i >= 0; --i)
// {
// if ((val.hi & ((long64)1 << i)) != 0)
// remainder = char((remainder * 2) + 1); else
// remainder *= char(2);
// if (remainder >= 10)
// {
// result.hi += ((long64)1 << i);
// remainder -= char(10);
// }
// }
// for (int i = 63; i >= 0; --i)
// {
// if ((val.lo & ((long64)1 << i)) != 0)
// remainder = char((remainder * 2) + 1); else
// remainder *= char(2);
// if (remainder >= 10)
// {
// result.lo += ((long64)1 << i);
// remainder -= char(10);
// }
// }
//}
};
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
bool FullRangeNeeded(const Polygon &pts)
{
bool result = false;
for (Polygon::size_type i = 0; i < pts.size(); ++i)
{
if (Abs(pts[i].X) > hiRange || Abs(pts[i].Y) > hiRange)
throw "Coordinate exceeds range bounds.";
else if (Abs(pts[i].X) > loRange || Abs(pts[i].Y) > loRange)
result = true;
}
return result;
}
//------------------------------------------------------------------------------
bool Orientation(const Polygon &poly)
{
int highI = (int)poly.size() -1;
if (highI < 2) return false;
int j = 0, jplus, jminus;
for (int i = 0; i <= highI; ++i)
{
if (poly[i].Y < poly[j].Y) continue;
if ((poly[i].Y > poly[j].Y || poly[i].X < poly[j].X)) j = i;
};
if (j == highI) jplus = 0;
else jplus = j +1;
if (j == 0) jminus = highI;
else jminus = j -1;
IntPoint vec1, vec2;
//get cross product of vectors of the edges adjacent to highest point ...
vec1.X = poly[j].X - poly[jminus].X;
vec1.Y = poly[j].Y - poly[jminus].Y;
vec2.X = poly[jplus].X - poly[j].X;
vec2.Y = poly[jplus].Y - poly[j].Y;
if (Abs(vec1.X) > loRange || Abs(vec1.Y) > loRange ||
Abs(vec2.X) > loRange || Abs(vec2.Y) > loRange)
{
if (Abs(vec1.X) > hiRange || Abs(vec1.Y) > hiRange ||
Abs(vec2.X) > hiRange || Abs(vec2.Y) > hiRange)
throw "Coordinate exceeds range bounds.";
Int128 cross = Int128(vec1.X) * Int128(vec2.Y) -
Int128(vec2.X) * Int128(vec1.Y);
return cross >= 0;
}
else
return (vec1.X * vec2.Y - vec2.X * vec1.Y) >= 0;
}
//------------------------------------------------------------------------------
inline bool PointsEqual( const IntPoint &pt1, const IntPoint &pt2)
{
return ( pt1.X == pt2.X && pt1.Y == pt2.Y );
}
//------------------------------------------------------------------------------
bool Orientation(OutRec *outRec, bool UseFullInt64Range)
{
//first make sure bottomPt is correctly assigned ...
OutPt *opBottom = outRec->pts, *op = outRec->pts->next;
while (op != outRec->pts)
{
if (op->pt.Y >= opBottom->pt.Y)
{
if (op->pt.Y > opBottom->pt.Y || op->pt.X < opBottom->pt.X)
opBottom = op;
}
op = op->next;
}
outRec->bottomPt = opBottom;
opBottom->idx = outRec->idx;
op = opBottom;
//find vertices either side of bottomPt (skipping duplicate points) ....
OutPt *opPrev = op->prev;
OutPt *opNext = op->next;
while (op != opPrev && PointsEqual(op->pt, opPrev->pt))
opPrev = opPrev->prev;
while (op != opNext && PointsEqual(op->pt, opNext->pt))
opNext = opNext->next;
IntPoint ip1, ip2;
ip1.X = op->pt.X - opPrev->pt.X;
ip1.Y = op->pt.Y - opPrev->pt.Y;
ip2.X = opNext->pt.X - op->pt.X;
ip2.Y = opNext->pt.Y - op->pt.Y;
if (UseFullInt64Range)
return Int128(ip1.X) * Int128(ip2.Y) - Int128(ip2.X) * Int128(ip1.Y) >= 0;
else
return (ip1.X * ip2.Y - ip2.X * ip1.Y) >= 0;
}
//------------------------------------------------------------------------------
double Area(const Polygon &poly)
{
int highI = (int)poly.size() -1;
if (highI < 2) return 0;
if (FullRangeNeeded(poly)) {
Int128 a;
a = (Int128(poly[highI].X) * Int128(poly[0].Y)) -
Int128(poly[0].X) * Int128(poly[highI].Y);
for (int i = 0; i < highI; ++i)
a += Int128(poly[i].X) * Int128(poly[i+1].Y) -
Int128(poly[i+1].X) * Int128(poly[i].Y);
return a.AsDouble() / 2;
}
else
{
double a;
a = (double)poly[highI].X * poly[0].Y - (double)poly[0].X * poly[highI].Y;
for (int i = 0; i < highI; ++i)
a += (double)poly[i].X * poly[i+1].Y - (double)poly[i+1].X * poly[i].Y;
return a/2;
}
}
//------------------------------------------------------------------------------
double Area(const OutRec &outRec, bool UseFullInt64Range)
{
OutPt *op = outRec.pts;
if (UseFullInt64Range) {
Int128 a(0);
do {
a += (Int128(op->prev->pt.X) * Int128(op->pt.Y)) -
Int128(op->pt.X) * Int128(op->prev->pt.Y);
op = op->next;
} while (op != outRec.pts);
return a.AsDouble() / 2;
}
else
{
double a = 0;
do {
a += (op->prev->pt.X * op->pt.Y) - (op->pt.X * op->prev->pt.Y);
op = op->next;
} while (op != outRec.pts);
return a/2;
}
}
//------------------------------------------------------------------------------
bool PointIsVertex(const IntPoint &pt, OutPt *pp)
{
OutPt *pp2 = pp;
do
{
if (PointsEqual(pp2->pt, pt)) return true;
pp2 = pp2->next;
}
while (pp2 != pp);
return false;
}
//------------------------------------------------------------------------------
bool PointInPolygon(const IntPoint &pt, OutPt *pp, bool UseFullInt64Range)
{
OutPt *pp2 = pp;
bool result = false;
if (UseFullInt64Range) {
do
{
if ((((pp2->pt.Y <= pt.Y) && (pt.Y < pp2->prev->pt.Y)) ||
((pp2->prev->pt.Y <= pt.Y) && (pt.Y < pp2->pt.Y))) &&
Int128(pt.X - pp2->pt.X) < (Int128(pp2->prev->pt.X - pp2->pt.X) *
Int128(pt.Y - pp2->pt.Y)) / Int128(pp2->prev->pt.Y - pp2->pt.Y))
result = !result;
pp2 = pp2->next;
}
while (pp2 != pp);
}
else
{
do
{
if ((((pp2->pt.Y <= pt.Y) && (pt.Y < pp2->prev->pt.Y)) ||
((pp2->prev->pt.Y <= pt.Y) && (pt.Y < pp2->pt.Y))) &&
(pt.X < (pp2->prev->pt.X - pp2->pt.X) * (pt.Y - pp2->pt.Y) /
(pp2->prev->pt.Y - pp2->pt.Y) + pp2->pt.X )) result = !result;
pp2 = pp2->next;
}
while (pp2 != pp);
}
return result;
}
//------------------------------------------------------------------------------
bool SlopesEqual(TEdge &e1, TEdge &e2, bool UseFullInt64Range)
{
if (UseFullInt64Range)
return Int128(e1.ytop - e1.ybot) * Int128(e2.xtop - e2.xbot) ==
Int128(e1.xtop - e1.xbot) * Int128(e2.ytop - e2.ybot);
else return (e1.ytop - e1.ybot)*(e2.xtop - e2.xbot) ==
(e1.xtop - e1.xbot)*(e2.ytop - e2.ybot);
}
//------------------------------------------------------------------------------
bool SlopesEqual(const IntPoint pt1, const IntPoint pt2,
const IntPoint pt3, bool UseFullInt64Range)
{
if (UseFullInt64Range)
return Int128(pt1.Y-pt2.Y) * Int128(pt2.X-pt3.X) ==
Int128(pt1.X-pt2.X) * Int128(pt2.Y-pt3.Y);
else return (pt1.Y-pt2.Y)*(pt2.X-pt3.X) == (pt1.X-pt2.X)*(pt2.Y-pt3.Y);
}
//------------------------------------------------------------------------------
bool SlopesEqual(const IntPoint pt1, const IntPoint pt2,
const IntPoint pt3, const IntPoint pt4, bool UseFullInt64Range)
{
if (UseFullInt64Range)
return Int128(pt1.Y-pt2.Y) * Int128(pt3.X-pt4.X) ==
Int128(pt1.X-pt2.X) * Int128(pt3.Y-pt4.Y);
else return (pt1.Y-pt2.Y)*(pt3.X-pt4.X) == (pt1.X-pt2.X)*(pt3.Y-pt4.Y);
}
//------------------------------------------------------------------------------
double GetDx(const IntPoint pt1, const IntPoint pt2)
{
return (pt1.Y == pt2.Y) ?
HORIZONTAL : (double)(pt2.X - pt1.X) / (double)(pt2.Y - pt1.Y);
}
//---------------------------------------------------------------------------
void SetDx(TEdge &e)
{
if (e.ybot == e.ytop) e.dx = HORIZONTAL;
else e.dx = (double)(e.xtop - e.xbot) / (double)(e.ytop - e.ybot);
}
//---------------------------------------------------------------------------
void SwapSides(TEdge &edge1, TEdge &edge2)
{
EdgeSide side = edge1.side;
edge1.side = edge2.side;
edge2.side = side;
}
//------------------------------------------------------------------------------
void SwapPolyIndexes(TEdge &edge1, TEdge &edge2)
{
int outIdx = edge1.outIdx;
edge1.outIdx = edge2.outIdx;
edge2.outIdx = outIdx;
}
//------------------------------------------------------------------------------
inline long64 Round(double val)
{
return (val < 0) ?
static_cast<long64>(val - 0.5) : static_cast<long64>(val + 0.5);
}
//------------------------------------------------------------------------------
long64 TopX(TEdge &edge, const long64 currentY)
{
return ( currentY == edge.ytop ) ?
edge.xtop : edge.xbot + Round(edge.dx *(currentY - edge.ybot));
}
//------------------------------------------------------------------------------
long64 TopX(const IntPoint pt1, const IntPoint pt2, const long64 currentY)
{
//preconditions: pt1.Y <> pt2.Y and pt1.Y > pt2.Y
if (currentY >= pt1.Y) return pt1.X;
else if (currentY == pt2.Y) return pt2.X;
else if (pt1.X == pt2.X) return pt1.X;
else
{
double q = (double)(pt1.X-pt2.X)/(double)(pt1.Y-pt2.Y);
return Round(pt1.X + (currentY - pt1.Y) *q);
}
}
//------------------------------------------------------------------------------
bool IntersectPoint(TEdge &edge1, TEdge &edge2,
IntPoint &ip, bool UseFullInt64Range)
{
double b1, b2;
if (SlopesEqual(edge1, edge2, UseFullInt64Range)) return false;
else if (NEAR_ZERO(edge1.dx))
{
ip.X = edge1.xbot;
if (NEAR_EQUAL(edge2.dx, HORIZONTAL))
{
ip.Y = edge2.ybot;
} else
{
b2 = edge2.ybot - (edge2.xbot/edge2.dx);
ip.Y = Round(ip.X/edge2.dx + b2);
}
}
else if (NEAR_ZERO(edge2.dx))
{
ip.X = edge2.xbot;
if (NEAR_EQUAL(edge1.dx, HORIZONTAL))
{
ip.Y = edge1.ybot;
} else
{
b1 = edge1.ybot - (edge1.xbot/edge1.dx);
ip.Y = Round(ip.X/edge1.dx + b1);
}
} else
{
b1 = edge1.xbot - edge1.ybot * edge1.dx;
b2 = edge2.xbot - edge2.ybot * edge2.dx;
b2 = (b2-b1)/(edge1.dx - edge2.dx);
ip.Y = Round(b2);
ip.X = Round(edge1.dx * b2 + b1);
}
return
//can be *so close* to the top of one edge that the rounded Y equals one ytop ...
(ip.Y == edge1.ytop && ip.Y >= edge2.ytop && edge1.tmpX > edge2.tmpX) ||
(ip.Y == edge2.ytop && ip.Y >= edge1.ytop && edge1.tmpX > edge2.tmpX) ||
(ip.Y > edge1.ytop && ip.Y > edge2.ytop);
}
//------------------------------------------------------------------------------
void ReversePolyPtLinks(OutPt &pp)
{
OutPt *pp1, *pp2;
pp1 = &pp;
do {
pp2 = pp1->next;
pp1->next = pp1->prev;
pp1->prev = pp2;
pp1 = pp2;
} while( pp1 != &pp );
}
//------------------------------------------------------------------------------
void DisposeOutPts(OutPt*& pp)
{
if (pp == 0) return;
pp->prev->next = 0;
while( pp )
{
OutPt *tmpPp = pp;
pp = pp->next;
delete tmpPp ;
}
}
//------------------------------------------------------------------------------
void InitEdge(TEdge *e, TEdge *eNext,
TEdge *ePrev, const IntPoint &pt, PolyType polyType)
{
std::memset( e, 0, sizeof( TEdge ));
e->next = eNext;
e->prev = ePrev;
e->xcurr = pt.X;
e->ycurr = pt.Y;
if (e->ycurr >= e->next->ycurr)
{
e->xbot = e->xcurr;
e->ybot = e->ycurr;
e->xtop = e->next->xcurr;
e->ytop = e->next->ycurr;
e->windDelta = 1;
} else
{
e->xtop = e->xcurr;
e->ytop = e->ycurr;
e->xbot = e->next->xcurr;
e->ybot = e->next->ycurr;
e->windDelta = -1;
}
SetDx(*e);
e->polyType = polyType;
e->outIdx = -1;
}
//------------------------------------------------------------------------------
inline void SwapX(TEdge &e)
{
//swap horizontal edges' top and bottom x's so they follow the natural
//progression of the bounds - ie so their xbots will align with the
//adjoining lower edge. [Helpful in the ProcessHorizontal() method.]
e.xcurr = e.xtop;
e.xtop = e.xbot;
e.xbot = e.xcurr;
}
//------------------------------------------------------------------------------
void SwapPoints(IntPoint &pt1, IntPoint &pt2)
{
IntPoint tmp = pt1;
pt1 = pt2;
pt2 = tmp;
}
//------------------------------------------------------------------------------
bool GetOverlapSegment(IntPoint pt1a, IntPoint pt1b, IntPoint pt2a,
IntPoint pt2b, IntPoint &pt1, IntPoint &pt2)
{
//precondition: segments are colinear.
if ( pt1a.Y == pt1b.Y || Abs((pt1a.X - pt1b.X)/(pt1a.Y - pt1b.Y)) > 1 )
{
if (pt1a.X > pt1b.X) SwapPoints(pt1a, pt1b);
if (pt2a.X > pt2b.X) SwapPoints(pt2a, pt2b);
if (pt1a.X > pt2a.X) pt1 = pt1a; else pt1 = pt2a;
if (pt1b.X < pt2b.X) pt2 = pt1b; else pt2 = pt2b;
return pt1.X < pt2.X;
} else
{
if (pt1a.Y < pt1b.Y) SwapPoints(pt1a, pt1b);
if (pt2a.Y < pt2b.Y) SwapPoints(pt2a, pt2b);
if (pt1a.Y < pt2a.Y) pt1 = pt1a; else pt1 = pt2a;
if (pt1b.Y > pt2b.Y) pt2 = pt1b; else pt2 = pt2b;
return pt1.Y > pt2.Y;
}
}
//------------------------------------------------------------------------------
bool FirstIsBottomPt(const OutPt* btmPt1, const OutPt* btmPt2)
{
OutPt *p = btmPt1->prev;
while (PointsEqual(p->pt, btmPt1->pt) && (p != btmPt1)) p = p->prev;
double dx1p = std::fabs(GetDx(btmPt1->pt, p->pt));
p = btmPt1->next;
while (PointsEqual(p->pt, btmPt1->pt) && (p != btmPt1)) p = p->next;
double dx1n = std::fabs(GetDx(btmPt1->pt, p->pt));
p = btmPt2->prev;
while (PointsEqual(p->pt, btmPt2->pt) && (p != btmPt2)) p = p->prev;
double dx2p = std::fabs(GetDx(btmPt2->pt, p->pt));
p = btmPt2->next;
while (PointsEqual(p->pt, btmPt2->pt) && (p != btmPt2)) p = p->next;
double dx2n = std::fabs(GetDx(btmPt2->pt, p->pt));
return (dx1p >= dx2p && dx1p >= dx2n) || (dx1n >= dx2p && dx1n >= dx2n);
}
//------------------------------------------------------------------------------
OutPt* GetBottomPt(OutPt *pp)
{
OutPt* dups = 0;
OutPt* p = pp->next;
while (p != pp)
{
if (p->pt.Y > pp->pt.Y)
{
pp = p;
dups = 0;
}
else if (p->pt.Y == pp->pt.Y && p->pt.X <= pp->pt.X)
{
if (p->pt.X < pp->pt.X)
{
dups = 0;
pp = p;
} else
{
if (p->next != pp && p->prev != pp) dups = p;
}
}
p = p->next;
}
if (dups)
{
//there appears to be at least 2 vertices at bottomPt so ...
while (dups != p)
{
if (!FirstIsBottomPt(p, dups)) pp = dups;
dups = dups->next;
while (!PointsEqual(dups->pt, pp->pt)) dups = dups->next;
}
}
return pp;
}
//------------------------------------------------------------------------------
bool FindSegment(OutPt* &pp, IntPoint &pt1, IntPoint &pt2)
{
//outPt1 & outPt2 => the overlap segment (if the function returns true)
if (!pp) return false;
OutPt* pp2 = pp;
IntPoint pt1a = pt1, pt2a = pt2;
do
{
if (SlopesEqual(pt1a, pt2a, pp->pt, pp->prev->pt, true) &&
SlopesEqual(pt1a, pt2a, pp->pt, true) &&
GetOverlapSegment(pt1a, pt2a, pp->pt, pp->prev->pt, pt1, pt2))
return true;
pp = pp->next;
}
while (pp != pp2);
return false;
}
//------------------------------------------------------------------------------
bool Pt3IsBetweenPt1AndPt2(const IntPoint pt1,
const IntPoint pt2, const IntPoint pt3)
{
if (PointsEqual(pt1, pt3) || PointsEqual(pt2, pt3)) return true;
else if (pt1.X != pt2.X) return (pt1.X < pt3.X) == (pt3.X < pt2.X);
else return (pt1.Y < pt3.Y) == (pt3.Y < pt2.Y);
}
//------------------------------------------------------------------------------
OutPt* InsertPolyPtBetween(OutPt* p1, OutPt* p2, const IntPoint pt)
{
if (p1 == p2) throw "JoinError";
OutPt* result = new OutPt;
result->pt = pt;
if (p2 == p1->next)
{
p1->next = result;
p2->prev = result;
result->next = p2;
result->prev = p1;
} else
{
p2->next = result;
p1->prev = result;
result->next = p1;
result->prev = p2;
}
return result;
}
//------------------------------------------------------------------------------
// ClipperBase class methods ...
//------------------------------------------------------------------------------
ClipperBase::ClipperBase() //constructor
{
m_MinimaList = 0;
m_CurrentLM = 0;
m_UseFullRange = true;
}
//------------------------------------------------------------------------------
ClipperBase::~ClipperBase() //destructor
{
Clear();
}
//------------------------------------------------------------------------------
bool ClipperBase::AddPolygon( const Polygon &pg, PolyType polyType)
{
int len = (int)pg.size();
if (len < 3) return false;
Polygon p(len);
p[0] = pg[0];
int j = 0;
long64 maxVal;
if (m_UseFullRange) maxVal = hiRange; else maxVal = loRange;
for (int i = 0; i < len; ++i)
{
if (Abs(pg[i].X) > maxVal || Abs(pg[i].Y) > maxVal)
{
if (Abs(pg[i].X) > hiRange || Abs(pg[i].Y) > hiRange)
throw "Coordinate exceeds range bounds";
maxVal = hiRange;
m_UseFullRange = true;
}
if (i == 0 || PointsEqual(p[j], pg[i])) continue;
else if (j > 0 && SlopesEqual(p[j-1], p[j], pg[i], m_UseFullRange))
{
if (PointsEqual(p[j-1], pg[i])) j--;
} else j++;
p[j] = pg[i];
}
if (j < 2) return false;
len = j+1;
while (len > 2)
{
//nb: test for point equality before testing slopes ...
if (PointsEqual(p[j], p[0])) j--;
else if (PointsEqual(p[0], p[1]) ||
SlopesEqual(p[j], p[0], p[1], m_UseFullRange))
p[0] = p[j--];
else if (SlopesEqual(p[j-1], p[j], p[0], m_UseFullRange)) j--;
else if (SlopesEqual(p[0], p[1], p[2], m_UseFullRange))
{
for (int i = 2; i <= j; ++i) p[i-1] = p[i];
j--;
}
else break;
len--;
}
if (len < 3) return false;
//create a new edge array ...
TEdge *edges = new TEdge [len];
m_edges.push_back(edges);
//convert vertices to a double-linked-list of edges and initialize ...
edges[0].xcurr = p[0].X;
edges[0].ycurr = p[0].Y;
InitEdge(&edges[len-1], &edges[0], &edges[len-2], p[len-1], polyType);
for (int i = len-2; i > 0; --i)
InitEdge(&edges[i], &edges[i+1], &edges[i-1], p[i], polyType);
InitEdge(&edges[0], &edges[1], &edges[len-1], p[0], polyType);
//reset xcurr & ycurr and find 'eHighest' (given the Y axis coordinates
//increase downward so the 'highest' edge will have the smallest ytop) ...
TEdge *e = &edges[0];
TEdge *eHighest = e;
do
{
e->xcurr = e->xbot;
e->ycurr = e->ybot;
if (e->ytop < eHighest->ytop) eHighest = e;
e = e->next;
}
while ( e != &edges[0]);
//make sure eHighest is positioned so the following loop works safely ...
if (eHighest->windDelta > 0) eHighest = eHighest->next;
if (NEAR_EQUAL(eHighest->dx, HORIZONTAL)) eHighest = eHighest->next;
//finally insert each local minima ...
e = eHighest;
do {
e = AddBoundsToLML(e);
}
while( e != eHighest );
return true;
}
//------------------------------------------------------------------------------
void ClipperBase::InsertLocalMinima(LocalMinima *newLm)
{
if( ! m_MinimaList )
{
m_MinimaList = newLm;
}
else if( newLm->Y >= m_MinimaList->Y )
{
newLm->next = m_MinimaList;
m_MinimaList = newLm;
} else
{
LocalMinima* tmpLm = m_MinimaList;
while( tmpLm->next && ( newLm->Y < tmpLm->next->Y ) )
tmpLm = tmpLm->next;
newLm->next = tmpLm->next;
tmpLm->next = newLm;
}
}
//------------------------------------------------------------------------------
TEdge* ClipperBase::AddBoundsToLML(TEdge *e)
{
//Starting at the top of one bound we progress to the bottom where there's
//a local minima. We then go to the top of the next bound. These two bounds
//form the left and right (or right and left) bounds of the local minima.
e->nextInLML = 0;
e = e->next;
for (;;)
{
if (NEAR_EQUAL(e->dx, HORIZONTAL))
{
//nb: proceed through horizontals when approaching from their right,
// but break on horizontal minima if approaching from their left.
// This ensures 'local minima' are always on the left of horizontals.
if (e->next->ytop < e->ytop && e->next->xbot > e->prev->xbot) break;
if (e->xtop != e->prev->xbot) SwapX(*e);
e->nextInLML = e->prev;
}
else if (e->ycurr == e->prev->ycurr) break;
else e->nextInLML = e->prev;
e = e->next;
}
//e and e.prev are now at a local minima ...
LocalMinima* newLm = new LocalMinima;
newLm->next = 0;
newLm->Y = e->prev->ybot;
if ( NEAR_EQUAL(e->dx, HORIZONTAL) ) //horizontal edges never start a left bound
{
if (e->xbot != e->prev->xbot) SwapX(*e);
newLm->leftBound = e->prev;
newLm->rightBound = e;
} else if (e->dx < e->prev->dx)
{
newLm->leftBound = e->prev;
newLm->rightBound = e;
} else
{
newLm->leftBound = e;
newLm->rightBound = e->prev;
}
newLm->leftBound->side = esLeft;
newLm->rightBound->side = esRight;
InsertLocalMinima( newLm );
for (;;)
{
if ( e->next->ytop == e->ytop && !NEAR_EQUAL(e->next->dx, HORIZONTAL) ) break;
e->nextInLML = e->next;
e = e->next;
if ( NEAR_EQUAL(e->dx, HORIZONTAL) && e->xbot != e->prev->xtop) SwapX(*e);
}
return e->next;
}
//------------------------------------------------------------------------------
bool ClipperBase::AddPolygons(const Polygons &ppg, PolyType polyType)
{
bool result = false;
for (Polygons::size_type i = 0; i < ppg.size(); ++i)
if (AddPolygon(ppg[i], polyType)) result = true;
return result;
}
//------------------------------------------------------------------------------
void ClipperBase::Clear()
{
DisposeLocalMinimaList();
for (EdgeList::size_type i = 0; i < m_edges.size(); ++i) delete [] m_edges[i];
m_edges.clear();
m_UseFullRange = false;
}
//------------------------------------------------------------------------------
void ClipperBase::Reset()
{
m_CurrentLM = m_MinimaList;
if( !m_CurrentLM ) return; //ie nothing to process
//reset all edges ...
LocalMinima* lm = m_MinimaList;
while( lm )
{
TEdge* e = lm->leftBound;
while( e )
{
e->xcurr = e->xbot;
e->ycurr = e->ybot;
e->side = esLeft;
e->outIdx = -1;
e = e->nextInLML;
}
e = lm->rightBound;
while( e )
{
e->xcurr = e->xbot;
e->ycurr = e->ybot;
e->side = esRight;
e->outIdx = -1;
e = e->nextInLML;
}
lm = lm->next;
}
}
//------------------------------------------------------------------------------
void ClipperBase::DisposeLocalMinimaList()
{
while( m_MinimaList )
{
LocalMinima* tmpLm = m_MinimaList->next;
delete m_MinimaList;
m_MinimaList = tmpLm;
}
m_CurrentLM = 0;
}
//------------------------------------------------------------------------------
void ClipperBase::PopLocalMinima()
{
if( ! m_CurrentLM ) return;
m_CurrentLM = m_CurrentLM->next;
}
//------------------------------------------------------------------------------
IntRect ClipperBase::GetBounds()
{
IntRect result;
LocalMinima* lm = m_MinimaList;
if (!lm)
{
result.left = result.top = result.right = result.bottom = 0;
return result;
}
result.left = lm->leftBound->xbot;
result.top = lm->leftBound->ybot;
result.right = lm->leftBound->xbot;
result.bottom = lm->leftBound->ybot;
while (lm)
{
if (lm->leftBound->ybot > result.bottom)
result.bottom = lm->leftBound->ybot;
TEdge* e = lm->leftBound;
for (;;) {
TEdge* bottomE = e;
while (e->nextInLML)
{
if (e->xbot < result.left) result.left = e->xbot;
if (e->xbot > result.right) result.right = e->xbot;
e = e->nextInLML;
}
if (e->xbot < result.left) result.left = e->xbot;
if (e->xbot > result.right) result.right = e->xbot;
if (e->xtop < result.left) result.left = e->xtop;
if (e->xtop > result.right) result.right = e->xtop;
if (e->ytop < result.top) result.top = e->ytop;
if (bottomE == lm->leftBound) e = lm->rightBound;
else break;
}
lm = lm->next;
}
return result;
}
//------------------------------------------------------------------------------
// TClipper methods ...
//------------------------------------------------------------------------------
Clipper::Clipper() : ClipperBase() //constructor
{
m_Scanbeam = 0;
m_ActiveEdges = 0;
m_SortedEdges = 0;
m_IntersectNodes = 0;
m_ExecuteLocked = false;
m_UseFullRange = false;
m_ReverseOutput = false;
}
//------------------------------------------------------------------------------
Clipper::~Clipper() //destructor
{
Clear();
DisposeScanbeamList();
}
//------------------------------------------------------------------------------
void Clipper::Clear()
{
if (m_edges.size() == 0) return; //avoids problems with ClipperBase destructor
DisposeAllPolyPts();
ClipperBase::Clear();
}
//------------------------------------------------------------------------------
void Clipper::DisposeScanbeamList()
{
while ( m_Scanbeam ) {
Scanbeam* sb2 = m_Scanbeam->next;
delete m_Scanbeam;
m_Scanbeam = sb2;
}
}
//------------------------------------------------------------------------------
void Clipper::Reset()
{
ClipperBase::Reset();
m_Scanbeam = 0;
m_ActiveEdges = 0;
m_SortedEdges = 0;
DisposeAllPolyPts();
LocalMinima* lm = m_MinimaList;
while (lm)
{
InsertScanbeam(lm->Y);
InsertScanbeam(lm->leftBound->ytop);
lm = lm->next;
}
}
//------------------------------------------------------------------------------
bool Clipper::Execute(ClipType clipType, Polygons &solution,
PolyFillType subjFillType, PolyFillType clipFillType)
{
if( m_ExecuteLocked ) return false;
m_ExecuteLocked = true;
solution.resize(0);
m_SubjFillType = subjFillType;
m_ClipFillType = clipFillType;
m_ClipType = clipType;
bool succeeded = ExecuteInternal(false);
if (succeeded) BuildResult(solution);
m_ExecuteLocked = false;
return succeeded;
}
//------------------------------------------------------------------------------
bool Clipper::Execute(ClipType clipType, ExPolygons &solution,
PolyFillType subjFillType, PolyFillType clipFillType)
{
if( m_ExecuteLocked ) return false;
m_ExecuteLocked = true;
solution.resize(0);
m_SubjFillType = subjFillType;
m_ClipFillType = clipFillType;
m_ClipType = clipType;
bool succeeded = ExecuteInternal(true);
if (succeeded) BuildResultEx(solution);
m_ExecuteLocked = false;
return succeeded;
}
//------------------------------------------------------------------------------
bool PolySort(OutRec *or1, OutRec *or2)
{
if (or1 == or2) return false;
if (!or1->pts || !or2->pts)
{
if (or1->pts != or2->pts)
{
return or1->pts ? true : false;
}
else return false;
}
int i1, i2;
if (or1->isHole)
i1 = or1->FirstLeft->idx; else
i1 = or1->idx;
if (or2->isHole)
i2 = or2->FirstLeft->idx; else
i2 = or2->idx;
int result = i1 - i2;
if (result == 0 && (or1->isHole != or2->isHole))
{
return or1->isHole ? false : true;
}
else return result < 0;
}
//------------------------------------------------------------------------------
OutRec* FindAppendLinkEnd(OutRec *outRec)
{
while (outRec->AppendLink) outRec = outRec->AppendLink;
return outRec;
}
//------------------------------------------------------------------------------
void Clipper::FixHoleLinkage(OutRec *outRec)
{
OutRec *tmp;
if (outRec->bottomPt)
tmp = m_PolyOuts[outRec->bottomPt->idx]->FirstLeft;
else
tmp = outRec->FirstLeft;
if (outRec == tmp) throw clipperException("HoleLinkage error");
if (tmp)
{
if (tmp->AppendLink) tmp = FindAppendLinkEnd(tmp);
if (tmp == outRec) tmp = 0;
else if (tmp->isHole)
{
FixHoleLinkage(tmp);
tmp = tmp->FirstLeft;
}
}
outRec->FirstLeft = tmp;
if (!tmp) outRec->isHole = false;
outRec->AppendLink = 0;
}
//------------------------------------------------------------------------------
bool Clipper::ExecuteInternal(bool fixHoleLinkages)
{
bool succeeded;
try {
Reset();
if (!m_CurrentLM ) return true;
long64 botY = PopScanbeam();
do {
InsertLocalMinimaIntoAEL(botY);
ClearHorzJoins();
ProcessHorizontals();
long64 topY = PopScanbeam();
succeeded = ProcessIntersections(botY, topY);
if (!succeeded) break;
ProcessEdgesAtTopOfScanbeam(topY);
botY = topY;
} while( m_Scanbeam );
}
catch(...) {
succeeded = false;
}
if (succeeded)
{
//tidy up output polygons and fix orientations where necessary ...
for (PolyOutList::size_type i = 0; i < m_PolyOuts.size(); ++i)
{
OutRec *outRec = m_PolyOuts[i];
if (!outRec->pts) continue;
FixupOutPolygon(*outRec);
if (!outRec->pts) continue;
if (outRec->isHole && fixHoleLinkages) FixHoleLinkage(outRec);
if (outRec->bottomPt == outRec->bottomFlag &&
(Orientation(outRec, m_UseFullRange) != (Area(*outRec, m_UseFullRange) > 0)))
DisposeBottomPt(*outRec);
if (outRec->isHole ==
(m_ReverseOutput ^ Orientation(outRec, m_UseFullRange)))
ReversePolyPtLinks(*outRec->pts);
}
JoinCommonEdges(fixHoleLinkages);
if (fixHoleLinkages)
std::sort(m_PolyOuts.begin(), m_PolyOuts.end(), PolySort);
}
ClearJoins();
ClearHorzJoins();
return succeeded;
}
//------------------------------------------------------------------------------
void Clipper::InsertScanbeam(const long64 Y)
{
if( !m_Scanbeam )
{
m_Scanbeam = new Scanbeam;
m_Scanbeam->next = 0;
m_Scanbeam->Y = Y;
}
else if( Y > m_Scanbeam->Y )
{
Scanbeam* newSb = new Scanbeam;
newSb->Y = Y;
newSb->next = m_Scanbeam;
m_Scanbeam = newSb;
} else
{
Scanbeam* sb2 = m_Scanbeam;
while( sb2->next && ( Y <= sb2->next->Y ) ) sb2 = sb2->next;
if( Y == sb2->Y ) return; //ie ignores duplicates
Scanbeam* newSb = new Scanbeam;
newSb->Y = Y;
newSb->next = sb2->next;
sb2->next = newSb;
}
}
//------------------------------------------------------------------------------
long64 Clipper::PopScanbeam()
{
long64 Y = m_Scanbeam->Y;
Scanbeam* sb2 = m_Scanbeam;
m_Scanbeam = m_Scanbeam->next;
delete sb2;
return Y;
}
//------------------------------------------------------------------------------
void Clipper::DisposeAllPolyPts(){
for (PolyOutList::size_type i = 0; i < m_PolyOuts.size(); ++i)
DisposeOutRec(i);
m_PolyOuts.clear();
}
//------------------------------------------------------------------------------
void Clipper::DisposeOutRec(PolyOutList::size_type index)
{
OutRec *outRec = m_PolyOuts[index];
if (outRec->pts) DisposeOutPts(outRec->pts);
delete outRec;
m_PolyOuts[index] = 0;
}
//------------------------------------------------------------------------------
void Clipper::SetWindingCount(TEdge &edge)
{
TEdge *e = edge.prevInAEL;
//find the edge of the same polytype that immediately preceeds 'edge' in AEL
while ( e && e->polyType != edge.polyType ) e = e->prevInAEL;
if ( !e )
{
edge.windCnt = edge.windDelta;
edge.windCnt2 = 0;
e = m_ActiveEdges; //ie get ready to calc windCnt2
} else if ( IsEvenOddFillType(edge) )
{
//EvenOdd filling ...
edge.windCnt = 1;
edge.windCnt2 = e->windCnt2;
e = e->nextInAEL; //ie get ready to calc windCnt2
} else
{
//nonZero, Positive or Negative filling ...
if ( e->windCnt * e->windDelta < 0 )
{
if (Abs(e->windCnt) > 1)
{
if (e->windDelta * edge.windDelta < 0) edge.windCnt = e->windCnt;
else edge.windCnt = e->windCnt + edge.windDelta;
} else
edge.windCnt = e->windCnt + e->windDelta + edge.windDelta;
} else
{
if ( Abs(e->windCnt) > 1 && e->windDelta * edge.windDelta < 0)
edge.windCnt = e->windCnt;
else if ( e->windCnt + edge.windDelta == 0 )
edge.windCnt = e->windCnt;
else edge.windCnt = e->windCnt + edge.windDelta;
}
edge.windCnt2 = e->windCnt2;
e = e->nextInAEL; //ie get ready to calc windCnt2
}
//update windCnt2 ...
if ( IsEvenOddAltFillType(edge) )
{
//EvenOdd filling ...
while ( e != &edge )
{
edge.windCnt2 = (edge.windCnt2 == 0) ? 1 : 0;
e = e->nextInAEL;
}
} else
{
//nonZero, Positive or Negative filling ...
while ( e != &edge )
{
edge.windCnt2 += e->windDelta;
e = e->nextInAEL;
}
}
}
//------------------------------------------------------------------------------
bool Clipper::IsEvenOddFillType(const TEdge& edge) const
{
if (edge.polyType == ptSubject)
return m_SubjFillType == pftEvenOdd; else
return m_ClipFillType == pftEvenOdd;
}
//------------------------------------------------------------------------------
bool Clipper::IsEvenOddAltFillType(const TEdge& edge) const
{
if (edge.polyType == ptSubject)
return m_ClipFillType == pftEvenOdd; else
return m_SubjFillType == pftEvenOdd;
}
//------------------------------------------------------------------------------
bool Clipper::IsContributing(const TEdge& edge) const
{
PolyFillType pft, pft2;
if (edge.polyType == ptSubject)
{
pft = m_SubjFillType;
pft2 = m_ClipFillType;
} else
{
pft = m_ClipFillType;
pft2 = m_SubjFillType;
}
switch(pft)
{
case pftEvenOdd:
case pftNonZero:
if (Abs(edge.windCnt) != 1) return false;
break;
case pftPositive:
if (edge.windCnt != 1) return false;
break;
default: //pftNegative
if (edge.windCnt != -1) return false;
}
switch(m_ClipType)
{
case ctIntersection:
switch(pft2)
{
case pftEvenOdd:
case pftNonZero:
return (edge.windCnt2 != 0);
case pftPositive:
return (edge.windCnt2 > 0);
default:
return (edge.windCnt2 < 0);
}
case ctUnion:
switch(pft2)
{
case pftEvenOdd:
case pftNonZero:
return (edge.windCnt2 == 0);
case pftPositive:
return (edge.windCnt2 <= 0);
default:
return (edge.windCnt2 >= 0);
}
case ctDifference:
if (edge.polyType == ptSubject)
switch(pft2)
{
case pftEvenOdd:
case pftNonZero:
return (edge.windCnt2 == 0);
case pftPositive:
return (edge.windCnt2 <= 0);
default:
return (edge.windCnt2 >= 0);
}
else
switch(pft2)
{
case pftEvenOdd:
case pftNonZero:
return (edge.windCnt2 != 0);
case pftPositive:
return (edge.windCnt2 > 0);
default:
return (edge.windCnt2 < 0);
}
default:
return true;
}
}
//------------------------------------------------------------------------------
void Clipper::AddLocalMinPoly(TEdge *e1, TEdge *e2, const IntPoint &pt)
{
TEdge *e, *prevE;
if( NEAR_EQUAL(e2->dx, HORIZONTAL) || ( e1->dx > e2->dx ) )
{
AddOutPt( e1, pt );
e2->outIdx = e1->outIdx;
e1->side = esLeft;
e2->side = esRight;
e = e1;
if (e->prevInAEL == e2)
prevE = e2->prevInAEL;
else
prevE = e->prevInAEL;
} else
{
AddOutPt( e2, pt );
e1->outIdx = e2->outIdx;
e1->side = esRight;
e2->side = esLeft;
e = e2;
if (e->prevInAEL == e1)
prevE = e1->prevInAEL;
else
prevE = e->prevInAEL;
}
if (prevE && prevE->outIdx >= 0 &&
(TopX(*prevE, pt.Y) == TopX(*e, pt.Y)) &&
SlopesEqual(*e, *prevE, m_UseFullRange))
AddJoin(e, prevE, -1, -1);
}
//------------------------------------------------------------------------------
void Clipper::AddLocalMaxPoly(TEdge *e1, TEdge *e2, const IntPoint &pt)
{
AddOutPt( e1, pt );
if( e1->outIdx == e2->outIdx )
{
e1->outIdx = -1;
e2->outIdx = -1;
}
else if (e1->outIdx < e2->outIdx)
AppendPolygon(e1, e2);
else
AppendPolygon(e2, e1);
}
//------------------------------------------------------------------------------
void Clipper::AddEdgeToSEL(TEdge *edge)
{
//SEL pointers in PEdge are reused to build a list of horizontal edges.
//However, we don't need to worry about order with horizontal edge processing.
if( !m_SortedEdges )
{
m_SortedEdges = edge;
edge->prevInSEL = 0;
edge->nextInSEL = 0;
}
else
{
edge->nextInSEL = m_SortedEdges;
edge->prevInSEL = 0;
m_SortedEdges->prevInSEL = edge;
m_SortedEdges = edge;
}
}
//------------------------------------------------------------------------------
void Clipper::CopyAELToSEL()
{
TEdge* e = m_ActiveEdges;
m_SortedEdges = e;
if (!m_ActiveEdges) return;
m_SortedEdges->prevInSEL = 0;
e = e->nextInAEL;
while ( e )
{
e->prevInSEL = e->prevInAEL;
e->prevInSEL->nextInSEL = e;
e->nextInSEL = 0;
e = e->nextInAEL;
}
}
//------------------------------------------------------------------------------
void Clipper::AddJoin(TEdge *e1, TEdge *e2, int e1OutIdx, int e2OutIdx)
{
JoinRec* jr = new JoinRec;
if (e1OutIdx >= 0)
jr->poly1Idx = e1OutIdx; else
jr->poly1Idx = e1->outIdx;
jr->pt1a = IntPoint(e1->xcurr, e1->ycurr);
jr->pt1b = IntPoint(e1->xtop, e1->ytop);
if (e2OutIdx >= 0)
jr->poly2Idx = e2OutIdx; else
jr->poly2Idx = e2->outIdx;
jr->pt2a = IntPoint(e2->xcurr, e2->ycurr);
jr->pt2b = IntPoint(e2->xtop, e2->ytop);
m_Joins.push_back(jr);
}
//------------------------------------------------------------------------------
void Clipper::ClearJoins()
{
for (JoinList::size_type i = 0; i < m_Joins.size(); i++)
delete m_Joins[i];
m_Joins.resize(0);
}
//------------------------------------------------------------------------------
void Clipper::AddHorzJoin(TEdge *e, int idx)
{
HorzJoinRec* hj = new HorzJoinRec;
hj->edge = e;
hj->savedIdx = idx;
m_HorizJoins.push_back(hj);
}
//------------------------------------------------------------------------------
void Clipper::ClearHorzJoins()
{
for (HorzJoinList::size_type i = 0; i < m_HorizJoins.size(); i++)
delete m_HorizJoins[i];
m_HorizJoins.resize(0);
}
//------------------------------------------------------------------------------
void Clipper::InsertLocalMinimaIntoAEL( const long64 botY)
{
while( m_CurrentLM && ( m_CurrentLM->Y == botY ) )
{
TEdge* lb = m_CurrentLM->leftBound;
TEdge* rb = m_CurrentLM->rightBound;
InsertEdgeIntoAEL( lb );
InsertScanbeam( lb->ytop );
InsertEdgeIntoAEL( rb );
if (IsEvenOddFillType(*lb))
{
lb->windDelta = 1;
rb->windDelta = 1;
}
else
{
rb->windDelta = -lb->windDelta;
}
SetWindingCount( *lb );
rb->windCnt = lb->windCnt;
rb->windCnt2 = lb->windCnt2;
if( NEAR_EQUAL(rb->dx, HORIZONTAL) )
{
//nb: only rightbounds can have a horizontal bottom edge
AddEdgeToSEL( rb );
InsertScanbeam( rb->nextInLML->ytop );
}
else
InsertScanbeam( rb->ytop );
if( IsContributing(*lb) )
AddLocalMinPoly( lb, rb, IntPoint(lb->xcurr, m_CurrentLM->Y) );
//if any output polygons share an edge, they'll need joining later ...
if (rb->outIdx >= 0)
{
if (NEAR_EQUAL(rb->dx, HORIZONTAL))
{
for (HorzJoinList::size_type i = 0; i < m_HorizJoins.size(); ++i)
{
IntPoint pt, pt2; //returned by GetOverlapSegment() but unused here.
HorzJoinRec* hj = m_HorizJoins[i];
//if horizontals rb and hj.edge overlap, flag for joining later ...
if (GetOverlapSegment(IntPoint(hj->edge->xbot, hj->edge->ybot),
IntPoint(hj->edge->xtop, hj->edge->ytop),
IntPoint(rb->xbot, rb->ybot),
IntPoint(rb->xtop, rb->ytop), pt, pt2))
AddJoin(hj->edge, rb, hj->savedIdx);
}
}
}
if( lb->nextInAEL != rb )
{
if (rb->outIdx >= 0 && rb->prevInAEL->outIdx >= 0 &&
SlopesEqual(*rb->prevInAEL, *rb, m_UseFullRange))
AddJoin(rb, rb->prevInAEL);
TEdge* e = lb->nextInAEL;
IntPoint pt = IntPoint(lb->xcurr, lb->ycurr);
while( e != rb )
{
if(!e) throw clipperException("InsertLocalMinimaIntoAEL: missing rightbound!");
//nb: For calculating winding counts etc, IntersectEdges() assumes
//that param1 will be to the right of param2 ABOVE the intersection ...
IntersectEdges( rb , e , pt , ipNone); //order important here
e = e->nextInAEL;
}
}
PopLocalMinima();
}
}
//------------------------------------------------------------------------------
void Clipper::DeleteFromAEL(TEdge *e)
{
TEdge* AelPrev = e->prevInAEL;
TEdge* AelNext = e->nextInAEL;
if( !AelPrev && !AelNext && (e != m_ActiveEdges) ) return; //already deleted
if( AelPrev ) AelPrev->nextInAEL = AelNext;
else m_ActiveEdges = AelNext;
if( AelNext ) AelNext->prevInAEL = AelPrev;
e->nextInAEL = 0;
e->prevInAEL = 0;
}
//------------------------------------------------------------------------------
void Clipper::DeleteFromSEL(TEdge *e)
{
TEdge* SelPrev = e->prevInSEL;
TEdge* SelNext = e->nextInSEL;
if( !SelPrev && !SelNext && (e != m_SortedEdges) ) return; //already deleted
if( SelPrev ) SelPrev->nextInSEL = SelNext;
else m_SortedEdges = SelNext;
if( SelNext ) SelNext->prevInSEL = SelPrev;
e->nextInSEL = 0;
e->prevInSEL = 0;
}
//------------------------------------------------------------------------------
void Clipper::IntersectEdges(TEdge *e1, TEdge *e2,
const IntPoint &pt, IntersectProtects protects)
{
//e1 will be to the left of e2 BELOW the intersection. Therefore e1 is before
//e2 in AEL except when e1 is being inserted at the intersection point ...
bool e1stops = !(ipLeft & protects) && !e1->nextInLML &&
e1->xtop == pt.X && e1->ytop == pt.Y;
bool e2stops = !(ipRight & protects) && !e2->nextInLML &&
e2->xtop == pt.X && e2->ytop == pt.Y;
bool e1Contributing = ( e1->outIdx >= 0 );
bool e2contributing = ( e2->outIdx >= 0 );
//update winding counts...
//assumes that e1 will be to the right of e2 ABOVE the intersection
if ( e1->polyType == e2->polyType )
{
if ( IsEvenOddFillType( *e1) )
{
int oldE1WindCnt = e1->windCnt;
e1->windCnt = e2->windCnt;
e2->windCnt = oldE1WindCnt;
} else
{
if (e1->windCnt + e2->windDelta == 0 ) e1->windCnt = -e1->windCnt;
else e1->windCnt += e2->windDelta;
if ( e2->windCnt - e1->windDelta == 0 ) e2->windCnt = -e2->windCnt;
else e2->windCnt -= e1->windDelta;
}
} else
{
if (!IsEvenOddFillType(*e2)) e1->windCnt2 += e2->windDelta;
else e1->windCnt2 = ( e1->windCnt2 == 0 ) ? 1 : 0;
if (!IsEvenOddFillType(*e1)) e2->windCnt2 -= e1->windDelta;
else e2->windCnt2 = ( e2->windCnt2 == 0 ) ? 1 : 0;
}
PolyFillType e1FillType, e2FillType, e1FillType2, e2FillType2;
if (e1->polyType == ptSubject)
{
e1FillType = m_SubjFillType;
e1FillType2 = m_ClipFillType;
} else
{
e1FillType = m_ClipFillType;
e1FillType2 = m_SubjFillType;
}
if (e2->polyType == ptSubject)
{
e2FillType = m_SubjFillType;
e2FillType2 = m_ClipFillType;
} else
{
e2FillType = m_ClipFillType;
e2FillType2 = m_SubjFillType;
}
long64 e1Wc, e2Wc;
switch (e1FillType)
{
case pftPositive: e1Wc = e1->windCnt; break;
case pftNegative: e1Wc = -e1->windCnt; break;
default: e1Wc = Abs(e1->windCnt);
}
switch(e2FillType)
{
case pftPositive: e2Wc = e2->windCnt; break;
case pftNegative: e2Wc = -e2->windCnt; break;
default: e2Wc = Abs(e2->windCnt);
}
if ( e1Contributing && e2contributing )
{
if ( e1stops || e2stops ||
(e1Wc != 0 && e1Wc != 1) || (e2Wc != 0 && e2Wc != 1) ||
(e1->polyType != e2->polyType && m_ClipType != ctXor) )
AddLocalMaxPoly(e1, e2, pt);
else
DoBothEdges( e1, e2, pt );
}
else if ( e1Contributing )
{
if ((e2Wc == 0 || e2Wc == 1) &&
(m_ClipType != ctIntersection ||
e2->polyType == ptSubject || (e2->windCnt2 != 0)))
DoEdge1(e1, e2, pt);
}
else if ( e2contributing )
{
if ((e1Wc == 0 || e1Wc == 1) &&
(m_ClipType != ctIntersection ||
e1->polyType == ptSubject || (e1->windCnt2 != 0)))
DoEdge2(e1, e2, pt);
}
else if ( (e1Wc == 0 || e1Wc == 1) &&
(e2Wc == 0 || e2Wc == 1) && !e1stops && !e2stops )
{
//neither edge is currently contributing ...
long64 e1Wc2, e2Wc2;
switch (e1FillType2)
{
case pftPositive: e1Wc2 = e1->windCnt2; break;
case pftNegative : e1Wc2 = -e1->windCnt2; break;
default: e1Wc2 = Abs(e1->windCnt2);
}
switch (e2FillType2)
{
case pftPositive: e2Wc2 = e2->windCnt2; break;
case pftNegative: e2Wc2 = -e2->windCnt2; break;
default: e2Wc2 = Abs(e2->windCnt2);
}
if (e1->polyType != e2->polyType)
AddLocalMinPoly(e1, e2, pt);
else if (e1Wc == 1 && e2Wc == 1)
switch( m_ClipType ) {
case ctIntersection:
if (e1Wc2 > 0 && e2Wc2 > 0)
AddLocalMinPoly(e1, e2, pt);
break;
case ctUnion:
if ( e1Wc2 <= 0 && e2Wc2 <= 0 )
AddLocalMinPoly(e1, e2, pt);
break;
case ctDifference:
if (((e1->polyType == ptClip) && (e1Wc2 > 0) && (e2Wc2 > 0)) ||
((e1->polyType == ptSubject) && (e1Wc2 <= 0) && (e2Wc2 <= 0)))
AddLocalMinPoly(e1, e2, pt);
break;
case ctXor:
AddLocalMinPoly(e1, e2, pt);
}
else
SwapSides( *e1, *e2 );
}
if( (e1stops != e2stops) &&
( (e1stops && (e1->outIdx >= 0)) || (e2stops && (e2->outIdx >= 0)) ) )
{
SwapSides( *e1, *e2 );
SwapPolyIndexes( *e1, *e2 );
}
//finally, delete any non-contributing maxima edges ...
if( e1stops ) DeleteFromAEL( e1 );
if( e2stops ) DeleteFromAEL( e2 );
}
//------------------------------------------------------------------------------
void Clipper::SetHoleState(TEdge *e, OutRec *outRec)
{
bool isHole = false;
TEdge *e2 = e->prevInAEL;
while (e2)
{
if (e2->outIdx >= 0)
{
isHole = !isHole;
if (! outRec->FirstLeft)
outRec->FirstLeft = m_PolyOuts[e2->outIdx];
}
e2 = e2->prevInAEL;
}
if (isHole) outRec->isHole = true;
}
//------------------------------------------------------------------------------
OutRec* GetLowermostRec(OutRec *outRec1, OutRec *outRec2)
{
//work out which polygon fragment has the correct hole state ...
OutPt *outPt1 = outRec1->bottomPt;
OutPt *outPt2 = outRec2->bottomPt;
if (outPt1->pt.Y > outPt2->pt.Y) return outRec1;
else if (outPt1->pt.Y < outPt2->pt.Y) return outRec2;
else if (outPt1->pt.X < outPt2->pt.X) return outRec1;
else if (outPt1->pt.X > outPt2->pt.X) return outRec2;
else if (outPt1->next == outPt1) return outRec2;
else if (outPt2->next == outPt2) return outRec1;
else if (FirstIsBottomPt(outPt1, outPt2)) return outRec1;
else return outRec2;
}
//------------------------------------------------------------------------------
bool Param1RightOfParam2(OutRec* outRec1, OutRec* outRec2)
{
do
{
outRec1 = outRec1->FirstLeft;
if (outRec1 == outRec2) return true;
} while (outRec1);
return false;
}
//------------------------------------------------------------------------------
void Clipper::AppendPolygon(TEdge *e1, TEdge *e2)
{
//get the start and ends of both output polygons ...
OutRec *outRec1 = m_PolyOuts[e1->outIdx];
OutRec *outRec2 = m_PolyOuts[e2->outIdx];
OutRec *holeStateRec;
if (Param1RightOfParam2(outRec1, outRec2)) holeStateRec = outRec2;
else if (Param1RightOfParam2(outRec2, outRec1)) holeStateRec = outRec1;
else holeStateRec = GetLowermostRec(outRec1, outRec2);
OutPt* p1_lft = outRec1->pts;
OutPt* p1_rt = p1_lft->prev;
OutPt* p2_lft = outRec2->pts;
OutPt* p2_rt = p2_lft->prev;
EdgeSide side;
//join e2 poly onto e1 poly and delete pointers to e2 ...
if( e1->side == esLeft )
{
if( e2->side == esLeft )
{
//z y x a b c
ReversePolyPtLinks(*p2_lft);
p2_lft->next = p1_lft;
p1_lft->prev = p2_lft;
p1_rt->next = p2_rt;
p2_rt->prev = p1_rt;
outRec1->pts = p2_rt;
} else
{
//x y z a b c
p2_rt->next = p1_lft;
p1_lft->prev = p2_rt;
p2_lft->prev = p1_rt;
p1_rt->next = p2_lft;
outRec1->pts = p2_lft;
}
side = esLeft;
} else
{
if( e2->side == esRight )
{
//a b c z y x
ReversePolyPtLinks( *p2_lft );
p1_rt->next = p2_rt;
p2_rt->prev = p1_rt;
p2_lft->next = p1_lft;
p1_lft->prev = p2_lft;
} else
{
//a b c x y z
p1_rt->next = p2_lft;
p2_lft->prev = p1_rt;
p1_lft->prev = p2_rt;
p2_rt->next = p1_lft;
}
side = esRight;
}
if (holeStateRec == outRec2)
{
outRec1->bottomPt = outRec2->bottomPt;
outRec1->bottomPt->idx = outRec1->idx;
if (outRec2->FirstLeft != outRec1)
outRec1->FirstLeft = outRec2->FirstLeft;
outRec1->isHole = outRec2->isHole;
}
outRec2->pts = 0;
outRec2->bottomPt = 0;
outRec2->AppendLink = outRec1;
int OKIdx = e1->outIdx;
int ObsoleteIdx = e2->outIdx;
e1->outIdx = -1; //nb: safe because we only get here via AddLocalMaxPoly
e2->outIdx = -1;
TEdge* e = m_ActiveEdges;
while( e )
{
if( e->outIdx == ObsoleteIdx )
{
e->outIdx = OKIdx;
e->side = side;
break;
}
e = e->nextInAEL;
}
for (JoinList::size_type i = 0; i < m_Joins.size(); ++i)
{
if (m_Joins[i]->poly1Idx == ObsoleteIdx) m_Joins[i]->poly1Idx = OKIdx;
if (m_Joins[i]->poly2Idx == ObsoleteIdx) m_Joins[i]->poly2Idx = OKIdx;
}
for (HorzJoinList::size_type i = 0; i < m_HorizJoins.size(); ++i)
{
if (m_HorizJoins[i]->savedIdx == ObsoleteIdx)
m_HorizJoins[i]->savedIdx = OKIdx;
}
}
//------------------------------------------------------------------------------
OutRec* Clipper::CreateOutRec()
{
OutRec* result = new OutRec;
result->isHole = false;
result->FirstLeft = 0;
result->AppendLink = 0;
result->pts = 0;
result->bottomPt = 0;
result->sides = esNeither;
result->bottomFlag = 0;
return result;
}
//------------------------------------------------------------------------------
void Clipper::DisposeBottomPt(OutRec &outRec)
{
OutPt* next = outRec.bottomPt->next;
OutPt* prev = outRec.bottomPt->prev;
if (outRec.pts == outRec.bottomPt) outRec.pts = next;
delete outRec.bottomPt;
next->prev = prev;
prev->next = next;
outRec.bottomPt = next;
FixupOutPolygon(outRec);
}
//------------------------------------------------------------------------------
void Clipper::AddOutPt(TEdge *e, const IntPoint &pt)
{
bool ToFront = (e->side == esLeft);
if( e->outIdx < 0 )
{
OutRec *outRec = CreateOutRec();
m_PolyOuts.push_back(outRec);
outRec->idx = (int)m_PolyOuts.size()-1;
e->outIdx = outRec->idx;
OutPt* op = new OutPt;
outRec->pts = op;
outRec->bottomPt = op;
op->pt = pt;
op->idx = outRec->idx;
op->next = op;
op->prev = op;
SetHoleState(e, outRec);
} else
{
OutRec *outRec = m_PolyOuts[e->outIdx];
OutPt* op = outRec->pts;
if ((ToFront && PointsEqual(pt, op->pt)) ||
(!ToFront && PointsEqual(pt, op->prev->pt))) return;
if ((e->side | outRec->sides) != outRec->sides)
{
//check for 'rounding' artefacts ...
if (outRec->sides == esNeither && pt.Y == op->pt.Y)
{
if (ToFront)
{
if (pt.X == op->pt.X +1) return; //ie wrong side of bottomPt
}
else if (pt.X == op->pt.X -1) return; //ie wrong side of bottomPt
}
outRec->sides = (EdgeSide)(outRec->sides | e->side);
if (outRec->sides == esBoth)
{
//A vertex from each side has now been added.
//Vertices of one side of an output polygon are quite commonly close to
//or even 'touching' edges of the other side of the output polygon.
//Very occasionally vertices from one side can 'cross' an edge on the
//the other side. The distance 'crossed' is always less that a unit
//and is purely an artefact of coordinate rounding. Nevertheless, this
//results in very tiny self-intersections. Because of the way
//orientation is calculated, even tiny self-intersections can cause
//the Orientation function to return the wrong result. Therefore, it's
//important to ensure that any self-intersections close to BottomPt are
//detected and removed before orientation is assigned.
OutPt *opBot, *op2;
if (ToFront)
{
opBot = outRec->pts;
op2 = opBot->next; //op2 == right side
if (opBot->pt.Y != op2->pt.Y && opBot->pt.Y != pt.Y &&
((opBot->pt.X - pt.X)/(opBot->pt.Y - pt.Y) <
(opBot->pt.X - op2->pt.X)/(opBot->pt.Y - op2->pt.Y)))
outRec->bottomFlag = opBot;
} else
{
opBot = outRec->pts->prev;
op2 = opBot->prev; //op2 == left side
if (opBot->pt.Y != op2->pt.Y && opBot->pt.Y != pt.Y &&
((opBot->pt.X - pt.X)/(opBot->pt.Y - pt.Y) >
(opBot->pt.X - op2->pt.X)/(opBot->pt.Y - op2->pt.Y)))
outRec->bottomFlag = opBot;
}
}
}
OutPt* op2 = new OutPt;
op2->pt = pt;
op2->idx = outRec->idx;
if (op2->pt.Y == outRec->bottomPt->pt.Y &&
op2->pt.X < outRec->bottomPt->pt.X)
outRec->bottomPt = op2;
op2->next = op;
op2->prev = op->prev;
op2->prev->next = op2;
op->prev = op2;
if (ToFront) outRec->pts = op2;
}
}
//------------------------------------------------------------------------------
void Clipper::ProcessHorizontals()
{
TEdge* horzEdge = m_SortedEdges;
while( horzEdge )
{
DeleteFromSEL( horzEdge );
ProcessHorizontal( horzEdge );
horzEdge = m_SortedEdges;
}
}
//------------------------------------------------------------------------------
bool Clipper::IsTopHorz(const long64 XPos)
{
TEdge* e = m_SortedEdges;
while( e )
{
if( ( XPos >= std::min(e->xcurr, e->xtop) ) &&
( XPos <= std::max(e->xcurr, e->xtop) ) ) return false;
e = e->nextInSEL;
}
return true;
}
//------------------------------------------------------------------------------
bool IsMinima(TEdge *e)
{
return e && (e->prev->nextInLML != e) && (e->next->nextInLML != e);
}
//------------------------------------------------------------------------------
bool IsMaxima(TEdge *e, const long64 Y)
{
return e && e->ytop == Y && !e->nextInLML;
}
//------------------------------------------------------------------------------
bool IsIntermediate(TEdge *e, const long64 Y)
{
return e->ytop == Y && e->nextInLML;
}
//------------------------------------------------------------------------------
TEdge *GetMaximaPair(TEdge *e)
{
if( !IsMaxima(e->next, e->ytop) || e->next->xtop != e->xtop )
return e->prev; else
return e->next;
}
//------------------------------------------------------------------------------
void Clipper::SwapPositionsInAEL(TEdge *edge1, TEdge *edge2)
{
if( !edge1->nextInAEL && !edge1->prevInAEL ) return;
if( !edge2->nextInAEL && !edge2->prevInAEL ) return;
if( edge1->nextInAEL == edge2 )
{
TEdge* next = edge2->nextInAEL;
if( next ) next->prevInAEL = edge1;
TEdge* prev = edge1->prevInAEL;
if( prev ) prev->nextInAEL = edge2;
edge2->prevInAEL = prev;
edge2->nextInAEL = edge1;
edge1->prevInAEL = edge2;
edge1->nextInAEL = next;
}
else if( edge2->nextInAEL == edge1 )
{
TEdge* next = edge1->nextInAEL;
if( next ) next->prevInAEL = edge2;
TEdge* prev = edge2->prevInAEL;
if( prev ) prev->nextInAEL = edge1;
edge1->prevInAEL = prev;
edge1->nextInAEL = edge2;
edge2->prevInAEL = edge1;
edge2->nextInAEL = next;
}
else
{
TEdge* next = edge1->nextInAEL;
TEdge* prev = edge1->prevInAEL;
edge1->nextInAEL = edge2->nextInAEL;
if( edge1->nextInAEL ) edge1->nextInAEL->prevInAEL = edge1;
edge1->prevInAEL = edge2->prevInAEL;
if( edge1->prevInAEL ) edge1->prevInAEL->nextInAEL = edge1;
edge2->nextInAEL = next;
if( edge2->nextInAEL ) edge2->nextInAEL->prevInAEL = edge2;
edge2->prevInAEL = prev;
if( edge2->prevInAEL ) edge2->prevInAEL->nextInAEL = edge2;
}
if( !edge1->prevInAEL ) m_ActiveEdges = edge1;
else if( !edge2->prevInAEL ) m_ActiveEdges = edge2;
}
//------------------------------------------------------------------------------
void Clipper::SwapPositionsInSEL(TEdge *edge1, TEdge *edge2)
{
if( !( edge1->nextInSEL ) && !( edge1->prevInSEL ) ) return;
if( !( edge2->nextInSEL ) && !( edge2->prevInSEL ) ) return;
if( edge1->nextInSEL == edge2 )
{
TEdge* next = edge2->nextInSEL;
if( next ) next->prevInSEL = edge1;
TEdge* prev = edge1->prevInSEL;
if( prev ) prev->nextInSEL = edge2;
edge2->prevInSEL = prev;
edge2->nextInSEL = edge1;
edge1->prevInSEL = edge2;
edge1->nextInSEL = next;
}
else if( edge2->nextInSEL == edge1 )
{
TEdge* next = edge1->nextInSEL;
if( next ) next->prevInSEL = edge2;
TEdge* prev = edge2->prevInSEL;
if( prev ) prev->nextInSEL = edge1;
edge1->prevInSEL = prev;
edge1->nextInSEL = edge2;
edge2->prevInSEL = edge1;
edge2->nextInSEL = next;
}
else
{
TEdge* next = edge1->nextInSEL;
TEdge* prev = edge1->prevInSEL;
edge1->nextInSEL = edge2->nextInSEL;
if( edge1->nextInSEL ) edge1->nextInSEL->prevInSEL = edge1;
edge1->prevInSEL = edge2->prevInSEL;
if( edge1->prevInSEL ) edge1->prevInSEL->nextInSEL = edge1;
edge2->nextInSEL = next;
if( edge2->nextInSEL ) edge2->nextInSEL->prevInSEL = edge2;
edge2->prevInSEL = prev;
if( edge2->prevInSEL ) edge2->prevInSEL->nextInSEL = edge2;
}
if( !edge1->prevInSEL ) m_SortedEdges = edge1;
else if( !edge2->prevInSEL ) m_SortedEdges = edge2;
}
//------------------------------------------------------------------------------
TEdge* GetNextInAEL(TEdge *e, Direction dir)
{
return dir == dLeftToRight ? e->nextInAEL : e->prevInAEL;
}
//------------------------------------------------------------------------------
void Clipper::ProcessHorizontal(TEdge *horzEdge)
{
Direction dir;
long64 horzLeft, horzRight;
if( horzEdge->xcurr < horzEdge->xtop )
{
horzLeft = horzEdge->xcurr;
horzRight = horzEdge->xtop;
dir = dLeftToRight;
} else
{
horzLeft = horzEdge->xtop;
horzRight = horzEdge->xcurr;
dir = dRightToLeft;
}
TEdge* eMaxPair;
if( horzEdge->nextInLML ) eMaxPair = 0;
else eMaxPair = GetMaximaPair(horzEdge);
TEdge* e = GetNextInAEL( horzEdge , dir );
while( e )
{
TEdge* eNext = GetNextInAEL( e, dir );
if (eMaxPair ||
((dir == dLeftToRight) && (e->xcurr <= horzRight)) ||
((dir == dRightToLeft) && (e->xcurr >= horzLeft)))
{
//ok, so far it looks like we're still in range of the horizontal edge
if ( e->xcurr == horzEdge->xtop && !eMaxPair )
{
if (SlopesEqual(*e, *horzEdge->nextInLML, m_UseFullRange))
{
//if output polygons share an edge, they'll need joining later ...
if (horzEdge->outIdx >= 0 && e->outIdx >= 0)
AddJoin(horzEdge->nextInLML, e, horzEdge->outIdx);
break; //we've reached the end of the horizontal line
}
else if (e->dx < horzEdge->nextInLML->dx)
//we really have got to the end of the intermediate horz edge so quit.
//nb: More -ve slopes follow more +ve slopes ABOVE the horizontal.
break;
}
if( e == eMaxPair )
{
//horzEdge is evidently a maxima horizontal and we've arrived at its end.
if (dir == dLeftToRight)
IntersectEdges(horzEdge, e, IntPoint(e->xcurr, horzEdge->ycurr), ipNone);
else
IntersectEdges(e, horzEdge, IntPoint(e->xcurr, horzEdge->ycurr), ipNone);
if (eMaxPair->outIdx >= 0) throw clipperException("ProcessHorizontal error");
return;
}
else if( NEAR_EQUAL(e->dx, HORIZONTAL) && !IsMinima(e) && !(e->xcurr > e->xtop) )
{
//An overlapping horizontal edge. Overlapping horizontal edges are
//processed as if layered with the current horizontal edge (horizEdge)
//being infinitesimally lower that the next (e). Therfore, we
//intersect with e only if e.xcurr is within the bounds of horzEdge ...
if( dir == dLeftToRight )
IntersectEdges( horzEdge , e, IntPoint(e->xcurr, horzEdge->ycurr),
(IsTopHorz( e->xcurr ))? ipLeft : ipBoth );
else
IntersectEdges( e, horzEdge, IntPoint(e->xcurr, horzEdge->ycurr),
(IsTopHorz( e->xcurr ))? ipRight : ipBoth );
}
else if( dir == dLeftToRight )
{
IntersectEdges( horzEdge, e, IntPoint(e->xcurr, horzEdge->ycurr),
(IsTopHorz( e->xcurr ))? ipLeft : ipBoth );
}
else
{
IntersectEdges( e, horzEdge, IntPoint(e->xcurr, horzEdge->ycurr),
(IsTopHorz( e->xcurr ))? ipRight : ipBoth );
}
SwapPositionsInAEL( horzEdge, e );
}
else if( (dir == dLeftToRight && e->xcurr > horzRight && m_SortedEdges) ||
(dir == dRightToLeft && e->xcurr < horzLeft && m_SortedEdges) ) break;
e = eNext;
} //end while
if( horzEdge->nextInLML )
{
if( horzEdge->outIdx >= 0 )
AddOutPt( horzEdge, IntPoint(horzEdge->xtop, horzEdge->ytop));
UpdateEdgeIntoAEL( horzEdge );
}
else
{
if ( horzEdge->outIdx >= 0 )
IntersectEdges( horzEdge, eMaxPair,
IntPoint(horzEdge->xtop, horzEdge->ycurr), ipBoth);
if (eMaxPair->outIdx >= 0) throw clipperException("ProcessHorizontal error");
DeleteFromAEL(eMaxPair);
DeleteFromAEL(horzEdge);
}
}
//------------------------------------------------------------------------------
void Clipper::UpdateEdgeIntoAEL(TEdge *&e)
{
if( !e->nextInLML ) throw
clipperException("UpdateEdgeIntoAEL: invalid call");
TEdge* AelPrev = e->prevInAEL;
TEdge* AelNext = e->nextInAEL;
e->nextInLML->outIdx = e->outIdx;
if( AelPrev ) AelPrev->nextInAEL = e->nextInLML;
else m_ActiveEdges = e->nextInLML;
if( AelNext ) AelNext->prevInAEL = e->nextInLML;
e->nextInLML->side = e->side;
e->nextInLML->windDelta = e->windDelta;
e->nextInLML->windCnt = e->windCnt;
e->nextInLML->windCnt2 = e->windCnt2;
e = e->nextInLML;
e->prevInAEL = AelPrev;
e->nextInAEL = AelNext;
if( !NEAR_EQUAL(e->dx, HORIZONTAL) ) InsertScanbeam( e->ytop );
}
//------------------------------------------------------------------------------
bool Clipper::ProcessIntersections(const long64 botY, const long64 topY)
{
if( !m_ActiveEdges ) return true;
try {
BuildIntersectList(botY, topY);
if ( !m_IntersectNodes) return true;
if ( FixupIntersections() ) ProcessIntersectList();
else return false;
}
catch(...) {
m_SortedEdges = 0;
DisposeIntersectNodes();
throw clipperException("ProcessIntersections error");
}
return true;
}
//------------------------------------------------------------------------------
void Clipper::DisposeIntersectNodes()
{
while ( m_IntersectNodes )
{
IntersectNode* iNode = m_IntersectNodes->next;
delete m_IntersectNodes;
m_IntersectNodes = iNode;
}
}
//------------------------------------------------------------------------------
void Clipper::BuildIntersectList(const long64 botY, const long64 topY)
{
if ( !m_ActiveEdges ) return;
//prepare for sorting ...
TEdge* e = m_ActiveEdges;
e->tmpX = TopX( *e, topY );
m_SortedEdges = e;
m_SortedEdges->prevInSEL = 0;
e = e->nextInAEL;
while( e )
{
e->prevInSEL = e->prevInAEL;
e->prevInSEL->nextInSEL = e;
e->nextInSEL = 0;
e->tmpX = TopX( *e, topY );
e = e->nextInAEL;
}
//bubblesort ...
bool isModified = true;
while( isModified && m_SortedEdges )
{
isModified = false;
e = m_SortedEdges;
while( e->nextInSEL )
{
TEdge *eNext = e->nextInSEL;
IntPoint pt;
if(e->tmpX > eNext->tmpX &&
IntersectPoint(*e, *eNext, pt, m_UseFullRange))
{
if (pt.Y > botY)
{
pt.Y = botY;
pt.X = TopX(*e, pt.Y);
}
AddIntersectNode( e, eNext, pt );
SwapPositionsInSEL(e, eNext);
isModified = true;
}
else
e = eNext;
}
if( e->prevInSEL ) e->prevInSEL->nextInSEL = 0;
else break;
}
m_SortedEdges = 0;
}
//------------------------------------------------------------------------------
bool ProcessParam1BeforeParam2(IntersectNode &node1, IntersectNode &node2)
{
bool result;
if (node1.pt.Y == node2.pt.Y)
{
if (node1.edge1 == node2.edge1 || node1.edge2 == node2.edge1)
{
result = node2.pt.X > node1.pt.X;
return node2.edge1->dx > 0 ? !result : result;
}
else if (node1.edge1 == node2.edge2 || node1.edge2 == node2.edge2)
{
result = node2.pt.X > node1.pt.X;
return node2.edge2->dx > 0 ? !result : result;
}
else return node2.pt.X > node1.pt.X;
}
else return node1.pt.Y > node2.pt.Y;
}
//------------------------------------------------------------------------------
void Clipper::AddIntersectNode(TEdge *e1, TEdge *e2, const IntPoint &pt)
{
IntersectNode* newNode = new IntersectNode;
newNode->edge1 = e1;
newNode->edge2 = e2;
newNode->pt = pt;
newNode->next = 0;
if( !m_IntersectNodes ) m_IntersectNodes = newNode;
else if( ProcessParam1BeforeParam2(*newNode, *m_IntersectNodes) )
{
newNode->next = m_IntersectNodes;
m_IntersectNodes = newNode;
}
else
{
IntersectNode* iNode = m_IntersectNodes;
while( iNode->next && ProcessParam1BeforeParam2(*iNode->next, *newNode) )
iNode = iNode->next;
newNode->next = iNode->next;
iNode->next = newNode;
}
}
//------------------------------------------------------------------------------
void Clipper::ProcessIntersectList()
{
while( m_IntersectNodes )
{
IntersectNode* iNode = m_IntersectNodes->next;
{
IntersectEdges( m_IntersectNodes->edge1 ,
m_IntersectNodes->edge2 , m_IntersectNodes->pt, ipBoth );
SwapPositionsInAEL( m_IntersectNodes->edge1 , m_IntersectNodes->edge2 );
}
delete m_IntersectNodes;
m_IntersectNodes = iNode;
}
}
//------------------------------------------------------------------------------
void Clipper::DoMaxima(TEdge *e, long64 topY)
{
TEdge* eMaxPair = GetMaximaPair(e);
long64 X = e->xtop;
TEdge* eNext = e->nextInAEL;
while( eNext != eMaxPair )
{
if (!eNext) throw clipperException("DoMaxima error");
IntersectEdges( e, eNext, IntPoint(X, topY), ipBoth );
eNext = eNext->nextInAEL;
}
if( e->outIdx < 0 && eMaxPair->outIdx < 0 )
{
DeleteFromAEL( e );
DeleteFromAEL( eMaxPair );
}
else if( e->outIdx >= 0 && eMaxPair->outIdx >= 0 )
{
IntersectEdges( e, eMaxPair, IntPoint(X, topY), ipNone );
}
else throw clipperException("DoMaxima error");
}
//------------------------------------------------------------------------------
void Clipper::ProcessEdgesAtTopOfScanbeam(const long64 topY)
{
TEdge* e = m_ActiveEdges;
while( e )
{
//1. process maxima, treating them as if they're 'bent' horizontal edges,
// but exclude maxima with horizontal edges. nb: e can't be a horizontal.
if( IsMaxima(e, topY) && !NEAR_EQUAL(GetMaximaPair(e)->dx, HORIZONTAL) )
{
//'e' might be removed from AEL, as may any following edges so ...
TEdge* ePrior = e->prevInAEL;
DoMaxima(e, topY);
if( !ePrior ) e = m_ActiveEdges;
else e = ePrior->nextInAEL;
}
else
{
//2. promote horizontal edges, otherwise update xcurr and ycurr ...
if( IsIntermediate(e, topY) && NEAR_EQUAL(e->nextInLML->dx, HORIZONTAL) )
{
if (e->outIdx >= 0)
{
AddOutPt(e, IntPoint(e->xtop, e->ytop));
for (HorzJoinList::size_type i = 0; i < m_HorizJoins.size(); ++i)
{
IntPoint pt, pt2;
HorzJoinRec* hj = m_HorizJoins[i];
if (GetOverlapSegment(IntPoint(hj->edge->xbot, hj->edge->ybot),
IntPoint(hj->edge->xtop, hj->edge->ytop),
IntPoint(e->nextInLML->xbot, e->nextInLML->ybot),
IntPoint(e->nextInLML->xtop, e->nextInLML->ytop), pt, pt2))
AddJoin(hj->edge, e->nextInLML, hj->savedIdx, e->outIdx);
}
AddHorzJoin(e->nextInLML, e->outIdx);
}
UpdateEdgeIntoAEL(e);
AddEdgeToSEL(e);
} else
{
//this just simplifies horizontal processing ...
e->xcurr = TopX( *e, topY );
e->ycurr = topY;
}
e = e->nextInAEL;
}
}
//3. Process horizontals at the top of the scanbeam ...
ProcessHorizontals();
//4. Promote intermediate vertices ...
e = m_ActiveEdges;
while( e )
{
if( IsIntermediate( e, topY ) )
{
if( e->outIdx >= 0 ) AddOutPt(e, IntPoint(e->xtop,e->ytop));
UpdateEdgeIntoAEL(e);
//if output polygons share an edge, they'll need joining later ...
if (e->outIdx >= 0 && e->prevInAEL && e->prevInAEL->outIdx >= 0 &&
e->prevInAEL->xcurr == e->xbot && e->prevInAEL->ycurr == e->ybot &&
SlopesEqual(IntPoint(e->xbot,e->ybot), IntPoint(e->xtop, e->ytop),
IntPoint(e->xbot,e->ybot),
IntPoint(e->prevInAEL->xtop, e->prevInAEL->ytop), m_UseFullRange))
{
AddOutPt(e->prevInAEL, IntPoint(e->xbot, e->ybot));
AddJoin(e, e->prevInAEL);
}
else if (e->outIdx >= 0 && e->nextInAEL && e->nextInAEL->outIdx >= 0 &&
e->nextInAEL->ycurr > e->nextInAEL->ytop &&
e->nextInAEL->ycurr <= e->nextInAEL->ybot &&
e->nextInAEL->xcurr == e->xbot && e->nextInAEL->ycurr == e->ybot &&
SlopesEqual(IntPoint(e->xbot,e->ybot), IntPoint(e->xtop, e->ytop),
IntPoint(e->xbot,e->ybot),
IntPoint(e->nextInAEL->xtop, e->nextInAEL->ytop), m_UseFullRange))
{
AddOutPt(e->nextInAEL, IntPoint(e->xbot, e->ybot));
AddJoin(e, e->nextInAEL);
}
}
e = e->nextInAEL;
}
}
//------------------------------------------------------------------------------
void Clipper::FixupOutPolygon(OutRec &outRec)
{
//FixupOutPolygon() - removes duplicate points and simplifies consecutive
//parallel edges by removing the middle vertex.
OutPt *lastOK = 0;
outRec.pts = outRec.bottomPt;
OutPt *pp = outRec.bottomPt;
for (;;)
{
if (pp->prev == pp || pp->prev == pp->next )
{
DisposeOutPts(pp);
outRec.pts = 0;
outRec.bottomPt = 0;
return;
}
//test for duplicate points and for same slope (cross-product) ...
if ( PointsEqual(pp->pt, pp->next->pt) ||
SlopesEqual(pp->prev->pt, pp->pt, pp->next->pt, m_UseFullRange) )
{
lastOK = 0;
OutPt *tmp = pp;
if (pp == outRec.bottomPt)
outRec.bottomPt = 0; //flags need for updating
pp->prev->next = pp->next;
pp->next->prev = pp->prev;
pp = pp->prev;
delete tmp;
}
else if (pp == lastOK) break;
else
{
if (!lastOK) lastOK = pp;
pp = pp->next;
}
}
if (!outRec.bottomPt) {
outRec.bottomPt = GetBottomPt(pp);
outRec.bottomPt->idx = outRec.idx;
outRec.pts = outRec.bottomPt;
}
}
//------------------------------------------------------------------------------
void Clipper::BuildResult(Polygons &polys)
{
int k = 0;
polys.resize(m_PolyOuts.size());
for (PolyOutList::size_type i = 0; i < m_PolyOuts.size(); ++i)
{
if (m_PolyOuts[i]->pts)
{
Polygon* pg = &polys[k];
pg->clear();
OutPt* p = m_PolyOuts[i]->pts;
do
{
pg->push_back(p->pt);
p = p->next;
} while (p != m_PolyOuts[i]->pts);
//make sure each polygon has at least 3 vertices ...
if (pg->size() < 3) pg->clear(); else k++;
}
}
polys.resize(k);
}
//------------------------------------------------------------------------------
void Clipper::BuildResultEx(ExPolygons &polys)
{
PolyOutList::size_type i = 0;
int k = 0;
polys.resize(0);
polys.reserve(m_PolyOuts.size());
while (i < m_PolyOuts.size() && m_PolyOuts[i]->pts)
{
ExPolygon epg;
OutPt* p = m_PolyOuts[i]->pts;
do {
epg.outer.push_back(p->pt);
p = p->next;
} while (p != m_PolyOuts[i]->pts);
i++;
//make sure polygons have at least 3 vertices ...
if (epg.outer.size() < 3) continue;
while (i < m_PolyOuts.size()
&& m_PolyOuts[i]->pts && m_PolyOuts[i]->isHole)
{
Polygon pg;
p = m_PolyOuts[i]->pts;
do {
pg.push_back(p->pt);
p = p->next;
} while (p != m_PolyOuts[i]->pts);
epg.holes.push_back(pg);
i++;
}
polys.push_back(epg);
k++;
}
polys.resize(k);
}
//------------------------------------------------------------------------------
void SwapIntersectNodes(IntersectNode &int1, IntersectNode &int2)
{
TEdge *e1 = int1.edge1;
TEdge *e2 = int1.edge2;
IntPoint p = int1.pt;
int1.edge1 = int2.edge1;
int1.edge2 = int2.edge2;
int1.pt = int2.pt;
int2.edge1 = e1;
int2.edge2 = e2;
int2.pt = p;
}
//------------------------------------------------------------------------------
bool Clipper::FixupIntersections()
{
if ( !m_IntersectNodes->next ) return true;
CopyAELToSEL();
IntersectNode *int1 = m_IntersectNodes;
IntersectNode *int2 = m_IntersectNodes->next;
while (int2)
{
TEdge *e1 = int1->edge1;
TEdge *e2;
if (e1->prevInSEL == int1->edge2) e2 = e1->prevInSEL;
else if (e1->nextInSEL == int1->edge2) e2 = e1->nextInSEL;
else
{
//The current intersection is out of order, so try and swap it with
//a subsequent intersection ...
while (int2)
{
if (int2->edge1->nextInSEL == int2->edge2 ||
int2->edge1->prevInSEL == int2->edge2) break;
else int2 = int2->next;
}
if ( !int2 ) return false; //oops!!!
//found an intersect node that can be swapped ...
SwapIntersectNodes(*int1, *int2);
e1 = int1->edge1;
e2 = int1->edge2;
}
SwapPositionsInSEL(e1, e2);
int1 = int1->next;
int2 = int1->next;
}
m_SortedEdges = 0;
//finally, check the last intersection too ...
return (int1->edge1->prevInSEL == int1->edge2 ||
int1->edge1->nextInSEL == int1->edge2);
}
//------------------------------------------------------------------------------
bool E2InsertsBeforeE1(TEdge &e1, TEdge &e2)
{
return e2.xcurr == e1.xcurr ? e2.dx > e1.dx : e2.xcurr < e1.xcurr;
}
//------------------------------------------------------------------------------
void Clipper::InsertEdgeIntoAEL(TEdge *edge)
{
edge->prevInAEL = 0;
edge->nextInAEL = 0;
if( !m_ActiveEdges )
{
m_ActiveEdges = edge;
}
else if( E2InsertsBeforeE1(*m_ActiveEdges, *edge) )
{
edge->nextInAEL = m_ActiveEdges;
m_ActiveEdges->prevInAEL = edge;
m_ActiveEdges = edge;
} else
{
TEdge* e = m_ActiveEdges;
while( e->nextInAEL && !E2InsertsBeforeE1(*e->nextInAEL , *edge) )
e = e->nextInAEL;
edge->nextInAEL = e->nextInAEL;
if( e->nextInAEL ) e->nextInAEL->prevInAEL = edge;
edge->prevInAEL = e;
e->nextInAEL = edge;
}
}
//----------------------------------------------------------------------
void Clipper::DoEdge1(TEdge *edge1, TEdge *edge2, const IntPoint &pt)
{
AddOutPt(edge1, pt);
SwapSides(*edge1, *edge2);
SwapPolyIndexes(*edge1, *edge2);
}
//----------------------------------------------------------------------
void Clipper::DoEdge2(TEdge *edge1, TEdge *edge2, const IntPoint &pt)
{
AddOutPt(edge2, pt);
SwapSides(*edge1, *edge2);
SwapPolyIndexes(*edge1, *edge2);
}
//----------------------------------------------------------------------
void Clipper::DoBothEdges(TEdge *edge1, TEdge *edge2, const IntPoint &pt)
{
AddOutPt(edge1, pt);
AddOutPt(edge2, pt);
SwapSides( *edge1 , *edge2 );
SwapPolyIndexes( *edge1 , *edge2 );
}
//----------------------------------------------------------------------
void Clipper::CheckHoleLinkages1(OutRec *outRec1, OutRec *outRec2)
{
//when a polygon is split into 2 polygons, make sure any holes the original
//polygon contained link to the correct polygon ...
for (PolyOutList::size_type i = 0; i < m_PolyOuts.size(); ++i)
{
OutRec *orec = m_PolyOuts[i];
if (orec->isHole && orec->bottomPt && orec->FirstLeft == outRec1 &&
!PointInPolygon(orec->bottomPt->pt, outRec1->pts, m_UseFullRange))
orec->FirstLeft = outRec2;
}
}
//----------------------------------------------------------------------
void Clipper::CheckHoleLinkages2(OutRec *outRec1, OutRec *outRec2)
{
//if a hole is owned by outRec2 then make it owned by outRec1 ...
for (PolyOutList::size_type i = 0; i < m_PolyOuts.size(); ++i)
if (m_PolyOuts[i]->isHole && m_PolyOuts[i]->bottomPt &&
m_PolyOuts[i]->FirstLeft == outRec2)
m_PolyOuts[i]->FirstLeft = outRec1;
}
//----------------------------------------------------------------------
void Clipper::JoinCommonEdges(bool fixHoleLinkages)
{
for (JoinList::size_type i = 0; i < m_Joins.size(); i++)
{
JoinRec* j = m_Joins[i];
OutRec *outRec1 = m_PolyOuts[j->poly1Idx];
OutPt *pp1a = outRec1->pts;
OutRec *outRec2 = m_PolyOuts[j->poly2Idx];
OutPt *pp2a = outRec2->pts;
IntPoint pt1 = j->pt2a, pt2 = j->pt2b;
IntPoint pt3 = j->pt1a, pt4 = j->pt1b;
if (!FindSegment(pp1a, pt1, pt2)) continue;
if (j->poly1Idx == j->poly2Idx)
{
//we're searching the same polygon for overlapping segments so
//segment 2 mustn't be the same as segment 1 ...
pp2a = pp1a->next;
if (!FindSegment(pp2a, pt3, pt4) || (pp2a == pp1a)) continue;
}
else if (!FindSegment(pp2a, pt3, pt4)) continue;
if (!GetOverlapSegment(pt1, pt2, pt3, pt4, pt1, pt2)) continue;
OutPt *p1, *p2, *p3, *p4;
OutPt *prev = pp1a->prev;
//get p1 & p2 polypts - the overlap start & endpoints on poly1
if (PointsEqual(pp1a->pt, pt1)) p1 = pp1a;
else if (PointsEqual(prev->pt, pt1)) p1 = prev;
else p1 = InsertPolyPtBetween(pp1a, prev, pt1);
if (PointsEqual(pp1a->pt, pt2)) p2 = pp1a;
else if (PointsEqual(prev->pt, pt2)) p2 = prev;
else if ((p1 == pp1a) || (p1 == prev))
p2 = InsertPolyPtBetween(pp1a, prev, pt2);
else if (Pt3IsBetweenPt1AndPt2(pp1a->pt, p1->pt, pt2))
p2 = InsertPolyPtBetween(pp1a, p1, pt2); else
p2 = InsertPolyPtBetween(p1, prev, pt2);
//get p3 & p4 polypts - the overlap start & endpoints on poly2
prev = pp2a->prev;
if (PointsEqual(pp2a->pt, pt1)) p3 = pp2a;
else if (PointsEqual(prev->pt, pt1)) p3 = prev;
else p3 = InsertPolyPtBetween(pp2a, prev, pt1);
if (PointsEqual(pp2a->pt, pt2)) p4 = pp2a;
else if (PointsEqual(prev->pt, pt2)) p4 = prev;
else if ((p3 == pp2a) || (p3 == prev))
p4 = InsertPolyPtBetween(pp2a, prev, pt2);
else if (Pt3IsBetweenPt1AndPt2(pp2a->pt, p3->pt, pt2))
p4 = InsertPolyPtBetween(pp2a, p3, pt2); else
p4 = InsertPolyPtBetween(p3, prev, pt2);
//p1.pt == p3.pt and p2.pt == p4.pt so join p1 to p3 and p2 to p4 ...
if (p1->next == p2 && p3->prev == p4)
{
p1->next = p3;
p3->prev = p1;
p2->prev = p4;
p4->next = p2;
}
else if (p1->prev == p2 && p3->next == p4)
{
p1->prev = p3;
p3->next = p1;
p2->next = p4;
p4->prev = p2;
}
else
continue; //an orientation is probably wrong
if (j->poly2Idx == j->poly1Idx)
{
//instead of joining two polygons, we've just created a new one by
//splitting one polygon into two.
outRec1->pts = GetBottomPt(p1);
outRec1->bottomPt = outRec1->pts;
outRec1->bottomPt->idx = outRec1->idx;
outRec2 = CreateOutRec();
m_PolyOuts.push_back(outRec2);
outRec2->idx = (int)m_PolyOuts.size()-1;
j->poly2Idx = outRec2->idx;
outRec2->pts = GetBottomPt(p2);
outRec2->bottomPt = outRec2->pts;
outRec2->bottomPt->idx = outRec2->idx;
if (PointInPolygon(outRec2->pts->pt, outRec1->pts, m_UseFullRange))
{
//outRec2 is contained by outRec1 ...
outRec2->isHole = !outRec1->isHole;
outRec2->FirstLeft = outRec1;
if (outRec2->isHole ==
(m_ReverseOutput ^ Orientation(outRec2, m_UseFullRange)))
ReversePolyPtLinks(*outRec2->pts);
} else if (PointInPolygon(outRec1->pts->pt, outRec2->pts, m_UseFullRange))
{
//outRec1 is contained by outRec2 ...
outRec2->isHole = outRec1->isHole;
outRec1->isHole = !outRec2->isHole;
outRec2->FirstLeft = outRec1->FirstLeft;
outRec1->FirstLeft = outRec2;
if (outRec1->isHole ==
(m_ReverseOutput ^ Orientation(outRec1, m_UseFullRange)))
ReversePolyPtLinks(*outRec1->pts);
//make sure any contained holes now link to the correct polygon ...
if (fixHoleLinkages) CheckHoleLinkages1(outRec1, outRec2);
} else
{
outRec2->isHole = outRec1->isHole;
outRec2->FirstLeft = outRec1->FirstLeft;
//make sure any contained holes now link to the correct polygon ...
if (fixHoleLinkages) CheckHoleLinkages1(outRec1, outRec2);
}
//now fixup any subsequent joins that match this polygon
for (JoinList::size_type k = i+1; k < m_Joins.size(); k++)
{
JoinRec* j2 = m_Joins[k];
if (j2->poly1Idx == j->poly1Idx && PointIsVertex(j2->pt1a, p2))
j2->poly1Idx = j->poly2Idx;
if (j2->poly2Idx == j->poly1Idx && PointIsVertex(j2->pt2a, p2))
j2->poly2Idx = j->poly2Idx;
}
//now cleanup redundant edges too ...
FixupOutPolygon(*outRec1);
FixupOutPolygon(*outRec2);
if (Orientation(outRec1, m_UseFullRange) != (Area(*outRec1, m_UseFullRange) > 0))
DisposeBottomPt(*outRec1);
if (Orientation(outRec2, m_UseFullRange) != (Area(*outRec2, m_UseFullRange) > 0))
DisposeBottomPt(*outRec2);
} else
{
//joined 2 polygons together ...
//make sure any holes contained by outRec2 now link to outRec1 ...
if (fixHoleLinkages) CheckHoleLinkages2(outRec1, outRec2);
//now cleanup redundant edges too ...
FixupOutPolygon(*outRec1);
if (outRec1->pts)
{
outRec1->isHole = !Orientation(outRec1, m_UseFullRange);
if (outRec1->isHole && !outRec1->FirstLeft)
outRec1->FirstLeft = outRec2->FirstLeft;
}
//delete the obsolete pointer ...
int OKIdx = outRec1->idx;
int ObsoleteIdx = outRec2->idx;
outRec2->pts = 0;
outRec2->bottomPt = 0;
outRec2->AppendLink = outRec1;
//now fixup any subsequent Joins that match this polygon
for (JoinList::size_type k = i+1; k < m_Joins.size(); k++)
{
JoinRec* j2 = m_Joins[k];
if (j2->poly1Idx == ObsoleteIdx) j2->poly1Idx = OKIdx;
if (j2->poly2Idx == ObsoleteIdx) j2->poly2Idx = OKIdx;
}
}
}
}
//------------------------------------------------------------------------------
void ReversePolygon(Polygon& p)
{
std::reverse(p.begin(), p.end());
}
//------------------------------------------------------------------------------
void ReversePolygons(Polygons& p)
{
for (Polygons::size_type i = 0; i < p.size(); ++i)
ReversePolygon(p[i]);
}
//------------------------------------------------------------------------------
// OffsetPolygon functions ...
//------------------------------------------------------------------------------
struct DoublePoint
{
double X;
double Y;
DoublePoint(double x = 0, double y = 0) : X(x), Y(y) {}
};
//------------------------------------------------------------------------------
Polygon BuildArc(const IntPoint &pt,
const double a1, const double a2, const double r)
{
long64 steps = std::max(6, int(std::sqrt(std::fabs(r)) * std::fabs(a2 - a1)));
if (steps > 0x100000) steps = 0x100000;
int n = (unsigned)steps;
Polygon result(n);
double da = (a2 - a1) / (n -1);
double a = a1;
for (int i = 0; i < n; ++i)
{
result[i].X = pt.X + Round(std::cos(a)*r);
result[i].Y = pt.Y + Round(std::sin(a)*r);
a += da;
}
return result;
}
//------------------------------------------------------------------------------
DoublePoint GetUnitNormal( const IntPoint &pt1, const IntPoint &pt2)
{
if(pt2.X == pt1.X && pt2.Y == pt1.Y)
return DoublePoint(0, 0);
double dx = (double)(pt2.X - pt1.X);
double dy = (double)(pt2.Y - pt1.Y);
double f = 1 *1.0/ std::sqrt( dx*dx + dy*dy );
dx *= f;
dy *= f;
return DoublePoint(dy, -dx);
}
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
class PolyOffsetBuilder
{
private:
Polygons m_p;
Polygon* m_curr_poly;
std::vector<DoublePoint> normals;
double m_delta, m_RMin, m_R;
size_t m_i, m_j, m_k;
static const int buffLength = 128;
JoinType m_jointype;
public:
PolyOffsetBuilder(const Polygons& in_polys, Polygons& out_polys,
double delta, JoinType jointype, double MiterLimit)
{
//nb precondition - out_polys != ptsin_polys
if (NEAR_ZERO(delta))
{
out_polys = in_polys;
return;
}
this->m_p = in_polys;
this->m_delta = delta;
this->m_jointype = jointype;
if (MiterLimit <= 1) MiterLimit = 1;
m_RMin = 2/(MiterLimit*MiterLimit);
double deltaSq = delta*delta;
out_polys.clear();
out_polys.resize(in_polys.size());
for (m_i = 0; m_i < in_polys.size(); m_i++)
{
m_curr_poly = &out_polys[m_i];
size_t len = in_polys[m_i].size();
if (len > 1 && m_p[m_i][0].X == m_p[m_i][len - 1].X &&
m_p[m_i][0].Y == m_p[m_i][len-1].Y) len--;
//when 'shrinking' polygons - to minimize artefacts
//strip those polygons that have an area < pi * delta^2 ...
double a1 = Area(in_polys[m_i]);
if (delta < 0) { if (a1 > 0 && a1 < deltaSq *pi) len = 0; }
else if (a1 < 0 && -a1 < deltaSq *pi) len = 0; //holes have neg. area
if (len == 0 || (len < 3 && delta <= 0))
continue;
else if (len == 1)
{
Polygon arc;
arc = BuildArc(in_polys[m_i][len-1], 0, 2 * pi, delta);
out_polys[m_i] = arc;
continue;
}
//build normals ...
normals.clear();
normals.resize(len);
normals[len-1] = GetUnitNormal(in_polys[m_i][len-1], in_polys[m_i][0]);
for (m_j = 0; m_j < len -1; ++m_j)
normals[m_j] = GetUnitNormal(in_polys[m_i][m_j], in_polys[m_i][m_j+1]);
m_k = len -1;
for (m_j = 0; m_j < len; ++m_j)
{
switch (jointype)
{
case jtMiter:
{
m_R = 1 + (normals[m_j].X*normals[m_k].X +
normals[m_j].Y*normals[m_k].Y);
if (m_R >= m_RMin) DoMiter(); else DoSquare(MiterLimit);
break;
}
case jtSquare: DoSquare(); break;
case jtRound: DoRound(); break;
}
m_k = m_j;
}
}
//finally, clean up untidy corners using Clipper ...
Clipper clpr;
clpr.AddPolygons(out_polys, ptSubject);
if (delta > 0)
{
if (!clpr.Execute(ctUnion, out_polys, pftPositive, pftPositive))
out_polys.clear();
}
else
{
IntRect r = clpr.GetBounds();
Polygon outer(4);
outer[0] = IntPoint(r.left - 10, r.bottom + 10);
outer[1] = IntPoint(r.right + 10, r.bottom + 10);
outer[2] = IntPoint(r.right + 10, r.top - 10);
outer[3] = IntPoint(r.left - 10, r.top - 10);
clpr.AddPolygon(outer, ptSubject);
if (clpr.Execute(ctUnion, out_polys, pftNegative, pftNegative))
{
out_polys.erase(out_polys.begin());
ReversePolygons(out_polys);
} else
out_polys.clear();
}
}
//------------------------------------------------------------------------------
private:
void AddPoint(const IntPoint& pt)
{
Polygon::size_type len = m_curr_poly->size();
if (len == m_curr_poly->capacity())
m_curr_poly->reserve(len + buffLength);
m_curr_poly->push_back(pt);
}
//------------------------------------------------------------------------------
void DoSquare(double mul = 1.0)
{
IntPoint pt1 = IntPoint((long64)Round(m_p[m_i][m_j].X + normals[m_k].X * m_delta),
(long64)Round(m_p[m_i][m_j].Y + normals[m_k].Y * m_delta));
IntPoint pt2 = IntPoint((long64)Round(m_p[m_i][m_j].X + normals[m_j].X * m_delta),
(long64)Round(m_p[m_i][m_j].Y + normals[m_j].Y * m_delta));
if ((normals[m_k].X * normals[m_j].Y - normals[m_j].X * normals[m_k].Y) * m_delta >= 0)
{
double a1 = std::atan2(normals[m_k].Y, normals[m_k].X);
double a2 = std::atan2(-normals[m_j].Y, -normals[m_j].X);
a1 = std::fabs(a2 - a1);
if (a1 > pi) a1 = pi * 2 - a1;
double dx = std::tan((pi - a1)/4) * std::fabs(m_delta * mul);
pt1 = IntPoint((long64)(pt1.X -normals[m_k].Y * dx),
(long64)(pt1.Y + normals[m_k].X * dx));
AddPoint(pt1);
pt2 = IntPoint((long64)(pt2.X + normals[m_j].Y * dx),
(long64)(pt2.Y -normals[m_j].X * dx));
AddPoint(pt2);
}
else
{
AddPoint(pt1);
AddPoint(m_p[m_i][m_j]);
AddPoint(pt2);
}
}
//------------------------------------------------------------------------------
void DoMiter()
{
if ((normals[m_k].X * normals[m_j].Y - normals[m_j].X * normals[m_k].Y) * m_delta >= 0)
{
double q = m_delta / m_R;
AddPoint(IntPoint((long64)Round(m_p[m_i][m_j].X +
(normals[m_k].X + normals[m_j].X) * q),
(long64)Round(m_p[m_i][m_j].Y + (normals[m_k].Y + normals[m_j].Y) * q)));
}
else
{
IntPoint pt1 = IntPoint((long64)Round(m_p[m_i][m_j].X + normals[m_k].X *
m_delta), (long64)Round(m_p[m_i][m_j].Y + normals[m_k].Y * m_delta));
IntPoint pt2 = IntPoint((long64)Round(m_p[m_i][m_j].X + normals[m_j].X *
m_delta), (long64)Round(m_p[m_i][m_j].Y + normals[m_j].Y * m_delta));
AddPoint(pt1);
AddPoint(m_p[m_i][m_j]);
AddPoint(pt2);
}
}
//------------------------------------------------------------------------------
void DoRound()
{
IntPoint pt1 = IntPoint((long64)Round(m_p[m_i][m_j].X + normals[m_k].X * m_delta),
(long64)Round(m_p[m_i][m_j].Y + normals[m_k].Y * m_delta));
IntPoint pt2 = IntPoint((long64)Round(m_p[m_i][m_j].X + normals[m_j].X * m_delta),
(long64)Round(m_p[m_i][m_j].Y + normals[m_j].Y * m_delta));
AddPoint(pt1);
//round off reflex angles (ie > 180 deg) unless almost flat (ie < ~10deg).
if ((normals[m_k].X*normals[m_j].Y - normals[m_j].X*normals[m_k].Y) * m_delta >= 0)
{
if (normals[m_j].X * normals[m_k].X + normals[m_j].Y * normals[m_k].Y < 0.985)
{
double a1 = std::atan2(normals[m_k].Y, normals[m_k].X);
double a2 = std::atan2(normals[m_j].Y, normals[m_j].X);
if (m_delta > 0 && a2 < a1) a2 += pi *2;
else if (m_delta < 0 && a2 > a1) a2 -= pi *2;
Polygon arc = BuildArc(m_p[m_i][m_j], a1, a2, m_delta);
for (Polygon::size_type m = 0; m < arc.size(); m++)
AddPoint(arc[m]);
}
}
else
AddPoint(m_p[m_i][m_j]);
AddPoint(pt2);
}
//--------------------------------------------------------------------------
}; //end PolyOffsetBuilder
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
void OffsetPolygons(const Polygons &in_polys, Polygons &out_polys,
double delta, JoinType jointype, double MiterLimit)
{
if (&out_polys == &in_polys)
{
Polygons poly2(in_polys);
PolyOffsetBuilder(poly2, out_polys, delta, jointype, MiterLimit);
}
else PolyOffsetBuilder(in_polys, out_polys, delta, jointype, MiterLimit);
}
//------------------------------------------------------------------------------
void SimplifyPolygon(const Polygon &in_poly, Polygons &out_polys, PolyFillType fillType)
{
Clipper c;
c.AddPolygon(in_poly, ptSubject);
c.Execute(ctUnion, out_polys, fillType, fillType);
}
//------------------------------------------------------------------------------
void SimplifyPolygons(const Polygons &in_polys, Polygons &out_polys, PolyFillType fillType)
{
Clipper c;
c.AddPolygons(in_polys, ptSubject);
c.Execute(ctUnion, out_polys, fillType, fillType);
}
//------------------------------------------------------------------------------
void SimplifyPolygons(Polygons &polys, PolyFillType fillType)
{
SimplifyPolygons(polys, polys, fillType);
}
//------------------------------------------------------------------------------
std::ostream& operator <<(std::ostream &s, IntPoint& p)
{
s << p.X << ' ' << p.Y << "\n";
return s;
}
//------------------------------------------------------------------------------
std::ostream& operator <<(std::ostream &s, Polygon &p)
{
for (Polygon::size_type i = 0; i < p.size(); i++)
s << p[i];
s << "\n";
return s;
}
//------------------------------------------------------------------------------
std::ostream& operator <<(std::ostream &s, Polygons &p)
{
for (Polygons::size_type i = 0; i < p.size(); i++)
s << p[i];
s << "\n";
return s;
}
//------------------------------------------------------------------------------
} //ClipperLib namespace
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