/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
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*/
#include <basegfx/polygon/b2dpolygontriangulator.hxx>
#include <osl/diagnose.h>
#include <basegfx/point/b2dpoint.hxx>
#include <basegfx/polygon/b2dpolygon.hxx>
#include <basegfx/vector/b2dvector.hxx>
#include <basegfx/polygon/b2dpolygontools.hxx>
#include <basegfx/polygon/b2dpolypolygontools.hxx>
#include <basegfx/range/b2drange.hxx>
#include <basegfx/numeric/ftools.hxx>
#include <algorithm>
namespace basegfx
{
namespace
{
class EdgeEntry
{
EdgeEntry* mpNext;
B2DPoint maStart;
B2DPoint maEnd;
double mfAtan2;
public:
EdgeEntry(const B2DPoint& rStart, const B2DPoint& rEnd)
: mpNext(0L),
maStart(rStart),
maEnd(rEnd),
mfAtan2(0.0)
{
// make sure edge goes down. If horizontal, let it go to the right (left-handed).
bool bSwap(false);
if(::basegfx::fTools::equal(maStart.getY(), maEnd.getY()))
{
if(maStart.getX() > maEnd.getX())
{
bSwap = true;
}
}
else if(maStart.getY() > maEnd.getY())
{
bSwap = true;
}
if(bSwap)
{
maStart = rEnd;
maEnd = rStart;
}
mfAtan2 = atan2(maEnd.getY() - maStart.getY(), maEnd.getX() - maStart.getX());
}
~EdgeEntry()
{
}
bool operator<(const EdgeEntry& rComp) const
{
if(::basegfx::fTools::equal(maStart.getY(), rComp.maStart.getY()))
{
if(::basegfx::fTools::equal(maStart.getX(), rComp.maStart.getX()))
{
// same in x and y -> same start point. Sort emitting vectors from left to right.
return (mfAtan2 > rComp.mfAtan2);
}
return (maStart.getX() < rComp.maStart.getX());
}
return (maStart.getY() < rComp.maStart.getY());
}
bool operator==(const EdgeEntry& rComp) const
{
return (maStart.equal(rComp.maStart) && maEnd.equal(rComp.maEnd));
}
bool operator!=(const EdgeEntry& rComp) const
{
return !(*this == rComp);
}
const B2DPoint& getStart() const { return maStart; }
const B2DPoint& getEnd() const { return maEnd; }
EdgeEntry* getNext() const { return mpNext; }
void setNext(EdgeEntry* pNext) { mpNext = pNext; }
};
typedef ::std::vector< EdgeEntry > EdgeEntries;
typedef ::std::vector< EdgeEntry* > EdgeEntryPointers;
class Triangulator
{
EdgeEntry* mpList;
EdgeEntries maStartEntries;
EdgeEntryPointers maNewEdgeEntries;
B2DPolygon maResult;
void handleClosingEdge(const B2DPoint& rStart, const B2DPoint& rEnd);
bool CheckPointInTriangle(EdgeEntry* pEdgeA, EdgeEntry* pEdgeB, const B2DPoint& rTestPoint);
void createTriangle(const B2DPoint& rA, const B2DPoint& rB, const B2DPoint& rC);
public:
explicit Triangulator(const B2DPolyPolygon& rCandidate);
~Triangulator();
const B2DPolygon getResult() const { return maResult; }
};
void Triangulator::handleClosingEdge(const B2DPoint& rStart, const B2DPoint& rEnd)
{
// create an entry, else the comparison might use the wrong edges
EdgeEntry aNew(rStart, rEnd);
EdgeEntry* pCurr = mpList;
EdgeEntry* pPrev = 0L;
while(pCurr
&& pCurr->getStart().getY() <= aNew.getStart().getY()
&& *pCurr != aNew)
{
pPrev = pCurr;
pCurr = pCurr->getNext();
}
if(pCurr && *pCurr == aNew)
{
// found closing edge, remove
if(pPrev)
{
pPrev->setNext(pCurr->getNext());
}
else
{
mpList = pCurr->getNext();
}
}
else
{
// insert closing edge
EdgeEntry* pNew = new EdgeEntry(aNew);
maNewEdgeEntries.push_back(pNew);
pCurr = mpList;
pPrev = 0L;
while(pCurr && *pCurr < *pNew)
{
pPrev = pCurr;
pCurr = pCurr->getNext();
}
if(pPrev)
{
pNew->setNext(pPrev->getNext());
pPrev->setNext(pNew);
}
else
{
pNew->setNext(mpList);
mpList = pNew;
}
}
}
bool Triangulator::CheckPointInTriangle(EdgeEntry* pEdgeA, EdgeEntry* pEdgeB, const B2DPoint& rTestPoint)
{
// inside triangle or on edge?
if(tools::isPointInTriangle(pEdgeA->getStart(), pEdgeA->getEnd(), pEdgeB->getEnd(), rTestPoint, true))
{
// but not on point
if(!rTestPoint.equal(pEdgeA->getEnd()) && !rTestPoint.equal(pEdgeB->getEnd()))
{
// found point in triangle -> split triangle inserting two edges
EdgeEntry* pStart = new EdgeEntry(pEdgeA->getStart(), rTestPoint);
EdgeEntry* pEnd = new EdgeEntry(*pStart);
maNewEdgeEntries.push_back(pStart);
maNewEdgeEntries.push_back(pEnd);
pStart->setNext(pEnd);
pEnd->setNext(pEdgeA->getNext());
pEdgeA->setNext(pStart);
return false;
}
}
return true;
}
void Triangulator::createTriangle(const B2DPoint& rA, const B2DPoint& rB, const B2DPoint& rC)
{
maResult.append(rA);
maResult.append(rB);
maResult.append(rC);
}
// consume as long as there are edges
Triangulator::Triangulator(const B2DPolyPolygon& rCandidate)
: mpList(0L)
{
// add all available edges to the single linked local list which will be sorted
// by Y,X,atan2 when adding nodes
if(rCandidate.count())
{
for(sal_uInt32 a(0L); a < rCandidate.count(); a++)
{
const B2DPolygon aPolygonCandidate(rCandidate.getB2DPolygon(a));
const sal_uInt32 nCount(aPolygonCandidate.count());
if(nCount > 2L)
{
B2DPoint aPrevPnt(aPolygonCandidate.getB2DPoint(nCount - 1L));
for(sal_uInt32 b(0L); b < nCount; b++)
{
B2DPoint aNextPnt(aPolygonCandidate.getB2DPoint(b));
if( !aPrevPnt.equal(aNextPnt) )
{
maStartEntries.push_back(EdgeEntry(aPrevPnt, aNextPnt));
}
aPrevPnt = aNextPnt;
}
}
}
if(!maStartEntries.empty())
{
// sort initial list
::std::sort(maStartEntries.begin(), maStartEntries.end());
// insert to own simply linked list
EdgeEntries::iterator aPos(maStartEntries.begin());
mpList = &(*aPos++);
EdgeEntry* pLast = mpList;
while(aPos != maStartEntries.end())
{
EdgeEntry* pEntry = &(*aPos++);
pLast->setNext(pEntry);
pLast = pEntry;
}
}
}
while(mpList)
{
if(mpList->getNext() && mpList->getNext()->getStart().equal(mpList->getStart()))
{
// next candidate. There are two edges and start point is equal.
// Length is not zero.
EdgeEntry* pEdgeA = mpList;
EdgeEntry* pEdgeB = pEdgeA->getNext();
if( pEdgeA->getEnd().equal(pEdgeB->getEnd()) )
{
// start and end equal -> neutral triangle, delete both
mpList = pEdgeB->getNext();
}
else
{
const B2DVector aLeft(pEdgeA->getEnd() - pEdgeA->getStart());
const B2DVector aRight(pEdgeB->getEnd() - pEdgeA->getStart());
if(B2VectorOrientation::Neutral == getOrientation(aLeft, aRight))
{
// edges are parallel and have different length -> neutral triangle,
// delete both edges and handle closing edge
mpList = pEdgeB->getNext();
handleClosingEdge(pEdgeA->getEnd(), pEdgeB->getEnd());
}
else
{
// not parallel, look for points inside
B2DRange aRange(pEdgeA->getStart(), pEdgeA->getEnd());
aRange.expand(pEdgeB->getEnd());
EdgeEntry* pTestEdge = pEdgeB->getNext();
bool bNoPointInTriangle(true);
// look for start point in triangle
while(bNoPointInTriangle && pTestEdge)
{
if(aRange.getMaxY() < pTestEdge->getStart().getY())
{
// edge is below test range and edges are sorted -> stop looking
break;
}
else
{
// do not look for edges with same start point, they are sorted and cannot end inside.
if(!pTestEdge->getStart().equal(pEdgeA->getStart()))
{
if(aRange.isInside(pTestEdge->getStart()))
{
bNoPointInTriangle = CheckPointInTriangle(pEdgeA, pEdgeB, pTestEdge->getStart());
}
}
}
// next candidate
pTestEdge = pTestEdge->getNext();
}
if(bNoPointInTriangle)
{
// look for end point in triange
pTestEdge = pEdgeB->getNext();
while(bNoPointInTriangle && pTestEdge)
{
if(aRange.getMaxY() < pTestEdge->getStart().getY())
{
// edge is below test range and edges are sorted -> stop looking
break;
}
else
{
// do not look for edges with same end point, they are sorted and cannot end inside.
if(!pTestEdge->getEnd().equal(pEdgeA->getStart()))
{
if(aRange.isInside(pTestEdge->getEnd()))
{
bNoPointInTriangle = CheckPointInTriangle(pEdgeA, pEdgeB, pTestEdge->getEnd());
}
}
}
// next candidate
pTestEdge = pTestEdge->getNext();
}
}
if(bNoPointInTriangle)
{
// create triangle, remove edges, handle closing edge
mpList = pEdgeB->getNext();
createTriangle(pEdgeA->getStart(), pEdgeB->getEnd(), pEdgeA->getEnd());
handleClosingEdge(pEdgeA->getEnd(), pEdgeB->getEnd());
}
}
}
}
else
{
// only one entry at start point, delete it
mpList = mpList->getNext();
}
}
}
Triangulator::~Triangulator()
{
EdgeEntryPointers::iterator aIter(maNewEdgeEntries.begin());
while(aIter != maNewEdgeEntries.end())
{
delete (*aIter++);
}
}
} // end of anonymous namespace
} // end of namespace basegfx
namespace basegfx
{
namespace triangulator
{
B2DPolygon triangulate(const B2DPolygon& rCandidate)
{
B2DPolygon aRetval;
// subdivide locally (triangulate does not work with beziers), remove double and neutral points
B2DPolygon aCandidate(rCandidate.areControlPointsUsed() ? tools::adaptiveSubdivideByAngle(rCandidate) : rCandidate);
aCandidate.removeDoublePoints();
aCandidate = tools::removeNeutralPoints(aCandidate);
if(2L == aCandidate.count())
{
// candidate IS a triangle, just append
aRetval.append(aCandidate);
}
else if(aCandidate.count() > 2L)
{
if(tools::isConvex(aCandidate))
{
// polygon is convex, just use a triangle fan
tools::addTriangleFan(aCandidate, aRetval);
}
else
{
// polygon is concave.
const B2DPolyPolygon aCandPolyPoly(aCandidate);
Triangulator aTriangulator(aCandPolyPoly);
aRetval = aTriangulator.getResult();
}
}
return aRetval;
}
B2DPolygon triangulate(const B2DPolyPolygon& rCandidate)
{
B2DPolygon aRetval;
// subdivide locally (triangulate does not work with beziers)
B2DPolyPolygon aCandidate(rCandidate.areControlPointsUsed() ? tools::adaptiveSubdivideByAngle(rCandidate) : rCandidate);
if(1L == aCandidate.count())
{
// single polygon -> single polygon triangulation
const B2DPolygon aSinglePolygon(aCandidate.getB2DPolygon(0L));
aRetval = triangulate(aSinglePolygon);
}
else
{
Triangulator aTriangulator(aCandidate);
aRetval = aTriangulator.getResult();
}
return aRetval;
}
} // end of namespace triangulator
} // end of namespace basegfx
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