shape_poly_set.cpp

Go to the documentation of this file.

/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2015-2019 CERN
 * Copyright (C) 2021-2023 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * @author Tomasz Wlostowski <[email protected]>
 * @author Alejandro García Montoro <[email protected]>
 *
 * Point in polygon algorithm adapted from Clipper Library (C) Angus Johnson,
 * subject to Clipper library license.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
#include <algorithm>
#include <assert.h> // for assert
#include <cmath> // for sqrt, cos, hypot, isinf
#include <cstdio>
#include <istream> // for operator<<, operator>>
#include <limits> // for numeric_limits
#include <map>
#include <memory>
#include <set>
#include <string> // for char_traits, operator!=
#include <type_traits> // for swap, move
#include <unordered_set>
#include <vector>
 
#include <clipper.hpp> // for Clipper, PolyNode, Clipp...
#include <clipper2/clipper.h>
#include <geometry/geometry_utils.h>
#include <geometry/polygon_triangulation.h>
#include <geometry/seg.h> // for SEG, OPT_VECTOR2I
#include <geometry/shape.h>
#include <geometry/shape_line_chain.h>
#include <geometry/shape_poly_set.h>
#include <math/box2.h> // for BOX2I
#include <math/util.h> // for KiROUND, rescale
#include <math/vector2d.h> // for VECTOR2I, VECTOR2D, VECTOR2
#include <md5_hash.h>
#include <hash.h>
#include <geometry/shape_segment.h>
#include <geometry/shape_circle.h>
 
// Do not keep this for release. Only for testing clipper
#include <advanced_config.h>
 
#include <wx/log.h>
 
 
SHAPE_POLY_SET::SHAPE_POLY_SET() :
 SHAPE( SH_POLY_SET )
{
}
 
 
SHAPE_POLY_SET::SHAPE_POLY_SET( const BOX2D& aRect ) :
 SHAPE( SH_POLY_SET )
{
 NewOutline();
 Append( VECTOR2I( aRect.GetLeft(), aRect.GetTop() ) );
 Append( VECTOR2I( aRect.GetRight(), aRect.GetTop() ) );
 Append( VECTOR2I( aRect.GetRight(), aRect.GetBottom() ) );
 Append( VECTOR2I( aRect.GetLeft(), aRect.GetBottom() ) );
 Outline( 0 ).SetClosed( true );
}
 
 
SHAPE_POLY_SET::SHAPE_POLY_SET( const SHAPE_LINE_CHAIN& aOutline ) :
 SHAPE( SH_POLY_SET )
{
 AddOutline( aOutline );
}
 
 
SHAPE_POLY_SET::SHAPE_POLY_SET( const POLYGON& aPolygon ) :
 SHAPE( SH_POLY_SET )
{
 AddPolygon( aPolygon );
}
 
 
SHAPE_POLY_SET::SHAPE_POLY_SET( const SHAPE_POLY_SET& aOther ) :
 SHAPE( aOther ),
 m_polys( aOther.m_polys )
{
 if( aOther.IsTriangulationUpToDate() )
 {
 m_triangulatedPolys.reserve( aOther.TriangulatedPolyCount() );
 
 for( unsigned i = 0; i < aOther.TriangulatedPolyCount(); i++ )
 {
 const TRIANGULATED_POLYGON* poly = aOther.TriangulatedPolygon( i );
 m_triangulatedPolys.push_back( std::make_unique<TRIANGULATED_POLYGON>( *poly ) );
 }
 
 m_hash = aOther.GetHash();
 m_triangulationValid = true;
 }
 else
 {
 m_triangulationValid = false;
 m_hash = MD5_HASH();
 m_triangulatedPolys.clear();
 }
}
 
 
SHAPE_POLY_SET::SHAPE_POLY_SET( const SHAPE_POLY_SET& aOther, DROP_TRIANGULATION_FLAG ) :
 SHAPE( aOther ),
 m_polys( aOther.m_polys )
{
 m_triangulationValid = false;
 m_hash = MD5_HASH();
 m_triangulatedPolys.clear();
}
 
 
SHAPE_POLY_SET::~SHAPE_POLY_SET()
{
}
 
 
SHAPE* SHAPE_POLY_SET::Clone() const
{
 return new SHAPE_POLY_SET( *this );
}
 
 
SHAPE_POLY_SET SHAPE_POLY_SET::CloneDropTriangulation() const
{
 return SHAPE_POLY_SET( *this, DROP_TRIANGULATION_FLAG::SINGLETON );
}
 
 
bool SHAPE_POLY_SET::GetRelativeIndices( int aGlobalIdx,
 SHAPE_POLY_SET::VERTEX_INDEX* aRelativeIndices ) const
{
 int polygonIdx = 0;
 unsigned int contourIdx = 0;
 int vertexIdx = 0;
 
 int currentGlobalIdx = 0;
 
 for( polygonIdx = 0; polygonIdx < OutlineCount(); polygonIdx++ )
 {
 const POLYGON& currentPolygon = CPolygon( polygonIdx );
 
 for( contourIdx = 0; contourIdx < currentPolygon.size(); contourIdx++ )
 {
 const SHAPE_LINE_CHAIN& currentContour = currentPolygon[contourIdx];
 int totalPoints = currentContour.PointCount();
 
 for( vertexIdx = 0; vertexIdx < totalPoints; vertexIdx++ )
 {
 // Check if the current vertex is the globally indexed as aGlobalIdx
 if( currentGlobalIdx == aGlobalIdx )
 {
 aRelativeIndices->m_polygon = polygonIdx;
 aRelativeIndices->m_contour = contourIdx;
 aRelativeIndices->m_vertex = vertexIdx;
 
 return true;
 }
 
 // Advance
 currentGlobalIdx++;
 }
 }
 }
 
 return false;
}
 
 
bool SHAPE_POLY_SET::GetGlobalIndex( SHAPE_POLY_SET::VERTEX_INDEX aRelativeIndices,
 int& aGlobalIdx ) const
{
 int selectedVertex = aRelativeIndices.m_vertex;
 unsigned int selectedContour = aRelativeIndices.m_contour;
 unsigned int selectedPolygon = aRelativeIndices.m_polygon;
 
 // Check whether the vertex indices make sense in this poly set
 if( selectedPolygon < m_polys.size() && selectedContour < m_polys[selectedPolygon].size()
 && selectedVertex < m_polys[selectedPolygon][selectedContour].PointCount() )
 {
 POLYGON currentPolygon;
 
 aGlobalIdx = 0;
 
 for( unsigned int polygonIdx = 0; polygonIdx < selectedPolygon; polygonIdx++ )
 {
 currentPolygon = Polygon( polygonIdx );
 
 for( unsigned int contourIdx = 0; contourIdx < currentPolygon.size(); contourIdx++ )
 aGlobalIdx += currentPolygon[contourIdx].PointCount();
 }
 
 currentPolygon = Polygon( selectedPolygon );
 
 for( unsigned int contourIdx = 0; contourIdx < selectedContour; contourIdx++ )
 aGlobalIdx += currentPolygon[contourIdx].PointCount();
 
 aGlobalIdx += selectedVertex;
 
 return true;
 }
 else
 {
 return false;
 }
}
 
 
int SHAPE_POLY_SET::NewOutline()
{
 SHAPE_LINE_CHAIN empty_path;
 POLYGON poly;
 
 empty_path.SetClosed( true );
 poly.push_back( empty_path );
 m_polys.push_back( poly );
 return m_polys.size() - 1;
}
 
 
int SHAPE_POLY_SET::NewHole( int aOutline )
{
 SHAPE_LINE_CHAIN empty_path;
 
 empty_path.SetClosed( true );
 
 // Default outline is the last one
 if( aOutline < 0 )
 aOutline += m_polys.size();
 
 // Add hole to the selected outline
 m_polys[aOutline].push_back( empty_path );
 
 return m_polys.back().size() - 2;
}
 
 
int SHAPE_POLY_SET::Append( int x, int y, int aOutline, int aHole, bool aAllowDuplication )
{
 assert( m_polys.size() );
 
 if( aOutline < 0 )
 aOutline += m_polys.size();
 
 int idx;
 
 if( aHole < 0 )
 idx = 0;
 else
 idx = aHole + 1;
 
 assert( aOutline < (int) m_polys.size() );
 assert( idx < (int) m_polys[aOutline].size() );
 
 m_polys[aOutline][idx].Append( x, y, aAllowDuplication );
 
 return m_polys[aOutline][idx].PointCount();
}
 
 
int SHAPE_POLY_SET::Append( const SHAPE_ARC& aArc, int aOutline, int aHole, double aAccuracy )
{
 assert( m_polys.size() );
 
 if( aOutline < 0 )
 aOutline += m_polys.size();
 
 int idx;
 
 if( aHole < 0 )
 idx = 0;
 else
 idx = aHole + 1;
 
 assert( aOutline < (int) m_polys.size() );
 assert( idx < (int) m_polys[aOutline].size() );
 
 m_polys[aOutline][idx].Append( aArc, aAccuracy );
 
 return m_polys[aOutline][idx].PointCount();
}
 
 
void SHAPE_POLY_SET::InsertVertex( int aGlobalIndex, const VECTOR2I& aNewVertex )
{
 VERTEX_INDEX index;
 
 if( aGlobalIndex < 0 )
 aGlobalIndex = 0;
 
 if( aGlobalIndex >= TotalVertices() )
 {
 Append( aNewVertex );
 }
 else
 {
 // Assure the position to be inserted exists; throw an exception otherwise
 if( GetRelativeIndices( aGlobalIndex, &index ) )
 m_polys[index.m_polygon][index.m_contour].Insert( index.m_vertex, aNewVertex );
 else
 throw( std::out_of_range( "aGlobalIndex-th vertex does not exist" ) );
 }
}
 
 
int SHAPE_POLY_SET::VertexCount( int aOutline, int aHole ) const
{
 if( m_polys.size() == 0 ) // Empty poly set
 return 0;
 
 if( aOutline < 0 ) // Use last outline
 aOutline += m_polys.size();
 
 int idx;
 
 if( aHole < 0 )
 idx = 0;
 else
 idx = aHole + 1;
 
 if( aOutline >= (int) m_polys.size() ) // not existing outline
 return 0;
 
 if( idx >= (int) m_polys[aOutline].size() ) // not existing hole
 return 0;
 
 return m_polys[aOutline][idx].PointCount();
}
 
 
int SHAPE_POLY_SET::FullPointCount() const
{
 int full_count = 0;
 
 if( m_polys.size() == 0 ) // Empty poly set
 return full_count;
 
 for( int ii = 0; ii < OutlineCount(); ii++ )
 {
 // the first polygon in m_polys[ii] is the main contour,
 // only others are holes:
 for( int idx = 0; idx <= HoleCount( ii ); idx++ )
 {
 full_count += m_polys[ii][idx].PointCount();
 }
 }
 
 return full_count;
}
 
 
SHAPE_POLY_SET SHAPE_POLY_SET::Subset( int aFirstPolygon, int aLastPolygon )
{
 assert( aFirstPolygon >= 0 && aLastPolygon <= OutlineCount() );
 
 SHAPE_POLY_SET newPolySet;
 
 for( int index = aFirstPolygon; index < aLastPolygon; index++ )
 newPolySet.m_polys.push_back( Polygon( index ) );
 
 return newPolySet;
}
 
 
const VECTOR2I& SHAPE_POLY_SET::CVertex( int aIndex, int aOutline, int aHole ) const
{
 if( aOutline < 0 )
 aOutline += m_polys.size();
 
 int idx;
 
 if( aHole < 0 )
 idx = 0;
 else
 idx = aHole + 1;
 
 assert( aOutline < (int) m_polys.size() );
 assert( idx < (int) m_polys[aOutline].size() );
 
 return m_polys[aOutline][idx].CPoint( aIndex );
}
 
 
const VECTOR2I& SHAPE_POLY_SET::CVertex( int aGlobalIndex ) const
{
 SHAPE_POLY_SET::VERTEX_INDEX index;
 
 // Assure the passed index references a legal position; abort otherwise
 if( !GetRelativeIndices( aGlobalIndex, &index ) )
 throw( std::out_of_range( "aGlobalIndex-th vertex does not exist" ) );
 
 return m_polys[index.m_polygon][index.m_contour].CPoint( index.m_vertex );
}
 
 
const VECTOR2I& SHAPE_POLY_SET::CVertex( SHAPE_POLY_SET::VERTEX_INDEX index ) const
{
 return CVertex( index.m_vertex, index.m_polygon, index.m_contour - 1 );
}
 
 
bool SHAPE_POLY_SET::GetNeighbourIndexes( int aGlobalIndex, int* aPrevious, int* aNext ) const
{
 SHAPE_POLY_SET::VERTEX_INDEX index;
 
 // If the edge does not exist, throw an exception, it is an illegal access memory error
 if( !GetRelativeIndices( aGlobalIndex, &index ) )
 return false;
 
 // Calculate the previous and next index of aGlobalIndex, corresponding to
 // the same contour;
 VERTEX_INDEX inext = index;
 int lastpoint = m_polys[index.m_polygon][index.m_contour].SegmentCount();
 
 if( index.m_vertex == 0 )
 {
 index.m_vertex = lastpoint;
 inext.m_vertex = 1;
 }
 else if( index.m_vertex == lastpoint )
 {
 index.m_vertex--;
 inext.m_vertex = 0;
 }
 else
 {
 inext.m_vertex++;
 index.m_vertex--;
 }
 
 if( aPrevious )
 {
 int previous;
 GetGlobalIndex( index, previous );
 *aPrevious = previous;
 }
 
 if( aNext )
 {
 int next;
 GetGlobalIndex( inext, next );
 *aNext = next;
 }
 
 return true;
}
 
 
bool SHAPE_POLY_SET::IsPolygonSelfIntersecting( int aPolygonIndex ) const
{
 std::vector<SEG> segments;
 segments.reserve( FullPointCount() );
 
 for( CONST_SEGMENT_ITERATOR it = CIterateSegmentsWithHoles( aPolygonIndex ); it; it++ )
 segments.emplace_back( *it );
 
 std::sort( segments.begin(), segments.end(), []( const SEG& a, const SEG& b )
 {
 int min_a_x = std::min( a.A.x, a.B.x );
 int min_b_x = std::min( b.A.x, b.B.x );
 
 return min_a_x < min_b_x || ( min_a_x == min_b_x && std::min( a.A.y, a.B.y ) < std::min( b.A.y, b.B.y ) );
 } );
 
 for( auto it = segments.begin(); it != segments.end(); ++it )
 {
 SEG& firstSegment = *it;
 
 // Iterate through all remaining segments.
 auto innerIterator = it;
 int max_x = std::max( firstSegment.A.x, firstSegment.B.x );
 int max_y = std::max( firstSegment.A.y, firstSegment.B.y );
 
 // Start in the next segment, we don't want to check collision between a segment and itself
 for( innerIterator++; innerIterator != segments.end(); innerIterator++ )
 {
 SEG& secondSegment = *innerIterator;
 int min_x = std::min( secondSegment.A.x, secondSegment.B.x );
 int min_y = std::min( secondSegment.A.y, secondSegment.B.y );
 
 // We are ordered in minimum point order, so checking the static max (first segment) against
 // the ordered min will tell us if any of the following segments are withing the BBox
 if( max_x < min_x || ( max_x == min_x && max_y < min_y ) )
 break;
 
 int index_diff = std::abs( firstSegment.Index() - secondSegment.Index() );
 bool adjacent = ( index_diff == 1) || (index_diff == ((int)segments.size() - 1) );
 
 // Check whether the two segments built collide, only when they are not adjacent.
 if( !adjacent && firstSegment.Collide( secondSegment, 0 ) )
 return true;
 }
 }
 
 return false;
}
 
 
bool SHAPE_POLY_SET::IsSelfIntersecting() const
{
 for( unsigned int polygon = 0; polygon < m_polys.size(); polygon++ )
 {
 if( IsPolygonSelfIntersecting( polygon ) )
 return true;
 }
 
 return false;
}
 
 
int SHAPE_POLY_SET::AddOutline( const SHAPE_LINE_CHAIN& aOutline )
{
 assert( aOutline.IsClosed() );
 
 POLYGON poly;
 
 poly.push_back( aOutline );
 
 m_polys.push_back( poly );
 
 return m_polys.size() - 1;
}
 
 
int SHAPE_POLY_SET::AddHole( const SHAPE_LINE_CHAIN& aHole, int aOutline )
{
 assert( m_polys.size() );
 
 if( aOutline < 0 )
 aOutline += m_polys.size();
 
 assert( aOutline < (int)m_polys.size() );
 
 POLYGON& poly = m_polys[aOutline];
 
 assert( poly.size() );
 
 poly.push_back( aHole );
 
 return poly.size() - 2;
}
 
 
int SHAPE_POLY_SET::AddPolygon( const POLYGON& apolygon )
{
 m_polys.push_back( apolygon );
 
 return m_polys.size() - 1;
}
 
 
double SHAPE_POLY_SET::Area()
{
 double area = 0.0;
 
 for( int i = 0; i < OutlineCount(); i++ )
 {
 area += Outline( i ).Area( true );
 
 for( int j = 0; j < HoleCount( i ); j++ )
 area -= Hole( i, j ).Area( true );
 }
 
 return area;
}
 
 
int SHAPE_POLY_SET::ArcCount() const
{
 int retval = 0;
 
 for( const POLYGON& poly : m_polys )
 {
 for( size_t i = 0; i < poly.size(); i++ )
 retval += poly[i].ArcCount();
 }
 
 return retval;
}
 
 
void SHAPE_POLY_SET::GetArcs( std::vector<SHAPE_ARC>& aArcBuffer ) const
{
 for( const POLYGON& poly : m_polys )
 {
 for( size_t i = 0; i < poly.size(); i++ )
 {
 for( SHAPE_ARC arc : poly[i].m_arcs )
 aArcBuffer.push_back( arc );
 }
 }
}
 
 
void SHAPE_POLY_SET::ClearArcs()
{
 for( POLYGON& poly : m_polys )
 {
 for( size_t i = 0; i < poly.size(); i++ )
 poly[i].ClearArcs();
 }
}
 
 
void SHAPE_POLY_SET::RebuildHolesFromContours()
{
 std::vector<SHAPE_LINE_CHAIN> contours;
 
 for( const POLYGON& poly : m_polys )
 contours.insert( contours.end(), poly.begin(), poly.end() );
 
 std::map<int, std::set<int>> parentToChildren;
 std::map<int, std::set<int>> childToParents;
 
 for( SHAPE_LINE_CHAIN& contour : contours )
 contour.GenerateBBoxCache();
 
 for( size_t i = 0; i < contours.size(); i++ )
 {
 const SHAPE_LINE_CHAIN& outline = contours[i];
 
 for( size_t j = 0; j < contours.size(); j++ )
 {
 if( i == j )
 continue;
 
 const SHAPE_LINE_CHAIN& candidate = contours[j];
 const VECTOR2I& pt0 = candidate.CPoint( 0 );
 
 if( outline.PointInside( pt0, 0, true ) )
 {
 parentToChildren[i].emplace( j );
 childToParents[j].emplace( i );
 }
 }
 }
 
 std::set<int> topLevelParents;
 
 for( size_t i = 0; i < contours.size(); i++ )
 {
 if( childToParents[i].size() == 0 )
 {
 topLevelParents.emplace( i );
 }
 }
 
 SHAPE_POLY_SET result;
 
 std::function<void( int, int, std::vector<int> )> process;
 
 process = [&]( int myId, int parentOutlineId, std::vector<int> path )
 {
 std::set<int> relParents = childToParents[myId];
 
 for( int pathId : path )
 {
 int erased = relParents.erase( pathId );
 wxASSERT( erased > 0 );
 }
 
 wxASSERT( relParents.size() == 0 );
 
 int myOutline = -1;
 
 bool isOutline = path.size() % 2 == 0;
 
 if( isOutline )
 {
 int outlineId = result.AddOutline( contours[myId] );
 myOutline = outlineId;
 }
 else
 {
 wxASSERT( parentOutlineId != -1 );
 int holeId = result.AddHole( contours[myId], parentOutlineId );
 }
 
 auto it = parentToChildren.find( myId );
 if( it != parentToChildren.end() )
 {
 std::vector<int> thisPath = path;
 thisPath.emplace_back( myId );
 
 std::set<int> thisPathSet;
 thisPathSet.insert( thisPath.begin(), thisPath.end() );
 
 for( int childId : it->second )
 {
 const std::set<int>& childPathSet = childToParents[childId];
 
 if( thisPathSet != childPathSet )
 continue; // Only interested in immediate children
 
 process( childId, myOutline, thisPath );
 }
 }
 };
 
 for( int topParentId : topLevelParents )
 {
 std::vector<int> path;
 process( topParentId, -1, path );
 }
 
 *this = result;
}
 
 
void SHAPE_POLY_SET::booleanOp( ClipperLib::ClipType aType, const SHAPE_POLY_SET& aOtherShape,
 POLYGON_MODE aFastMode )
{
 booleanOp( aType, *this, aOtherShape, aFastMode );
}
 
 
void SHAPE_POLY_SET::booleanOp( ClipperLib::ClipType aType, const SHAPE_POLY_SET& aShape,
 const SHAPE_POLY_SET& aOtherShape, POLYGON_MODE aFastMode )
{
 if( ( aShape.OutlineCount() > 1 || aOtherShape.OutlineCount() > 0 )
 && ( aShape.ArcCount() > 0 || aOtherShape.ArcCount() > 0 ) )
 {
 wxFAIL_MSG( wxT( "Boolean ops on curved polygons are not supported. You should call "
 "ClearArcs() before carrying out the boolean operation." ) );
 }
 
 ClipperLib::Clipper c;
 
 c.StrictlySimple( aFastMode == PM_STRICTLY_SIMPLE );
 
 std::vector<CLIPPER_Z_VALUE> zValues;
 std::vector<SHAPE_ARC> arcBuffer;
 std::map<VECTOR2I, CLIPPER_Z_VALUE> newIntersectPoints;
 
 for( const POLYGON& poly : aShape.m_polys )
 {
 for( size_t i = 0; i < poly.size(); i++ )
 {
 c.AddPath( poly[i].convertToClipper( i == 0, zValues, arcBuffer ),
 ClipperLib::ptSubject, true );
 }
 }
 
 for( const POLYGON& poly : aOtherShape.m_polys )
 {
 for( size_t i = 0; i < poly.size(); i++ )
 {
 c.AddPath( poly[i].convertToClipper( i == 0, zValues, arcBuffer ),
 ClipperLib::ptClip, true );
 }
 }
 
 ClipperLib::PolyTree solution;
 
 ClipperLib::ZFillCallback callback =
 [&]( ClipperLib::IntPoint & e1bot, ClipperLib::IntPoint & e1top,
 ClipperLib::IntPoint & e2bot, ClipperLib::IntPoint & e2top,
 ClipperLib::IntPoint & pt )
 {
 auto arcIndex =
 [&]( const ssize_t& aZvalue, const ssize_t& aCompareVal = -1 ) -> ssize_t
 {
 ssize_t retval;
 
 retval = zValues.at( aZvalue ).m_SecondArcIdx;
 
 if( retval == -1 || ( aCompareVal > 0 && retval != aCompareVal ) )
 retval = zValues.at( aZvalue ).m_FirstArcIdx;
 
 return retval;
 };
 
 auto arcSegment =
 [&]( const ssize_t& aBottomZ, const ssize_t aTopZ ) -> ssize_t
 {
 ssize_t retval = arcIndex( aBottomZ );
 
 if( retval != -1 )
 {
 if( retval != arcIndex( aTopZ, retval ) )
 retval = -1; // Not an arc segment as the two indices do not match
 }
 
 return retval;
 };
 
 ssize_t e1ArcSegmentIndex = arcSegment( e1bot.Z, e1top.Z );
 ssize_t e2ArcSegmentIndex = arcSegment( e2bot.Z, e2top.Z );
 
 CLIPPER_Z_VALUE newZval;
 
 if( e1ArcSegmentIndex != -1 )
 {
 newZval.m_FirstArcIdx = e1ArcSegmentIndex;
 newZval.m_SecondArcIdx = e2ArcSegmentIndex;
 }
 else
 {
 newZval.m_FirstArcIdx = e2ArcSegmentIndex;
 newZval.m_SecondArcIdx = -1;
 }
 
 size_t z_value_ptr = zValues.size();
 zValues.push_back( newZval );
 
 // Only worry about arc segments for later processing
 if( newZval.m_FirstArcIdx != -1 )
 newIntersectPoints.insert( { VECTOR2I( pt.X, pt.Y ), newZval } );
 
 pt.Z = z_value_ptr;
 //@todo amend X,Y values to true intersection between arcs or arc and segment
 };
 
 c.ZFillFunction( callback ); // register callback
 
 c.Execute( aType, solution, ClipperLib::pftNonZero, ClipperLib::pftNonZero );
 
 importTree( &solution, zValues, arcBuffer );
}
 
 
void SHAPE_POLY_SET::booleanOp( Clipper2Lib::ClipType aType, const SHAPE_POLY_SET& aOtherShape )
{
 booleanOp( aType, *this, aOtherShape );
}
 
 
void SHAPE_POLY_SET::booleanOp( Clipper2Lib::ClipType aType, const SHAPE_POLY_SET& aShape,
 const SHAPE_POLY_SET& aOtherShape )
{
 if( ( aShape.OutlineCount() > 1 || aOtherShape.OutlineCount() > 0 )
 && ( aShape.ArcCount() > 0 || aOtherShape.ArcCount() > 0 ) )
 {
 wxFAIL_MSG( wxT( "Boolean ops on curved polygons are not supported. You should call "
 "ClearArcs() before carrying out the boolean operation." ) );
 }
 
 Clipper2Lib::Clipper64 c;
 
 std::vector<CLIPPER_Z_VALUE> zValues;
 std::vector<SHAPE_ARC> arcBuffer;
 std::map<VECTOR2I, CLIPPER_Z_VALUE> newIntersectPoints;
 
 Clipper2Lib::Paths64 paths;
 Clipper2Lib::Paths64 clips;
 
 for( const POLYGON& poly : aShape.m_polys )
 {
 for( size_t i = 0; i < poly.size(); i++ )
 {
 paths.push_back( poly[i].convertToClipper2( i == 0, zValues, arcBuffer ) );
 }
 }
 
 for( const POLYGON& poly : aOtherShape.m_polys )
 {
 for( size_t i = 0; i < poly.size(); i++ )
 {
 clips.push_back( poly[i].convertToClipper2( i == 0, zValues, arcBuffer ) );
 }
 }
 
 c.AddSubject( paths );
 c.AddClip( clips );
 
 Clipper2Lib::PolyTree64 solution;
 
 Clipper2Lib::ZCallback64 callback =
 [&]( const Clipper2Lib::Point64 & e1bot, const Clipper2Lib::Point64 & e1top,
 const Clipper2Lib::Point64 & e2bot, const Clipper2Lib::Point64 & e2top,
 Clipper2Lib::Point64 & pt )
 {
 auto arcIndex =
 [&]( const ssize_t& aZvalue, const ssize_t& aCompareVal = -1 ) -> ssize_t
 {
 ssize_t retval;
 
 retval = zValues.at( aZvalue ).m_SecondArcIdx;
 
 if( retval == -1 || ( aCompareVal > 0 && retval != aCompareVal ) )
 retval = zValues.at( aZvalue ).m_FirstArcIdx;
 
 return retval;
 };
 
 auto arcSegment =
 [&]( const ssize_t& aBottomZ, const ssize_t aTopZ ) -> ssize_t
 {
 ssize_t retval = arcIndex( aBottomZ );
 
 if( retval != -1 )
 {
 if( retval != arcIndex( aTopZ, retval ) )
 retval = -1; // Not an arc segment as the two indices do not match
 }
 
 return retval;
 };
 
 ssize_t e1ArcSegmentIndex = arcSegment( e1bot.z, e1top.z );
 ssize_t e2ArcSegmentIndex = arcSegment( e2bot.z, e2top.z );
 
 CLIPPER_Z_VALUE newZval;
 
 if( e1ArcSegmentIndex != -1 )
 {
 newZval.m_FirstArcIdx = e1ArcSegmentIndex;
 newZval.m_SecondArcIdx = e2ArcSegmentIndex;
 }
 else
 {
 newZval.m_FirstArcIdx = e2ArcSegmentIndex;
 newZval.m_SecondArcIdx = -1;
 }
 
 size_t z_value_ptr = zValues.size();
 zValues.push_back( newZval );
 
 // Only worry about arc segments for later processing
 if( newZval.m_FirstArcIdx != -1 )
 newIntersectPoints.insert( { VECTOR2I( pt.x, pt.y ), newZval } );
 
 pt.z = z_value_ptr;
 //@todo amend X,Y values to true intersection between arcs or arc and segment
 };
 
 c.SetZCallback( callback ); // register callback
 
 c.Execute( aType, Clipper2Lib::FillRule::NonZero, solution );
 
 importTree( solution, zValues, arcBuffer );
 solution.Clear(); // Free used memory (not done in dtor)
}
 
 
void SHAPE_POLY_SET::BooleanAdd( const SHAPE_POLY_SET& b, POLYGON_MODE aFastMode )
{
 if( ADVANCED_CFG::GetCfg().m_UseClipper2 )
 booleanOp( Clipper2Lib::ClipType::Union, b );
 else
 booleanOp( ClipperLib::ctUnion, b, aFastMode );
}
 
 
void SHAPE_POLY_SET::BooleanSubtract( const SHAPE_POLY_SET& b, POLYGON_MODE aFastMode )
{
 if( ADVANCED_CFG::GetCfg().m_UseClipper2 )
 booleanOp( Clipper2Lib::ClipType::Difference, b );
 else
 booleanOp( ClipperLib::ctDifference, b, aFastMode );
}
 
 
void SHAPE_POLY_SET::BooleanIntersection( const SHAPE_POLY_SET& b, POLYGON_MODE aFastMode )
{
 if( ADVANCED_CFG::GetCfg().m_UseClipper2 )
 booleanOp( Clipper2Lib::ClipType::Intersection, b );
 else
 booleanOp( ClipperLib::ctIntersection, b, aFastMode );
}
 
 
void SHAPE_POLY_SET::BooleanXor( const SHAPE_POLY_SET& b, POLYGON_MODE aFastMode )
{
 if( ADVANCED_CFG::GetCfg().m_UseClipper2 )
 booleanOp( Clipper2Lib::ClipType::Xor, b );
 else
 booleanOp( ClipperLib::ctXor, b, aFastMode );
}
 
 
void SHAPE_POLY_SET::BooleanAdd( const SHAPE_POLY_SET& a, const SHAPE_POLY_SET& b,
 POLYGON_MODE aFastMode )
{
 if( ADVANCED_CFG::GetCfg().m_UseClipper2 )
 booleanOp( Clipper2Lib::ClipType::Union, a, b );
 else
 booleanOp( ClipperLib::ctUnion, a, b, aFastMode );
}
 
 
void SHAPE_POLY_SET::BooleanSubtract( const SHAPE_POLY_SET& a, const SHAPE_POLY_SET& b,
 POLYGON_MODE aFastMode )
{
 if( ADVANCED_CFG::GetCfg().m_UseClipper2 )
 booleanOp( Clipper2Lib::ClipType::Difference, a, b );
 else
 booleanOp( ClipperLib::ctDifference, a, b, aFastMode );
}
 
 
void SHAPE_POLY_SET::BooleanIntersection( const SHAPE_POLY_SET& a, const SHAPE_POLY_SET& b,
 POLYGON_MODE aFastMode )
{
 if( ADVANCED_CFG::GetCfg().m_UseClipper2 )
 booleanOp( Clipper2Lib::ClipType::Intersection, a, b );
 else
 booleanOp( ClipperLib::ctIntersection, a, b, aFastMode );
}
 
 
void SHAPE_POLY_SET::BooleanXor( const SHAPE_POLY_SET& a, const SHAPE_POLY_SET& b,
 POLYGON_MODE aFastMode )
{
 if( ADVANCED_CFG::GetCfg().m_UseClipper2 )
 booleanOp( Clipper2Lib::ClipType::Xor, a, b );
 else
 booleanOp( ClipperLib::ctXor, a, b, aFastMode );
}
 
 
void SHAPE_POLY_SET::InflateWithLinkedHoles( int aFactor,
 SHAPE_POLY_SET::CORNER_STRATEGY aCornerStrategy,
 int aMaxError, POLYGON_MODE aFastMode )
{
 Unfracture( aFastMode );
 Inflate( aFactor, aCornerStrategy, aMaxError );
 Fracture( aFastMode );
}
 
 
void SHAPE_POLY_SET::inflate1( int aAmount, int aCircleSegCount, CORNER_STRATEGY aCornerStrategy )
{
 using namespace ClipperLib;
 // A static table to avoid repetitive calculations of the coefficient
 // 1.0 - cos( M_PI / aCircleSegCount )
 // aCircleSegCount is most of time <= 64 and usually 8, 12, 16, 32
 #define SEG_CNT_MAX 64
 static double arc_tolerance_factor[SEG_CNT_MAX + 1];
 
 ClipperOffset c;
 
 // N.B. see the Clipper documentation for jtSquare/jtMiter/jtRound. They are poorly named
 // and are not what you'd think they are.
 // http://www.angusj.com/delphi/clipper/documentation/Docs/Units/ClipperLib/Types/JoinType.htm
 JoinType joinType = jtRound; // The way corners are offsetted
 double miterLimit = 2.0; // Smaller value when using jtMiter for joinType
 JoinType miterFallback = jtSquare;
 
 switch( aCornerStrategy )
 {
 case ALLOW_ACUTE_CORNERS:
 joinType = jtMiter;
 miterLimit = 10; // Allows large spikes
 miterFallback = jtSquare;
 break;
 
 case CHAMFER_ACUTE_CORNERS: // Acute angles are chamfered
 joinType = jtMiter;
 miterFallback = jtRound;
 break;
 
 case ROUND_ACUTE_CORNERS: // Acute angles are rounded
 joinType = jtMiter;
 miterFallback = jtSquare;
 break;
 
 case CHAMFER_ALL_CORNERS: // All angles are chamfered.
 joinType = jtSquare;
 miterFallback = jtSquare;
 break;
 
 case ROUND_ALL_CORNERS: // All angles are rounded.
 joinType = jtRound;
 miterFallback = jtSquare;
 break;
 }
 
 std::vector<CLIPPER_Z_VALUE> zValues;
 std::vector<SHAPE_ARC> arcBuffer;
 
 for( const POLYGON& poly : m_polys )
 {
 for( size_t i = 0; i < poly.size(); i++ )
 {
 c.AddPath( poly[i].convertToClipper( i == 0, zValues, arcBuffer ),
 joinType, etClosedPolygon );
 }
 }
 
 PolyTree solution;
 
 // Calculate the arc tolerance (arc error) from the seg count by circle. The seg count is
 // nn = M_PI / acos(1.0 - c.ArcTolerance / abs(aAmount))
 // http://www.angusj.com/delphi/clipper/documentation/Docs/Units/ClipperLib/Classes/ClipperOffset/Properties/ArcTolerance.htm
 
 if( aCircleSegCount < 6 ) // avoid incorrect aCircleSegCount values
 aCircleSegCount = 6;
 
 double coeff;
 
 if( aCircleSegCount > SEG_CNT_MAX || arc_tolerance_factor[aCircleSegCount] == 0 )
 {
 coeff = 1.0 - cos( M_PI / aCircleSegCount );
 
 if( aCircleSegCount <= SEG_CNT_MAX )
 arc_tolerance_factor[aCircleSegCount] = coeff;
 }
 else
 {
 coeff = arc_tolerance_factor[aCircleSegCount];
 }
 
 c.ArcTolerance = std::abs( aAmount ) * coeff;
 c.MiterLimit = miterLimit;
 c.MiterFallback = miterFallback;
 c.Execute( solution, aAmount );
 
 importTree( &solution, zValues, arcBuffer );
}
 
 
void SHAPE_POLY_SET::inflate2( int aAmount, int aCircleSegCount, CORNER_STRATEGY aCornerStrategy,
 bool aSimplify )
{
 using namespace Clipper2Lib;
 // A static table to avoid repetitive calculations of the coefficient
 // 1.0 - cos( M_PI / aCircleSegCount )
 // aCircleSegCount is most of time <= 64 and usually 8, 12, 16, 32
 #define SEG_CNT_MAX 64
 static double arc_tolerance_factor[SEG_CNT_MAX + 1];
 
 ClipperOffset c;
 
 // N.B. see the Clipper documentation for jtSquare/jtMiter/jtRound. They are poorly named
 // and are not what you'd think they are.
 // http://www.angusj.com/delphi/clipper/documentation/Docs/Units/ClipperLib/Types/JoinType.htm
 JoinType joinType = JoinType::Round; // The way corners are offsetted
 double miterLimit = 2.0; // Smaller value when using jtMiter for joinType
 
 switch( aCornerStrategy )
 {
 case ALLOW_ACUTE_CORNERS:
 joinType = JoinType::Miter;
 miterLimit = 10; // Allows large spikes
 break;
 
 case CHAMFER_ACUTE_CORNERS: // Acute angles are chamfered
 joinType = JoinType::Miter;
 break;
 
 case ROUND_ACUTE_CORNERS: // Acute angles are rounded
 joinType = JoinType::Miter;
 break;
 
 case CHAMFER_ALL_CORNERS: // All angles are chamfered.
 joinType = JoinType::Square;
 break;
 
 case ROUND_ALL_CORNERS: // All angles are rounded.
 joinType = JoinType::Round;
 break;
 }
 
 std::vector<CLIPPER_Z_VALUE> zValues;
 std::vector<SHAPE_ARC> arcBuffer;
 
 for( const POLYGON& poly : m_polys )
 {
 Paths64 paths;
 
 for( size_t i = 0; i < poly.size(); i++ )
 paths.push_back( poly[i].convertToClipper2( i == 0, zValues, arcBuffer ) );
 
 c.AddPaths( paths, joinType, EndType::Polygon );
 }
 
 // Calculate the arc tolerance (arc error) from the seg count by circle. The seg count is
 // nn = M_PI / acos(1.0 - c.ArcTolerance / abs(aAmount))
 // http://www.angusj.com/delphi/clipper/documentation/Docs/Units/ClipperLib/Classes/ClipperOffset/Properties/ArcTolerance.htm
 
 if( aCircleSegCount < 6 ) // avoid incorrect aCircleSegCount values
 aCircleSegCount = 6;
 
 double coeff;
 
 if( aCircleSegCount > SEG_CNT_MAX || arc_tolerance_factor[aCircleSegCount] == 0 )
 {
 coeff = 1.0 - cos( M_PI / aCircleSegCount );
 
 if( aCircleSegCount <= SEG_CNT_MAX )
 arc_tolerance_factor[aCircleSegCount] = coeff;
 }
 else
 {
 coeff = arc_tolerance_factor[aCircleSegCount];
 }
 
 c.ArcTolerance( std::abs( aAmount ) * coeff );
 c.MiterLimit( miterLimit );
 
 PolyTree64 tree;
 
 if( aSimplify )
 {
 Paths64 paths;
 c.Execute( aAmount, paths );
 
 Clipper2Lib::SimplifyPaths( paths, std::abs( aAmount ) * coeff, false );
 
 Clipper64 c2;
 c2.PreserveCollinear = false;
 c2.ReverseSolution = false;
 c2.AddSubject( paths );
 c2.Execute(ClipType::Union, FillRule::Positive, tree);
 }
 else
 {
 c.Execute( aAmount, tree );
 }
 
 importTree( tree, zValues, arcBuffer );
 tree.Clear();
}
 
 
void SHAPE_POLY_SET::Inflate( int aAmount, CORNER_STRATEGY aCornerStrategy, int aMaxError,
 bool aSimplify )
{
 int segCount = GetArcToSegmentCount( aAmount, aMaxError, FULL_CIRCLE );
 
 if( ADVANCED_CFG::GetCfg().m_UseClipper2 )
 inflate2( aAmount, segCount, aCornerStrategy, aSimplify );
 else
 inflate1( aAmount, segCount, aCornerStrategy );
}
 
 
void SHAPE_POLY_SET::importTree( ClipperLib::PolyTree* tree,
 const std::vector<CLIPPER_Z_VALUE>& aZValueBuffer,
 const std::vector<SHAPE_ARC>& aArcBuffer )
{
 m_polys.clear();
 
 for( ClipperLib::PolyNode* n = tree->GetFirst(); n; n = n->GetNext() )
 {
 if( !n->IsHole() )
 {
 POLYGON paths;
 paths.reserve( n->Childs.size() + 1 );
 
 paths.emplace_back( n->Contour, aZValueBuffer, aArcBuffer );
 
 for( unsigned int i = 0; i < n->Childs.size(); i++ )
 paths.emplace_back( n->Childs[i]->Contour, aZValueBuffer, aArcBuffer );
 
 m_polys.push_back( paths );
 }
 }
}
 
 
void SHAPE_POLY_SET::importPolyPath( const std::unique_ptr<Clipper2Lib::PolyPath64>& aPolyPath,
 const std::vector<CLIPPER_Z_VALUE>& aZValueBuffer,
 const std::vector<SHAPE_ARC>& aArcBuffer )
{
 if( !aPolyPath->IsHole() )
 {
 POLYGON paths;
 paths.reserve( aPolyPath->Count() + 1 );
 paths.emplace_back( aPolyPath->Polygon(), aZValueBuffer, aArcBuffer );
 
 for( const std::unique_ptr<Clipper2Lib::PolyPath64>& child : *aPolyPath )
 {
 paths.emplace_back( child->Polygon(), aZValueBuffer, aArcBuffer );
 
 for( const std::unique_ptr<Clipper2Lib::PolyPath64>& grandchild : *child )
 importPolyPath( grandchild, aZValueBuffer, aArcBuffer );
 }
 
 m_polys.push_back( paths );
 }
}
 
 
void SHAPE_POLY_SET::importTree( Clipper2Lib::PolyTree64& tree,
 const std::vector<CLIPPER_Z_VALUE>& aZValueBuffer,
 const std::vector<SHAPE_ARC>& aArcBuffer )
{
 m_polys.clear();
 
 for( const std::unique_ptr<Clipper2Lib::PolyPath64>& n : tree )
 importPolyPath( n, aZValueBuffer, aArcBuffer );
}
 
 
void SHAPE_POLY_SET::importPaths( Clipper2Lib::Paths64& aPath,
 const std::vector<CLIPPER_Z_VALUE>& aZValueBuffer,
 const std::vector<SHAPE_ARC>& aArcBuffer )
{
 m_polys.clear();
 POLYGON path;
 
 for( const Clipper2Lib::Path64& n : aPath )
 {
 if( Clipper2Lib::Area( n ) > 0 )
 {
 if( !path.empty() )
 m_polys.emplace_back( path );
 
 path.clear();
 }
 else
 {
 wxCHECK2_MSG( !path.empty(), continue, wxT( "Cannot add a hole before an outline" ) );
 }
 
 path.emplace_back( n, aZValueBuffer, aArcBuffer );
 }
 
 if( !path.empty() )
 m_polys.emplace_back( path );
}
 
 
struct FractureEdge
{
 FractureEdge( int y = 0 ) :
 m_connected( false ),
 m_next( nullptr )
 {
 m_p1.x = m_p2.y = y;
 }
 
 FractureEdge( bool connected, const VECTOR2I& p1, const VECTOR2I& p2 ) :
 m_connected( connected ),
 m_p1( p1 ),
 m_p2( p2 ),
 m_next( nullptr )
 {
 }
 
 bool matches( int y ) const
 {
 return ( y >= m_p1.y || y >= m_p2.y ) && ( y <= m_p1.y || y <= m_p2.y );
 }
 
 bool m_connected;
 VECTOR2I m_p1;
 VECTOR2I m_p2;
 FractureEdge* m_next;
};
 
 
typedef std::vector<FractureEdge*> FractureEdgeSet;
 
 
static int processEdge( FractureEdgeSet& edges, FractureEdge* edge )
{
 int x = edge->m_p1.x;
 int y = edge->m_p1.y;
 int min_dist = std::numeric_limits<int>::max();
 int x_nearest = 0;
 
 FractureEdge* e_nearest = nullptr;
 
 for( FractureEdge* e : edges )
 {
 if( !e->matches( y ) )
 continue;
 
 int x_intersect;
 
 if( e->m_p1.y == e->m_p2.y ) // horizontal edge
 {
 x_intersect = std::max( e->m_p1.x, e->m_p2.x );
 }
 else
 {
 x_intersect = e->m_p1.x + rescale( e->m_p2.x - e->m_p1.x, y - e->m_p1.y,
 e->m_p2.y - e->m_p1.y );
 }
 
 int dist = ( x - x_intersect );
 
 if( dist >= 0 && dist < min_dist && e->m_connected )
 {
 min_dist = dist;
 x_nearest = x_intersect;
 e_nearest = e;
 }
 }
 
 if( e_nearest && e_nearest->m_connected )
 {
 int count = 0;
 
 FractureEdge* lead1 = new FractureEdge( true, VECTOR2I( x_nearest, y ), VECTOR2I( x, y ) );
 FractureEdge* lead2 = new FractureEdge( true, VECTOR2I( x, y ), VECTOR2I( x_nearest, y ) );
 FractureEdge* split_2 = new FractureEdge( true, VECTOR2I( x_nearest, y ), e_nearest->m_p2 );
 
 edges.push_back( split_2 );
 edges.push_back( lead1 );
 edges.push_back( lead2 );
 
 FractureEdge* link = e_nearest->m_next;
 
 e_nearest->m_p2 = VECTOR2I( x_nearest, y );
 e_nearest->m_next = lead1;
 lead1->m_next = edge;
 
 FractureEdge* last;
 
 for( last = edge; last->m_next != edge; last = last->m_next )
 {
 last->m_connected = true;
 count++;
 }
 
 last->m_connected = true;
 last->m_next = lead2;
 lead2->m_next = split_2;
 split_2->m_next = link;
 
 return count + 1;
 }
 
 return 0;
}
 
 
void SHAPE_POLY_SET::fractureSingle( POLYGON& paths )
{
 FractureEdgeSet edges;
 FractureEdgeSet border_edges;
 FractureEdge* root = nullptr;
 
 bool first = true;
 
 if( paths.size() == 1 )
 return;
 
 int num_unconnected = 0;
 
 for( const SHAPE_LINE_CHAIN& path : paths )
 {
 const std::vector<VECTOR2I>& points = path.CPoints();
 int pointCount = points.size();
 
 FractureEdge* prev = nullptr, * first_edge = nullptr;
 
 int x_min = std::numeric_limits<int>::max();
 
 for( int i = 0; i < pointCount; i++ )
 {
 if( points[i].x < x_min )
 x_min = points[i].x;
 
 // Do not use path.CPoint() here; open-coding it using the local variables "points"
 // and "pointCount" gives a non-trivial performance boost to zone fill times.
 FractureEdge* fe = new FractureEdge( first, points[ i ],
 points[ i+1 == pointCount ? 0 : i+1 ] );
 
 if( !root )
 root = fe;
 
 if( !first_edge )
 first_edge = fe;
 
 if( prev )
 prev->m_next = fe;
 
 if( i == pointCount - 1 )
 fe->m_next = first_edge;
 
 prev = fe;
 edges.push_back( fe );
 
 if( !first )
 {
 if( fe->m_p1.x == x_min )
 border_edges.push_back( fe );
 }
 
 if( !fe->m_connected )
 num_unconnected++;
 }
 
 first = false; // first path is always the outline
 }
 
 // keep connecting holes to the main outline, until there's no holes left...
 while( num_unconnected > 0 )
 {
 int x_min = std::numeric_limits<int>::max();
 auto it = border_edges.begin();
 
 FractureEdge* smallestX = nullptr;
 
 // find the left-most hole edge and merge with the outline
 for( ; it != border_edges.end(); ++it )
 {
 FractureEdge* border_edge = *it;
 int xt = border_edge->m_p1.x;
 
 if( ( xt <= x_min ) && !border_edge->m_connected )
 {
 x_min = xt;
 smallestX = border_edge;
 }
 }
 
 int num_processed = processEdge( edges, smallestX );
 
 // If we can't handle the edge, the zone is broken (maybe)
 if( !num_processed )
 {
 wxLogWarning( wxT( "Broken polygon, dropping path" ) );
 
 for( FractureEdge* edge : edges )
 delete edge;
 
 return;
 }
 
 num_unconnected -= num_processed;
 }
 
 paths.clear();
 SHAPE_LINE_CHAIN newPath;
 
 newPath.SetClosed( true );
 
 FractureEdge* e;
 
 for( e = root; e->m_next != root; e = e->m_next )
 newPath.Append( e->m_p1 );
 
 newPath.Append( e->m_p1 );
 
 for( FractureEdge* edge : edges )
 delete edge;
 
 paths.push_back( std::move( newPath ) );
}
 
 
void SHAPE_POLY_SET::Fracture( POLYGON_MODE aFastMode )
{
 Simplify( aFastMode ); // remove overlapping holes/degeneracy
 
 for( POLYGON& paths : m_polys )
 fractureSingle( paths );
}
 
 
void SHAPE_POLY_SET::unfractureSingle( SHAPE_POLY_SET::POLYGON& aPoly )
{
 assert( aPoly.size() == 1 );
 
 struct EDGE
 {
 int m_index = 0;
 SHAPE_LINE_CHAIN* m_poly = nullptr;
 bool m_duplicate = false;
 
 EDGE( SHAPE_LINE_CHAIN* aPolygon, int aIndex ) :
 m_index( aIndex ),
 m_poly( aPolygon )
 {}
 
 bool compareSegs( const SEG& s1, const SEG& s2 ) const
 {
 return (s1.A == s2.B && s1.B == s2.A);
 }
 
 bool operator==( const EDGE& aOther ) const
 {
 return compareSegs( m_poly->CSegment( m_index ),
 aOther.m_poly->CSegment( aOther.m_index ) );
 }
 
 bool operator!=( const EDGE& aOther ) const
 {
 return !compareSegs( m_poly->CSegment( m_index ),
 aOther.m_poly->CSegment( aOther.m_index ) );
 }
 
 struct HASH
 {
 std::size_t operator()( const EDGE& aEdge ) const
 {
 const SEG& a = aEdge.m_poly->CSegment( aEdge.m_index );
 std::size_t seed = 0xa82de1c0;
 hash_combine( seed, a.A.x, a.B.x, a.A.y, a.B.y );
 return seed;
 }
 };
 };
 
 struct EDGE_LIST_ENTRY
 {
 int index;
 EDGE_LIST_ENTRY* next;
 };
 
 std::unordered_set<EDGE, EDGE::HASH> uniqueEdges;
 
 SHAPE_LINE_CHAIN lc = aPoly[0];
 lc.Simplify();
 
 auto edgeList = std::make_unique<EDGE_LIST_ENTRY[]>( lc.SegmentCount() );
 
 for( int i = 0; i < lc.SegmentCount(); i++ )
 {
 edgeList[i].index = i;
 edgeList[i].next = &edgeList[ (i != lc.SegmentCount() - 1) ? i + 1 : 0 ];
 }
 
 std::unordered_set<EDGE_LIST_ENTRY*> queue;
 
 for( int i = 0; i < lc.SegmentCount(); i++ )
 {
 EDGE e( &lc, i );
 uniqueEdges.insert( e );
 }
 
 for( int i = 0; i < lc.SegmentCount(); i++ )
 {
 EDGE e( &lc, i );
 auto it = uniqueEdges.find( e );
 
 if( it != uniqueEdges.end() && it->m_index != i )
 {
 int e1 = it->m_index;
 int e2 = i;
 
 if( e1 > e2 )
 std::swap( e1, e2 );
 
 int e1_prev = e1 - 1;
 
 if( e1_prev < 0 )
 e1_prev = lc.SegmentCount() - 1;
 
 int e2_prev = e2 - 1;
 
 if( e2_prev < 0 )
 e2_prev = lc.SegmentCount() - 1;
 
 int e1_next = e1 + 1;
 
 if( e1_next == lc.SegmentCount() )
 e1_next = 0;
 
 int e2_next = e2 + 1;
 
 if( e2_next == lc.SegmentCount() )
 e2_next = 0;
 
 edgeList[e1_prev].next = &edgeList[ e2_next ];
 edgeList[e2_prev].next = &edgeList[ e1_next ];
 edgeList[i].next = nullptr;
 edgeList[it->m_index].next = nullptr;
 }
 }
 
 for( int i = 0; i < lc.SegmentCount(); i++ )
 {
 if( edgeList[i].next )
 queue.insert( &edgeList[i] );
 }
 
 auto edgeBuf = std::make_unique<EDGE_LIST_ENTRY* []>( lc.SegmentCount() );
 
 int n = 0;
 int outline = -1;
 
 POLYGON result;
 double max_poly = 0.0;
 
 while( queue.size() )
 {
 EDGE_LIST_ENTRY* e_first = *queue.begin();
 EDGE_LIST_ENTRY* e = e_first;
 int cnt = 0;
 
 do
 {
 edgeBuf[cnt++] = e;
 e = e->next;
 } while( e && e != e_first );
 
 SHAPE_LINE_CHAIN outl;
 
 for( int i = 0; i < cnt; i++ )
 {
 VECTOR2I p = lc.CPoint( edgeBuf[i]->index );
 outl.Append( p );
 queue.erase( edgeBuf[i] );
 }
 
 outl.SetClosed( true );
 
 double area = std::fabs( outl.Area() );
 
 if( area > max_poly )
 {
 outline = n;
 max_poly = area;
 }
 
 result.push_back( outl );
 n++;
 }
 
 if( outline > 0 )
 std::swap( result[0], result[outline] );
 
 aPoly = result;
}
 
 
bool SHAPE_POLY_SET::HasHoles() const
{
 // Iterate through all the polygons on the set
 for( const POLYGON& paths : m_polys )
 {
 // If any of them has more than one contour, it is a hole.
 if( paths.size() > 1 )
 return true;
 }
 
 // Return false if and only if every polygon has just one outline, without holes.
 return false;
}
 
 
void SHAPE_POLY_SET::Unfracture( POLYGON_MODE aFastMode )
{
 for( POLYGON& path : m_polys )
 unfractureSingle( path );
 
 Simplify( aFastMode ); // remove overlapping holes/degeneracy
}
 
 
void SHAPE_POLY_SET::Simplify( POLYGON_MODE aFastMode )
{
 SHAPE_POLY_SET empty;
 
 if( ADVANCED_CFG::GetCfg().m_UseClipper2 )
 booleanOp( Clipper2Lib::ClipType::Union, empty );
 else
 booleanOp( ClipperLib::ctUnion, empty, aFastMode );
}
 
 
int SHAPE_POLY_SET::NormalizeAreaOutlines()
{
 // We are expecting only one main outline, but this main outline can have holes
 // if holes: combine holes and remove them from the main outline.
 // Note also we are using SHAPE_POLY_SET::PM_STRICTLY_SIMPLE in polygon
 // calculations, but it is not mandatory. It is used mainly
 // because there is usually only very few vertices in area outlines
 SHAPE_POLY_SET::POLYGON& outline = Polygon( 0 );
 SHAPE_POLY_SET holesBuffer;
 
 // Move holes stored in outline to holesBuffer:
 // The first SHAPE_LINE_CHAIN is the main outline, others are holes
 while( outline.size() > 1 )
 {
 holesBuffer.AddOutline( outline.back() );
 outline.pop_back();
 }
 
 Simplify( SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );
 
 // If any hole, subtract it to main outline
 if( holesBuffer.OutlineCount() )
 {
 holesBuffer.Simplify( SHAPE_POLY_SET::PM_FAST );
 BooleanSubtract( holesBuffer, SHAPE_POLY_SET::PM_STRICTLY_SIMPLE );
 }
 
 // In degenerate cases, simplify might return no outlines
 if( OutlineCount() > 0 )
 RemoveNullSegments();
 
 return OutlineCount();
}
 
 
const std::string SHAPE_POLY_SET::Format( bool aCplusPlus ) const
{
 std::stringstream ss;
 
 ss << "SHAPE_LINE_CHAIN poly; \n";
 
 for( unsigned i = 0; i < m_polys.size(); i++ )
 {
 for( unsigned j = 0; j < m_polys[i].size(); j++ )
 {
 
 ss << "{ auto tmp = " << m_polys[i][j].Format() << ";\n";
 
 SHAPE_POLY_SET poly;
 
 if( j == 0 )
 {
 ss << " poly.AddOutline(tmp); } \n";
 }
 else
 {
 ss << " poly.AddHole(tmp); } \n";
 }
 
 }
 }
 
 return ss.str();
}
 
 
bool SHAPE_POLY_SET::Parse( std::stringstream& aStream )
{
 std::string tmp;
 
 aStream >> tmp;
 
 if( tmp != "polyset" )
 return false;
 
 aStream >> tmp;
 
 int n_polys = atoi( tmp.c_str() );
 
 if( n_polys < 0 )
 return false;
 
 for( int i = 0; i < n_polys; i++ )
 {
 POLYGON paths;
 
 aStream >> tmp;
 
 if( tmp != "poly" )
 return false;
 
 aStream >> tmp;
 int n_outlines = atoi( tmp.c_str() );
 
 if( n_outlines < 0 )
 return false;
 
 for( int j = 0; j < n_outlines; j++ )
 {
 SHAPE_LINE_CHAIN outline;
 
 outline.SetClosed( true );
 
 aStream >> tmp;
 int n_vertices = atoi( tmp.c_str() );
 
 for( int v = 0; v < n_vertices; v++ )
 {
 VECTOR2I p;
 
 aStream >> tmp; p.x = atoi( tmp.c_str() );
 aStream >> tmp; p.y = atoi( tmp.c_str() );
 outline.Append( p );
 }
 
 paths.push_back( outline );
 }
 
 m_polys.push_back( paths );
 }
 
 return true;
}
 
 
const BOX2I SHAPE_POLY_SET::BBox( int aClearance ) const
{
 BOX2I bb;
 
 for( unsigned i = 0; i < m_polys.size(); i++ )
 {
 if( i == 0 )
 bb = m_polys[i][0].BBox();
 else
 bb.Merge( m_polys[i][0].BBox() );
 }
 
 bb.Inflate( aClearance );
 return bb;
}
 
 
const BOX2I SHAPE_POLY_SET::BBoxFromCaches() const
{
 BOX2I bb;
 
 for( unsigned i = 0; i < m_polys.size(); i++ )
 {
 if( i == 0 )
 bb = *m_polys[i][0].GetCachedBBox();
 else
 bb.Merge( *m_polys[i][0].GetCachedBBox() );
 }
 
 return bb;
}
 
 
bool SHAPE_POLY_SET::PointOnEdge( const VECTOR2I& aP ) const
{
 // Iterate through all the polygons in the set
 for( const POLYGON& polygon : m_polys )
 {
 // Iterate through all the line chains in the polygon
 for( const SHAPE_LINE_CHAIN& lineChain : polygon )
 {
 if( lineChain.PointOnEdge( aP ) )
 return true;
 }
 }
 
 return false;
}
 
 
bool SHAPE_POLY_SET::Collide( const SEG& aSeg, int aClearance, int* aActual,
 VECTOR2I* aLocation ) const
{
 VECTOR2I nearest;
 ecoord dist_sq = SquaredDistanceToSeg( aSeg, aLocation ? &nearest : nullptr );
 
 if( dist_sq == 0 || dist_sq < SEG::Square( aClearance ) )
 {
 if( aLocation )
 *aLocation = nearest;
 
 if( aActual )
 *aActual = sqrt( dist_sq );
 
 return true;
 }
 
 return false;
}
 
 
bool SHAPE_POLY_SET::Collide( const VECTOR2I& aP, int aClearance, int* aActual,
 VECTOR2I* aLocation ) const
{
 if( IsEmpty() || VertexCount() == 0 )
 return false;
 
 VECTOR2I nearest;
 ecoord dist_sq = SquaredDistance( aP, false, aLocation ? &nearest : nullptr );
 
 if( dist_sq == 0 || dist_sq < SEG::Square( aClearance ) )
 {
 if( aLocation )
 *aLocation = nearest;
 
 if( aActual )
 *aActual = sqrt( dist_sq );
 
 return true;
 }
 
 return false;
}
 
 
bool SHAPE_POLY_SET::Collide( const SHAPE* aShape, int aClearance, int* aActual,
 VECTOR2I* aLocation ) const
{
 // A couple of simple cases are worth trying before we fall back on triangulation.
 
 if( aShape->Type() == SH_SEGMENT )
 {
 const SHAPE_SEGMENT* segment = static_cast<const SHAPE_SEGMENT*>( aShape );
 int extra = segment->GetWidth() / 2;
 
 if( Collide( segment->GetSeg(), aClearance + extra, aActual, aLocation ) )
 {
 if( aActual )
 *aActual = std::max( 0, *aActual - extra );
 
 return true;
 }
 
 return false;
 }
 
 if( aShape->Type() == SH_CIRCLE )
 {
 const SHAPE_CIRCLE* circle = static_cast<const SHAPE_CIRCLE*>( aShape );
 int extra = circle->GetRadius();
 
 if( Collide( circle->GetCenter(), aClearance + extra, aActual, aLocation ) )
 {
 if( aActual )
 *aActual = std::max( 0, *aActual - extra );
 
 return true;
 }
 
 return false;
 }
 
 const_cast<SHAPE_POLY_SET*>( this )->CacheTriangulation( false );
 
 int actual = INT_MAX;
 VECTOR2I location;
 
 for( const std::unique_ptr<TRIANGULATED_POLYGON>& tpoly : m_triangulatedPolys )
 {
 for( const TRIANGULATED_POLYGON::TRI& tri : tpoly->Triangles() )
 {
 if( aActual || aLocation )
 {
 int triActual;
 VECTOR2I triLocation;
 
 if( aShape->Collide( &tri, aClearance, &triActual, &triLocation ) )
 {
 if( triActual < actual )
 {
 actual = triActual;
 location = triLocation;
 }
 }
 }
 else // A much faster version of above
 {
 if( aShape->Collide( &tri, aClearance ) )
 return true;
 }
 }
 }
 
 if( actual < INT_MAX )
 {
 if( aActual )
 *aActual = std::max( 0, actual );
 
 if( aLocation )
 *aLocation = location;
 
 return true;
 }
 
 return false;
}
 
 
void SHAPE_POLY_SET::RemoveAllContours()
{
 m_polys.clear();
}
 
 
void SHAPE_POLY_SET::RemoveContour( int aContourIdx, int aPolygonIdx )
{
 // Default polygon is the last one
 if( aPolygonIdx < 0 )
 aPolygonIdx += m_polys.size();
 
 m_polys[aPolygonIdx].erase( m_polys[aPolygonIdx].begin() + aContourIdx );
}
 
 
int SHAPE_POLY_SET::RemoveNullSegments()
{
 int removed = 0;
 
 ITERATOR iterator = IterateWithHoles();
 
 VECTOR2I contourStart = *iterator;
 VECTOR2I segmentStart, segmentEnd;
 
 VERTEX_INDEX indexStart;
 std::vector<VERTEX_INDEX> indices_to_remove;
 
 while( iterator )
 {
 // Obtain first point and its index
 segmentStart = *iterator;
 indexStart = iterator.GetIndex();
 
 // Obtain last point
 if( iterator.IsEndContour() )
 {
 segmentEnd = contourStart;
 
 // Advance
 iterator++;
 
 // If we have rolled into the next contour, remember its position
 // segmentStart and segmentEnd remain valid for comparison here
 if( iterator )
 contourStart = *iterator;
 }
 else
 {
 // Advance
 iterator++;
 
 // If we have reached the end of the SHAPE_POLY_SET, something is broken here
 wxCHECK_MSG( iterator, removed, wxT( "Invalid polygon. Reached end without noticing. Please report this error" ) );
 
 segmentEnd = *iterator;
 }
 
 // Remove segment start if both points are equal
 if( segmentStart == segmentEnd )
 {
 indices_to_remove.push_back( indexStart );
 removed++;
 }
 }
 
 // Proceed in reverse direction to remove the vertices because they are stored as absolute indices in a vector
 // Removing in reverse order preserves the remaining index values
 for( auto it = indices_to_remove.rbegin(); it != indices_to_remove.rend(); ++it )
 RemoveVertex( *it );
 
 return removed;
}
 
 
void SHAPE_POLY_SET::DeletePolygon( int aIdx )
{
 m_polys.erase( m_polys.begin() + aIdx );
}
 
 
void SHAPE_POLY_SET::DeletePolygonAndTriangulationData( int aIdx, bool aUpdateHash )
{
 m_polys.erase( m_polys.begin() + aIdx );
 
 if( m_triangulationValid )
 {
 for( int ii = m_triangulatedPolys.size() - 1; ii >= 0; --ii )
 {
 std::unique_ptr<TRIANGULATED_POLYGON>& triangleSet = m_triangulatedPolys[ii];
 
 if( triangleSet->GetSourceOutlineIndex() == aIdx )
 m_triangulatedPolys.erase( m_triangulatedPolys.begin() + ii );
 else if( triangleSet->GetSourceOutlineIndex() > aIdx )
 triangleSet->SetSourceOutlineIndex( triangleSet->GetSourceOutlineIndex() - 1 );
 }
 
 if( aUpdateHash )
 m_hash = checksum();
 }
}
 
 
void SHAPE_POLY_SET::UpdateTriangulationDataHash()
{
 m_hash = checksum();
}
 
 
void SHAPE_POLY_SET::Append( const SHAPE_POLY_SET& aSet )
{
 m_polys.insert( m_polys.end(), aSet.m_polys.begin(), aSet.m_polys.end() );
}
 
 
void SHAPE_POLY_SET::Append( const VECTOR2I& aP, int aOutline, int aHole )
{
 Append( aP.x, aP.y, aOutline, aHole );
}
 
 
bool SHAPE_POLY_SET::CollideVertex( const VECTOR2I& aPoint,
 SHAPE_POLY_SET::VERTEX_INDEX* aClosestVertex,
 int aClearance ) const
{
 // Shows whether there was a collision
 bool collision = false;
 
 // Difference vector between each vertex and aPoint.
 VECTOR2D delta;
 ecoord distance_squared;
 ecoord clearance_squared = SEG::Square( aClearance );
 
 for( CONST_ITERATOR iterator = CIterateWithHoles(); iterator; iterator++ )
 {
 // Get the difference vector between current vertex and aPoint
 delta = *iterator - aPoint;
 
 // Compute distance
 distance_squared = delta.SquaredEuclideanNorm();
 
 // Check for collisions
 if( distance_squared <= clearance_squared )
 {
 if( !aClosestVertex )
 return true;
 
 collision = true;
 
 // Update clearance to look for closer vertices
 clearance_squared = distance_squared;
 
 // Store the indices that identify the vertex
 *aClosestVertex = iterator.GetIndex();
 }
 }
 
 return collision;
}
 
 
bool SHAPE_POLY_SET::CollideEdge( const VECTOR2I& aPoint,
 SHAPE_POLY_SET::VERTEX_INDEX* aClosestVertex,
 int aClearance ) const
{
 // Shows whether there was a collision
 bool collision = false;
 ecoord clearance_squared = SEG::Square( aClearance );
 
 for( CONST_SEGMENT_ITERATOR iterator = CIterateSegmentsWithHoles(); iterator; iterator++ )
 {
 const SEG currentSegment = *iterator;
 ecoord distance_squared = currentSegment.SquaredDistance( aPoint );
 
 // Check for collisions
 if( distance_squared <= clearance_squared )
 {
 if( !aClosestVertex )
 return true;
 
 collision = true;
 
 // Update clearance to look for closer edges
 clearance_squared = distance_squared;
 
 // Store the indices that identify the vertex
 *aClosestVertex = iterator.GetIndex();
 }
 }
 
 return collision;
}
 
 
void SHAPE_POLY_SET::BuildBBoxCaches() const
{
 for( int polygonIdx = 0; polygonIdx < OutlineCount(); polygonIdx++ )
 {
 COutline( polygonIdx ).GenerateBBoxCache();
 
 for( int holeIdx = 0; holeIdx < HoleCount( polygonIdx ); holeIdx++ )
 CHole( polygonIdx, holeIdx ).GenerateBBoxCache();
 }
}
 
 
bool SHAPE_POLY_SET::Contains( const VECTOR2I& aP, int aSubpolyIndex, int aAccuracy,
 bool aUseBBoxCaches ) const
{
 if( m_polys.empty() )
 return false;
 
 // If there is a polygon specified, check the condition against that polygon
 if( aSubpolyIndex >= 0 )
 return containsSingle( aP, aSubpolyIndex, aAccuracy, aUseBBoxCaches );
 
 // In any other case, check it against all polygons in the set
 for( int polygonIdx = 0; polygonIdx < OutlineCount(); polygonIdx++ )
 {
 if( containsSingle( aP, polygonIdx, aAccuracy, aUseBBoxCaches ) )
 return true;
 }
 
 return false;
}
 
 
void SHAPE_POLY_SET::RemoveVertex( int aGlobalIndex )
{
 VERTEX_INDEX index;
 
 // Assure the to be removed vertex exists, abort otherwise
 if( GetRelativeIndices( aGlobalIndex, &index ) )
 RemoveVertex( index );
 else
 throw( std::out_of_range( "aGlobalIndex-th vertex does not exist" ) );
}
 
 
void SHAPE_POLY_SET::RemoveVertex( VERTEX_INDEX aIndex )
{
 m_polys[aIndex.m_polygon][aIndex.m_contour].Remove( aIndex.m_vertex );
}
 
 
void SHAPE_POLY_SET::SetVertex( int aGlobalIndex, const VECTOR2I& aPos )
{
 VERTEX_INDEX index;
 
 if( GetRelativeIndices( aGlobalIndex, &index ) )
 SetVertex( index, aPos );
 else
 throw( std::out_of_range( "aGlobalIndex-th vertex does not exist" ) );
}
 
 
void SHAPE_POLY_SET::SetVertex( const VERTEX_INDEX& aIndex, const VECTOR2I& aPos )
{
 m_polys[aIndex.m_polygon][aIndex.m_contour].SetPoint( aIndex.m_vertex, aPos );
}
 
 
bool SHAPE_POLY_SET::containsSingle( const VECTOR2I& aP, int aSubpolyIndex, int aAccuracy,
 bool aUseBBoxCaches ) const
{
 // Check that the point is inside the outline
 if( m_polys[aSubpolyIndex][0].PointInside( aP, aAccuracy ) )
 {
 // Check that the point is not in any of the holes
 for( int holeIdx = 0; holeIdx < HoleCount( aSubpolyIndex ); holeIdx++ )
 {
 const SHAPE_LINE_CHAIN& hole = CHole( aSubpolyIndex, holeIdx );
 
 // If the point is inside a hole it is outside of the polygon. Do not use aAccuracy
 // here as it's meaning would be inverted.
 if( hole.PointInside( aP, 1, aUseBBoxCaches ) )
 return false;
 }
 
 return true;
 }
 
 return false;
}
 
 
void SHAPE_POLY_SET::Move( const VECTOR2I& aVector )
{
 for( POLYGON& poly : m_polys )
 {
 for( SHAPE_LINE_CHAIN& path : poly )
 path.Move( aVector );
 }
 
 for( std::unique_ptr<TRIANGULATED_POLYGON>& tri : m_triangulatedPolys )
 tri->Move( aVector );
 
 m_hash = checksum();
}
 
 
void SHAPE_POLY_SET::Mirror( bool aX, bool aY, const VECTOR2I& aRef )
{
 for( POLYGON& poly : m_polys )
 {
 for( SHAPE_LINE_CHAIN& path : poly )
 path.Mirror( aX, aY, aRef );
 }
 
 if( m_triangulationValid )
 CacheTriangulation();
}
 
 
void SHAPE_POLY_SET::Rotate( const EDA_ANGLE& aAngle, const VECTOR2I& aCenter )
{
 for( POLYGON& poly : m_polys )
 {
 for( SHAPE_LINE_CHAIN& path : poly )
 path.Rotate( aAngle, aCenter );
 }
 
 // Don't re-cache if the triangulation is already invalid
 if( m_triangulationValid )
 CacheTriangulation();
}
 
 
int SHAPE_POLY_SET::TotalVertices() const
{
 int c = 0;
 
 for( const POLYGON& poly : m_polys )
 {
 for( const SHAPE_LINE_CHAIN& path : poly )
 c += path.PointCount();
 }
 
 return c;
}
 
 
SHAPE_POLY_SET::POLYGON SHAPE_POLY_SET::ChamferPolygon( unsigned int aDistance, int aIndex )
{
 return chamferFilletPolygon( CHAMFERED, aDistance, aIndex, 0 );
}
 
 
SHAPE_POLY_SET::POLYGON SHAPE_POLY_SET::FilletPolygon( unsigned int aRadius, int aErrorMax,
 int aIndex )
{
 return chamferFilletPolygon( FILLETED, aRadius, aIndex, aErrorMax );
}
 
 
SEG::ecoord SHAPE_POLY_SET::SquaredDistanceToPolygon( VECTOR2I aPoint, int aPolygonIndex,
 VECTOR2I* aNearest ) const
{
 // We calculate the min dist between the segment and each outline segment. However, if the
 // segment to test is inside the outline, and does not cross any edge, it can be seen outside
 // the polygon. Therefore test if a segment end is inside (testing only one end is enough).
 // Use an accuracy of "1" to say that we don't care if it's exactly on the edge or not.
 if( containsSingle( aPoint, aPolygonIndex, 1 ) )
 {
 if( aNearest )
 *aNearest = aPoint;
 
 return 0;
 }
 
 CONST_SEGMENT_ITERATOR iterator = CIterateSegmentsWithHoles( aPolygonIndex );
 
 SEG::ecoord minDistance = (*iterator).SquaredDistance( aPoint );
 
 for( iterator++; iterator && minDistance > 0; iterator++ )
 {
 SEG::ecoord currentDistance = (*iterator).SquaredDistance( aPoint );
 
 if( currentDistance < minDistance )
 {
 if( aNearest )
 *aNearest = (*iterator).NearestPoint( aPoint );
 
 minDistance = currentDistance;
 }
 }
 
 return minDistance;
}
 
 
SEG::ecoord SHAPE_POLY_SET::SquaredDistanceToPolygon( const SEG& aSegment, int aPolygonIndex,
 VECTOR2I* aNearest ) const
{
 // Check if the segment is fully-contained. If so, its midpoint is a good-enough nearest point.
 if( containsSingle( aSegment.A, aPolygonIndex, 1 ) &&
 containsSingle( aSegment.B, aPolygonIndex, 1 ) )
 {
 if( aNearest )
 *aNearest = ( aSegment.A + aSegment.B ) / 2;
 
 return 0;
 }
 
 CONST_SEGMENT_ITERATOR iterator = CIterateSegmentsWithHoles( aPolygonIndex );
 SEG::ecoord minDistance = (*iterator).SquaredDistance( aSegment );
 
 if( aNearest && minDistance == 0 )
 *aNearest = ( *iterator ).NearestPoint( aSegment );
 
 for( iterator++; iterator && minDistance > 0; iterator++ )
 {
 SEG::ecoord currentDistance = (*iterator).SquaredDistance( aSegment );
 
 if( currentDistance < minDistance )
 {
 if( aNearest )
 *aNearest = (*iterator).NearestPoint( aSegment );
 
 minDistance = currentDistance;
 }
 }
 
 // Return the maximum of minDistance and zero
 return minDistance < 0 ? 0 : minDistance;
}
 
 
SEG::ecoord SHAPE_POLY_SET::SquaredDistance( const VECTOR2I& aPoint, bool aOutlineOnly,
 VECTOR2I* aNearest ) const
{
 wxASSERT_MSG( !aOutlineOnly, wxT( "Warning: SHAPE_POLY_SET::SquaredDistance does not yet "
 "support aOutlineOnly==true" ) );
 
 SEG::ecoord currentDistance_sq;
 SEG::ecoord minDistance_sq = VECTOR2I::ECOORD_MAX;
 VECTOR2I nearest;
 
 // Iterate through all the polygons and get the minimum distance.
 for( unsigned int polygonIdx = 0; polygonIdx < m_polys.size(); polygonIdx++ )
 {
 currentDistance_sq = SquaredDistanceToPolygon( aPoint, polygonIdx,
 aNearest ? &nearest : nullptr );
 
 if( currentDistance_sq < minDistance_sq )
 {
 if( aNearest )
 *aNearest = nearest;
 
 minDistance_sq = currentDistance_sq;
 }
 }
 
 return minDistance_sq;
}
 
 
SEG::ecoord SHAPE_POLY_SET::SquaredDistanceToSeg( const SEG& aSegment, VECTOR2I* aNearest ) const
{
 SEG::ecoord currentDistance_sq;
 SEG::ecoord minDistance_sq = VECTOR2I::ECOORD_MAX;
 VECTOR2I nearest;
 
 // Iterate through all the polygons and get the minimum distance.
 for( unsigned int polygonIdx = 0; polygonIdx < m_polys.size(); polygonIdx++ )
 {
 currentDistance_sq = SquaredDistanceToPolygon( aSegment, polygonIdx,
 aNearest ? &nearest : nullptr );
 
 if( currentDistance_sq < minDistance_sq )
 {
 if( aNearest )
 *aNearest = nearest;
 
 minDistance_sq = currentDistance_sq;
 }
 }
 
 return minDistance_sq;
}
 
 
bool SHAPE_POLY_SET::IsVertexInHole( int aGlobalIdx )
{
 VERTEX_INDEX index;
 
 // Get the polygon and contour where the vertex is. If the vertex does not exist, return false
 if( !GetRelativeIndices( aGlobalIdx, &index ) )
 return false;
 
 // The contour is a hole if its index is greater than zero
 return index.m_contour > 0;
}
 
 
SHAPE_POLY_SET SHAPE_POLY_SET::Chamfer( int aDistance )
{
 SHAPE_POLY_SET chamfered;
 
 for( unsigned int idx = 0; idx < m_polys.size(); idx++ )
 chamfered.m_polys.push_back( ChamferPolygon( aDistance, idx ) );
 
 return chamfered;
}
 
 
SHAPE_POLY_SET SHAPE_POLY_SET::Fillet( int aRadius, int aErrorMax )
{
 SHAPE_POLY_SET filleted;
 
 for( size_t idx = 0; idx < m_polys.size(); idx++ )
 filleted.m_polys.push_back( FilletPolygon( aRadius, aErrorMax, idx ) );
 
 return filleted;
}
 
 
SHAPE_POLY_SET::POLYGON SHAPE_POLY_SET::chamferFilletPolygon( CORNER_MODE aMode,
 unsigned int aDistance,
 int aIndex, int aErrorMax )
{
 // Null segments create serious issues in calculations. Remove them:
 RemoveNullSegments();
 
 SHAPE_POLY_SET::POLYGON currentPoly = Polygon( aIndex );
 SHAPE_POLY_SET::POLYGON newPoly;
 
 // If the chamfering distance is zero, then the polygon remain intact.
 if( aDistance == 0 )
 {
 return currentPoly;
 }
 
 // Iterate through all the contours (outline and holes) of the polygon.
 for( SHAPE_LINE_CHAIN& currContour : currentPoly )
 {
 // Generate a new contour in the new polygon
 SHAPE_LINE_CHAIN newContour;
 
 // Iterate through the vertices of the contour
 for( int currVertex = 0; currVertex < currContour.PointCount(); currVertex++ )
 {
 // Current vertex
 int x1 = currContour.CPoint( currVertex ).x;
 int y1 = currContour.CPoint( currVertex ).y;
 
 // Indices for previous and next vertices.
 int prevVertex;
 int nextVertex;
 
 // Previous and next vertices indices computation. Necessary to manage the edge cases.
 
 // Previous vertex is the last one if the current vertex is the first one
 prevVertex = currVertex == 0 ? currContour.PointCount() - 1 : currVertex - 1;
 
 // next vertex is the first one if the current vertex is the last one.
 nextVertex = currVertex == currContour.PointCount() - 1 ? 0 : currVertex + 1;
 
 // Previous vertex computation
 double xa = currContour.CPoint( prevVertex ).x - x1;
 double ya = currContour.CPoint( prevVertex ).y - y1;
 
 // Next vertex computation
 double xb = currContour.CPoint( nextVertex ).x - x1;
 double yb = currContour.CPoint( nextVertex ).y - y1;
 
 // Avoid segments that will generate nans below
 if( std::abs( xa + xb ) < std::numeric_limits<double>::epsilon()
 && std::abs( ya + yb ) < std::numeric_limits<double>::epsilon() )
 {
 continue;
 }
 
 // Compute the new distances
 double lena = hypot( xa, ya );
 double lenb = hypot( xb, yb );
 
 // Make the final computations depending on the mode selected, chamfered or filleted.
 if( aMode == CORNER_MODE::CHAMFERED )
 {
 double distance = aDistance;
 
 // Chamfer one half of an edge at most
 if( 0.5 * lena < distance )
 distance = 0.5 * lena;
 
 if( 0.5 * lenb < distance )
 distance = 0.5 * lenb;
 
 int nx1 = KiROUND( distance * xa / lena );
 int ny1 = KiROUND( distance * ya / lena );
 
 newContour.Append( x1 + nx1, y1 + ny1 );
 
 int nx2 = KiROUND( distance * xb / lenb );
 int ny2 = KiROUND( distance * yb / lenb );
 
 newContour.Append( x1 + nx2, y1 + ny2 );
 }
 else // CORNER_MODE = FILLETED
 {
 double cosine = ( xa * xb + ya * yb ) / ( lena * lenb );
 
 double radius = aDistance;
 double denom = sqrt( 2.0 / ( 1 + cosine ) - 1 );
 
 // Do nothing in case of parallel edges
 if( std::isinf( denom ) )
 continue;
 
 // Limit rounding distance to one half of an edge
 if( 0.5 * lena * denom < radius )
 radius = 0.5 * lena * denom;
 
 if( 0.5 * lenb * denom < radius )
 radius = 0.5 * lenb * denom;
 
 // Calculate fillet arc absolute center point (xc, yx)
 double k = radius / sqrt( .5 * ( 1 - cosine ) );
 double lenab = sqrt( ( xa / lena + xb / lenb ) * ( xa / lena + xb / lenb ) +
 ( ya / lena + yb / lenb ) * ( ya / lena + yb / lenb ) );
 double xc = x1 + k * ( xa / lena + xb / lenb ) / lenab;
 double yc = y1 + k * ( ya / lena + yb / lenb ) / lenab;
 
 // Calculate arc start and end vectors
 k = radius / sqrt( 2 / ( 1 + cosine ) - 1 );
 double xs = x1 + k * xa / lena - xc;
 double ys = y1 + k * ya / lena - yc;
 double xe = x1 + k * xb / lenb - xc;
 double ye = y1 + k * yb / lenb - yc;
 
 // Cosine of arc angle
 double argument = ( xs * xe + ys * ye ) / ( radius * radius );
 
 // Make sure the argument is in [-1,1], interval in which the acos function is
 // defined
 if( argument < -1 )
 argument = -1;
 else if( argument > 1 )
 argument = 1;
 
 double arcAngle = acos( argument );
 int segments = GetArcToSegmentCount( radius, aErrorMax,
 EDA_ANGLE( arcAngle, RADIANS_T ) );
 
 double deltaAngle = arcAngle / segments;
 double startAngle = atan2( -ys, xs );
 
 // Flip arc for inner corners
 if( xa * yb - ya * xb <= 0 )
 deltaAngle *= -1;
 
 double nx = xc + xs;
 double ny = yc + ys;
 
 if( std::isnan( nx ) || std::isnan( ny ) )
 continue;
 
 newContour.Append( KiROUND( nx ), KiROUND( ny ) );
 
 // Store the previous added corner to make a sanity check
 int prevX = KiROUND( nx );
 int prevY = KiROUND( ny );
 
 for( int j = 0; j < segments; j++ )
 {
 nx = xc + cos( startAngle + ( j + 1 ) * deltaAngle ) * radius;
 ny = yc - sin( startAngle + ( j + 1 ) * deltaAngle ) * radius;
 
 if( std::isnan( nx ) || std::isnan( ny ) )
 continue;
 
 // Sanity check: the rounding can produce repeated corners; do not add them.
 if( KiROUND( nx ) != prevX || KiROUND( ny ) != prevY )
 {
 newContour.Append( KiROUND( nx ), KiROUND( ny ) );
 prevX = KiROUND( nx );
 prevY = KiROUND( ny );
 }
 }
 }
 }
 
 // Close the current contour and add it the new polygon
 newContour.SetClosed( true );
 newPoly.push_back( newContour );
 }
 
 return newPoly;
}
 
 
SHAPE_POLY_SET &SHAPE_POLY_SET::operator=( const SHAPE_POLY_SET& aOther )
{
 static_cast<SHAPE&>(*this) = aOther;
 m_polys = aOther.m_polys;
 
 m_triangulatedPolys.clear();
 
 for( unsigned i = 0; i < aOther.TriangulatedPolyCount(); i++ )
 {
 const TRIANGULATED_POLYGON* poly = aOther.TriangulatedPolygon( i );
 m_triangulatedPolys.push_back( std::make_unique<TRIANGULATED_POLYGON>( *poly ) );
 }
 
 m_hash = aOther.m_hash;
 m_triangulationValid = aOther.m_triangulationValid;
 
 return *this;
}
 
 
MD5_HASH SHAPE_POLY_SET::GetHash() const
{
 if( !m_hash.IsValid() )
 return checksum();
 
 return m_hash;
}
 
 
bool SHAPE_POLY_SET::IsTriangulationUpToDate() const
{
 if( !m_triangulationValid )
 return false;
 
 if( !m_hash.IsValid() )
 return false;
 
 MD5_HASH hash = checksum();
 
 return hash == m_hash;
}
 
 
static SHAPE_POLY_SET partitionPolyIntoRegularCellGrid( const SHAPE_POLY_SET& aPoly, int aSize )
{
 BOX2I bb = aPoly.BBox();
 
 double w = bb.GetWidth();
 double h = bb.GetHeight();
 
 if( w == 0.0 || h == 0.0 )
 return aPoly;
 
 int n_cells_x, n_cells_y;
 
 if( w > h )
 {
 n_cells_x = w / aSize;
 n_cells_y = floor( h / w * n_cells_x ) + 1;
 }
 else
 {
 n_cells_y = h / aSize;
 n_cells_x = floor( w / h * n_cells_y ) + 1;
 }
 
 SHAPE_POLY_SET ps1( aPoly ), ps2( aPoly ), maskSetOdd, maskSetEven;
 
 for( int yy = 0; yy < n_cells_y; yy++ )
 {
 for( int xx = 0; xx < n_cells_x; xx++ )
 {
 VECTOR2I p;
 
 p.x = bb.GetX() + w * xx / n_cells_x;
 p.y = bb.GetY() + h * yy / n_cells_y;
 
 VECTOR2I p2;
 
 p2.x = bb.GetX() + w * ( xx + 1 ) / n_cells_x;
 p2.y = bb.GetY() + h * ( yy + 1 ) / n_cells_y;
 
 
 SHAPE_LINE_CHAIN mask;
 mask.Append( VECTOR2I( p.x, p.y ) );
 mask.Append( VECTOR2I( p2.x, p.y ) );
 mask.Append( VECTOR2I( p2.x, p2.y ) );
 mask.Append( VECTOR2I( p.x, p2.y ) );
 mask.SetClosed( true );
 
 if( ( xx ^ yy ) & 1 )
 maskSetOdd.AddOutline( mask );
 else
 maskSetEven.AddOutline( mask );
 }
 }
 
 ps1.BooleanIntersection( maskSetOdd, SHAPE_POLY_SET::PM_FAST );
 ps2.BooleanIntersection( maskSetEven, SHAPE_POLY_SET::PM_FAST );
 ps1.Fracture( SHAPE_POLY_SET::PM_FAST );
 ps2.Fracture( SHAPE_POLY_SET::PM_FAST );
 
 for( int i = 0; i < ps2.OutlineCount(); i++ )
 ps1.AddOutline( ps2.COutline( i ) );
 
 if( ps1.OutlineCount() )
 return ps1;
 else
 return aPoly;
}
 
 
void SHAPE_POLY_SET::CacheTriangulation( bool aPartition, bool aSimplify )
{
 bool recalculate = !m_hash.IsValid();
 MD5_HASH hash;
 
 if( !m_triangulationValid )
 recalculate = true;
 
 if( !recalculate )
 {
 hash = checksum();
 
 if( m_hash != hash )
 {
 m_hash = hash;
 recalculate = true;
 }
 }
 
 if( !recalculate )
 return;
 
 auto triangulate =
 []( SHAPE_POLY_SET& polySet, int forOutline,
 std::vector<std::unique_ptr<TRIANGULATED_POLYGON>>& dest )
 {
 bool triangulationValid = false;
 int pass = 0;
 
 while( polySet.OutlineCount() > 0 )
 {
 if( !dest.empty() && dest.back()->GetTriangleCount() == 0 )
 dest.erase( dest.end() - 1 );
 
 dest.push_back( std::make_unique<TRIANGULATED_POLYGON>( forOutline ) );
 PolygonTriangulation tess( *dest.back() );
 
 // If the tessellation fails, we re-fracture the polygon, which will
 // first simplify the system before fracturing and removing the holes
 // This may result in multiple, disjoint polygons.
 if( !tess.TesselatePolygon( polySet.Polygon( 0 ).front() ) )
 {
 ++pass;
 
 if( pass == 1 )
 polySet.Fracture( PM_FAST );
 else if( pass == 2 )
 polySet.Fracture( PM_STRICTLY_SIMPLE );
 else
 break;
 
 triangulationValid = false;
 continue;
 }
 
 polySet.DeletePolygon( 0 );
 triangulationValid = true;
 }
 
 return triangulationValid;
 };
 
 m_triangulatedPolys.clear();
 m_triangulationValid = true;
 
 if( aPartition )
 {
 for( int ii = 0; ii < OutlineCount(); ++ii )
 {
 // This partitions into regularly-sized grids (1cm in Pcbnew)
 SHAPE_POLY_SET flattened( Outline( ii ) );
 
 for( int jj = 0; jj < HoleCount( ii ); ++jj )
 flattened.AddHole( Hole( ii, jj ) );
 
 flattened.ClearArcs();
 
 if( flattened.HasHoles() || flattened.IsSelfIntersecting() )
 flattened.Fracture( PM_FAST );
 else if( aSimplify )
 flattened.Simplify( PM_FAST );
 
 SHAPE_POLY_SET partitions = partitionPolyIntoRegularCellGrid( flattened, 1e7 );
 
 // This pushes the triangulation for all polys in partitions
 // to be referenced to the ii-th polygon
 m_triangulationValid &= triangulate( partitions, ii , m_triangulatedPolys );
 }
 }
 else
 {
 SHAPE_POLY_SET tmpSet( *this );
 
 tmpSet.ClearArcs();
 
 tmpSet.Fracture( PM_FAST );
 
 m_triangulationValid = triangulate( tmpSet, -1, m_triangulatedPolys );
 }
 
 if( m_triangulationValid )
 m_hash = checksum();
}
 
 
MD5_HASH SHAPE_POLY_SET::checksum() const
{
 MD5_HASH hash;
 
 hash.Hash( m_polys.size() );
 
 for( const POLYGON& outline : m_polys )
 {
 hash.Hash( outline.size() );
 
 for( const SHAPE_LINE_CHAIN& lc : outline )
 {
 hash.Hash( lc.PointCount() );
 
 for( int i = 0; i < lc.PointCount(); i++ )
 {
 hash.Hash( lc.CPoint( i ).x );
 hash.Hash( lc.CPoint( i ).y );
 }
 }
 }
 
 hash.Finalize();
 
 return hash;
}
 
 
bool SHAPE_POLY_SET::HasTouchingHoles() const
{
 for( int i = 0; i < OutlineCount(); i++ )
 {
 if( hasTouchingHoles( CPolygon( i ) ) )
 return true;
 }
 
 return false;
}
 
 
bool SHAPE_POLY_SET::hasTouchingHoles( const POLYGON& aPoly ) const
{
 std::set<long long> ptHashes;
 
 for( const SHAPE_LINE_CHAIN& lc : aPoly )
 {
 for( const VECTOR2I& pt : lc.CPoints() )
 {
 const long long ptHash = (long long) pt.x << 32 | pt.y;
 
 if( ptHashes.count( ptHash ) > 0 )
 return true;
 
 ptHashes.insert( ptHash );
 }
 }
 
 return false;
}
 
 
bool SHAPE_POLY_SET::HasIndexableSubshapes() const
{
 return IsTriangulationUpToDate();
}
 
 
size_t SHAPE_POLY_SET::GetIndexableSubshapeCount() const
{
 size_t n = 0;
 
 for( const std::unique_ptr<TRIANGULATED_POLYGON>& t : m_triangulatedPolys )
 n += t->GetTriangleCount();
 
 return n;
}
 
 
void SHAPE_POLY_SET::GetIndexableSubshapes( std::vector<const SHAPE*>& aSubshapes ) const
{
 aSubshapes.reserve( GetIndexableSubshapeCount() );
 
 for( const std::unique_ptr<TRIANGULATED_POLYGON>& tpoly : m_triangulatedPolys )
 {
 for( TRIANGULATED_POLYGON::TRI& tri : tpoly->Triangles() )
 aSubshapes.push_back( &tri );
 }
}
 
 
const BOX2I SHAPE_POLY_SET::TRIANGULATED_POLYGON::TRI::BBox( int aClearance ) const
{
 BOX2I bbox( parent->m_vertices[a] );
 bbox.Merge( parent->m_vertices[b] );
 bbox.Merge( parent->m_vertices[c] );
 
 if( aClearance != 0 )
 bbox.Inflate( aClearance );
 
 return bbox;
}
 
 
void SHAPE_POLY_SET::TRIANGULATED_POLYGON::AddTriangle( int a, int b, int c )
{
 m_triangles.emplace_back( a, b, c, this );
}
 
 
SHAPE_POLY_SET::TRIANGULATED_POLYGON::TRIANGULATED_POLYGON( const TRIANGULATED_POLYGON& aOther )
{
 m_sourceOutline = aOther.m_sourceOutline;
 m_vertices = aOther.m_vertices;
 m_triangles = aOther.m_triangles;
 
 for( TRI& tri : m_triangles )
 tri.parent = this;
}
 
 
SHAPE_POLY_SET::TRIANGULATED_POLYGON& SHAPE_POLY_SET::TRIANGULATED_POLYGON::operator=( const TRIANGULATED_POLYGON& aOther )
{
 m_sourceOutline = aOther.m_sourceOutline;
 m_vertices = aOther.m_vertices;
 m_triangles = aOther.m_triangles;
 
 for( TRI& tri : m_triangles )
 tri.parent = this;
 
 return *this;
}
 
 
SHAPE_POLY_SET::TRIANGULATED_POLYGON::TRIANGULATED_POLYGON( int aSourceOutline ) :
 m_sourceOutline( aSourceOutline )
{
}
 
 
SHAPE_POLY_SET::TRIANGULATED_POLYGON::~TRIANGULATED_POLYGON()
{
}
 
 
const SHAPE_POLY_SET
SHAPE_POLY_SET::BuildPolysetFromOrientedPaths( const std::vector<SHAPE_LINE_CHAIN>& aPaths,
 bool aReverseOrientation, bool aEvenOdd )
{
 ClipperLib::Clipper clipper;
 ClipperLib::PolyTree tree;
 
 // fixme: do we need aReverseOrientation?
 
 for( const SHAPE_LINE_CHAIN& path : aPaths )
 {
 ClipperLib::Path lc;
 
 for( int i = 0; i < path.PointCount(); i++ )
 {
 lc.emplace_back( path.CPoint( i ).x, path.CPoint( i ).y );
 }
 
 clipper.AddPath( lc, ClipperLib::ptSubject, true );
 }
 
 clipper.StrictlySimple( true );
 clipper.Execute( ClipperLib::ctUnion, tree,
 aEvenOdd ? ClipperLib::pftEvenOdd : ClipperLib::pftNonZero,
 ClipperLib::pftNonZero );
 SHAPE_POLY_SET result;
 
 for( ClipperLib::PolyNode* n = tree.GetFirst(); n; n = n->GetNext() )
 {
 if( !n->IsHole() )
 {
 int outl = result.NewOutline();
 
 for( unsigned int i = 0; i < n->Contour.size(); i++ )
 result.Outline( outl ).Append( n->Contour[i].X, n->Contour[i].Y );
 
 for( unsigned int i = 0; i < n->Childs.size(); i++ )
 {
 int outh = result.NewHole( outl );
 for( unsigned int j = 0; j < n->Childs[i]->Contour.size(); j++ )
 {
 result.Hole( outl, outh )
 .Append( n->Childs[i]->Contour[j].X, n->Childs[i]->Contour[j].Y );
 }
 }
 }
 }
 
 return result;
}
 
 
bool SHAPE_POLY_SET::PointInside( const VECTOR2I& aPt, int aAccuracy, bool aUseBBoxCache ) const
{
 for( int idx = 0; idx < OutlineCount(); idx++ )
 {
 if( COutline( idx ).PointInside( aPt, aAccuracy, aUseBBoxCache ) )
 return true;
 }
 
 return false;
}