pns_line.cpp

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/*
 * KiRouter - a push-and-(sometimes-)shove PCB router
 *
 * Copyright (C) 2013-2017 CERN
 * Copyright (C) 2016-2023 KiCad Developers, see AUTHORS.txt for contributors.
 * Author: Tomasz Wlostowski <[email protected]>
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */
 
#include <optional>
 
#include <math/box2.h>
#include <math/vector2d.h>
 
#include "pns_line.h"
#include "pns_node.h"
#include "pns_via.h"
#include "pns_utils.h"
#include "pns_router.h"
#include "pns_debug_decorator.h"
 
#include <geometry/shape_rect.h>
 
namespace PNS {
 
LINE::LINE( const LINE& aOther )
 : LINK_HOLDER( aOther ),
 m_line( aOther.m_line ),
 m_width( aOther.m_width ),
 m_snapThreshhold( aOther.m_snapThreshhold )
{
 m_net = aOther.m_net;
 m_movable = aOther.m_movable;
 m_layers = aOther.m_layers;
 
 m_via = nullptr;
 
 if( aOther.m_via )
 {
 m_via = aOther.m_via->Clone();
 m_via->SetOwner( this );
 m_via->SetNet( m_net );
 }
 
 m_marker = aOther.m_marker;
 m_rank = aOther.m_rank;
 m_blockingObstacle = aOther.m_blockingObstacle;
 
 copyLinks( &aOther );
}
 
 
LINE::~LINE()
{
 if( m_via && m_via->BelongsTo( this ) )
 delete m_via;
}
 
 
LINE& LINE::operator=( const LINE& aOther )
{
 m_line = aOther.m_line;
 m_width = aOther.m_width;
 m_net = aOther.m_net;
 m_movable = aOther.m_movable;
 m_layers = aOther.m_layers;
 
 m_via = nullptr;
 
 if( aOther.m_via )
 {
 m_via = aOther.m_via->Clone();
 m_via->SetOwner( this );
 m_via->SetNet( m_net );
 }
 
 m_marker = aOther.m_marker;
 m_rank = aOther.m_rank;
 m_owner = aOther.m_owner;
 m_snapThreshhold = aOther.m_snapThreshhold;
 m_blockingObstacle = aOther.m_blockingObstacle;
 
 copyLinks( &aOther );
 
 return *this;
}
 
 
LINE* LINE::Clone() const
{
 LINE* l = new LINE( *this );
 
 return l;
}
 
 
void LINE::Mark( int aMarker ) const
{
 m_marker = aMarker;
 
 for( const LINKED_ITEM* s : m_links )
 s->Mark( aMarker );
 
}
 
 
void LINE::Unmark( int aMarker ) const
{
 for( const LINKED_ITEM* s : m_links )
 s->Unmark( aMarker );
 
 m_marker = 0;
}
 
 
int LINE::Marker() const
{
 int marker = m_marker;
 
 for( LINKED_ITEM* s : m_links )
 marker |= s->Marker();
 
 return marker;
}
 
 
SEGMENT* SEGMENT::Clone() const
{
 SEGMENT* s = new SEGMENT;
 
 s->m_seg = m_seg;
 s->m_net = m_net;
 s->m_layers = m_layers;
 s->m_marker = m_marker;
 s->m_rank = m_rank;
 
 return s;
}
 
 
int LINE::CountCorners( int aAngles ) const
{
 int count = 0;
 
 for( int i = 0; i < m_line.SegmentCount() - 1; i++ )
 {
 const SEG seg1 = m_line.CSegment( i );
 const SEG seg2 = m_line.CSegment( i + 1 );
 
 const DIRECTION_45 dir1( seg1 );
 const DIRECTION_45 dir2( seg2 );
 
 DIRECTION_45::AngleType a = dir1.Angle( dir2 );
 
 if( a & aAngles )
 count++;
 }
 
 return count;
}
 
static int areNeighbours( int x, int y, int max = 0 )
{
 if( x > 0 && x - 1 == y )
 return true;
 
 if( x < max - 1 && x + 1 == y )
 return true;
 
 return false;
}
 
#ifdef TOM_EXTRA_DEBUG
SHAPE_LINE_CHAIN g_pnew, g_hnew;
#endif
 
bool LINE::Walkaround( const SHAPE_LINE_CHAIN& aObstacle, SHAPE_LINE_CHAIN& aPath, bool aCw ) const
{
 const SHAPE_LINE_CHAIN& line( CLine() );
 
 if( line.SegmentCount() < 1 )
 {
 return false;
 }
 
 const VECTOR2I pFirst = line.CPoint(0);
 
 bool inFirst = aObstacle.PointInside( pFirst ) && !aObstacle.PointOnEdge( pFirst );
 
 // We can't really walk around if the beginning of the path lies inside the obstacle hull.
 // Double check if it's not on the hull itself as this triggers many unroutable corner cases.
 if( inFirst )
 {
 return false;
 }
 
 enum VERTEX_TYPE { INSIDE = 0, OUTSIDE, ON_EDGE };
 
 // Represents an entry in directed graph of hull/path vertices. Scanning this graph
 // starting from the path's first point results (if possible) with a correct walkaround path
 struct VERTEX
 {
 // vertex classification (inside/outside/exactly on the hull)
 VERTEX_TYPE type;
 // true = vertex coming from the hull primitive
 bool isHull;
 // position
 VECTOR2I pos;
 // list of neighboring vertices
 std::vector<VERTEX*> neighbours;
 // index of this vertex in path (pnew)
 int indexp = -1;
 // index of this vertex in the hull (hnew)
 int indexh = -1;
 // visited indicator (for BFS search)
 bool visited = false;
 };
 
 SHAPE_LINE_CHAIN::INTERSECTIONS ips;
 
 HullIntersection( aObstacle, line, ips );
 
 SHAPE_LINE_CHAIN pnew( CLine() ), hnew( aObstacle );
 
 std::vector<VERTEX> vts;
 
 auto findVertex =
 [&]( const VECTOR2I& pos ) -> VERTEX*
 {
 for( VERTEX& v : vts )
 {
 if( v.pos == pos )
 return &v;
 }
 
 return nullptr;
 };
 
 // corner case for loopy tracks: insert the end loop point back into the hull
 if( const std::optional<SHAPE_LINE_CHAIN::INTERSECTION> isect = pnew.SelfIntersecting() )
 {
 if( isect->p != pnew.CPoint( -1 ) )
 pnew.Split( isect->p );
 }
 
 // insert all intersections found into the new hull/path SLCs
 for( SHAPE_LINE_CHAIN::INTERSECTION& ip : ips )
 {
 if( pnew.Find( ip.p, 1 ) < 0)
 pnew.Split(ip.p);
 
 if( hnew.Find( ip.p, 1 ) < 0 )
 hnew.Split(ip.p);
 }
 
 for( int i = 0; i < pnew.PointCount(); i++ )
 {
 const VECTOR2I& p = pnew.CPoint( i );
 bool onEdge = hnew.PointOnEdge( p );
 
 if ( !onEdge )
 continue;
 
 int idx = hnew.Find( p );
 
 if(idx < 0 )
 hnew.Split( p );
 }
 
 #ifdef TOM_EXTRA_DEBUG
 for( auto& ip : ips )
 {
 printf("Chk: %d %d\n", pnew.Find( ip.p ), hnew.Find(ip.p) );
 }
 #endif
 
 // we assume the default orientation of the hulls is clockwise, so just reverse the vertex
 // order if the caller wants a counter-clockwise walkaround
 if ( !aCw )
 hnew = hnew.Reverse();
 
 vts.reserve( 2 * ( hnew.PointCount() + pnew.PointCount() ) );
 
 // create a graph of hull/path vertices and classify them (inside/on edge/outside the hull)
 for( int i = 0; i < pnew.PointCount(); i++ )
 {
 const VECTOR2I& p = pnew.CPoint(i);
 bool onEdge = hnew.PointOnEdge( p );
 bool inside = hnew.PointInside( p );
 
 #ifdef TOM_EXTRA_DEBUG
 printf("pnew %d inside %d onedge %d\n", i, !!inside, !!onEdge );
 #endif
 
 VERTEX v;
 
 v.indexp = i;
 v.isHull = false;
 v.pos = p;
 v.type = inside && !onEdge ? INSIDE : onEdge ? ON_EDGE : OUTSIDE;
 vts.push_back( v );
 }
 
 #ifdef TOM_EXTRA_DEBUG
 g_pnew = pnew;
 g_hnew = hnew;
 #endif
 
 // each path vertex neighbour list points for sure to the next vertex in the path
 for( int i = 0; i < pnew.PointCount() - 1; i++ )
 {
 vts[i].neighbours.push_back( &vts[ i+1 ] );
 }
 
 // each path vertex neighbour list points for sure to the next vertex in the path
 for( int i = 1; i < pnew.PointCount() ; i++ )
 {
 vts[i].neighbours.push_back( &vts[ i-1 ] );
 }
 
 // insert hull vertices into the graph
 for( int i = 0; i < hnew.PointCount(); i++ )
 {
 const VECTOR2I& hp = hnew.CPoint( i );
 VERTEX* vn = findVertex( hp );
 
 // if vertex already present (it's very likely that in recursive shoving hull and path vertices will overlap)
 // just mark it as a path vertex that also belongs to the hull
 if( vn )
 {
 vn->isHull = true;
 vn->indexh = i;
 }
 else // new hull vertex
 {
 VERTEX v;
 v.pos = hp;
 v.type = ON_EDGE;
 v.indexh = i;
 v.isHull = true;
 vts.push_back( v );
 }
 }
 
 // go around the hull and fix up the neighbour link lists
 for( int i = 0; i < hnew.PointCount(); i++ )
 {
 VERTEX* vc = findVertex( hnew.CPoint( i ) );
 VERTEX* vnext = findVertex( hnew.CPoint( i+1 ) );
 
 if( vc && vnext )
 vc->neighbours.push_back( vnext );
 }
 
 // In the case that the initial path ends *inside* the current obstacle (i.e. the mouse cursor
 // is somewhere inside the hull for the current obstacle) we want to end the walkaround at the
 // point closest to the cursor
 bool inLast = aObstacle.PointInside( CPoint( -1 ) ) && !aObstacle.PointOnEdge( CPoint( -1 ) );
 bool appendV = true;
 int lastDst = INT_MAX;
 
 int i = 0;
#ifdef TOM_EXTRA_DEBUG
 for( VERTEX* &v: vts )
 {
 if( v.indexh < 0 && v.type == ON_EDGE )
 v.type = OUTSIDE; // hack
 
 printf("V %d pos %d %d ip %d ih %d type %d\n", i++, v.pos.x, v.pos.y, v.indexp, v.indexh, v.type );
 }
#endif
 // vts[0] = start point
 VERTEX* v = &vts[0];
 VERTEX* v_prev = nullptr;
 SHAPE_LINE_CHAIN out;
 
 int iterLimit = 1000;
 
 // keep scanning the graph until we reach the end point of the path
 while( v->indexp != ( pnew.PointCount() - 1 ) )
 {
 iterLimit--;
 
 // I'm not 100% sure this algorithm doesn't have bugs that may cause it to freeze,
 // so here's a temporary iteration limit
 if( iterLimit == 0 )
 return false;
 
 if( v->visited )
 {
 // loop found? stop walking
 break;
 }
 
#ifdef TOM_EXTRA_DEBUG
 printf("---\nvisit ip %d ih %d type %d outs %d neig %d\n", v->indexp, v->indexh, v->type, out.PointCount(), v->neighbours.size() );
#endif
 out.Append( v->pos );
 
 VERTEX* v_next = nullptr;
 
 if( v->type == OUTSIDE )
 {
 // current vertex is outside? first look for any vertex further down the path
 // that is not inside the hull
 out.Append( v->pos );
 VERTEX* v_next_fallback = nullptr;
 
 for( VERTEX* vn : v->neighbours )
 {
 if( areNeighbours( vn->indexp , v->indexp, pnew.PointCount() )
 && vn->type != INSIDE )
 {
 if( !vn->visited )
 {
 v_next = vn;
 break;
 }
 else if( vn != v_prev )
 {
 v_next_fallback = vn;
 }
 }
 }
 
 if( !v_next )
 v_next = v_next_fallback;
 
 // such a vertex must always be present, if not, bummer.
 if( !v_next )
 {
 #ifdef TOM_EXTRA_DEBUG
 printf("FAIL VN fallback %p\n", v_next_fallback );
 #endif
 return false;
 }
 }
 else if( v->type == ON_EDGE )
 {
 // look first for the first vertex outside the hull
 for( VERTEX* vn : v->neighbours )
 {
#ifdef TOM_EXTRA_DEBUG
 printf( "- OUT scan ip %d ih %d type %d\n", vn->indexp, vn->indexh, vn->type );
#endif
 
 if( vn->type == OUTSIDE && !vn->visited )
 {
 v_next = vn;
 break;
 }
 }
 
 // no outside vertices found? continue traversing the hull
 if( !v_next )
 {
 for( VERTEX* vn : v->neighbours )
 {
 #ifdef TOM_EXTRA_DEBUG
 printf("- scan ip %d ih %d type %d\n", vn->indexp, vn->indexh, vn->type );
 #endif
 if( vn->type == ON_EDGE && !vn->isHull &&
 areNeighbours( vn->indexp, v->indexp, pnew.PointCount() ) &&
 ( vn->indexh == ( ( v->indexh + 1 ) % hnew.PointCount() ) ) )
 {
 v_next = vn;
 break;
 }
 }
 }
 
 // still nothing found? try to find the next (index-wise) point on the hull. I guess
 // we should never reach this part of the code, but who really knows?
 if( !v_next )
 {
#ifdef TOM_EXTRA_DEBUG
 printf("still no v_next\n");
#endif
 for( VERTEX* vn : v->neighbours )
 {
 if( vn->type == ON_EDGE )
 {
 if( vn->indexh == ( ( v->indexh + 1 ) % hnew.PointCount() ) )
 {
 v_next = vn;
 break;
 }
 }
 }
 
 if( v_next )
 {
 for( VERTEX &vt : vts )
 {
 if( vt.isHull )
 vt.visited = false;
 }
 }
 
#ifdef TOM_EXTRA_DEBUG
 printf("v_next %p\n", v_next);
#endif
 
 // Did we get the next hull point but the end of the line is inside? Instead of walking
 // around the hull some more (which will just end up taking us back to the start), lets
 // just project the normal of the endpoint onto this next segment and call it quits.
 if( inLast && v_next )
 {
 int d = ( v_next->pos - CPoint( -1 ) ).SquaredEuclideanNorm();
 
 if( d < lastDst )
 {
 lastDst = d;
 }
 else
 {
 VECTOR2I proj = SEG( v->pos, v_next->pos ).NearestPoint( CPoint( -1 ) );
 out.Append( proj );
 appendV = false;
 break;
 }
 }
 }
 }
 
 v->visited = true;
 v_prev = v;
 v = v_next;
 
 if( !v )
 return false;
 }
 
 if( appendV )
 out.Append( v->pos );
 
 aPath = out;
 
 return true;
}
 
 
const SHAPE_LINE_CHAIN SEGMENT::Hull( int aClearance, int aWalkaroundThickness, int aLayer ) const
{
 /*DEBUG_DECORATOR* debugDecorator = ROUTER::GetInstance()->GetInterface()->GetDebugDecorator();
 
 PNS_DBG( debugDecorator, Message, wxString::Format( wxT( "seghull %d %d" ), aWalkaroundThickness, aClearance ) );
 PNS_DBG(debugDecorator, AddShape, &m_seg, RED, 0, wxT("theseg") );
 */
 
 return SegmentHull( m_seg, aClearance, aWalkaroundThickness );
}
 
const LINE LINE::ClipToNearestObstacle( NODE* aNode ) const
{
 const int IterationLimit = 5;
 int i;
 LINE l( *this );
 
 for( i = 0; i < IterationLimit; i++ )
 {
 NODE::OPT_OBSTACLE obs = aNode->NearestObstacle( &l );
 
 if( obs )
 {
 l.RemoveVia();
 VECTOR2I collisionPoint = obs->m_ipFirst;
 int segIdx = l.Line().NearestSegment( collisionPoint );
 
 if( l.Line().IsArcSegment( segIdx ) )
 {
 // Don't clip at arcs, start again
 l.Line().Clear();
 }
 else
 {
 SEG nearestSegment = l.Line().CSegment( segIdx );
 VECTOR2I nearestPt = nearestSegment.NearestPoint( collisionPoint );
 int p = l.Line().Split( nearestPt );
 l.Line().Remove( p + 1, -1 );
 }
 }
 else
 {
 break;
 }
 }
 
 if( i == IterationLimit )
 l.Line().Clear();
 
 return l;
}
 
 
 
SHAPE_LINE_CHAIN dragCornerInternal( const SHAPE_LINE_CHAIN& aOrigin, const VECTOR2I& aP )
{
 std::optional<SHAPE_LINE_CHAIN> picked;
 int i;
 int d = 2;
 
 wxASSERT( aOrigin.PointCount() > 0 );
 
 if( aOrigin.PointCount() == 1 )
 {
 return DIRECTION_45().BuildInitialTrace( aOrigin.CPoint( 0 ), aP );
 }
 else if( aOrigin.SegmentCount() == 1 )
 {
 DIRECTION_45 dir( aOrigin.CPoint( 0 ) - aOrigin.CPoint( 1 ) );
 
 return DIRECTION_45().BuildInitialTrace( aOrigin.CPoint( 0 ), aP, dir.IsDiagonal() );
 }
 
 if( aOrigin.CSegment( -1 ).Length() > 100000 * 30 ) // fixme: constant/parameter?
 d = 1;
 
 for( i = aOrigin.SegmentCount() - d; i >= 0; i-- )
 {
 DIRECTION_45 d_start( aOrigin.CSegment( i ) );
 const VECTOR2I& p_start = aOrigin.CPoint( i );
 SHAPE_LINE_CHAIN paths[2];
 DIRECTION_45 dirs[2];
 DIRECTION_45 d_prev = ( i > 0 ? DIRECTION_45( aOrigin.CSegment( i-1 ) )
 : DIRECTION_45() );
 int dirCount = 0;
 
 for( int j = 0; j < 2; j++ )
 {
 paths[j] = d_start.BuildInitialTrace( p_start, aP, j );
 
 if( paths[j].SegmentCount() < 1 )
 continue;
 
 assert( dirCount < int( sizeof( dirs ) / sizeof( dirs[0] ) ) );
 
 dirs[dirCount] = DIRECTION_45( paths[j].CSegment( 0 ) );
 ++dirCount;
 }
 
 for( int j = 0; j < dirCount; j++ )
 {
 if( dirs[j] == d_start )
 {
 picked = paths[j];
 break;
 }
 }
 
 if( picked )
 break;
 
 for( int j = 0; j < dirCount; j++ )
 {
 if( dirs[j].IsObtuse( d_prev ) )
 {
 picked = paths[j];
 break;
 }
 }
 
 if( picked )
 break;
 }
 
 if( picked )
 {
 SHAPE_LINE_CHAIN path = aOrigin.Slice( 0, i );
 path.Append( *picked );
 
 return path;
 }
 
 DIRECTION_45 dir( aOrigin.CPoint( -1 ) - aOrigin.CPoint( -2 ) );
 
 return DIRECTION_45().BuildInitialTrace( aOrigin.CPoint( 0 ), aP, dir.IsDiagonal() );
}
 
 
void LINE::dragCorner45( const VECTOR2I& aP, int aIndex )
{
 SHAPE_LINE_CHAIN path;
 
 int width = m_line.Width();
 VECTOR2I snapped = snapDraggedCorner( m_line, aP, aIndex );
 
 if( aIndex == 0 )
 {
 path = dragCornerInternal( m_line.Reverse(), snapped ).Reverse();
 }
 else if( aIndex == m_line.SegmentCount() )
 {
 path = dragCornerInternal( m_line, snapped );
 }
 else
 {
 // Are we next to an arc? Insert a new point so we slice correctly
 if( m_line.IsPtOnArc( static_cast<size_t>( aIndex ) + 1 ) )
 m_line.Insert( aIndex + 1, m_line.CPoint( aIndex + 1 ) );
 
 // fixme: awkward behaviour for "outwards" drags
 path = dragCornerInternal( m_line.Slice( 0, aIndex ), snapped );
 SHAPE_LINE_CHAIN path_rev =
 dragCornerInternal( m_line.Slice( aIndex, -1 ).Reverse(), snapped ).Reverse();
 path.Append( path_rev );
 }
 
 path.Simplify();
 path.SetWidth( width );
 m_line = path;
}
 
 
void LINE::dragCornerFree( const VECTOR2I& aP, int aIndex )
{
 ssize_t idx = static_cast<ssize_t>( aIndex );
 ssize_t numpts = static_cast<ssize_t>( m_line.PointCount() );
 
 // If we're asked to drag the end of an arc, insert a new vertex to drag instead
 if( m_line.IsPtOnArc( idx ) )
 {
 if( idx == 0 || ( idx > 0 && !m_line.IsPtOnArc( idx - 1 ) ) )
 {
 m_line.Insert( idx, m_line.GetPoint( idx ) );
 }
 else if( ( idx == numpts - 1 ) || ( idx < numpts - 1 && !m_line.IsArcSegment( idx ) ) )
 {
 idx++;
 m_line.Insert( idx, m_line.GetPoint( idx ) );
 }
 else
 {
 wxASSERT_MSG( false, wxT( "Attempt to dragCornerFree in the middle of an arc!" ) );
 }
 }
 
 m_line.SetPoint( idx, aP );
 m_line.Simplify();
}
 
void LINE::DragCorner( const VECTOR2I& aP, int aIndex, bool aFreeAngle )
{
 wxCHECK_RET( aIndex >= 0, wxT( "Negative index passed to LINE::DragCorner" ) );
 
 if( aFreeAngle )
 {
 dragCornerFree( aP, aIndex );
 }
 else
 {
 dragCorner45( aP, aIndex );
 }
}
 
void LINE::DragSegment( const VECTOR2I& aP, int aIndex, bool aFreeAngle )
{
 if( aFreeAngle )
 {
 assert( false );
 }
 else
 {
 dragSegment45( aP, aIndex );
 }
}
 
VECTOR2I LINE::snapDraggedCorner(
 const SHAPE_LINE_CHAIN& aPath, const VECTOR2I& aP, int aIndex ) const
{
 int s_start = std::max( aIndex - 2, 0 );
 int s_end = std::min( aIndex + 2, aPath.SegmentCount() - 1 );
 
 int i, j;
 int best_dist = INT_MAX;
 VECTOR2I best_snap = aP;
 
 if( m_snapThreshhold <= 0 )
 return aP;
 
 for( i = s_start; i <= s_end; i++ )
 {
 const SEG& a = aPath.CSegment( i );
 
 for( j = s_start; j < i; j++ )
 {
 const SEG& b = aPath.CSegment( j );
 
 if( !( DIRECTION_45( a ).IsObtuse( DIRECTION_45( b ) ) ) )
 continue;
 
 OPT_VECTOR2I ip = a.IntersectLines( b );
 
 if( ip )
 {
 int dist = ( *ip - aP ).EuclideanNorm();
 
 if( dist < m_snapThreshhold && dist < best_dist )
 {
 best_dist = dist;
 best_snap = *ip;
 }
 }
 }
 }
 
 return best_snap;
}
 
VECTOR2I LINE::snapToNeighbourSegments(
 const SHAPE_LINE_CHAIN& aPath, const VECTOR2I& aP, int aIndex ) const
{
 VECTOR2I snap_p[2];
 DIRECTION_45 dragDir( aPath.CSegment( aIndex ) );
 int snap_d[2] = { -1, -1 };
 
 if( m_snapThreshhold == 0 )
 return aP;
 
 if( aIndex >= 2 )
 {
 SEG s = aPath.CSegment( aIndex - 2 );
 
 if( DIRECTION_45( s ) == dragDir )
 snap_d[0] = s.LineDistance( aP );
 
 snap_p[0] = s.A;
 }
 
 if( aIndex < aPath.SegmentCount() - 2 )
 {
 SEG s = aPath.CSegment( aIndex + 2 );
 
 if( DIRECTION_45( s ) == dragDir )
 snap_d[1] = s.LineDistance( aP );
 
 snap_p[1] = s.A;
 }
 
 VECTOR2I best = aP;
 int minDist = INT_MAX;
 
 for( int i = 0; i < 2; i++ )
 {
 if( snap_d[i] >= 0 && snap_d[i] < minDist && snap_d[i] <= m_snapThreshhold )
 {
 minDist = snap_d[i];
 best = snap_p[i];
 }
 }
 
 return best;
}
 
void LINE::dragSegment45( const VECTOR2I& aP, int aIndex )
{
 SHAPE_LINE_CHAIN path( m_line );
 VECTOR2I target( aP );
 
 wxASSERT( aIndex < m_line.PointCount() );
 
 SEG guideA[2], guideB[2];
 int index = aIndex;
 
 target = snapToNeighbourSegments( path, aP, aIndex );
 
 // We require a valid s_prev and s_next. If we are at the start or end of the line, we insert
 // a new point at the start or end so there is a zero-length segment for prev or next (we will
 // resize it as part of the drag operation). If we are next to an arc, we do this also, as we
 // cannot drag away one of the arc's points.
 
 if( index == 0 || path.IsPtOnArc( index ) )
 {
 path.Insert( index > 0 ? index + 1 : 0, path.CPoint( index ) );
 index++;
 }
 
 if( index == path.SegmentCount() - 1 )
 {
 path.Insert( path.PointCount() - 1, path.CPoint( -1 ) );
 }
 else if( path.IsPtOnArc( index + 1 ) )
 {
 path.Insert( index + 1, path.CPoint( index + 1 ) );
 }
 
 SEG dragged = path.CSegment( index );
 DIRECTION_45 drag_dir( dragged );
 
 SEG s_prev = path.CSegment( index - 1 );
 SEG s_next = path.CSegment( index + 1 );
 
 DIRECTION_45 dir_prev( s_prev );
 DIRECTION_45 dir_next( s_next );
 
 if( dir_prev == drag_dir )
 {
 dir_prev = dir_prev.Left();
 path.Insert( index, path.CPoint( index ) );
 index++;
 }
 else if( dir_prev == DIRECTION_45::UNDEFINED )
 {
 dir_prev = drag_dir.Left();
 }
 
 if( dir_next == drag_dir )
 {
 dir_next = dir_next.Right();
 path.Insert( index + 1, path.CPoint( index + 1 ) );
 }
 else if( dir_next == DIRECTION_45::UNDEFINED )
 {
 dir_next = drag_dir.Right();
 }
 
 s_prev = path.CSegment( index - 1 );
 s_next = path.CSegment( index + 1 );
 dragged = path.CSegment( index );
 
 if( aIndex == 0 )
 {
 guideA[0] = SEG( dragged.A, dragged.A + drag_dir.Right().ToVector() );
 guideA[1] = SEG( dragged.A, dragged.A + drag_dir.Left().ToVector() );
 }
 else
 {
 if( dir_prev.Angle( drag_dir )
 & ( DIRECTION_45::ANG_OBTUSE | DIRECTION_45::ANG_HALF_FULL ) )
 {
 guideA[0] = SEG( s_prev.A, s_prev.A + drag_dir.Left().ToVector() );
 guideA[1] = SEG( s_prev.A, s_prev.A + drag_dir.Right().ToVector() );
 }
 else
 guideA[0] = guideA[1] = SEG( dragged.A, dragged.A + dir_prev.ToVector() );
 }
 
 if( aIndex == m_line.SegmentCount() - 1 )
 {
 guideB[0] = SEG( dragged.B, dragged.B + drag_dir.Right().ToVector() );
 guideB[1] = SEG( dragged.B, dragged.B + drag_dir.Left().ToVector() );
 }
 else
 {
 if( dir_next.Angle( drag_dir )
 & ( DIRECTION_45::ANG_OBTUSE | DIRECTION_45::ANG_HALF_FULL ) )
 {
 guideB[0] = SEG( s_next.B, s_next.B + drag_dir.Left().ToVector() );
 guideB[1] = SEG( s_next.B, s_next.B + drag_dir.Right().ToVector() );
 }
 else
 guideB[0] = guideB[1] = SEG( dragged.B, dragged.B + dir_next.ToVector() );
 }
 
 SEG s_current( target, target + drag_dir.ToVector() );
 
 int best_len = INT_MAX;
 SHAPE_LINE_CHAIN best;
 
 for( int i = 0; i < 2; i++ )
 {
 for( int j = 0; j < 2; j++ )
 {
 OPT_VECTOR2I ip1 = s_current.IntersectLines( guideA[i] );
 OPT_VECTOR2I ip2 = s_current.IntersectLines( guideB[j] );
 
 SHAPE_LINE_CHAIN np;
 
 if( !ip1 || !ip2 )
 continue;
 
 SEG s1( s_prev.A, *ip1 );
 SEG s2( *ip1, *ip2 );
 SEG s3( *ip2, s_next.B );
 
 OPT_VECTOR2I ip;
 
 if( ( ip = s1.Intersect( s_next ) ) )
 {
 np.Append( s1.A );
 np.Append( *ip );
 np.Append( s_next.B );
 }
 else if( ( ip = s3.Intersect( s_prev ) ) )
 {
 np.Append( s_prev.A );
 np.Append( *ip );
 np.Append( s3.B );
 }
 else if( ( ip = s1.Intersect( s3 ) ) )
 {
 np.Append( s_prev.A );
 np.Append( *ip );
 np.Append( s_next.B );
 }
 else
 {
 np.Append( s_prev.A );
 np.Append( *ip1 );
 np.Append( *ip2 );
 np.Append( s_next.B );
 }
 
 if( np.Length() < best_len )
 {
 best_len = np.Length();
 best = np;
 }
 }
 }
 
 if( m_line.PointCount() == 1 )
 m_line = best;
 else if( aIndex == 0 )
 m_line.Replace( 0, 1, best );
 else if( aIndex == m_line.SegmentCount() - 1 )
 m_line.Replace( -2, -1, best );
 else
 m_line.Replace( aIndex, aIndex + 1, best );
 
 m_line.Simplify();
}
 
 
bool LINE::CompareGeometry( const LINE& aOther )
{
 return m_line.CompareGeometry( aOther.m_line );
}
 
 
void LINE::Reverse()
{
 m_line = m_line.Reverse();
 
 std::reverse( m_links.begin(), m_links.end() );
}
 
 
void LINE::AppendVia( const VIA& aVia )
{
 if( m_line.PointCount() > 1 && aVia.Pos() == m_line.CPoint( 0 ) )
 {
 Reverse();
 }
 
 m_via = aVia.Clone();
 m_via->SetOwner( this );
 m_via->SetNet( m_net );
}
 
 
void LINE::SetRank( int aRank )
{
 m_rank = aRank;
 
 for( auto s : m_links )
 s->SetRank( aRank );
 
}
 
 
int LINE::Rank() const
{
 int min_rank = INT_MAX;
 
 if( IsLinked() )
 {
 for( const LINKED_ITEM* item : m_links )
 min_rank = std::min( min_rank, item->Rank() );
 }
 else
 {
 min_rank = m_rank;
 }
 
 int rank = ( min_rank == INT_MAX ) ? -1 : min_rank;
 
 return rank;
}
 
 
void LINE::ClipVertexRange( int aStart, int aEnd )
{
 int firstLink = 0;
 int lastLink = std::max( 0, static_cast<int>( m_links.size() ) - 1 );
 int linkIdx = 0;
 
 int numPoints = static_cast<int>( m_line.PointCount() );
 
 for( int i = 0; i >= 0 && i < m_line.PointCount(); i = m_line.NextShape( i ) )
 {
 if( i <= aStart )
 firstLink = linkIdx;
 
 if( i < 0 || i >= aEnd - 1 || linkIdx >= lastLink )
 {
 lastLink = linkIdx;
 break;
 }
 
 linkIdx++;
 }
 
 wxASSERT( lastLink >= firstLink );
 
 m_line = m_line.Slice( aStart, aEnd );
 
 if( IsLinked() )
 {
 wxASSERT( m_links.size() < INT_MAX );
 wxASSERT( static_cast<int>( m_links.size() ) >= ( lastLink - firstLink ) );
 
 // Note: The range includes aEnd, but we have n-1 segments.
 std::rotate(
 m_links.begin(),
 m_links.begin() + firstLink,
 m_links.begin() + lastLink
 );
 
 m_links.resize( lastLink - firstLink + 1 );
 }
}
 
 
bool LINE::HasLoops() const
{
 for( int i = 0; i < PointCount(); i++ )
 {
 for( int j = i + 2; j < PointCount(); j++ )
 {
 if( CPoint( i ) == CPoint( j ) )
 return true;
 }
 }
 
 return false;
}
 
 
static void extendBox( BOX2I& aBox, bool& aDefined, const VECTOR2I& aP )
{
 if( aDefined )
 {
 aBox.Merge( aP );
 }
 else
 {
 aBox = BOX2I( aP, VECTOR2I( 0, 0 ) );
 aDefined = true;
 }
}
 
 
OPT_BOX2I LINE::ChangedArea( const LINE* aOther ) const
{
 BOX2I area;
 bool areaDefined = false;
 
 int i_start = -1;
 int i_end_self = -1, i_end_other = -1;
 
 SHAPE_LINE_CHAIN self( m_line );
 self.Simplify();
 SHAPE_LINE_CHAIN other( aOther->m_line );
 other.Simplify();
 
 int np_self = self.PointCount();
 int np_other = other.PointCount();
 
 int n = std::min( np_self, np_other );
 
 for( int i = 0; i < n; i++ )
 {
 const VECTOR2I p1 = self.CPoint( i );
 const VECTOR2I p2 = other.CPoint( i );
 
 if( p1 != p2 )
 {
 if( i != n - 1 )
 {
 SEG s = self.CSegment( i );
 
 if( !s.Contains( p2 ) )
 {
 i_start = i;
 break;
 }
 }
 else
 {
 i_start = i;
 break;
 }
 }
 }
 
 for( int i = 0; i < n; i++ )
 {
 const VECTOR2I p1 = self.CPoint( np_self - 1 - i );
 const VECTOR2I p2 = other.CPoint( np_other - 1 - i );
 
 if( p1 != p2 )
 {
 i_end_self = np_self - 1 - i;
 i_end_other = np_other - 1 - i;
 break;
 }
 }
 
 if( i_start < 0 )
 i_start = n;
 
 if( i_end_self < 0 )
 i_end_self = np_self - 1;
 
 if( i_end_other < 0 )
 i_end_other = np_other - 1;
 
 for( int i = i_start; i <= i_end_self; i++ )
 extendBox( area, areaDefined, self.CPoint( i ) );
 
 for( int i = i_start; i <= i_end_other; i++ )
 extendBox( area, areaDefined, other.CPoint( i ) );
 
 if( areaDefined )
 {
 area.Inflate( std::max( Width(), aOther->Width() ) );
 return area;
 }
 
 return OPT_BOX2I();
}
 
 
bool LINE::HasLockedSegments() const
{
 for( const auto seg : m_links )
 {
 if( seg->Marker() & MK_LOCKED )
 return true;
 }
 return false;
}
 
 
void LINE::Clear()
{
 RemoveVia();
 m_line.Clear();
}
 
 
void LINE::RemoveVia()
{
 if( m_via && m_via->BelongsTo( this ) )
 delete m_via;
 
 m_via = nullptr;
}
 
 
const std::string SEGMENT::Format( ) const
{
 std::stringstream ss;
 ss << ITEM::Format() << " ";
 ss << m_seg.Format( false );
 return ss.str();
}
 
}