pns_diff_pair.cpp

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/*
 * KiRouter - a push-and-(sometimes-)shove PCB router
 *
 * Copyright (C) 2013-2015 CERN
 * Copyright (C) 2016-2021 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 <cstdio>
#include <cstdlib>
#include <cmath>
#include <limits>
 
#include <geometry/shape_rect.h>
 
#include "pns_diff_pair.h"
#include "pns_router.h"
 
namespace PNS {
 
class LINE;
 
 
DP_PRIMITIVE_PAIR::DP_PRIMITIVE_PAIR( ITEM* aPrimP, ITEM* aPrimN )
{
 m_primP = aPrimP->Clone();
 m_primN = aPrimN->Clone();
 
 m_anchorP = m_primP->Anchor( 0 );
 m_anchorN = m_primN->Anchor( 0 );
}
 
 
void DP_PRIMITIVE_PAIR::SetAnchors( const VECTOR2I& aAnchorP, const VECTOR2I& aAnchorN )
{
 m_anchorP = aAnchorP;
 m_anchorN = aAnchorN;
}
 
 
DP_PRIMITIVE_PAIR::DP_PRIMITIVE_PAIR( const VECTOR2I& aAnchorP, const VECTOR2I& aAnchorN )
{
 m_anchorP = aAnchorP;
 m_anchorN = aAnchorN;
 m_primP = m_primN = nullptr;
}
 
 
DP_PRIMITIVE_PAIR::DP_PRIMITIVE_PAIR( const DP_PRIMITIVE_PAIR& aOther )
{
 m_primP = m_primN = nullptr;
 
 if( aOther.m_primP )
 m_primP = aOther.m_primP->Clone();
 
 if( aOther.m_primN )
 m_primN = aOther.m_primN->Clone();
 
 m_anchorP = aOther.m_anchorP;
 m_anchorN = aOther.m_anchorN;
}
 
 
DP_PRIMITIVE_PAIR& DP_PRIMITIVE_PAIR::operator=( const DP_PRIMITIVE_PAIR& aOther )
{
 if( aOther.m_primP )
 m_primP = aOther.m_primP->Clone();
 
 if( aOther.m_primN )
 m_primN = aOther.m_primN->Clone();
 
 m_anchorP = aOther.m_anchorP;
 m_anchorN = aOther.m_anchorN;
 
 return *this;
}
 
 
DP_PRIMITIVE_PAIR::~DP_PRIMITIVE_PAIR()
{
 delete m_primP;
 delete m_primN;
}
 
 
bool DP_PRIMITIVE_PAIR::Directional() const
{
 if( !m_primP )
 return false;
 
 return m_primP->OfKind( ITEM::SEGMENT_T | ITEM::ARC_T );
}
 
 
DIRECTION_45 DP_PRIMITIVE_PAIR::anchorDirection( const ITEM* aItem, const VECTOR2I& aP ) const
{
 if( !aItem->OfKind ( ITEM::SEGMENT_T | ITEM::ARC_T ) )
 return DIRECTION_45();
 
 if( aItem->Anchor( 0 ) == aP )
 return DIRECTION_45( aItem->Anchor( 0 ) - aItem->Anchor( 1 ) );
 else
 return DIRECTION_45( aItem->Anchor( 1 ) - aItem->Anchor( 0 ) );
}
 
 
void DP_PRIMITIVE_PAIR::CursorOrientation( const VECTOR2I& aCursorPos, VECTOR2I& aMidpoint,
 VECTOR2I& aDirection ) const
{
 assert( m_primP && m_primN );
 
 VECTOR2I aP, aN;
 
 if( m_primP->OfKind( ITEM::SEGMENT_T ) && m_primN->OfKind( ITEM::SEGMENT_T ) )
 {
 aP = m_primP->Anchor( 1 );
 aN = m_primN->Anchor( 1 );
 
 // If both segments are parallel, use that as the direction. Otherwise, fall back on the
 // direction perpendicular to the anchor points.
 const SEG& segP = static_cast<SEGMENT*>( m_primP )->Seg();
 const SEG& segN = static_cast<SEGMENT*>( m_primN )->Seg();
 
 if( ( segP.B != segP.A ) && ( segN.B != segN.A ) && segP.ApproxParallel( segN ) )
 {
 aMidpoint = ( aP + aN ) / 2;
 aDirection = segP.B - segP.A;
 aDirection = aDirection.Resize( ( aP - aN ).EuclideanNorm() );
 return;
 }
 }
 else
 {
 aP = m_primP->Anchor( 0 );
 aN = m_primN->Anchor( 0 );
 }
 
 aMidpoint = ( aP + aN ) / 2;
 aDirection = ( aP - aN ).Perpendicular();
 
 if( aDirection.Dot( aCursorPos - aMidpoint ) < 0 )
 aDirection = -aDirection;
}
 
 
DIRECTION_45 DP_PRIMITIVE_PAIR::DirP() const
{
 return anchorDirection( m_primP, m_anchorP );
}
 
 
DIRECTION_45 DP_PRIMITIVE_PAIR::DirN() const
{
 return anchorDirection( m_primN, m_anchorN );
}
 
 
static DIRECTION_45::AngleType angle( const VECTOR2I &a, const VECTOR2I &b )
{
 DIRECTION_45 dir_a( a );
 DIRECTION_45 dir_b( b );
 
 return dir_a.Angle( dir_b );
}
 
 
static bool checkGap( const SHAPE_LINE_CHAIN &p, const SHAPE_LINE_CHAIN &n, int gap )
{
 SEG::ecoord gap_sq = SEG::Square( gap - 100 );
 
 for( int i = 0; i < p.SegmentCount(); i++ )
 {
 for( int j = 0; j < n.SegmentCount() ; j++ )
 {
 SEG::ecoord dist_sq = p.CSegment( i ).SquaredDistance( n.CSegment( j ) );
 
 if( dist_sq < gap_sq )
 return false;
 }
 }
 
 return true;
}
 
 
void DP_GATEWAY::Reverse()
{
 m_entryN = m_entryN.Reverse();
 m_entryP = m_entryP.Reverse();
}
 
 
bool DIFF_PAIR::BuildInitial( const DP_GATEWAY& aEntry, const DP_GATEWAY &aTarget,
 bool aPrefDiagonal )
{
 SHAPE_LINE_CHAIN p = DIRECTION_45().BuildInitialTrace( aEntry.AnchorP(), aTarget.AnchorP(),
 aPrefDiagonal );
 SHAPE_LINE_CHAIN n = DIRECTION_45().BuildInitialTrace( aEntry.AnchorN(), aTarget.AnchorN(),
 aPrefDiagonal );
 
 int mask = aEntry.AllowedAngles() | DIRECTION_45::ANG_STRAIGHT | DIRECTION_45::ANG_OBTUSE;
 
 SHAPE_LINE_CHAIN sum_n, sum_p;
 m_p = p;
 m_n = n;
 
 if( aEntry.HasEntryLines() )
 {
 if( !aEntry.Entry().CheckConnectionAngle( *this, mask ) )
 return false;
 
 sum_p = aEntry.Entry().CP();
 sum_n = aEntry.Entry().CN();
 sum_p.Append( p );
 sum_n.Append( n );
 }
 else
 {
 sum_p = p;
 sum_n = n;
 }
 
 mask = aTarget.AllowedAngles() | DIRECTION_45::ANG_STRAIGHT | DIRECTION_45::ANG_OBTUSE;
 
 m_p = sum_p;
 m_n = sum_n;
 
 if( aTarget.HasEntryLines() )
 {
 DP_GATEWAY t( aTarget );
 t.Reverse();
 
 if( !CheckConnectionAngle( t.Entry(), mask ) )
 return false;
 
 sum_p.Append( t.Entry().CP() );
 sum_n.Append( t.Entry().CN() );
 }
 
 m_p = sum_p;
 m_n = sum_n;
 
 if( !checkGap( p, n, m_gapConstraint ) )
 return false;
 
 if( p.SelfIntersecting() || n.SelfIntersecting() )
 return false;
 
 if( p.Intersects( n ) )
 return false;
 
 return true;
}
 
 
bool DIFF_PAIR::CheckConnectionAngle( const DIFF_PAIR& aOther, int aAllowedAngles ) const
{
 bool checkP, checkN;
 
 if( m_p.SegmentCount() == 0 || aOther.m_p.SegmentCount() == 0 )
 {
 checkP = true;
 }
 else
 {
 DIRECTION_45 p0( m_p.CSegment( -1 ) );
 DIRECTION_45 p1( aOther.m_p.CSegment( 0 ) );
 
 checkP = ( p0.Angle( p1 ) & aAllowedAngles ) != 0;
 }
 
 if( m_n.SegmentCount() == 0 || aOther.m_n.SegmentCount() == 0 )
 {
 checkN = true;
 }
 else
 {
 DIRECTION_45 n0( m_n.CSegment( -1 ) );
 DIRECTION_45 n1( aOther.m_n.CSegment( 0 ) );
 
 checkN = ( n0.Angle( n1 ) & aAllowedAngles ) != 0;
 }
 
 return checkP && checkN;
}
 
 
const DIFF_PAIR DP_GATEWAY::Entry() const
{
 return DIFF_PAIR( m_entryP, m_entryN, 0 );
}
 
 
void DP_GATEWAYS::BuildOrthoProjections( DP_GATEWAYS& aEntries, const VECTOR2I& aCursorPos,
 int aOrthoScore )
{
 for( const DP_GATEWAY& g : aEntries.Gateways() )
 {
 VECTOR2I midpoint( ( g.AnchorP() + g.AnchorN() ) / 2 );
 SEG guide_s( midpoint, midpoint + VECTOR2I( 1, 0 ) );
 SEG guide_d( midpoint, midpoint + VECTOR2I( 1, 1 ) );
 
 VECTOR2I proj_s = guide_s.LineProject( aCursorPos );
 VECTOR2I proj_d = guide_d.LineProject( aCursorPos );
 
 int dist_s = ( proj_s - aCursorPos ).EuclideanNorm();
 int dist_d = ( proj_d - aCursorPos ).EuclideanNorm();
 
 VECTOR2I proj = ( dist_s < dist_d ? proj_s : proj_d );
 
 DP_GATEWAYS targets( m_gap );
 
 targets.m_viaGap = m_viaGap;
 targets.m_viaDiameter = m_viaDiameter;
 targets.m_fitVias = m_fitVias;
 
 targets.BuildForCursor( proj );
 
 for( DP_GATEWAY t : targets.Gateways() )
 {
 t.SetPriority( aOrthoScore );
 m_gateways.push_back( t );
 }
 }
}
 
 
bool DP_GATEWAYS::FitGateways( DP_GATEWAYS& aEntry, DP_GATEWAYS& aTarget, bool aPrefDiagonal,
 DIFF_PAIR& aDp )
{
 DP_CANDIDATE best;
 
 int bestScore = -1000;
 bool found = false;
 
 for( const DP_GATEWAY& g_entry : aEntry.Gateways() )
 {
 for( const DP_GATEWAY& g_target : aTarget.Gateways() )
 {
 for( bool preferred : { false, true } )
 {
 int score = preferred ? 0 : -3;
 score += g_entry.Priority();
 score += g_target.Priority();
 
 if( score >= bestScore )
 {
 DIFF_PAIR l( m_gap );
 
 if( l.BuildInitial( g_entry, g_target, preferred ? aPrefDiagonal
 : !aPrefDiagonal ) )
 {
 best.p = l.CP();
 best.n = l.CN();
 bestScore = score;
 found = true;
 }
 }
 }
 }
 }
 
 
 if( found )
 {
 aDp.SetGap( m_gap );
 aDp.SetShape( best.p, best.n );
 return true;
 }
 
 return false;
}
 
 
bool DP_GATEWAYS::checkDiagonalAlignment( const VECTOR2I& a, const VECTOR2I& b ) const
{
 VECTOR2I dir( std::abs (a.x - b.x), std::abs ( a.y - b.y ) );
 
 return (dir.x == 0 && dir.y != 0) || (dir.x == dir.y) || (dir.y == 0 && dir.x != 0);
}
 
 
void DP_GATEWAYS::FilterByOrientation( int aAngleMask, DIRECTION_45 aRefOrientation )
{
 alg::delete_if( m_gateways,
 [aAngleMask, aRefOrientation]( const DP_GATEWAY& dp )
 {
 DIRECTION_45 orient( dp.AnchorP() - dp.AnchorN() );
 return ( orient.Angle( aRefOrientation ) & aAngleMask );
 } );
}
 
static VECTOR2I makeGapVector( VECTOR2I dir, int length )
{
 int l = length / 2;
 VECTOR2I rv;
 
 if( dir.EuclideanNorm() == 0 )
 return dir;
 
 do
 {
 rv = dir.Resize( l );
 l++;
 } while( ( rv * 2 ).EuclideanNorm() < length );
 
 return rv;
}
 
void DP_GATEWAYS::BuildFromPrimitivePair( const DP_PRIMITIVE_PAIR& aPair, bool aPreferDiagonal )
{
 VECTOR2I majorDirection;
 VECTOR2I p0_p, p0_n;
 int orthoFanDistance = 0;
 int diagFanDistance = 0;
 const SHAPE* shP = nullptr;
 
 if( aPair.PrimP() == nullptr )
 {
 BuildGeneric( aPair.AnchorP(), aPair.AnchorN(), true );
 return;
 }
 
 const int pvMask = ITEM::SOLID_T | ITEM::VIA_T;
 
 if( aPair.PrimP()->OfKind( pvMask ) && aPair.PrimN()->OfKind( pvMask ) )
 {
 p0_p = aPair.AnchorP();
 p0_n = aPair.AnchorN();
 
 shP = aPair.PrimP()->Shape();
 }
 else if( aPair.PrimP()->OfKind( ITEM::SEGMENT_T | ITEM::ARC_T )
 && aPair.PrimN()->OfKind( ITEM::SEGMENT_T | ITEM::ARC_T ) )
 {
 buildDpContinuation( aPair, aPreferDiagonal );
 
 return;
 }
 
 majorDirection = ( p0_p - p0_n ).Perpendicular();
 
 if( shP == nullptr )
 return;
 
 switch( shP->Type() )
 {
 case SH_CIRCLE:
 BuildGeneric ( p0_p, p0_n, true );
 return;
 
 case SH_RECT:
 {
 int w = static_cast<const SHAPE_RECT*>( shP )->GetWidth();
 int h = static_cast<const SHAPE_RECT*>( shP )->GetHeight();
 
 if( w < h )
 std::swap( w, h );
 
 orthoFanDistance = ( w + 1 )* 3 / 2;
 diagFanDistance = ( w - h );
 break;
 }
 
 case SH_SEGMENT:
 {
 int w = static_cast<const SHAPE_SEGMENT*>( shP )->GetWidth();
 SEG s = static_cast<const SHAPE_SEGMENT*>( shP )->GetSeg();
 
 orthoFanDistance = w + ( s.B - s.A ).EuclideanNorm();
 diagFanDistance = ( s.B - s.A ).EuclideanNorm();
 break;
 }
 
 case SH_SIMPLE:
 case SH_COMPOUND:
 {
 BOX2I bbox = shP->BBox();
 int w = bbox.GetWidth();
 int h = bbox.GetHeight();
 
 if( w < h )
 std::swap( w, h );
 
 orthoFanDistance = ( w + 1 )* 3 / 2;
 diagFanDistance = ( w - h );
 break;
 }
 
 default:
 wxFAIL_MSG( wxString::Format( wxT( "Unsupported starting primitive: %d (%s)." ),
 shP->Type(),
 SHAPE_TYPE_asString( shP->Type() ) ) );
 break;
 }
 
 if( checkDiagonalAlignment( p0_p, p0_n ) )
 {
 int padDist = ( p0_p - p0_n ).EuclideanNorm();
 
 for( int k = 0; k < 2; k++ )
 {
 VECTOR2I dir, dp, dv;
 
 if( k == 0 )
 dir = makeGapVector( majorDirection, orthoFanDistance );
 else
 dir = makeGapVector( majorDirection, diagFanDistance );
 
 int d = std::max( 0, padDist - m_gap );
 dp = makeGapVector( dir, d );
 dv = makeGapVector( p0_n - p0_p, d );
 
 for( int i = 0; i < 2; i++ )
 {
 int sign = i ? -1 : 1;
 
 VECTOR2I gw_p( p0_p + sign * ( dir + dp ) + dv );
 VECTOR2I gw_n( p0_n + sign * ( dir + dp ) - dv );
 
 SHAPE_LINE_CHAIN entryP( { p0_p, p0_p + sign * dir, gw_p } );
 SHAPE_LINE_CHAIN entryN( { p0_n, p0_n + sign * dir, gw_n } );
 
 DP_GATEWAY gw( gw_p, gw_n, false );
 
 gw.SetEntryLines( entryP, entryN );
 gw.SetPriority( 100 - k );
 m_gateways.push_back( gw );
 }
 }
 }
 
 BuildGeneric( p0_p, p0_n, true );
}
 
 
void DP_GATEWAYS::BuildForCursor( const VECTOR2I& aCursorPos )
{
 int gap = m_fitVias ? m_viaGap + m_viaDiameter : m_gap;
 
 for( bool diagonal : { false, true } )
 {
 for( int i = 0; i < 4; i++ )
 {
 VECTOR2I dir;
 
 if( !diagonal )
 {
 dir = makeGapVector( VECTOR2I( gap, gap ), gap );
 
 if( i % 2 == 0 )
 dir.x = -dir.x;
 
 if( i / 2 == 0 )
 dir.y = -dir.y;
 }
 else
 {
 if( i /2 == 0 )
 dir = VECTOR2I( (gap + 1) / 2 * ( ( i % 2 ) ? -1 : 1 ), 0 );
 else
 dir = VECTOR2I( 0, (gap + 1) / 2 * ( ( i % 2 ) ? -1 : 1 ) );
 }
 
 if( m_fitVias )
 BuildGeneric( aCursorPos + dir, aCursorPos - dir, true, true );
 else
 m_gateways.emplace_back( aCursorPos + dir, aCursorPos - dir, diagonal );
 }
 }
}
 
 
void DP_GATEWAYS::buildEntries( const VECTOR2I& p0_p, const VECTOR2I& p0_n )
{
 for( DP_GATEWAY &g : m_gateways )
 {
 if( !g.HasEntryLines() )
 {
 SHAPE_LINE_CHAIN lead_p = DIRECTION_45().BuildInitialTrace ( g.AnchorP(), p0_p,
 g.IsDiagonal() ).Reverse();
 SHAPE_LINE_CHAIN lead_n = DIRECTION_45().BuildInitialTrace ( g.AnchorN(), p0_n,
 g.IsDiagonal() ).Reverse();
 g.SetEntryLines( lead_p, lead_n );
 }
 }
}
 
 
void DP_GATEWAYS::buildDpContinuation( const DP_PRIMITIVE_PAIR& aPair, bool aIsDiagonal )
{
 DP_GATEWAY gw( aPair.AnchorP(), aPair.AnchorN(), aIsDiagonal );
 gw.SetPriority( 100 );
 m_gateways.push_back( gw );
 
 if( !aPair.Directional() )
 return;
 
 // If we're at a "normal" angle (cardinal or 45-degree-diagonal), then add gateways that angle
 // the anchor points by 22.5-degrees for connection to tracks which are at +/- 45 degrees from
 // the existing direction.
 
 int EPSILON = 5; // 0.005um
 double SIN_22_5 = 0.38268; // sin(22.5)
 double SIN_23_5 = 0.39875; // sin(23.5)
 
 auto addAngledGateways =
 [&]( int length, int priority )
 {
 SHAPE_LINE_CHAIN entryLineP;
 entryLineP.Append( aPair.AnchorP() );
 entryLineP.Append( aPair.AnchorP() + aPair.DirP().ToVector().Resize( length ) );
 DP_GATEWAY gwExtendP( entryLineP.CLastPoint(), aPair.AnchorN(), aIsDiagonal );
 gwExtendP.SetPriority( priority );
 gwExtendP.SetEntryLines( entryLineP, SHAPE_LINE_CHAIN() );
 m_gateways.push_back( gwExtendP );
 
 SHAPE_LINE_CHAIN entryLineN;
 entryLineN.Append( aPair.AnchorN() );
 entryLineN.Append( aPair.AnchorN() + aPair.DirN().ToVector().Resize( length ) );
 DP_GATEWAY gwExtendN( aPair.AnchorP(), entryLineN.CLastPoint(), aIsDiagonal );
 gwExtendN.SetPriority( priority );
 gwExtendN.SetEntryLines( SHAPE_LINE_CHAIN(), entryLineN );
 m_gateways.push_back( gwExtendN );
 };
 
 VECTOR2I delta = aPair.AnchorP() - aPair.AnchorN();
 
 if( abs( delta.x ) < EPSILON || abs( delta.y ) < EPSILON || abs( delta.x - delta.y ) < EPSILON )
 {
 addAngledGateways( KiROUND( (double) m_gap * SIN_22_5 ), 20 );
 
 // fixme; sin(22.5) doesn't always work, so we also add some lower priority ones with a
 // bit of wiggle room. See https://gitlab.com/kicad/code/kicad/-/issues/12459.
 addAngledGateways( KiROUND( (double) m_gap * SIN_23_5 ), 5 );
 }
}
 
 
void DP_GATEWAYS::BuildGeneric( const VECTOR2I& p0_p, const VECTOR2I& p0_n, bool aBuildEntries,
 bool aViaMode )
{
 SEG st_p[2], st_n[2];
 SEG d_n[2], d_p[2];
 
 const int padToGapThreshold = 3;
 int padDist = ( p0_n - p0_p ).EuclideanNorm();
 
 st_p[0] = SEG(p0_p + VECTOR2I( -100, 0 ), p0_p + VECTOR2I( 100, 0 ) );
 st_n[0] = SEG(p0_n + VECTOR2I( -100, 0 ), p0_n + VECTOR2I( 100, 0 ) );
 st_p[1] = SEG(p0_p + VECTOR2I( 0, -100 ), p0_p + VECTOR2I( 0, 100 ) );
 st_n[1] = SEG(p0_n + VECTOR2I( 0, -100 ), p0_n + VECTOR2I( 0, 100 ) );
 d_p[0] = SEG( p0_p + VECTOR2I( -100, -100 ), p0_p + VECTOR2I( 100, 100 ) );
 d_p[1] = SEG( p0_p + VECTOR2I( 100, -100 ), p0_p + VECTOR2I( -100, 100 ) );
 d_n[0] = SEG( p0_n + VECTOR2I( -100, -100 ), p0_n + VECTOR2I( 100, 100 ) );
 d_n[1] = SEG( p0_n + VECTOR2I( 100, -100 ), p0_n + VECTOR2I( -100, 100 ) );
 
 // midpoint exit & side-by exits
 for( int i = 0; i < 2; i++ )
 {
 bool straightColl = st_p[i].Collinear( st_n[i] );
 bool diagColl = d_p[i].Collinear( d_n[i] );
 
 if( straightColl || diagColl )
 {
 VECTOR2I dir = makeGapVector( p0_n - p0_p, m_gap / 2 );
 VECTOR2I m = ( p0_p + p0_n ) / 2;
 int prio = ( padDist > padToGapThreshold * m_gap ) ? 2 : 1;
 
 if( !aViaMode )
 {
 m_gateways.emplace_back( m - dir, m + dir, diagColl, DIRECTION_45::ANG_RIGHT,
 prio );
 
 dir = makeGapVector( p0_n - p0_p, 2 * m_gap );
 m_gateways.emplace_back( p0_p - dir, p0_p - dir + dir.Perpendicular(), diagColl );
 m_gateways.emplace_back( p0_p - dir, p0_p - dir - dir.Perpendicular(), diagColl );
 m_gateways.emplace_back( p0_n + dir + dir.Perpendicular(), p0_n + dir, diagColl );
 m_gateways.emplace_back( p0_n + dir - dir.Perpendicular(), p0_n + dir, diagColl );
 }
 }
 }
 
 for( int i = 0; i < 2; i++ )
 {
 for( int j = 0; j < 2; j++ )
 {
 OPT_VECTOR2I ips[2];
 
 ips[0] = d_n[i].IntersectLines( d_p[j] );
 ips[1] = st_p[i].IntersectLines( st_n[j] );
 
 if( d_n[i].Collinear( d_p[j] ) )
 ips[0] = OPT_VECTOR2I();
 
 if( st_p[i].Collinear( st_p[j] ) )
 ips[1] = OPT_VECTOR2I();
 
 // diagonal-diagonal and straight-straight cases - the most typical case if the pads
 // are on the same straight/diagonal line
 for( int k = 0; k < 2; k++ )
 {
 if( ips[k] )
 {
 const VECTOR2I m( *ips[k] );
 
 if( m != p0_p && m != p0_n )
 {
 int prio = ( padDist > padToGapThreshold * m_gap ? 10 : 20 );
 VECTOR2I g_p( ( p0_p - m ).Resize( ceil( (double) m_gap * M_SQRT1_2 ) ) );
 VECTOR2I g_n( ( p0_n - m ).Resize( ceil( (double) m_gap * M_SQRT1_2 ) ) );
 
 m_gateways.emplace_back( m + g_p, m + g_n, k == 0 ? true : false,
 DIRECTION_45::ANG_OBTUSE, prio );
 }
 }
 }
 
 ips[0] = st_n[i].IntersectLines( d_p[j] );
 ips[1] = st_p[i].IntersectLines( d_n[j] );
 
 // diagonal-straight cases: 8 possibilities of "weirder" exists
 for( int k = 0; k < 2; k++ )
 {
 if( ips[k] )
 {
 const VECTOR2I m( *ips[k] );
 
 if( !aViaMode && m != p0_p && m != p0_n )
 {
 VECTOR2I g_p, g_n;
 
 g_p = ( p0_p - m ).Resize( ceil( (double) m_gap * M_SQRT2 ) );
 g_n = ( p0_n - m ).Resize( ceil( (double) m_gap ) );
 
 if( angle( g_p, g_n ) != DIRECTION_45::ANG_ACUTE )
 m_gateways.emplace_back( m + g_p, m + g_n, true );
 
 g_p = ( p0_p - m ).Resize( m_gap );
 g_n = ( p0_n - m ).Resize( ceil( (double) m_gap * M_SQRT2 ) );
 
 if( angle( g_p, g_n ) != DIRECTION_45::ANG_ACUTE )
 m_gateways.emplace_back( m + g_p, m + g_n, true );
 }
 }
 }
 }
 }
 
 if( aBuildEntries )
 buildEntries( p0_p, p0_n );
}
 
 
DP_PRIMITIVE_PAIR DIFF_PAIR::EndingPrimitives()
{
 if( m_hasVias )
 {
 return DP_PRIMITIVE_PAIR( &m_via_p, &m_via_n );
 }
 else
 {
 const LINE lP( PLine() );
 const LINE lN( NLine() );
 
 SEGMENT sP( lP, lP.CSegment( -1 ) );
 SEGMENT sN( lN, lN.CSegment( -1 ) );
 
 DP_PRIMITIVE_PAIR dpair( &sP, &sN );
 dpair.SetAnchors( sP.Seg().B, sN.Seg().B );
 
 return dpair;
 }
}
 
 
bool commonParallelProjection( SEG p, SEG n, SEG &pClip, SEG& nClip )
{
 SEG n_proj_p( p.LineProject( n.A ), p.LineProject( n.B ) );
 
 int64_t t_a = 0;
 int64_t t_b = p.TCoef( p.B );
 
 int64_t tproj_a = p.TCoef( n_proj_p.A );
 int64_t tproj_b = p.TCoef( n_proj_p.B );
 
 if( t_b < t_a )
 std::swap( t_b, t_a );
 
 if( tproj_b < tproj_a )
 std::swap( tproj_b, tproj_a );
 
 if( t_b <= tproj_a )
 return false;
 
 if( t_a >= tproj_b )
 return false;
 
 int64_t t[4] = { 0, p.TCoef( p.B ), p.TCoef( n_proj_p.A ), p.TCoef( n_proj_p.B ) };
 std::vector<int64_t> tv( t, t + 4 );
 std::sort( tv.begin(), tv.end() ); // fixme: awful and disgusting way of finding 2 midpoints
 
 int64_t pLenSq = p.SquaredLength();
 
 VECTOR2I dp = p.B - p.A;
 pClip.A.x = p.A.x + rescale( (int64_t)dp.x, tv[1], pLenSq );
 pClip.A.y = p.A.y + rescale( (int64_t)dp.y, tv[1], pLenSq );
 
 pClip.B.x = p.A.x + rescale( (int64_t)dp.x, tv[2], pLenSq );
 pClip.B.y = p.A.y + rescale( (int64_t)dp.y, tv[2], pLenSq );
 
 nClip.A = n.LineProject( pClip.A );
 nClip.B = n.LineProject( pClip.B );
 
 return true;
}
 
 
double DIFF_PAIR::Skew() const
{
 return m_p.Length() - m_n.Length();
}
 
 
void DIFF_PAIR::CoupledSegmentPairs( COUPLED_SEGMENTS_VEC& aPairs ) const
{
 SHAPE_LINE_CHAIN p( m_p );
 SHAPE_LINE_CHAIN n( m_n );
 
 p.Simplify();
 n.Simplify();
 
 for( int i = 0; i < p.SegmentCount(); i++ )
 {
 for( int j = 0; j < n.SegmentCount(); j++ )
 {
 SEG sp = p.Segment( i );
 SEG sn = n.Segment( j );
 
 SEG p_clip, n_clip;
 
 int64_t dist = std::abs( sp.Distance( sn ) - m_width );
 
 if( sp.ApproxParallel( sn, 2 ) && m_gapConstraint.Matches( dist ) &&
 commonParallelProjection( sp, sn, p_clip, n_clip ) )
 {
 const COUPLED_SEGMENTS spair( p_clip, sp, i, n_clip, sn, j );
 aPairs.push_back( spair );
 }
 }
 }
}
 
 
int64_t DIFF_PAIR::CoupledLength( const SHAPE_LINE_CHAIN& aP, const SHAPE_LINE_CHAIN& aN ) const
{
 int64_t total = 0;
 
 for( int i = 0; i < aP.SegmentCount(); i++ )
 {
 for( int j = 0; j < aN.SegmentCount(); j++ )
 {
 SEG sp = aP.CSegment( i );
 SEG sn = aN.CSegment( j );
 
 SEG p_clip, n_clip;
 
 int64_t dist = std::abs( sp.Distance(sn) - m_width );
 
 if( sp.ApproxParallel( sn ) && m_gapConstraint.Matches( dist ) &&
 commonParallelProjection( sp, sn, p_clip, n_clip ) )
 total += p_clip.Length();
 }
 }
 
 return total;
}
 
 
double DIFF_PAIR::CoupledLength() const
{
 COUPLED_SEGMENTS_VEC pairs;
 
 CoupledSegmentPairs( pairs );
 
 double l = 0.0;
 
 for( const COUPLED_SEGMENTS& pair : pairs )
 l += pair.coupledP.Length();
 
 return l;
}
 
 
double DIFF_PAIR::CoupledLengthFactor() const
{
 double t = TotalLength();
 
 if( t == 0.0 )
 return 0.0;
 
 return CoupledLength() / t;
}
 
 
double DIFF_PAIR::TotalLength() const
{
 double lenP = m_p.Length();
 double lenN = m_n.Length();
 
 return (lenN + lenP ) / 2.0;
}
 
 
int DIFF_PAIR::CoupledLength ( const SEG& aP, const SEG& aN ) const
{
 SEG p_clip, n_clip;
 int64_t dist = std::abs( aP.Distance( aN ) - m_width );
 
 if( aP.ApproxParallel( aN ) && m_gapConstraint.Matches( dist )
 && commonParallelProjection ( aP, aN, p_clip, n_clip ) )
 {
 return p_clip.Length();
 }
 
 return 0;
}
 
}