shape_arc.cpp

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2017 CERN
 * Copyright (C) 2019-2024 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 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 <core/kicad_algo.h>
#include <geometry/circle.h>
#include <geometry/geometry_utils.h>
#include <geometry/seg.h> // for SEG
#include <geometry/shape_arc.h>
#include <geometry/shape_line_chain.h>
#include <convert_basic_shapes_to_polygon.h>
#include <trigo.h>
 
 
std::ostream& operator<<( std::ostream& aStream, const SHAPE_ARC& aArc )
{
 aStream << "Arc( P0=" << aArc.GetP0() << " P1=" << aArc.GetP1() << " Mid=" << aArc.GetArcMid()
 << " Width=" << aArc.GetWidth() << " )";
 return aStream;
}
 
 
SHAPE_ARC::SHAPE_ARC( const VECTOR2I& aArcCenter, const VECTOR2I& aArcStartPoint,
 const EDA_ANGLE& aCenterAngle, int aWidth ) :
 SHAPE( SH_ARC ),
 m_width( aWidth )
{
 m_start = aArcStartPoint;
 
 VECTOR2D mid = aArcStartPoint;
 VECTOR2D end = aArcStartPoint;
 VECTOR2D center = aArcCenter;
 
 RotatePoint( mid, center, -aCenterAngle / 2.0 );
 RotatePoint( end, center, -aCenterAngle );
 
 m_mid = VECTOR2I( KiROUND( mid.x ), KiROUND( mid.y ) );
 m_end = VECTOR2I( KiROUND( end.x ), KiROUND( end.y ) );
 
 update_values();
}
 
 
SHAPE_ARC::SHAPE_ARC( const VECTOR2I& aArcStart, const VECTOR2I& aArcMid,
 const VECTOR2I& aArcEnd, int aWidth ) :
 SHAPE( SH_ARC ),
 m_start( aArcStart ),
 m_mid( aArcMid ),
 m_end( aArcEnd ),
 m_width( aWidth )
{
 update_values();
}
 
 
SHAPE_ARC::SHAPE_ARC( const SEG& aSegmentA, const SEG& aSegmentB, int aRadius, int aWidth ) :
 SHAPE( SH_ARC )
{
 m_width = aWidth;
 
 /*
 * Construct an arc that is tangent to two segments with a given radius.
 *
 * p
 * A
 * A \
 * / \
 * / . . \ segB
 * /. .\
 * segA / c \
 * / B
 * /
 * /
 * B
 *
 *
 * segA is the fist segment (with its points A and B)
 * segB is the second segment (with its points A and B)
 * p is the point at which segA and segB would intersect if they were projected
 * c is the centre of the arc to be constructed
 * rad is the radius of the arc to be constructed
 *
 * We can create two vectors, between point p and segA /segB
 * pToA = p - segA.B //< note that segA.A would also be valid as it is colinear
 * pToB = p - segB.B //< note that segB.A would also be valid as it is colinear
 *
 * Let the angle formed by segA and segB be called 'alpha':
 * alpha = angle( pToA ) - angle( pToB )
 *
 * The distance PC can be computed as
 * distPC = rad / abs( sin( alpha / 2 ) )
 *
 * The polar angle of the vector PC can be computed as:
 * anglePC = angle( pToA ) + alpha / 2
 *
 * Therefore:
 * C.x = P.x + distPC*cos( anglePC )
 * C.y = P.y + distPC*sin( anglePC )
 */
 
 OPT_VECTOR2I p = aSegmentA.Intersect( aSegmentB, true, true );
 
 if( !p || aSegmentA.Length() == 0 || aSegmentB.Length() == 0 )
 {
 // Catch bugs in debug
 wxASSERT_MSG( false, "The input segments do not intersect or one is zero length." );
 
 // Make a 180 degree arc around aSegmentA in case we end up here in release
 m_start = aSegmentA.A;
 m_end = aSegmentA.B;
 m_mid = m_start;
 
 VECTOR2I arcCenter = aSegmentA.Center();
 RotatePoint( m_mid, arcCenter, ANGLE_90 ); // mid point at 90 degrees
 }
 else
 {
 VECTOR2I pToA = aSegmentA.B - *p;
 VECTOR2I pToB = aSegmentB.B - *p;
 
 if( pToA.EuclideanNorm() == 0 )
 pToA = aSegmentA.A - *p;
 
 if( pToB.EuclideanNorm() == 0 )
 pToB = aSegmentB.A - *p;
 
 EDA_ANGLE pToAangle( pToA );
 EDA_ANGLE pToBangle( pToB );
 
 EDA_ANGLE alpha = ( pToAangle - pToBangle ).Normalize180();
 
 double distPC = (double) aRadius / abs( sin( alpha.AsRadians() / 2 ) );
 EDA_ANGLE angPC = pToAangle - alpha / 2;
 VECTOR2I arcCenter;
 
 arcCenter.x = p->x + KiROUND( distPC * angPC.Cos() );
 arcCenter.y = p->y + KiROUND( distPC * angPC.Sin() );
 
 // The end points of the arc are the orthogonal projected lines from the line segments
 // to the center of the arc
 m_start = aSegmentA.LineProject( arcCenter );
 m_end = aSegmentB.LineProject( arcCenter );
 
 //The mid point is rotated start point around center, half the angle of the arc.
 VECTOR2I startVector = m_start - arcCenter;
 VECTOR2I endVector = m_end - arcCenter;
 
 EDA_ANGLE startAngle( startVector );
 EDA_ANGLE endAngle( endVector );
 EDA_ANGLE midPointRotAngle = ( startAngle - endAngle ).Normalize180() / 2;
 
 m_mid = m_start;
 RotatePoint( m_mid, arcCenter, midPointRotAngle );
 }
 
 update_values();
}
 
 
SHAPE_ARC::SHAPE_ARC( const SHAPE_ARC& aOther )
 : SHAPE( SH_ARC )
{
 m_start = aOther.m_start;
 m_end = aOther.m_end;
 m_mid = aOther.m_mid;
 m_width = aOther.m_width;
 m_bbox = aOther.m_bbox;
 m_center = aOther.m_center;
 m_radius = aOther.m_radius;
}
 
 
SHAPE_ARC& SHAPE_ARC::ConstructFromStartEndAngle( const VECTOR2I& aStart, const VECTOR2I& aEnd,
 const EDA_ANGLE& aAngle, double aWidth )
{
 m_start = aStart;
 m_mid = aStart;
 m_end = aEnd;
 m_width = aWidth;
 
 VECTOR2I center( CalcArcCenter( aStart, aEnd, aAngle ) );
 
 RotatePoint( m_mid, center, -aAngle / 2.0 );
 
 update_values();
 
 return *this;
}
 
 
SHAPE_ARC& SHAPE_ARC::ConstructFromStartEndCenter( const VECTOR2I& aStart, const VECTOR2I& aEnd,
 const VECTOR2I& aCenter, bool aClockwise,
 double aWidth )
{
 VECTOR2I startLine = aStart - aCenter;
 VECTOR2I endLine = aEnd - aCenter;
 
 EDA_ANGLE startAngle( startLine );
 EDA_ANGLE endAngle( endLine );
 
 startAngle.Normalize();
 endAngle.Normalize();
 
 EDA_ANGLE angle = endAngle - startAngle;
 
 if( aClockwise )
 angle = angle.Normalize() - ANGLE_360;
 else
 angle = angle.Normalize();
 
 m_start = aStart;
 m_end = aEnd;
 m_mid = aStart;
 
 RotatePoint( m_mid, aCenter, -angle / 2.0 );
 
 update_values();
 
 return *this;
}
 
 
bool SHAPE_ARC::Collide( const SEG& aSeg, int aClearance, int* aActual, VECTOR2I* aLocation ) const
{
 if( aSeg.A == aSeg.B )
 return Collide( aSeg.A, aClearance, aActual, aLocation );
 
 VECTOR2I center = GetCenter();
 CIRCLE circle( center, GetRadius() );
 
 // Possible points of the collision are:
 // 1. Intersetion of the segment with the full circle
 // 2. Closest point on the segment to the center of the circle
 // 3. Closest point on the segment to the end points of the arc
 // 4. End points of the segment
 
 std::vector<VECTOR2I> candidatePts = circle.Intersect( aSeg );
 
 candidatePts.push_back( aSeg.NearestPoint( center ) );
 candidatePts.push_back( aSeg.NearestPoint( m_start ) );
 candidatePts.push_back( aSeg.NearestPoint( m_end ) );
 candidatePts.push_back( aSeg.A );
 candidatePts.push_back( aSeg.B );
 
 bool any_collides = false;
 
 for( const VECTOR2I& candidate : candidatePts )
 {
 bool collides = Collide( candidate, aClearance, aActual, aLocation );
 any_collides |= collides;
 
 if( collides && ( !aActual || *aActual == 0 ) )
 return true;
 }
 
 return any_collides;
}
 
 
int SHAPE_ARC::IntersectLine( const SEG& aSeg, std::vector<VECTOR2I>* aIpsBuffer ) const
{
 if( aSeg.A == aSeg.B ) // One point does not define a line....
 return 0;
 
 CIRCLE circ( GetCenter(), GetRadius() );
 
 std::vector<VECTOR2I> intersections = circ.IntersectLine( aSeg );
 
 size_t originalSize = aIpsBuffer->size();
 
 for( const VECTOR2I& intersection : intersections )
 {
 if( sliceContainsPoint( intersection ) )
 aIpsBuffer->push_back( intersection );
 }
 
 return aIpsBuffer->size() - originalSize;
}
 
 
int SHAPE_ARC::Intersect( const SHAPE_ARC& aArc, std::vector<VECTOR2I>* aIpsBuffer ) const
{
 CIRCLE thiscirc( GetCenter(), GetRadius() );
 CIRCLE othercirc( aArc.GetCenter(), aArc.GetRadius() );
 
 std::vector<VECTOR2I> intersections = thiscirc.Intersect( othercirc );
 
 size_t originalSize = aIpsBuffer->size();
 
 for( const VECTOR2I& intersection : intersections )
 {
 if( sliceContainsPoint( intersection ) && aArc.sliceContainsPoint( intersection ) )
 aIpsBuffer->push_back( intersection );
 }
 
 return aIpsBuffer->size() - originalSize;
}
 
 
void SHAPE_ARC::update_values()
{
 m_center = CalcArcCenter( m_start, m_mid, m_end );
 m_radius = std::sqrt( ( VECTOR2D( m_start ) - m_center ).SquaredEuclideanNorm() );
 
 std::vector<VECTOR2I> points;
 // Put start and end points in the point list
 points.push_back( m_start );
 points.push_back( m_end );
 
 EDA_ANGLE start_angle = GetStartAngle();
 EDA_ANGLE end_angle = start_angle + GetCentralAngle();
 
 // we always count quadrants clockwise (increasing angle)
 if( start_angle > end_angle )
 std::swap( start_angle, end_angle );
 
 int quad_angle_start = std::ceil( start_angle.AsDegrees() / 90.0 );
 int quad_angle_end = std::floor( end_angle.AsDegrees() / 90.0 );
 
 // very large radius means the arc is similar to a segment
 // so do not try to add more points, center cannot be handled
 // Very large is here > INT_MAX/2
 if( m_radius < (double)INT_MAX/2.0 )
 {
 const int radius = KiROUND( m_radius );
 
 // count through quadrants included in arc
 for( int quad_angle = quad_angle_start; quad_angle <= quad_angle_end; ++quad_angle )
 {
 VECTOR2I quad_pt = m_center;
 
 switch( quad_angle % 4 )
 {
 case 0: quad_pt += { radius, 0 }; break;
 case 1: case -3: quad_pt += { 0, radius }; break;
 case 2: case -2: quad_pt += { -radius, 0 }; break;
 case 3: case -1: quad_pt += { 0, -radius }; break;
 default:
 assert( false );
 }
 
 points.push_back( quad_pt );
 }
 }
 
 m_bbox.Compute( points );
}
 
 
const BOX2I SHAPE_ARC::BBox( int aClearance ) const
{
 BOX2I bbox( m_bbox );
 
 if( m_width != 0 )
 bbox.Inflate( KiROUND( m_width / 2.0 ) + 1 );
 
 if( aClearance != 0 )
 bbox.Inflate( aClearance );
 
 return bbox;
}
 
 
bool SHAPE_ARC::IsClockwise() const
{
 return GetCentralAngle() < ANGLE_0;
}
 
 
VECTOR2I SHAPE_ARC::NearestPoint( const VECTOR2I& aP ) const
{
 const static int s_epsilon = 8;
 
 CIRCLE fullCircle( GetCenter(), GetRadius() );
 VECTOR2I nearestPt = fullCircle.NearestPoint( aP );
 
 if( ( nearestPt - m_start ).SquaredEuclideanNorm() <= s_epsilon )
 return m_start;
 
 if( ( nearestPt - m_end ).SquaredEuclideanNorm() <= s_epsilon )
 return m_end;
 
 if( sliceContainsPoint( nearestPt ) )
 return nearestPt;
 
 if( ( aP - m_start ).SquaredEuclideanNorm() <= ( aP - m_end ).SquaredEuclideanNorm() )
 return m_start;
 else
 return m_end;
}
 
 
bool SHAPE_ARC::Collide( const VECTOR2I& aP, int aClearance, int* aActual,
 VECTOR2I* aLocation ) const
{
 int minDist = aClearance + m_width / 2;
 auto bbox = BBox( minDist );
 
 // Fast check using bounding box:
 if( !bbox.Contains( aP ) )
 return false;
 
 CIRCLE fullCircle( GetCenter(), GetRadius() );
 VECTOR2I nearestPt = fullCircle.NearestPoint( aP );
 
 int dist = ( nearestPt - aP ).EuclideanNorm();
 
 // If not a 360 degree arc, need to use arc angles to decide if point collides
 if( m_start != m_end )
 {
 bool ccw = GetCentralAngle() > ANGLE_0;
 EDA_ANGLE angleToPt( aP - fullCircle.Center ); // Angle from center to the point
 EDA_ANGLE rotatedPtAngle = ( angleToPt.Normalize() - GetStartAngle() ).Normalize();
 EDA_ANGLE rotatedEndAngle = ( GetEndAngle() - GetStartAngle() ).Normalize();
 
 if( ( ccw && rotatedPtAngle > rotatedEndAngle )
 || ( !ccw && rotatedPtAngle < rotatedEndAngle ) )
 {
 int distStartpt = ( aP - m_start ).EuclideanNorm();
 int distEndpt = ( aP - m_end ).EuclideanNorm();
 dist = std::min( distStartpt, distEndpt );
 }
 }
 
 if( dist <= minDist )
 {
 if( aLocation )
 *aLocation = nearestPt;
 
 if( aActual )
 *aActual = std::max( 0, dist - m_width / 2 );
 
 return true;
 }
 
 return false;
}
 
 
EDA_ANGLE SHAPE_ARC::GetStartAngle() const
{
 EDA_ANGLE angle( m_start - GetCenter() );
 return angle.Normalize();
}
 
 
EDA_ANGLE SHAPE_ARC::GetEndAngle() const
{
 EDA_ANGLE angle( m_end - GetCenter() );
 return angle.Normalize();
}
 
 
const VECTOR2I& SHAPE_ARC::GetCenter() const
{
 return m_center;
}
 
 
double SHAPE_ARC::GetLength() const
{
 double radius = GetRadius();
 EDA_ANGLE includedAngle = GetCentralAngle();
 
 return std::abs( radius * includedAngle.AsRadians() );
}
 
 
EDA_ANGLE SHAPE_ARC::GetCentralAngle() const
{
 // Arcs with same start and end points can be 0 deg or 360 deg arcs.
 // However, they are expected to be circles.
 // So return 360 degrees as central arc:
 if( m_start == m_end )
 return ANGLE_360;
 
 VECTOR2I center = GetCenter();
 EDA_ANGLE angle1 = EDA_ANGLE( m_mid - center ) - EDA_ANGLE( m_start - center );
 EDA_ANGLE angle2 = EDA_ANGLE( m_end - center ) - EDA_ANGLE( m_mid - center );
 
 return angle1.Normalize180() + angle2.Normalize180();
}
 
 
double SHAPE_ARC::GetRadius() const
{
 return m_radius;
}
 
 
const SHAPE_LINE_CHAIN SHAPE_ARC::ConvertToPolyline( double aAccuracy,
 double* aEffectiveAccuracy ) const
{
 SHAPE_LINE_CHAIN rv;
 double r = GetRadius();
 EDA_ANGLE sa = GetStartAngle();
 VECTOR2I c = GetCenter();
 EDA_ANGLE ca = GetCentralAngle();
 
 SEG startToEnd( GetP0(), GetP1() );
 double halfAccuracy = std::max( 1.0, aAccuracy / 2 );
 
 int n;
 
 // To calculate the arc to segment count, use the external radius instead of the radius.
 // for a arc with small radius and large width, the difference can be significant
 double external_radius = r+(m_width/2);
 double effectiveAccuracy;
 
 if( external_radius < halfAccuracy
 || startToEnd.Distance( GetArcMid() ) < halfAccuracy ) // Should be a very rare case
 {
 // In this case, the arc is approximated by one segment, with a effective error
 // between -aAccuracy/2 and +aAccuracy/2, as expected.
 n = 0;
 effectiveAccuracy = external_radius;
 }
 else
 {
 n = GetArcToSegmentCount( external_radius, aAccuracy, ca );
 
 // Recalculate the effective error of approximation, that can be < aAccuracy
 int seg360 = n * 360.0 / fabs( ca.AsDegrees() );
 effectiveAccuracy = CircleToEndSegmentDeltaRadius( external_radius, seg360 );
 }
 
 // Split the error on either side of the arc. Since we want the start and end points
 // to be exactly on the arc, the first and last segments need to be shorter to stay within
 // the error band (since segments normally start 1/2 the error band outside the arc).
 r += effectiveAccuracy / 2;
 n = n * 2;
 
 rv.Append( m_start );
 
 for( int i = 1; i < n ; i += 2 )
 {
 EDA_ANGLE a = sa;
 
 if( n != 0 )
 a += ( ca * i ) / n;
 
 double x = c.x + r * a.Cos();
 double y = c.y + r * a.Sin();
 
 rv.Append( KiROUND( x ), KiROUND( y ) );
 }
 
 rv.Append( m_end );
 
 if( aEffectiveAccuracy )
 *aEffectiveAccuracy = effectiveAccuracy;
 
 return rv;
}
 
 
void SHAPE_ARC::Move( const VECTOR2I& aVector )
{
 m_start += aVector;
 m_end += aVector;
 m_mid += aVector;
 update_values();
}
 
 
void SHAPE_ARC::Rotate( const EDA_ANGLE& aAngle, const VECTOR2I& aCenter )
{
 RotatePoint( m_start, aCenter, aAngle );
 RotatePoint( m_end, aCenter, aAngle );
 RotatePoint( m_mid, aCenter, aAngle );
 
 update_values();
}
 
 
void SHAPE_ARC::Mirror( bool aX, bool aY, const VECTOR2I& aVector )
{
 if( aX )
 {
 m_start.x = -m_start.x + 2 * aVector.x;
 m_end.x = -m_end.x + 2 * aVector.x;
 m_mid.x = -m_mid.x + 2 * aVector.x;
 }
 
 if( aY )
 {
 m_start.y = -m_start.y + 2 * aVector.y;
 m_end.y = -m_end.y + 2 * aVector.y;
 m_mid.y = -m_mid.y + 2 * aVector.y;
 }
 
 update_values();
}
 
 
void SHAPE_ARC::Mirror( const SEG& axis )
{
 m_start = axis.ReflectPoint( m_start );
 m_end = axis.ReflectPoint( m_end );
 m_mid = axis.ReflectPoint( m_mid );
 
 update_values();
}
 
 
void SHAPE_ARC::Reverse()
{
 std::swap( m_start, m_end );
}
 
 
SHAPE_ARC SHAPE_ARC::Reversed() const
{
 return SHAPE_ARC( m_end, m_mid, m_start, m_width );
}
 
 
bool SHAPE_ARC::sliceContainsPoint( const VECTOR2I& p ) const
{
 EDA_ANGLE sa = GetStartAngle().Normalize();
 EDA_ANGLE ca = GetCentralAngle();
 EDA_ANGLE ea = sa + ca;
 
 EDA_ANGLE phi( p - GetCenter() ); // Angle from center to the point
 phi.Normalize();
 
 if( ca >= ANGLE_0 )
 {
 while( phi < sa )
 phi += ANGLE_360;
 
 return phi >= sa && phi <= ea;
 }
 else
 {
 while( phi > sa )
 phi -= ANGLE_360;
 
 return phi <= sa && phi >= ea;
 }
}
 
 
void SHAPE_ARC::TransformToPolygon( SHAPE_POLY_SET& aBuffer, int aError, ERROR_LOC aErrorLoc ) const
{
 TransformArcToPolygon( aBuffer, m_start, m_mid, m_end, m_width, aError, aErrorLoc );
}