kicad/common/geometry/shape_arc.cpp

/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2017 CERN
 * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
 *
 * 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 <vector>

#include <geometry/geometry_utils.h>
#include <geometry/shape_arc.h>
#include <geometry/shape_line_chain.h>

bool SHAPE_ARC::Collide( const SEG& aSeg, int aClearance ) const
{
    int minDist = aClearance + m_width / 2;
    auto centerDist = aSeg.Distance( m_pc );
    auto p1 = GetP1();

    if( centerDist < minDist )
        return true;

    auto ab = (aSeg.B - aSeg.A );
    auto ac = ( m_pc - aSeg.A );

    auto lenAbSq = ab.SquaredEuclideanNorm();

    auto lambda = (double) ac.Dot( ab ) / (double) lenAbSq;


    if( lambda >= 0.0 && lambda <= 1.0 )
    {
        VECTOR2I p;

        p.x = (double) aSeg.A.x * lambda + (double) aSeg.B.x * (1.0 - lambda);
        p.y = (double) aSeg.A.y * lambda + (double) aSeg.B.y * (1.0 - lambda);

        auto p0pdist = ( m_p0 - p ).EuclideanNorm();

        if( p0pdist < minDist )
            return true;

        auto p1pdist = ( p1 - p ).EuclideanNorm();

        if( p1pdist < minDist )
            return true;
    }

    auto p0dist = aSeg.Distance( m_p0 );

    if( p0dist > minDist )
        return true;

    auto p1dist = aSeg.Distance( p1 );

    if( p1dist > minDist )
        return false;


    return true;
}

#if 0
bool SHAPE_ARC::ConstructFromCorners( VECTOR2I aP0, VECTOR2I aP1, double aCenterAngle )
{
    VECTOR2D mid = ( VECTOR2D( aP0 ) + VECTOR2D( aP1 ) ) * 0.5;
    VECTOR2D chord = VECTOR2D( aP1 ) - VECTOR2D( aP0 );
    double c = (aP1 - aP0).EuclideanNorm() / 2;
    VECTOR2D d = chord.Rotate( M_PI / 2.0 ).Resize( c );

    m_pc = mid + d * ( 1.0 / tan( aCenterAngle / 2.0 * M_PI / 180.0 ) );
    m_p0 = aP0;
    m_p1 = aP1;

    return true;
}

bool SHAPE_ARC::ConstructFromCornerAndAngles( VECTOR2I aP0,
        double aStartAngle,
        double aCenterAngle,
        double aRadius )
{
    m_p0 = aP0;
    auto d1 = VECTOR2D( 1.0, 0.0 ).Rotate( aStartAngle * M_PI / 180.0 ) * aRadius;
    auto d2 =
        VECTOR2D( 1.0, 0.0 ).Rotate( (aStartAngle + aCenterAngle) * M_PI / 180.0 ) * aRadius;

    m_pc = m_p0 - (VECTOR2I) d1;
    m_p1 = m_pc + (VECTOR2I) d2;

    if( aCenterAngle < 0 )
        std::swap( m_p0, m_p1 );

    return true;
}

bool SHAPE_ARC::ConstructFromCenterAndAngles( VECTOR2I aCenter, double aRadius, double aStartAngle, double aCenterAngle )
{
    double ea = aStartAngle + aCenterAngle;

    m_fullCircle = false;
    m_pc = aCenter;
    m_p0.x = (int) ( (double) aCenter.x + aRadius * cos( aStartAngle * M_PI / 180.0 ) );
    m_p0.y = (int) ( (double) aCenter.y + aRadius * sin( aStartAngle * M_PI / 180.0 ) );
    m_p1.x = (int) ( (double) aCenter.x + aRadius * cos( ea * M_PI / 180.0 ) );
    m_p1.y = (int) ( (double) aCenter.y + aRadius * sin( ea * M_PI / 180.0 ) );

    if( aCenterAngle == 360.0 )
    {
        m_fullCircle = true;
        return true;
    }
    else if ( aCenterAngle < 0.0 )
    {
        std::swap(m_p0, m_p1);
    }

    return true;
}
#endif


const VECTOR2I SHAPE_ARC::GetP1() const
{
    VECTOR2D rvec = m_p0 - m_pc;
    auto ca = m_centralAngle * M_PI / 180.0;
    VECTOR2I p1;

    p1.x = (int) ( m_pc.x + rvec.x * cos( ca ) - rvec.y * sin( ca ) );
    p1.y = (int) ( m_pc.y + rvec.x * sin( ca ) + rvec.y * cos( ca ) );

    return p1;
}


const BOX2I SHAPE_ARC::BBox( int aClearance ) const
{
    BOX2I bbox;
    std::vector<VECTOR2I> points;
    points.push_back( m_pc );
    points.push_back( m_p0 );
    points.push_back( GetP1() );

    double start_angle = GetStartAngle();
    double 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 / 90.0 );
    int quad_angle_end = std::floor( end_angle / 90.0 );

    // count through quadrants included in arc
    for( int quad_angle = quad_angle_start; quad_angle <= quad_angle_end; ++quad_angle )
    {
        const int radius = GetRadius();
        VECTOR2I  quad_pt = m_pc;

        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 );
    }

    bbox.Compute( points );

    if( aClearance != 0 )
        bbox.Inflate( aClearance );

    return bbox;
}


bool SHAPE_ARC::Collide( const VECTOR2I& aP, int aClearance ) const
{
    assert( false );
    return false;
}


double SHAPE_ARC::GetStartAngle() const
{
    VECTOR2D d( m_p0 - m_pc );

    auto ang = 180.0 / M_PI * atan2( d.y, d.x );

    return ang;
}

double SHAPE_ARC::GetEndAngle() const
{
    double a =  GetStartAngle() + m_centralAngle;

    if( a < 0.0 )
        a += 360.0;
    else if ( a >= 360.0 )
        a -= 360.0;

    return a;
}

double SHAPE_ARC::GetCentralAngle() const
{
    return m_centralAngle;
}

int SHAPE_ARC::GetRadius() const
{
    return (m_p0 - m_pc).EuclideanNorm();
}

const SHAPE_LINE_CHAIN SHAPE_ARC::ConvertToPolyline( double aAccuracy ) const
{
    SHAPE_LINE_CHAIN rv;
    double r = GetRadius();
    double sa = GetStartAngle();
    auto c = GetCenter();
    int n;

    if( r == 0.0 )
    {
        n = 0;
    }
    else
    {
        n = GetArcToSegmentCount( r, aAccuracy, m_centralAngle );
    }

    for( int i = 0; i <= n ; i++ )
    {
        double a = sa;

        if( n != 0 )
            sa += m_centralAngle * (double) i / (double) n;

        double x = c.x + r * cos( a * M_PI / 180.0 );
        double y = c.y + r * sin( a * M_PI / 180.0 );

        rv.Append( (int) x, (int) y );
    }

    return rv;
}