line.cxx

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
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#include <tools/line.hxx>
#include <tools/helpers.hxx>
 
#include <cmath>
 
namespace tools
{
 
double Line::GetLength() const
{
    return hypot( maStart.X() - maEnd.X(), maStart.Y() - maEnd.Y() );
}
 
bool Line::Intersection( const Line& rLine, Point& rIntersection ) const
{
    double  fX, fY;
    bool    bRet;
 
    if( Intersection( rLine, fX, fY ) )
    {
        rIntersection.setX( FRound( fX ) );
        rIntersection.setY( FRound( fY ) );
        bRet = true;
    }
    else
        bRet = false;
 
    return bRet;
}
 
bool Line::Intersection( const tools::Line& rLine, double& rIntersectionX, double& rIntersectionY ) const
{
    const double    fAx = static_cast<double>(maEnd.X()) - maStart.X();
    const double    fAy = static_cast<double>(maEnd.Y()) - maStart.Y();
    const double    fBx = static_cast<double>(rLine.maStart.X()) - rLine.maEnd.X();
    const double    fBy = static_cast<double>(rLine.maStart.Y()) - rLine.maEnd.Y();
    const double    fDen = fAy * fBx - fAx * fBy;
    bool            bOk = false;
 
    if( fDen != 0. )
    {
        const double    fCx = static_cast<double>(maStart.X()) - rLine.maStart.X();
        const double    fCy = static_cast<double>(maStart.Y()) - rLine.maStart.Y();
        const double    fA = fBy * fCx - fBx * fCy;
        const bool      bGreater = ( fDen > 0. );
 
        bOk = true;
 
        if ( bGreater )
        {
            if ( ( fA < 0. ) || ( fA > fDen ) )
                bOk = false;
        }
        else if ( ( fA > 0. ) || ( fA < fDen ) )
            bOk = false;
 
        if ( bOk )
        {
            const double fB = fAx * fCy - fAy * fCx;
 
            if ( bGreater )
            {
                if ( ( fB < 0. ) || ( fB > fDen ) )
                    bOk = false;
            }
            else if ( ( fB > 0. ) || ( fB < fDen ) )
                bOk = false;
 
            if( bOk )
            {
                const double fAlpha = fA / fDen;
 
                rIntersectionX = ( maStart.X() + fAlpha * fAx );
                rIntersectionY = ( maStart.Y() + fAlpha * fAy );
            }
        }
    }
 
    return bOk;
}
 
double Line::GetDistance( const double& rPtX, const double& rPtY ) const
{
    double fDist;
 
    if( maStart != maEnd )
    {
        const double fDistX = static_cast<double>(maEnd.X()) - maStart.X();
        const double fDistY = static_cast<double>(maEnd.Y()) - maStart.Y();
        const double fACX = static_cast<double>(maStart.X()) - rPtX;
        const double fACY = static_cast<double>(maStart.Y()) - rPtY;
        const double fL2 = fDistX * fDistX + fDistY * fDistY;
        const double fR = ( fACY * -fDistY - fACX * fDistX ) / fL2;
        const double fS = ( fACY * fDistX - fACX * fDistY ) / fL2;
 
        if( fR < 0.0 )
        {
            fDist = hypot( maStart.X() - rPtX, maStart.Y() - rPtY );
 
            if( fS < 0.0 )
                fDist *= -1.0;
        }
        else if( fR <= 1.0 )
            fDist = fS * sqrt( fL2 );
        else
        {
            fDist = hypot( maEnd.X() - rPtX, maEnd.Y() - rPtY );
 
            if( fS < 0.0 )
                fDist *= -1.0;
        }
    }
    else
        fDist = hypot( maStart.X() - rPtX, maStart.Y() - rPtY );
 
    return fDist;
}
 
} //namespace tools
 
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