mapnik/deps/agg/src/agg_vpgen_segmentator.cpp

//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
//          mcseemagg@yahoo.com
//          http://www.antigrain.com
//----------------------------------------------------------------------------

#include <math.h>
#include "agg_vpgen_segmentator.h"

namespace agg
{

void vpgen_segmentator::move_to(double x, double y)
{
    m_x1 = x;
    m_y1 = y;
    m_dx = 0.0;
    m_dy = 0.0;
    m_dl = 2.0;
    m_ddl = 2.0;
    m_cmd = path_cmd_move_to;
}

void vpgen_segmentator::line_to(double x, double y)
{
    m_x1 += m_dx;
    m_y1 += m_dy;
    m_dx  = x - m_x1;
    m_dy  = y - m_y1;
    double len = sqrt(m_dx * m_dx + m_dy * m_dy) * m_approximation_scale;
    if(len < 1e-30) len = 1e-30;
    m_ddl = 1.0 / len;
    m_dl  = (m_cmd == path_cmd_move_to) ? 0.0 : m_ddl;
    if(m_cmd == path_cmd_stop) m_cmd = path_cmd_line_to;
}

unsigned vpgen_segmentator::vertex(double* x, double* y)
{
    if(m_cmd == path_cmd_stop) return path_cmd_stop;

    unsigned cmd = m_cmd;
    m_cmd = path_cmd_line_to;
    if(m_dl >= 1.0 - m_ddl)
    {
        m_dl = 1.0;
        m_cmd = path_cmd_stop;
        *x = m_x1 + m_dx;
        *y = m_y1 + m_dy;
        return cmd;
    }
    *x = m_x1 + m_dx * m_dl;
    *y = m_y1 + m_dy * m_dl;
    m_dl += m_ddl;
    return cmd;
}

}