mapnik/deps/agg/src/agg_arrowhead.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
//----------------------------------------------------------------------------
//
// Simple arrowhead/arrowtail generator
//
//----------------------------------------------------------------------------

#include "agg_arrowhead.h"

namespace agg
{

//------------------------------------------------------------------------
arrowhead::arrowhead() :
    m_head_d1(1.0),
    m_head_d2(1.0),
    m_head_d3(1.0),
    m_head_d4(0.0),
    m_tail_d1(1.0),
    m_tail_d2(1.0),
    m_tail_d3(1.0),
    m_tail_d4(0.0),
    m_head_flag(false),
    m_tail_flag(false),
    m_curr_id(0),
    m_curr_coord(0)
{
}



//------------------------------------------------------------------------
void arrowhead::rewind(unsigned path_id)
{
    m_curr_id = path_id;
    m_curr_coord = 0;
    if(path_id == 0)
    {
        if(!m_tail_flag)
        {
            m_cmd[0] = path_cmd_stop;
            return;
        }
        m_coord[0]  =  m_tail_d1;             m_coord[1]  =  0.0;
        m_coord[2]  =  m_tail_d1 - m_tail_d4; m_coord[3]  =  m_tail_d3;
        m_coord[4]  = -m_tail_d2 - m_tail_d4; m_coord[5]  =  m_tail_d3;
        m_coord[6]  = -m_tail_d2;             m_coord[7]  =  0.0;
        m_coord[8]  = -m_tail_d2 - m_tail_d4; m_coord[9]  = -m_tail_d3;
        m_coord[10] =  m_tail_d1 - m_tail_d4; m_coord[11] = -m_tail_d3;

        m_cmd[0] = path_cmd_move_to;
        m_cmd[1] = path_cmd_line_to;
        m_cmd[2] = path_cmd_line_to;
        m_cmd[3] = path_cmd_line_to;
        m_cmd[4] = path_cmd_line_to;
        m_cmd[5] = path_cmd_line_to;
        m_cmd[7] = path_cmd_end_poly | path_flags_close | path_flags_ccw;
        m_cmd[6] = path_cmd_stop;
        return;
    }

    if(path_id == 1)
    {
        if(!m_head_flag)
        {
            m_cmd[0] = path_cmd_stop;
            return;
        }
        m_coord[0]  = -m_head_d1;            m_coord[1]  = 0.0;
        m_coord[2]  = m_head_d2 + m_head_d4; m_coord[3]  = -m_head_d3;
        m_coord[4]  = m_head_d2;             m_coord[5]  = 0.0;
        m_coord[6]  = m_head_d2 + m_head_d4; m_coord[7]  = m_head_d3;

        m_cmd[0] = path_cmd_move_to;
        m_cmd[1] = path_cmd_line_to;
        m_cmd[2] = path_cmd_line_to;
        m_cmd[3] = path_cmd_line_to;
        m_cmd[4] = path_cmd_end_poly | path_flags_close | path_flags_ccw;
        m_cmd[5] = path_cmd_stop;
        return;
    }
}


//------------------------------------------------------------------------
unsigned arrowhead::vertex(double* x, double* y)
{
    if(m_curr_id < 2)
    {
        unsigned curr_idx = m_curr_coord * 2;
        *x = m_coord[curr_idx];
        *y = m_coord[curr_idx + 1];
        return m_cmd[m_curr_coord++];
    }
    return path_cmd_stop;
}

}