agg/source/agg_arrowhead.cpp

   1 //----------------------------------------------------------------------------
   2 // Anti-Grain Geometry - Version 2.3
   3 // Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
   4 //
   5 // Permission to copy, use, modify, sell and distribute this software
   6 // is granted provided this copyright notice appears in all copies.
   7 // This software is provided "as is" without express or implied
   8 // warranty, and with no claim as to its suitability for any purpose.
   9 //
  10 //----------------------------------------------------------------------------
  11 // Contact: mcseem@antigrain.com
  12 //          mcseemagg@yahoo.com
  13 //          http://www.antigrain.com
  14 //----------------------------------------------------------------------------
  15 //
  16 // Simple arrowhead/arrowtail generator
  17 //
  18 //----------------------------------------------------------------------------
  19
  20 #include "agg_arrowhead.h"
  21
  22 namespace agg
  23 {
  24
  25     //------------------------------------------------------------------------
  26     arrowhead::arrowhead() :
  27         m_head_d1(1.0),
  28         m_head_d2(1.0),
  29         m_head_d3(1.0),
  30         m_head_d4(0.0),
  31         m_tail_d1(1.0),
  32         m_tail_d2(1.0),
  33         m_tail_d3(1.0),
  34         m_tail_d4(0.0),
  35         m_head_flag(false),
  36         m_tail_flag(false),
  37         m_curr_id(0),
  38         m_curr_coord(0)
  39     {
  40     }
  41
  42
  43
  44     //------------------------------------------------------------------------
  45     void arrowhead::rewind(unsigned id)
  46     {
  47         m_curr_id = id;
  48         m_curr_coord = 0;
  49         if(id == 0)
  50         {
  51             if(!m_tail_flag)
  52             {
  53                 m_cmd[0] = path_cmd_stop;
  54                 return;
  55             }
  56             m_coord[0]  =  m_tail_d1;             m_coord[1]  =  0.0;
  57             m_coord[2]  =  m_tail_d1 - m_tail_d4; m_coord[3]  =  m_tail_d3;
  58             m_coord[4]  = -m_tail_d2 - m_tail_d4; m_coord[5]  =  m_tail_d3;
  59             m_coord[6]  = -m_tail_d2;             m_coord[7]  =  0.0;
  60             m_coord[8]  = -m_tail_d2 - m_tail_d4; m_coord[9]  = -m_tail_d3;
  61             m_coord[10] =  m_tail_d1 - m_tail_d4; m_coord[11] = -m_tail_d3;
  62
  63             m_cmd[0] = path_cmd_move_to;
  64             m_cmd[1] = path_cmd_line_to;
  65             m_cmd[2] = path_cmd_line_to;
  66             m_cmd[3] = path_cmd_line_to;
  67             m_cmd[4] = path_cmd_line_to;
  68             m_cmd[5] = path_cmd_line_to;
  69             m_cmd[7] = (unsigned)path_cmd_end_poly | (unsigned)path_flags_close | (unsigned)path_flags_ccw;
  70             m_cmd[6] = path_cmd_stop;
  71             return;
  72         }
  73
  74         if(id == 1)
  75         {
  76             if(!m_head_flag)
  77             {
  78                 m_cmd[0] = path_cmd_stop;
  79                 return;
  80             }
  81             m_coord[0]  = -m_head_d1;            m_coord[1]  = 0.0;
  82             m_coord[2]  = m_head_d2 + m_head_d4; m_coord[3]  = -m_head_d3;
  83             m_coord[4]  = m_head_d2;             m_coord[5]  = 0.0;
  84             m_coord[6]  = m_head_d2 + m_head_d4; m_coord[7]  = m_head_d3;
  85
  86             m_cmd[0] = path_cmd_move_to;
  87             m_cmd[1] = path_cmd_line_to;
  88             m_cmd[2] = path_cmd_line_to;
  89             m_cmd[3] = path_cmd_line_to;
  90             m_cmd[4] = (unsigned)path_cmd_end_poly | (unsigned)path_flags_close | (unsigned)path_flags_ccw;
  91             m_cmd[5] = path_cmd_stop;
  92             return;
  93         }
  94     }
  95
  96
  97     //------------------------------------------------------------------------
  98     unsigned arrowhead::vertex(double* x, double* y)
  99     {
 100         if(m_curr_id < 2)
 101         {
 102             unsigned curr_idx = m_curr_coord * 2;
 103             *x = m_coord[curr_idx];
 104             *y = m_coord[curr_idx + 1];
 105             return m_cmd[m_curr_coord++];
 106         }
 107         return path_cmd_stop;
 108     }
 109
 110 }