agg/source/agg_vpgen_segmentator.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 #include <math.h>
  17 #include "agg_vpgen_segmentator.h"
  18
  19 namespace agg
  20 {
  21
  22     void vpgen_segmentator::move_to(double x, double y)
  23     {
  24         m_x1 = x;
  25         m_y1 = y;
  26         m_dx = 0.0;
  27         m_dy = 0.0;
  28         m_dl = 2.0;
  29         m_ddl = 2.0;
  30         m_cmd = path_cmd_move_to;
  31     }
  32
  33     void vpgen_segmentator::line_to(double x, double y)
  34     {
  35         m_x1 += m_dx;
  36         m_y1 += m_dy;
  37         m_dx  = x - m_x1;
  38         m_dy  = y - m_y1;
  39         double len = sqrt(m_dx * m_dx + m_dy * m_dy) * m_approximation_scale;
  40         if(len < 1e-30) len = 1e-30;
  41         m_ddl = 1.0 / len;
  42         m_dl  = (m_cmd == path_cmd_move_to) ? 0.0 : m_ddl;
  43         if(m_cmd == path_cmd_stop) m_cmd = path_cmd_line_to;
  44     }
  45
  46     unsigned vpgen_segmentator::vertex(double* x, double* y)
  47     {
  48         if(m_cmd == path_cmd_stop) return path_cmd_stop;
  49
  50         unsigned cmd = m_cmd;
  51         m_cmd = path_cmd_line_to;
  52         if(m_dl >= 1.0 - m_ddl)
  53         {
  54             m_dl = 1.0;
  55             m_cmd = path_cmd_stop;
  56             *x = m_x1 + m_dx;
  57             *y = m_y1 + m_dy;
  58             return cmd;
  59         }
  60         *x = m_x1 + m_dx * m_dl;
  61         *y = m_y1 + m_dy * m_dl;
  62         m_dl += m_ddl;
  63         return cmd;
  64     }
  65
  66 }
  67