agg/source/agg_vcgen_bspline.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 "agg_vcgen_bspline.h"
  17
  18 namespace agg
  19 {
  20
  21     //------------------------------------------------------------------------
  22     vcgen_bspline::vcgen_bspline() :
  23         m_src_vertices(),
  24         m_spline_x(),
  25         m_spline_y(),
  26         m_interpolation_step(1.0/50.0),
  27         m_closed(0),
  28         m_status(initial),
  29         m_src_vertex(0)
  30     {
  31     }
  32
  33
  34     //------------------------------------------------------------------------
  35     void vcgen_bspline::remove_all()
  36     {
  37         m_src_vertices.remove_all();
  38         m_closed = 0;
  39         m_status = initial;
  40         m_src_vertex = 0;
  41     }
  42
  43
  44     //------------------------------------------------------------------------
  45     void vcgen_bspline::add_vertex(double x, double y, unsigned cmd)
  46     {
  47         m_status = initial;
  48         if(is_move_to(cmd))
  49         {
  50             m_src_vertices.modify_last(point_type(x, y));
  51         }
  52         else
  53         {
  54             if(is_vertex(cmd))
  55             {
  56                 m_src_vertices.add(point_type(x, y));
  57             }
  58             else
  59             {
  60                 m_closed = get_close_flag(cmd);
  61             }
  62         }
  63     }
  64
  65
  66     //------------------------------------------------------------------------
  67     void vcgen_bspline::rewind(unsigned)
  68     {
  69         m_cur_abscissa = 0.0;
  70         m_max_abscissa = 0.0;
  71         m_src_vertex = 0;
  72         if(m_status == initial && m_src_vertices.size() > 2)
  73         {
  74             if(m_closed)
  75             {
  76                 m_spline_x.init(m_src_vertices.size() + 8);
  77                 m_spline_y.init(m_src_vertices.size() + 8);
  78                 m_spline_x.add_point(0.0, m_src_vertices.prev(m_src_vertices.size() - 3).x);
  79                 m_spline_y.add_point(0.0, m_src_vertices.prev(m_src_vertices.size() - 3).y);
  80                 m_spline_x.add_point(1.0, m_src_vertices[m_src_vertices.size() - 3].x);
  81                 m_spline_y.add_point(1.0, m_src_vertices[m_src_vertices.size() - 3].y);
  82                 m_spline_x.add_point(2.0, m_src_vertices[m_src_vertices.size() - 2].x);
  83                 m_spline_y.add_point(2.0, m_src_vertices[m_src_vertices.size() - 2].y);
  84                 m_spline_x.add_point(3.0, m_src_vertices[m_src_vertices.size() - 1].x);
  85                 m_spline_y.add_point(3.0, m_src_vertices[m_src_vertices.size() - 1].y);
  86             }
  87             else
  88             {
  89                 m_spline_x.init(m_src_vertices.size());
  90                 m_spline_y.init(m_src_vertices.size());
  91             }
  92             unsigned i;
  93             for(i = 0; i < m_src_vertices.size(); i++)
  94             {
  95                 double x = m_closed ? i + 4 : i;
  96                 m_spline_x.add_point(x, m_src_vertices[i].x);
  97                 m_spline_y.add_point(x, m_src_vertices[i].y);
  98             }
  99             m_cur_abscissa = 0.0;
 100             m_max_abscissa = m_src_vertices.size() - 1;
 101             if(m_closed)
 102             {
 103                 m_cur_abscissa = 4.0;
 104                 m_max_abscissa += 5.0;
 105                 m_spline_x.add_point(m_src_vertices.size() + 4, m_src_vertices[0].x);
 106                 m_spline_y.add_point(m_src_vertices.size() + 4, m_src_vertices[0].y);
 107                 m_spline_x.add_point(m_src_vertices.size() + 5, m_src_vertices[1].x);
 108                 m_spline_y.add_point(m_src_vertices.size() + 5, m_src_vertices[1].y);
 109                 m_spline_x.add_point(m_src_vertices.size() + 6, m_src_vertices[2].x);
 110                 m_spline_y.add_point(m_src_vertices.size() + 6, m_src_vertices[2].y);
 111                 m_spline_x.add_point(m_src_vertices.size() + 7, m_src_vertices.next(2).x);
 112                 m_spline_y.add_point(m_src_vertices.size() + 7, m_src_vertices.next(2).y);
 113             }
 114             m_spline_x.prepare();
 115             m_spline_y.prepare();
 116             m_status = ready;
 117         }
 118     }
 119
 120
 121
 122
 123
 124
 125     //------------------------------------------------------------------------
 126     unsigned vcgen_bspline::vertex(double* x, double* y)
 127     {
 128         unsigned cmd = path_cmd_line_to;
 129         while(!is_stop(cmd))
 130         {
 131             switch(m_status)
 132             {
 133             case initial:
 134                 rewind(0);
 135
 136             case ready:
 137                 if(m_src_vertices.size() < 2)
 138                 {
 139                     cmd = path_cmd_stop;
 140                     break;
 141                 }
 142
 143                 if(m_src_vertices.size() == 2)
 144                 {
 145                     *x = m_src_vertices[m_src_vertex].x;
 146                     *y = m_src_vertices[m_src_vertex].y;
 147                     m_src_vertex++;
 148                     if(m_src_vertex == 1) return path_cmd_move_to;
 149                     if(m_src_vertex == 2) return path_cmd_line_to;
 150                     cmd = path_cmd_stop;
 151                     break;
 152                 }
 153
 154                 cmd = path_cmd_move_to;
 155                 m_status = polygon;
 156                 m_src_vertex = 0;
 157
 158             case polygon:
 159                 if(m_cur_abscissa >= m_max_abscissa)
 160                 {
 161                     if(m_closed)
 162                     {
 163                         m_status = end_poly;
 164                         break;
 165                     }
 166                     else
 167                     {
 168                         *x = m_src_vertices[m_src_vertices.size() - 1].x;
 169                         *y = m_src_vertices[m_src_vertices.size() - 1].y;
 170                         m_status = end_poly;
 171                         return path_cmd_line_to;
 172                     }
 173                 }
 174
 175                 *x = m_spline_x.get_stateful(m_cur_abscissa);
 176                 *y = m_spline_y.get_stateful(m_cur_abscissa);
 177                 m_src_vertex++;
 178                 m_cur_abscissa += m_interpolation_step;
 179                 return (m_src_vertex == 1) ? path_cmd_move_to : path_cmd_line_to;
 180
 181             case end_poly:
 182                 m_status = stop;
 183                 return path_cmd_end_poly | m_closed;
 184
 185             case stop:
 186                 return path_cmd_stop;
 187             }
 188         }
 189         return cmd;
 190     }
 191
 192
 193 }
 194