agg/inc/agg_conv_clip_polygon.h

   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 // Polygon clipping converter
  17 // There an optimized Liang-Basky algorithm is used.
  18 // The algorithm doesn't optimize the degenerate edges, i.e. it will never
  19 // break a closed polygon into two or more ones, instead, there will be
  20 // degenerate edges coinciding with the respective clipping boundaries.
  21 // This is a sub-optimal solution, because that optimization would require
  22 // extra, rather expensive math while the rasterizer tolerates it quite well,
  23 // without any considerable overhead.
  24 //
  25 //----------------------------------------------------------------------------
  26 #ifndef AGG_CONV_CLIP_POLYGON_INCLUDED
  27 #define AGG_CONV_CLIP_POLYGON_INCLUDED
  28
  29 #include "agg_basics.h"
  30 #include "agg_conv_adaptor_vpgen.h"
  31 #include "agg_vpgen_clip_polygon.h"
  32 #include "agg_vertex_iterator.h"
  33
  34 namespace agg
  35 {
  36
  37     //=======================================================conv_clip_polygon
  38     template<class VertexSource>
  39     struct conv_clip_polygon : public conv_adaptor_vpgen<VertexSource, vpgen_clip_polygon>
  40     {
  41         typedef conv_adaptor_vpgen<VertexSource, vpgen_clip_polygon> base_type;
  42
  43         conv_clip_polygon(VertexSource& vs) :
  44             conv_adaptor_vpgen<VertexSource, vpgen_clip_polygon>(vs) {}
  45
  46         void clip_box(double x1, double y1, double x2, double y2)
  47         {
  48             base_type::vpgen().clip_box(x1, y1, x2, y2);
  49         }
  50
  51         double x1() const { return base_type::vpgen().x1(); }
  52         double y1() const { return base_type::vpgen().y1(); }
  53         double x2() const { return base_type::vpgen().x2(); }
  54         double y2() const { return base_type::vpgen().y2(); }
  55
  56         typedef conv_clip_polygon<VertexSource> source_type;
  57         typedef vertex_iterator<source_type> iterator;
  58         iterator begin(unsigned id) { return iterator(*this, id); }
  59         iterator end() { return iterator(path_cmd_stop); }
  60
  61     private:
  62         conv_clip_polygon(const conv_clip_polygon<VertexSource>&);
  63         const conv_clip_polygon<VertexSource>&
  64             operator = (const conv_clip_polygon<VertexSource>&);
  65     };
  66
  67 }
  68
  69 #endif