1 //---------------------------------------------------------------------------- 2 // Anti-Grain Geometry - Version 2.2 3 // Copyright (C) 2002-2004 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 70