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 #ifndef AGG_VPGEN_CLIP_POLYLINE_INCLUDED 17 #define AGG_VPGEN_CLIP_POLYLINE_INCLUDED 18 19 #include "agg_basics.h" 20 21 namespace agg 22 { 23 24 //======================================================vpgen_clip_polyline 25 // 26 // See Implementation agg_vpgen_clip_polyline.cpp 27 // 28 class vpgen_clip_polyline 29 { 30 public: 31 vpgen_clip_polyline() : 32 m_clip_box(0, 0, 1, 1), 33 m_x1(0), 34 m_y1(0), 35 m_f1(0), 36 m_x2(0), 37 m_y2(0), 38 m_f2(0), 39 m_num_vertices(0), 40 m_vertex(0) 41 { 42 } 43 44 void clip_box(double x1, double y1, double x2, double y2) 45 { 46 m_clip_box.x1 = x1; 47 m_clip_box.y1 = y1; 48 m_clip_box.x2 = x2; 49 m_clip_box.y2 = y2; 50 m_clip_box.normalize(); 51 } 52 53 54 double x1() const { return m_clip_box.x1; } 55 double y1() const { return m_clip_box.y1; } 56 double x2() const { return m_clip_box.x2; } 57 double y2() const { return m_clip_box.y2; } 58 59 static bool auto_close() { return false; } 60 static bool auto_unclose() { return true; } 61 62 void reset(); 63 void move_to(double x, double y); 64 void line_to(double x, double y); 65 unsigned vertex(double* x, double* y); 66 67 private: 68 enum clipping_flags_def 69 { 70 clip_x1 = 1, 71 clip_x2 = 2, 72 clip_y1 = 4, 73 clip_y2 = 8 74 }; 75 76 // Determine the clipping code of the vertex according to the 77 // Cyrus-Beck line clipping algorithm 78 //-------------------------------------------------------------------- 79 unsigned clipping_flags_x(double x) 80 { 81 unsigned f = 0; 82 if(x < m_clip_box.x1) f |= clip_x1; 83 if(x > m_clip_box.x2) f |= clip_x2; 84 return f; 85 } 86 87 unsigned clipping_flags_y(double y) 88 { 89 unsigned f = 0; 90 if(y < m_clip_box.y1) f |= clip_y1; 91 if(y > m_clip_box.y2) f |= clip_y2; 92 return f; 93 } 94 95 unsigned clipping_flags(double x, double y) 96 { 97 return clipping_flags_x(x) | clipping_flags_y(y); 98 } 99 100 bool move_point(double& x, double& y, unsigned& flags); 101 void clip_line_segment(); 102 103 private: 104 rect_d m_clip_box; 105 double m_x1; 106 double m_y1; 107 unsigned m_f1; 108 double m_x2; 109 double m_y2; 110 unsigned m_f2; 111 double m_x[2]; 112 double m_y[2]; 113 unsigned m_cmd[2]; 114 unsigned m_num_vertices; 115 unsigned m_vertex; 116 }; 117 118 } 119 120 121 #endif 122