agg/inc/agg_vpgen_clip_polyline.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 #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