agg/inc/agg_scanline_bin.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 // Class scanline_bin - binary scanline.
  17 //
  18 //----------------------------------------------------------------------------
  19 #ifndef AGG_SCANLINE_BIN_INCLUDED
  20 #define AGG_SCANLINE_BIN_INCLUDED
  21
  22 #include "agg_basics.h"
  23
  24 namespace agg
  25 {
  26
  27     //=============================================================scanline_bin
  28     //
  29     // This is binary scaline container which supports the interface
  30     // used in the rasterizer::render(). See description of agg_scanline_u8
  31     // for details.
  32     //
  33     // Rendering:
  34     //-------------------------------------------------------------------------
  35     //
  36     //  int y = sl.y();
  37     //
  38     // ************************************
  39     // ...Perform vertical clipping here...
  40     // ************************************
  41     //
  42     //  unsigned num_spans = sl.num_spans();
  43     //  const agg::scanline_bin::span* cur_span = sl.spans();
  44     //
  45     //  do
  46     //  {
  47     //      x = cur_span->x;
  48     //      len = cur_span->len;
  49     //
  50     //      **************************************
  51     //      ...Perform horizontal clipping here...
  52     //      **************************************
  53     //
  54     //      hor_line(x, y, len)
  55     //      ++cur_span;
  56     //  }
  57     //  while(--num_spans);
  58     //
  59     //------------------------------------------------------------------------
  60     class scanline_bin
  61     {
  62     public:
  63         struct span
  64         {
  65             int16 x;
  66             int16 len;
  67         };
  68
  69         typedef const span* const_iterator;
  70
  71         ~scanline_bin()
  72         {
  73             delete [] m_spans;
  74         }
  75
  76         scanline_bin() :
  77             m_max_len(0),
  78             m_last_x(0x7FFF),
  79             m_spans(0),
  80             m_cur_span(0)
  81         {
  82         }
  83
  84         void reset(int min_x, int max_x);
  85         void add_cell(int x, unsigned);
  86         void add_cells(int x, unsigned len, const void*);
  87         void add_span(int x, unsigned len, unsigned);
  88         void finalize(int y) { m_y = y; }
  89         void reset_spans();
  90
  91         int            y()         const { return m_y; }
  92         unsigned       num_spans() const { return unsigned(m_cur_span - m_spans); }
  93         const_iterator begin()     const { return m_spans + 1; }
  94
  95     private:
  96         scanline_bin(const scanline_bin&);
  97         const scanline_bin operator = (const scanline_bin&);
  98
  99         unsigned  m_max_len;
 100         int       m_last_x;
 101         int       m_y;
 102         span*     m_spans;
 103         span*     m_cur_span;
 104     };
 105
 106
 107     //------------------------------------------------------------------------
 108     inline void scanline_bin::reset(int min_x, int max_x)
 109     {
 110         unsigned max_len = max_x - min_x + 3;
 111         if(max_len > m_max_len)
 112         {
 113             delete [] m_spans;
 114             m_spans   = new span [max_len];
 115             m_max_len = max_len;
 116         }
 117         m_last_x    = 0x7FFF;
 118         m_cur_span  = m_spans;
 119     }
 120
 121
 122     //------------------------------------------------------------------------
 123     inline void scanline_bin::reset_spans()
 124     {
 125         m_last_x    = 0x7FFF;
 126         m_cur_span  = m_spans;
 127     }
 128
 129
 130     //------------------------------------------------------------------------
 131     inline void scanline_bin::add_cell(int x, unsigned)
 132     {
 133         if(x == m_last_x+1)
 134         {
 135             m_cur_span->len++;
 136         }
 137         else
 138         {
 139             ++m_cur_span;
 140             m_cur_span->x = (int16)x;
 141             m_cur_span->len = 1;
 142         }
 143         m_last_x = x;
 144     }
 145
 146
 147     //------------------------------------------------------------------------
 148     inline void scanline_bin::add_span(int x, unsigned len, unsigned)
 149     {
 150         if(x == m_last_x+1)
 151         {
 152             m_cur_span->len = (int16)(m_cur_span->len + len);
 153         }
 154         else
 155         {
 156             ++m_cur_span;
 157             m_cur_span->x = (int16)x;
 158             m_cur_span->len = (int16)len;
 159         }
 160         m_last_x = x + len - 1;
 161     }
 162
 163     //------------------------------------------------------------------------
 164     inline void scanline_bin::add_cells(int x, unsigned len, const void*)
 165     {
 166         add_span(x, len, 0);
 167     }
 168 }
 169
 170
 171 #endif