headers/libs/agg/agg_span_interpolator_trans.h

   1 //----------------------------------------------------------------------------
   2 // Anti-Grain Geometry - Version 2.4
   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 // Horizontal span interpolator for use with an arbitrary transformer
  17 // The efficiency highly depends on the operations done in the transformer
  18 //
  19 //----------------------------------------------------------------------------
  20
  21 #ifndef AGG_SPAN_INTERPOLATOR_TRANS_INCLUDED
  22 #define AGG_SPAN_INTERPOLATOR_TRANS_INCLUDED
  23
  24 #include "agg_basics.h"
  25
  26 namespace agg
  27 {
  28     //=================================================span_interpolator_trans
  29     template<class Transformer, unsigned SubpixelShift = 8>
  30     class span_interpolator_trans
  31     {
  32     public:
  33         typedef Transformer trans_type;
  34         enum subpixel_scale_e
  35         {
  36             subpixel_shift = SubpixelShift,
  37             subpixel_scale = 1 << subpixel_shift
  38         };
  39
  40         //--------------------------------------------------------------------
  41         span_interpolator_trans() {}
  42         span_interpolator_trans(const trans_type& trans) : m_trans(&trans) {}
  43         span_interpolator_trans(const trans_type& trans,
  44                                 double x, double y, unsigned) :
  45             m_trans(&trans)
  46         {
  47             begin(x, y, 0);
  48         }
  49
  50         //----------------------------------------------------------------
  51         const trans_type& transformer() const { return *m_trans; }
  52         void transformer(const trans_type& trans) { m_trans = &trans; }
  53
  54         //----------------------------------------------------------------
  55         void begin(double x, double y, unsigned)
  56         {
  57             m_x = x;
  58             m_y = y;
  59             m_trans->transform(&x, &y);
  60             m_ix = iround(x * subpixel_scale);
  61             m_iy = iround(y * subpixel_scale);
  62         }
  63
  64         //----------------------------------------------------------------
  65         void operator++()
  66         {
  67             m_x += 1.0;
  68             double x = m_x;
  69             double y = m_y;
  70             m_trans->transform(&x, &y);
  71             m_ix = iround(x * subpixel_scale);
  72             m_iy = iround(y * subpixel_scale);
  73         }
  74
  75         //----------------------------------------------------------------
  76         void coordinates(int* x, int* y) const
  77         {
  78             *x = m_ix;
  79             *y = m_iy;
  80         }
  81
  82     private:
  83         const trans_type* m_trans;
  84         double            m_x;
  85         double            m_y;
  86         int               m_ix;
  87         int               m_iy;
  88     };
  89
  90 }
  91
  92 #endif