Anti-Grain Geometry Tutorial
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>
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  //--------------------------------------------------------------------
42  span_interpolator_trans(trans_type& trans) : m_trans(&trans) {}
43  span_interpolator_trans(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  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
Definition: agg_arc.cpp:24