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
26namespace 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
93