1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
|
//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.3
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
// mcseemagg@yahoo.com
// http://www.antigrain.com
//----------------------------------------------------------------------------
#ifndef AGG_SPAN_GRADIENT_ALPHA_INCLUDED
#define AGG_SPAN_GRADIENT_ALPHA_INCLUDED
#include "agg_span_gradient.h"
namespace agg
{
//======================================================span_gradient_alpha
template<class ColorT,
class Interpolator,
class GradientF,
class AlphaF>
class span_gradient_alpha
{
public:
typedef Interpolator interpolator_type;
typedef ColorT color_type;
typedef typename color_type::value_type alpha_type;
enum
{
downscale_shift = interpolator_type::subpixel_shift - gradient_subpixel_shift
};
//--------------------------------------------------------------------
span_gradient_alpha() {}
//--------------------------------------------------------------------
span_gradient_alpha(interpolator_type& inter,
const GradientF& gradient_function,
const AlphaF& alpha_function,
double d1, double d2) :
m_interpolator(&inter),
m_gradient_function(&gradient_function),
m_alpha_function(&alpha_function),
m_d1(int(d1 * gradient_subpixel_size)),
m_d2(int(d2 * gradient_subpixel_size))
{}
//--------------------------------------------------------------------
interpolator_type& interpolator() { return *m_interpolator; }
const GradientF& gradient_function() const { return *m_gradient_function; }
const AlphaF& alpha_function() const { return *m_alpha_function; }
double d1() const { return double(m_d1) / gradient_subpixel_size; }
double d2() const { return double(m_d2) / gradient_subpixel_size; }
//--------------------------------------------------------------------
void interpolator(interpolator_type& i) { m_interpolator = &i; }
void gradient_function(const GradientF& gf) { m_gradient_function = &gf; }
void alpha_function(const AlphaF& af) { m_alpha_function = ⁡ }
void d1(double v) { m_d1 = int(v * gradient_subpixel_size); }
void d2(double v) { m_d2 = int(v * gradient_subpixel_size); }
//--------------------------------------------------------------------
void convert(color_type* span, int x, int y, unsigned len)
{
int dd = m_d2 - m_d1;
if(dd < 1) dd = 1;
m_interpolator->begin(x+0.5, y+0.5, len);
do
{
m_interpolator->coordinates(&x, &y);
int d = m_gradient_function->calculate(x >> downscale_shift,
y >> downscale_shift, dd);
d = ((d - m_d1) * (int)m_alpha_function->size()) / dd;
if(d < 0) d = 0;
if(d >= (int)m_alpha_function->size()) d = m_alpha_function->size() - 1;
span->a = (*m_alpha_function)[d];
++span;
++(*m_interpolator);
}
while(--len);
}
private:
interpolator_type* m_interpolator;
const GradientF* m_gradient_function;
const AlphaF* m_alpha_function;
int m_d1;
int m_d2;
};
//=======================================================gradient_alpha_x
template<class ColorT> struct gradient_alpha_x
{
typedef typename ColorT::value_type alpha_type;
alpha_type operator [] (alpha_type x) const { return x; }
};
//====================================================gradient_alpha_x_u8
struct gradient_alpha_x_u8
{
typedef int8u alpha_type;
alpha_type operator [] (alpha_type x) const { return x; }
};
//==========================================gradient_alpha_one_munus_x_u8
struct gradient_alpha_one_munus_x_u8
{
typedef int8u alpha_type;
alpha_type operator [] (alpha_type x) const { return 255-x; }
};
}
#endif
|
