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
|
//----------------------------------------------------------------------------
// 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
//----------------------------------------------------------------------------
//
// Arc vertex generator
//
//----------------------------------------------------------------------------
#include <math.h>
#include "agg_arc.h"
namespace agg
{
//------------------------------------------------------------------------
arc::arc(double x, double y,
double rx, double ry,
double a1, double a2,
bool ccw) :
m_x(x), m_y(y), m_rx(rx), m_ry(ry), m_scale(1.0)
{
normalize(a1, a2, ccw);
}
//------------------------------------------------------------------------
void arc::init(double x, double y,
double rx, double ry,
double a1, double a2,
bool ccw)
{
m_x = x; m_y = y;
m_rx = rx; m_ry = ry;
normalize(a1, a2, ccw);
}
//------------------------------------------------------------------------
void arc::approximation_scale(double s)
{
m_scale = s;
if(m_initialized)
{
normalize(m_start, m_end, m_ccw);
}
}
//------------------------------------------------------------------------
void arc::rewind(unsigned)
{
m_path_cmd = path_cmd_move_to;
m_angle = m_start;
}
//------------------------------------------------------------------------
unsigned arc::vertex(double* x, double* y)
{
if(is_stop(m_path_cmd)) return path_cmd_stop;
if((m_angle < m_end) != m_ccw)
{
*x = m_x + cos(m_end) * m_rx;
*y = m_y + sin(m_end) * m_ry;
m_path_cmd = path_cmd_stop;
return path_cmd_line_to;
}
*x = m_x + cos(m_angle) * m_rx;
*y = m_y + sin(m_angle) * m_ry;
m_angle += m_da;
unsigned pf = m_path_cmd;
m_path_cmd = path_cmd_line_to;
return pf;
}
//------------------------------------------------------------------------
void arc::normalize(double a1, double a2, bool ccw)
{
m_da = fabs(1.0 / ((m_rx + m_ry) * 0.5 * m_scale));
if(ccw)
{
while(a2 < a1) a2 += pi * 2.0;
}
else
{
while(a1 < a2) a1 += pi * 2.0;
m_da = -m_da;
}
m_ccw = ccw;
m_start = a1;
m_end = a2;
m_initialized = true;
}
}
|
