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
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
|
/* Copyright (C) 2001-2021 Artifex Software, Inc.
All Rights Reserved.
This software is provided AS-IS with no warranty, either express or
implied.
This software is distributed under license and may not be copied,
modified or distributed except as expressly authorized under the terms
of the license contained in the file LICENSE in this distribution.
Refer to licensing information at http://www.artifex.com or contact
Artifex Software, Inc., 1305 Grant Avenue - Suite 200, Novato,
CA 94945, U.S.A., +1(415)492-9861, for further information.
*/
/* HSB color operators for Ghostscript library */
#include "gx.h"
#include "gscolor.h"
#include "gshsb.h" /* interface definition */
#include "gxfrac.h"
/* Forward references */
static void color_hsb_to_rgb(double h, double s, double b, float rgb[3]);
static void color_rgb_to_hsb(double r, double g, double b, float hsb[3]);
/* Force a parameter into the range [0.0..1.0]. */
#define force_unit(p) (p < 0.0 ? 0.0 : p > 1.0 ? 1.0 : p)
/* sethsbcolor */
int
gs_sethsbcolor(gs_gstate * pgs, double h, double s, double b)
{
float rgb[3];
color_hsb_to_rgb(force_unit(h), force_unit(s), force_unit(b), rgb);
return gs_setrgbcolor(pgs, rgb[0], rgb[1], rgb[2]);
}
/* currenthsbcolor */
int
gs_currenthsbcolor(const gs_gstate * pgs, float pr3[3])
{
float rgb[3];
gs_currentrgbcolor(pgs, rgb);
color_rgb_to_hsb(rgb[0], rgb[1], rgb[2], pr3);
return 0;
}
/* ------ Internal routines ------ */
/* Note: the color model conversion algorithms are taken from */
/* Rogers, Procedural Elements for Computer Graphics, pp. 401-403. */
/* Convert RGB to HSB. */
static void
color_rgb_to_hsb(double r, double g, double b, float hsb[3])
{
frac red = float2frac(r), green = float2frac(g), blue = float2frac(b);
#define rhue hsb[0]
#define rsat hsb[1]
#define rbri hsb[2]
if (red == green && green == blue) {
rhue = 0; /* arbitrary */
rsat = 0;
rbri = r; /* pick any one */
} else { /* Convert rgb to hsb */
frac V, Temp, diff;
long H;
V = (red > green ? red : green);
if (blue > V)
V = blue;
Temp = (red > green ? green : red);
if (blue < Temp)
Temp = blue;
diff = V - Temp;
if (V == red)
H = (green - blue) * frac_1_long / diff;
else if (V == green)
H = (blue - red) * frac_1_long / diff + 2 * frac_1_long;
else /* V == blue */
H = (red - green) * frac_1_long / diff + 4 * frac_1_long;
if (H < 0)
H += 6 * frac_1_long;
rhue = H / (frac_1 * 6.0);
rsat = diff / (float)V;
rbri = frac2float(V);
}
#undef rhue
#undef rsat
#undef rbri
}
/* Convert HSB to RGB. */
static void
color_hsb_to_rgb(double hue, double saturation, double brightness, float rgb[3])
{
if (saturation == 0) {
rgb[0] = rgb[1] = rgb[2] = brightness;
} else { /* Convert hsb to rgb. */
/* We rely on the fact that the product of two */
/* fracs fits into an unsigned long. */
double h6 = hue * 6;
ulong V = float2frac(brightness); /* force arithmetic to long */
frac S = float2frac(saturation);
int I = (int)h6;
ulong F = float2frac(h6 - I); /* ditto */
/* M = V*(1-S), N = V*(1-S*F), K = V*(1-S*(1-F)) = M-N+V */
frac M = V * (frac_1_long - S) / frac_1_long;
frac N = V * (frac_1_long - S * F / frac_1_long) / frac_1_long;
frac K = M - N + V;
frac R, G, B;
switch (I) {
default:
R = V;
G = K;
B = M;
break;
case 1:
R = N;
G = V;
B = M;
break;
case 2:
R = M;
G = V;
B = K;
break;
case 3:
R = M;
G = N;
B = V;
break;
case 4:
R = K;
G = M;
B = V;
break;
case 5:
R = V;
G = M;
B = N;
break;
}
rgb[0] = frac2float(R);
rgb[1] = frac2float(G);
rgb[2] = frac2float(B);
#ifdef DEBUG
if (gs_debug_c('c')) {
dlprintf7("[c]hsb(%g,%g,%g)->VSFI(%ld,%d,%ld,%d)->\n",
hue, saturation, brightness, V, S, F, I);
dlprintf6(" RGB(%d,%d,%d)->rgb(%g,%g,%g)\n",
R, G, B, rgb[0], rgb[1], rgb[2]);
}
#endif
}
}
|
GitWeb