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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
/* $Xorg: LabMxC.c,v 1.3 2000/08/17 19:44:40 cpqbld Exp $ */
/*
* Code and supporting documentation (c) Copyright 1990 1991 Tektronix, Inc.
* All Rights Reserved
*
* This file is a component of an X Window System-specific implementation
* of XCMS based on the TekColor Color Management System. Permission is
* hereby granted to use, copy, modify, sell, and otherwise distribute this
* software and its documentation for any purpose and without fee, provided
* that this copyright, permission, and disclaimer notice is reproduced in
* all copies of this software and in supporting documentation. TekColor
* is a trademark of Tektronix, Inc.
*
* Tektronix makes no representation about the suitability of this software
* for any purpose. It is provided "as is" and with all faults.
*
* TEKTRONIX DISCLAIMS ALL WARRANTIES APPLICABLE TO THIS SOFTWARE,
* INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE. IN NO EVENT SHALL TEKTRONIX BE LIABLE FOR ANY
* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
* RESULTING FROM LOSS OF USE, DATA, OR PROFITS, WHETHER IN AN ACTION OF
* CONTRACT, NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR THE PERFORMANCE OF THIS SOFTWARE.
*
*
*
* NAME
* CIELabMxC.c
*
* DESCRIPTION
* Source for the XcmsCIELabQueryMaxC() gamut boundary
* querying routine.
*
*/
/* $XFree86: xc/lib/X11/LabMxC.c,v 1.3 2001/01/17 19:41:39 dawes Exp $ */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "Xlibint.h"
#include "Xcmsint.h"
#include <math.h>
#include "Cv.h"
/*
* DEFINES
*/
#define MAXBISECTCOUNT 100
#define EPS (XcmsFloat)0.001
#define START_CHROMA (XcmsFloat)3.6
#define TOPL (XcmsFloat)100.0
/************************************************************************
* *
* PUBLIC ROUTINES *
* *
************************************************************************/
/*
* NAME
* XcmsCIELabQueryMaxC - max chroma for a hue_angle and L_star
*
* SYNOPSIS
*/
Status
XcmsCIELabQueryMaxC(
XcmsCCC ccc,
XcmsFloat hue_angle, /* hue angle in degrees */
XcmsFloat L_star,
XcmsColor *pColor_return)
/*
* DESCRIPTION
* Return the maximum chroma for a specific hue_angle and L_star.
* The returned format is in XcmsCIELabFormat.
*
*
* ASSUMPTIONS
* This routine assumes that the white point associated with
* the color specification is the Screen White Point. The
* Screen White Point will also be associated with the
* returned color specification.
*
* RETURNS
* XcmsFailure - Failure
* XcmsSuccess - Succeeded
*
*/
{
XcmsCCCRec myCCC;
XcmsColor tmp;
XcmsColor max_lc;
XcmsFloat n_L_star, last_L_star, prev_L_star;
XcmsFloat hue, lastaStar, lastbStar, /*lastChroma,*/ maxDist, nT, rFactor;
XcmsRGBi rgb_saved;
int nCount, nMaxCount;
/*
* Check Arguments
*/
if (ccc == NULL || pColor_return == NULL) {
return(XcmsFailure);
}
/* Use my own CCC and inherit screen white Pt */
memcpy ((char *)&myCCC, (char *)ccc, sizeof(XcmsCCCRec));
myCCC.clientWhitePt.format = XcmsUndefinedFormat;
myCCC.gamutCompProc = (XcmsCompressionProc)NULL;/* no gamut comp func */
while (hue_angle < 0.0) {
hue_angle += 360.0;
}
while (hue_angle >= 360.0) {
hue_angle -= 360.0;
}
hue = radians(hue_angle);
tmp.spec.CIELab.L_star = L_star;
tmp.spec.CIELab.a_star = XCMS_CIEASTAROFHUE(hue, START_CHROMA);
tmp.spec.CIELab.b_star = XCMS_CIEBSTAROFHUE(hue, START_CHROMA);
tmp.pixel = pColor_return->pixel;
tmp.format = XcmsCIELabFormat;
/* Step 1: compute the maximum L_star and chroma for this hue. */
memcpy((char *)&max_lc, (char *)&tmp, sizeof(XcmsColor));
if (_XcmsCIELabQueryMaxLCRGB(&myCCC, hue, &max_lc, &rgb_saved)
== XcmsFailure) {
return(XcmsFailure);
}
/*
* Step 2: Do a bisection here to compute the maximum chroma
* Note the differences between when the point to be found
* is above the maximum LC point and when it is below.
*/
if (L_star <= max_lc.spec.CIELab.L_star) {
maxDist = max_lc.spec.CIELab.L_star;
} else {
maxDist = TOPL - max_lc.spec.CIELab.L_star;
}
n_L_star = L_star;
last_L_star = -1.0;
nMaxCount = MAXBISECTCOUNT;
rFactor = 1.0;
for (nCount = 0; nCount < nMaxCount; nCount++) {
prev_L_star = last_L_star;
last_L_star = tmp.spec.CIELab.L_star;
/* lastChroma = XCMS_CIELAB_PMETRIC_CHROMA(tmp.spec.CIELab.a_star, */
/* tmp.spec.CIELab.b_star); */
lastaStar = tmp.spec.CIELab.a_star;
lastbStar = tmp.spec.CIELab.b_star;
nT = (n_L_star - max_lc.spec.CIELab.L_star) / maxDist * rFactor;
if (nT > 0) {
tmp.spec.RGBi.red = rgb_saved.red * (1.0 - nT) + nT;
tmp.spec.RGBi.green = rgb_saved.green * (1.0 - nT) + nT;
tmp.spec.RGBi.blue = rgb_saved.blue * (1.0 - nT) + nT;
} else {
tmp.spec.RGBi.red = rgb_saved.red + (rgb_saved.red * nT);
tmp.spec.RGBi.green = rgb_saved.green + (rgb_saved.green * nT);
tmp.spec.RGBi.blue = rgb_saved.blue + (rgb_saved.blue * nT);
}
tmp.format = XcmsRGBiFormat;
/* convert from RGB to CIELab */
if (_XcmsConvertColorsWithWhitePt(&myCCC, &tmp,
ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIELabFormat,
(Bool *) NULL) == XcmsFailure) {
return(XcmsFailure);
}
/*
* Now check if we've reached the target L_star
*/
/* printf("result Lstar = %lf\n", tmp.spec.CIELab.L_star); */
if (tmp.spec.CIELab.L_star <= L_star + EPS &&
tmp.spec.CIELab.L_star >= L_star - EPS) {
memcpy((char *)pColor_return, (char *)&tmp, sizeof(XcmsColor));
return(XcmsSuccess);
}
if (nT > 0) {
n_L_star += ((TOPL - n_L_star) *
(L_star - tmp.spec.CIELab.L_star)) / (TOPL - L_star);
} else {
n_L_star *= L_star / tmp.spec.CIELuv.L_star;
}
if (tmp.spec.CIELab.L_star <= prev_L_star + EPS &&
tmp.spec.CIELab.L_star >= prev_L_star - EPS) {
rFactor *= 0.5; /* selective relaxation employed */
/* printf("rFactor = %lf\n", rFactor); */
}
}
if (XCMS_FABS(last_L_star - L_star) <
XCMS_FABS(tmp.spec.CIELab.L_star - L_star)) {
tmp.spec.CIELab.a_star = lastaStar;
tmp.spec.CIELab.b_star = lastbStar;
/* tmp.spec.CIELab.a_star = XCMS_CIEASTAROFHUE(hue, lastChroma); */
/* tmp.spec.CIELab.b_star = XCMS_CIEBSTAROFHUE(hue, lastChroma); */
}
tmp.spec.CIELab.L_star = L_star;
memcpy((char *)pColor_return, (char *)&tmp, sizeof(XcmsColor));
return(XcmsSuccess);
}
|
