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
206
207
208
209
210
211
212
213
214
215
216
217
|
/* $Xorg: LuvMxLC.c,v 1.3 2000/08/17 19:44:45 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
* CIELuvMxVC.c
*
* DESCRIPTION
* Source for the XcmsCIELuvQueryMaxLC() gamut boundary
* querying routine.
*
* DOCUMENTATION
* "TekColor Color Management System, System Implementor's Manual"
* and
* Fred W. Billmeyer & Max Saltzman, "Principles of Color
* Technology", John Wily & Sons, Inc, 1981.
*/
/* $XFree86: xc/lib/X11/LuvMxLC.c,v 1.2 2003/04/13 19:22:17 dawes Exp $ */
#include "Xlibint.h"
#include "Xcmsint.h"
#include "Cv.h"
/*
* DEFINES
*/
#define MIN(x,y) ((x) > (y) ? (y) : (x))
#define MIN3(x,y,z) ((x) > (MIN((y), (z))) ? (MIN((y), (z))) : (x))
#define MAX(x,y) ((x) > (y) ? (x) : (y))
#define MAX3(x,y,z) ((x) > (MAX((y), (z))) ? (x) : (MAX((y), (z))))
#define START_LSTAR (XcmsFloat)40.0
#define START_CHROMA (XcmsFloat)2.2
/************************************************************************
* *
* API PRIVATE ROUTINES *
* *
************************************************************************/
/*
* NAME
* _XcmsCIELuvQueryMaxLCRGB - Compute maximum L* and chroma.
*
* SYNOPSIS
*/
Status
_XcmsCIELuvQueryMaxLCRGB(
XcmsCCC ccc,
XcmsFloat hue, /* hue in radians */
XcmsColor *pColor_return,
XcmsRGBi *pRGB_return)
/*
* DESCRIPTION
* Return the maximum psychometric chroma for a specified
* hue angle(radians), and the corresponding L*. This is computed
* by a binary search of all possible chromas. An assumption
* is made that there are no local maxima. Use the unrounded
* Max psychometric chroma because the difference check can be
* small.
*
* NOTE: No local CCC is used because this is a private
* routine and all routines that call it are expected
* to behave properly, i.e. send a local CCC with
* no white adjust function and no gamut compression
* function.
*
* This routine only accepts hue as input and outputs
* Luv and RGBi.
*
* RETURNS
* XcmsFailure - Failure
* XcmsSuccess - Succeeded
*
*/
{
XcmsFloat nSmall, nLarge;
XcmsColor tmp;
tmp.format = XcmsCIELuvFormat;
/* Use some unreachable color on the given hue angle */
tmp.spec.CIELuv.L_star = START_LSTAR;
tmp.spec.CIELuv.u_star = XCMS_CIEUSTAROFHUE(hue, START_CHROMA);
tmp.spec.CIELuv.v_star = XCMS_CIEVSTAROFHUE(hue, START_CHROMA);
/*
* Convert from Luv to RGB
*
* Note that the CIEXYZ to RGBi conversion routine must stuff the
* out of bounds RGBi values in tmp when the ccc->gamutCompProc
* is NULL.
*/
if ((_XcmsConvertColorsWithWhitePt(ccc, &tmp, ScreenWhitePointOfCCC(ccc),
(unsigned int)1, XcmsRGBiFormat, (Bool *) NULL)
== XcmsFailure) && tmp.format != XcmsRGBiFormat) {
return (XcmsFailure);
}
/* Now pick the smallest RGB */
nSmall = MIN3(tmp.spec.RGBi.red,
tmp.spec.RGBi.green,
tmp.spec.RGBi.blue);
/* Make the smallest RGB equal to zero */
tmp.spec.RGBi.red -= nSmall;
tmp.spec.RGBi.green -= nSmall;
tmp.spec.RGBi.blue -= nSmall;
/* Now pick the largest RGB */
nLarge = MAX3(tmp.spec.RGBi.red,
tmp.spec.RGBi.green,
tmp.spec.RGBi.blue);
/* Scale the RGB values based on the largest one */
tmp.spec.RGBi.red /= nLarge;
tmp.spec.RGBi.green /= nLarge;
tmp.spec.RGBi.blue /= nLarge;
tmp.format = XcmsRGBiFormat;
/* If the calling routine wants RGB value give them the ones used. */
if (pRGB_return) {
pRGB_return->red = tmp.spec.RGBi.red;
pRGB_return->green = tmp.spec.RGBi.green;
pRGB_return->blue = tmp.spec.RGBi.blue;
}
/* Convert from RGBi to Luv */
if (_XcmsConvertColorsWithWhitePt(ccc, &tmp,
ScreenWhitePointOfCCC(ccc), 1, XcmsCIELuvFormat, (Bool *) NULL)
== XcmsFailure) {
return (XcmsFailure);
}
memcpy((char *)pColor_return, (char *)&tmp, sizeof(XcmsColor));
return (XcmsSuccess);
}
/************************************************************************
* *
* PUBLIC ROUTINES *
* *
************************************************************************/
/*
* NAME
* XcmsCIELuvQueryMaxLC - Compute maximum L* and chroma.
*
* SYNOPSIS
*/
Status
XcmsCIELuvQueryMaxLC (ccc, hue_angle, pColor_return)
XcmsCCC ccc;
XcmsFloat hue_angle; /* hue angle in degrees */
XcmsColor *pColor_return;
/*
* DESCRIPTION
* Return the point of maximum chroma for the specified
* hue angle.
*
* 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;
/*
* Check Arguments
*/
if (ccc == NULL || pColor_return == NULL) {
return(XcmsFailure);
}
/* Use my own CCC */
memcpy ((char *)&myCCC, (char *)ccc, sizeof(XcmsCCCRec));
myCCC.clientWhitePt.format = XcmsUndefinedFormat;
myCCC.gamutCompProc = (XcmsCompressionProc)NULL;
while (hue_angle < 0.0) {
hue_angle += 360.0;
}
while (hue_angle >= 360.0) {
hue_angle -= 360.0;
}
return(_XcmsCIELuvQueryMaxLCRGB (&myCCC, radians(hue_angle), pColor_return,
(XcmsRGBi *)NULL));
}
|
