1
2 /*
3 * Code and supporting documentation (c) Copyright 1990 1991 Tektronix, Inc.
4 * All Rights Reserved
5 *
6 * This file is a component of an X Window System-specific implementation
7 * of Xcms based on the TekColor Color Management System. Permission is
8 * hereby granted to use, copy, modify, sell, and otherwise distribute this
9 * software and its documentation for any purpose and without fee, provided
10 * that this copyright, permission, and disclaimer notice is reproduced in
11 * all copies of this software and in supporting documentation. TekColor
12 * is a trademark of Tektronix, Inc.
13 *
14 * Tektronix makes no representation about the suitability of this software
15 * for any purpose. It is provided "as is" and with all faults.
16 *
17 * TEKTRONIX DISCLAIMS ALL WARRANTIES APPLICABLE TO THIS SOFTWARE,
18 * INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
19 * PARTICULAR PURPOSE. IN NO EVENT SHALL TEKTRONIX BE LIABLE FOR ANY
20 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
21 * RESULTING FROM LOSS OF USE, DATA, OR PROFITS, WHETHER IN AN ACTION OF
22 * CONTRACT, NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
23 * CONNECTION WITH THE USE OR THE PERFORMANCE OF THIS SOFTWARE.
24 *
25 * NAME
26 * CIExyY.c
27 *
28 * DESCRIPTION
29 * This file contains routines that support the CIE xyY
30 * color space to include conversions to and from the CIE
31 * XYZ space.
32 *
33 * DOCUMENTATION
34 * "TekColor Color Management System, System Implementor's Manual"
35 */
36
37 #ifdef HAVE_CONFIG_H
38 #include <config.h>
39 #endif
40 #include <stdio.h>
41 #include <X11/Xos.h>
42 #include "Xlibint.h"
43 #include "Xcmsint.h"
44 #include "Cv.h"
45
46 /*
47 * DEFINES
48 */
49 #define EPS 0.00001 /* some extremely small number */
50 #ifdef DBL_EPSILON
51 # define XMY_DBL_EPSILON DBL_EPSILON
52 #else
53 # define XMY_DBL_EPSILON 0.00001
54 #endif
55
56 /*
57 * FORWARD DECLARATIONS
58 */
59
60 static int CIExyY_ParseString(register char *spec, XcmsColor *pColor);
61 static Status XcmsCIExyY_ValidSpec(XcmsColor *pColor);
62
63
64 /*
65 * LOCAL VARIABLES
66 */
67
68 /*
69 * NULL terminated list of functions applied to get from CIExyY to CIEXYZ
70 */
71 static XcmsConversionProc Fl_CIExyY_to_CIEXYZ[] = {
72 XcmsCIExyYToCIEXYZ,
73 NULL
74 };
75
76 /*
77 * NULL terminated list of functions applied to get from CIEXYZ to CIExyY
78 */
79 static XcmsConversionProc Fl_CIEXYZ_to_CIExyY[] = {
80 XcmsCIEXYZToCIExyY,
81 NULL
82 };
83
84
85 /*
86 * GLOBALS
87 */
88
89 /*
90 * CIE xyY Color Space
91 */
92 XcmsColorSpace XcmsCIExyYColorSpace =
93 {
94 _XcmsCIExyY_prefix, /* prefix */
95 XcmsCIExyYFormat, /* id */
96 CIExyY_ParseString, /* parseString */
97 Fl_CIExyY_to_CIEXYZ, /* to_CIEXYZ */
98 Fl_CIEXYZ_to_CIExyY, /* from_CIEXYZ */
99 1
100 };
101
102
103
104 /************************************************************************
105 * *
106 * PRIVATE ROUTINES *
107 * *
108 ************************************************************************/
109
110 /*
111 * NAME
112 * CIExyY_ParseString
113 *
114 * SYNOPSIS
115 */
116 static int
CIExyY_ParseString(register char * spec,XcmsColor * pColor)117 CIExyY_ParseString(
118 register char *spec,
119 XcmsColor *pColor)
120 /*
121 * DESCRIPTION
122 * This routines takes a string and attempts to convert
123 * it into a XcmsColor structure with XcmsCIExyYFormat.
124 * The assumed CIExyY string syntax is:
125 * CIExyY:<x>/<y>/<Y>
126 * Where x, y, and Y are in string input format for floats
127 * consisting of:
128 * a. an optional sign
129 * b. a string of numbers possibly containing a decimal point,
130 * c. an optional exponent field containing an 'E' or 'e'
131 * followed by a possibly signed integer string.
132 *
133 * RETURNS
134 * 0 if failed, non-zero otherwise.
135 */
136 {
137 int n;
138 char *pchar;
139
140 if ((pchar = strchr(spec, ':')) == NULL) {
141 return(XcmsFailure);
142 }
143 n = (int)(pchar - spec);
144
145 /*
146 * Check for proper prefix.
147 */
148 if (strncmp(spec, _XcmsCIExyY_prefix, (size_t)n) != 0) {
149 return(XcmsFailure);
150 }
151
152 /*
153 * Attempt to parse the value portion.
154 */
155 if (sscanf(spec + n + 1, "%lf/%lf/%lf",
156 &pColor->spec.CIExyY.x,
157 &pColor->spec.CIExyY.y,
158 &pColor->spec.CIExyY.Y) != 3) {
159 char *s; /* Maybe failed due to locale */
160 int f;
161 if ((s = strdup(spec))) {
162 for (f = 0; s[f]; ++f)
163 if (s[f] == '.')
164 s[f] = ',';
165 else if (s[f] == ',')
166 s[f] = '.';
167 if (sscanf(s + n + 1, "%lf/%lf/%lf",
168 &pColor->spec.CIExyY.x,
169 &pColor->spec.CIExyY.y,
170 &pColor->spec.CIExyY.Y) != 3) {
171 free(s);
172 return(XcmsFailure);
173 }
174 free(s);
175 } else
176 return(XcmsFailure);
177 }
178 pColor->format = XcmsCIExyYFormat;
179 pColor->pixel = 0;
180 return(XcmsCIExyY_ValidSpec(pColor));
181 }
182
183
184
185 /************************************************************************
186 * *
187 * PUBLIC ROUTINES *
188 * *
189 ************************************************************************/
190
191 /*
192 * NAME
193 * CIExyY_ValidSpec()
194 *
195 * SYNOPSIS
196 */
197 static Status
XcmsCIExyY_ValidSpec(XcmsColor * pColor)198 XcmsCIExyY_ValidSpec(
199 XcmsColor *pColor)
200 /*
201 * DESCRIPTION
202 * Checks a valid CIExyY color specification.
203 *
204 * RETURNS
205 * XcmsFailure if invalid.
206 * XcmsSuccess if valid.
207 *
208 */
209 {
210 if (pColor->format != XcmsCIExyYFormat
211 ||
212 (pColor->spec.CIExyY.x < 0.0 - XMY_DBL_EPSILON)
213 ||
214 (pColor->spec.CIExyY.x > 1.0 + XMY_DBL_EPSILON)
215 ||
216 (pColor->spec.CIExyY.y < 0.0 - XMY_DBL_EPSILON)
217 ||
218 (pColor->spec.CIExyY.y > 1.0 + XMY_DBL_EPSILON)
219 ||
220 (pColor->spec.CIExyY.Y < 0.0 - XMY_DBL_EPSILON)
221 ||
222 (pColor->spec.CIExyY.Y > 1.0 + XMY_DBL_EPSILON)) {
223 return(XcmsFailure);
224 }
225 return(XcmsSuccess);
226 }
227
228
229 /*
230 * NAME
231 * XcmsCIExyYToCIEXYZ - convert CIExyY to CIEXYZ
232 *
233 * SYNOPSIS
234 */
235 Status
XcmsCIExyYToCIEXYZ(XcmsCCC ccc,XcmsColor * pxyY_WhitePt,XcmsColor * pColors_in_out,unsigned int nColors)236 XcmsCIExyYToCIEXYZ(
237 XcmsCCC ccc,
238 XcmsColor *pxyY_WhitePt,
239 XcmsColor *pColors_in_out,
240 unsigned int nColors)
241 /*
242 * DESCRIPTION
243 * Converts color specifications in an array of XcmsColor
244 * structures from CIExyY format to CIEXYZ format.
245 *
246 * RETURNS
247 * XcmsFailure if failed,
248 * XcmsSuccess if succeeded.
249 */
250 {
251 XcmsColor *pColor = pColors_in_out;
252 XcmsColor whitePt;
253 XcmsCIEXYZ XYZ_return;
254 XcmsFloat div; /* temporary storage in case divisor is zero */
255 XcmsFloat u, v, x, y, z; /* temporary storage */
256 unsigned int i;
257
258 /*
259 * Check arguments
260 */
261 if (pxyY_WhitePt == NULL || pColors_in_out == NULL) {
262 return(XcmsFailure);
263 }
264
265
266 /*
267 * Now convert each XcmsColor structure to CIEXYZ form
268 */
269 for (i = 0; i < nColors; i++, pColor++) {
270 /* Make sure original format is CIExyY and valid */
271 if (!XcmsCIExyY_ValidSpec(pColor)) {
272 return(XcmsFailure);
273 }
274
275 if ((div = (-2 * pColor->spec.CIExyY.x) + (12 * pColor->spec.CIExyY.y) + 3) == 0.0) {
276 /* Note that the divisor is zero */
277 /* This return is abitrary. */
278 XYZ_return.X = 0;
279 XYZ_return.Y = 0;
280 XYZ_return.Z = 0;
281 } else {
282 /*
283 * Make sure white point is in CIEXYZ form
284 */
285 if (pxyY_WhitePt->format != XcmsCIEXYZFormat) {
286 /* Make copy of the white point because we're going to modify it */
287 memcpy((char *)&whitePt, (char *)pxyY_WhitePt, sizeof(XcmsColor));
288 if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1,
289 XcmsCIEXYZFormat)) {
290 return(XcmsFailure);
291 }
292 pxyY_WhitePt = &whitePt;
293 }
294
295 /* Make sure it is a white point, i.e., Y == 1.0 */
296 if (pxyY_WhitePt->spec.CIEXYZ.Y != 1.0) {
297 return(XcmsFailure);
298 }
299
300 /* Convert from xyY to uvY to XYZ */
301 u = (4 * pColor->spec.CIExyY.x) / div;
302 v = (9 * pColor->spec.CIExyY.y) / div;
303 div = (6.0 * u) - (16.0 * v) + 12.0;
304 if (div == 0.0) {
305 /* Note that the divisor is zero */
306 /* This return is abitrary. */
307 if ((div = (6.0 * whitePt.spec.CIEuvY.u_prime) -
308 (16.0 * whitePt.spec.CIEuvY.v_prime) + 12.0) == 0.0) {
309 div = EPS;
310 }
311 x = 9.0 * whitePt.spec.CIEuvY.u_prime / div;
312 y = 4.0 * whitePt.spec.CIEuvY.u_prime / div;
313 } else {
314 /* convert u, v to small xyz */
315 x = 9.0 * u / div;
316 y = 4.0 * v / div;
317 }
318 z = 1.0 - x - y;
319 if (y == 0.0) y = EPS; /* Have to worry about divide by 0 */
320 XYZ_return.Y = pColor->spec.CIExyY.Y;
321 XYZ_return.X = x * XYZ_return.Y / y;
322 XYZ_return.Z = z * XYZ_return.Y / y;
323 }
324
325 /* Copy result to pColor */
326 memcpy ((char *)&pColor->spec, (char *)&XYZ_return, sizeof(XcmsCIEXYZ));
327
328 /* Identify that the format is now CIEXYZ */
329 pColor->format = XcmsCIEXYZFormat;
330 }
331 return(XcmsSuccess);
332 }
333
334
335 /*
336 * NAME
337 * XcmsCIEXYZToCIExyY - convert CIEXYZ to CIExyY
338 *
339 * SYNOPSIS
340 */
341 /* ARGSUSED */
342 Status
XcmsCIEXYZToCIExyY(XcmsCCC ccc,XcmsColor * pxyY_WhitePt,XcmsColor * pColors_in_out,unsigned int nColors)343 XcmsCIEXYZToCIExyY(
344 XcmsCCC ccc,
345 XcmsColor *pxyY_WhitePt,
346 XcmsColor *pColors_in_out,
347 unsigned int nColors)
348 /*
349 * DESCRIPTION
350 * Converts color specifications in an array of XcmsColor
351 * structures from CIEXYZ format to CIExyY format.
352 *
353 * RETURNS
354 * XcmsFailure if failed,
355 * XcmsSuccess if succeeded.
356 *
357 */
358 {
359 XcmsColor *pColor = pColors_in_out;
360 XcmsCIExyY xyY_return;
361 XcmsFloat div; /* temporary storage in case divisor is zero */
362 unsigned int i;
363
364 /*
365 * Check arguments
366 * pxyY_WhitePt ignored
367 */
368 if (pColors_in_out == NULL) {
369 return(XcmsFailure);
370 }
371
372 /*
373 * Now convert each XcmsColor structure to CIEXYZ form
374 */
375 for (i = 0; i < nColors; i++, pColor++) {
376
377 if (!_XcmsCIEXYZ_ValidSpec(pColor)) {
378 return(XcmsFailure);
379 }
380 /* Now convert for XYZ to xyY */
381 if ((div = pColor->spec.CIEXYZ.X + pColor->spec.CIEXYZ.Y + pColor->spec.CIEXYZ.Z) == 0.0) {
382 div = EPS;
383 }
384 xyY_return.x = pColor->spec.CIEXYZ.X / div;
385 xyY_return.y = pColor->spec.CIEXYZ.Y / div;
386 xyY_return.Y = pColor->spec.CIEXYZ.Y;
387
388 /* Copy result to pColor */
389 memcpy ((char *)&pColor->spec, (char *)&xyY_return, sizeof(XcmsCIExyY));
390
391 /* Identify that the format is now CIEXYZ */
392 pColor->format = XcmsCIExyYFormat;
393 }
394 return(XcmsSuccess);
395 }
396