aboutsummaryrefslogtreecommitdiff
path: root/libX11/src/xcms/uvY.c
blob: a4abc66cdfe2924ee1958909356dd888e88ae398 (plain)
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
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423

/*
 * 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
 *		CIEuvy.c
 *
 *	DESCRIPTION
 *		This file contains routines that support the CIE u'v'Y
 *		color space to include conversions to and from the CIE
 *		XYZ space.
 *
 *	DOCUMENTATION
 *		"TekColor Color Management System, System Implementor's Manual"
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <X11/Xos.h>
#include "Xlibint.h"
#include "Xcmsint.h"
#include "Cv.h"

#include <stdio.h>

/*
 *	FORWARD DECLARATIONS
 */
static int CIEuvY_ParseString(register char *spec, XcmsColor *pColor);

/*
 *	DEFINES
 *		Internal definitions that need NOT be exported to any package
 *		or program using this package.
 */
#ifdef DBL_EPSILON
#  define XMY_DBL_EPSILON DBL_EPSILON
#else
#  define XMY_DBL_EPSILON 0.00001
#endif


/*
 *	LOCAL VARIABLES
 */

    /*
     * NULL terminated list of functions applied to get from CIEuvY to CIEXYZ
     */
static XcmsConversionProc Fl_CIEuvY_to_CIEXYZ[] = {
    XcmsCIEuvYToCIEXYZ,
    NULL
};

    /*
     * NULL terminated list of functions applied to get from CIEXYZ to CIEuvY
     */
static XcmsConversionProc Fl_CIEXYZ_to_CIEuvY[] = {
    XcmsCIEXYZToCIEuvY,
    NULL
};


/*
 *	GLOBALS
 */

    /*
     * CIE uvY Color Space
     */
XcmsColorSpace	XcmsCIEuvYColorSpace =
    {
	_XcmsCIEuvY_prefix,		/* prefix */
	XcmsCIEuvYFormat,		/* id */
	CIEuvY_ParseString,	/* parseString */
	Fl_CIEuvY_to_CIEXYZ,	/* to_CIEXYZ */
	Fl_CIEXYZ_to_CIEuvY,	/* from_CIEXYZ */
	1
    };



/************************************************************************
 *									*
 *			 PRIVATE ROUTINES				*
 *									*
 ************************************************************************/

/*
 *	NAME
 *		CIEuvY_ParseString
 *
 *	SYNOPSIS
 */
static int
CIEuvY_ParseString(
    register char *spec,
    XcmsColor *pColor)
/*
 *	DESCRIPTION
 *		This routines takes a string and attempts to convert
 *		it into a XcmsColor structure with XcmsCIEuvYFormat.
 *		The assumed CIEuvY string syntax is:
 *		    CIEuvY:<u>/<v>/<Y>
 *		Where u, v, and Y are in string input format for floats
 *		consisting of:
 *		    a. an optional sign
 *		    b. a string of numbers possibly containing a decimal point,
 *		    c. an optional exponent field containing an 'E' or 'e'
 *			followed by a possibly signed integer string.
 *
 *	RETURNS
 *		0 if failed, non-zero otherwise.
 */
{
    int n;
    char *pchar;

    if ((pchar = strchr(spec, ':')) == NULL) {
	return(XcmsFailure);
    }
    n = (int)(pchar - spec);

    /*
     * Check for proper prefix.
     */
    if (strncmp(spec, _XcmsCIEuvY_prefix, n) != 0) {
	return(XcmsFailure);
    }

    /*
     * Attempt to parse the value portion.
     */
    if (sscanf(spec + n + 1, "%lf/%lf/%lf",
	    &pColor->spec.CIEuvY.u_prime,
	    &pColor->spec.CIEuvY.v_prime,
	    &pColor->spec.CIEuvY.Y) != 3) {
        char *s; /* Maybe failed due to locale */
        int f;
        if ((s = strdup(spec))) {
            for (f = 0; s[f]; ++f)
                if (s[f] == '.')
                    s[f] = ',';
                else if (s[f] == ',')
                    s[f] = '.';
	    if (sscanf(s + n + 1, "%lf/%lf/%lf",
		       &pColor->spec.CIEuvY.u_prime,
		       &pColor->spec.CIEuvY.v_prime,
		       &pColor->spec.CIEuvY.Y) != 3) {
                free(s);
                return(XcmsFailure);
            }
            free(s);
        } else
	    return(XcmsFailure);
    }
    pColor->format = XcmsCIEuvYFormat;
    pColor->pixel = 0;
    return(_XcmsCIEuvY_ValidSpec(pColor));
}


/************************************************************************
 *									*
 *			 PUBLIC ROUTINES				*
 *									*
 ************************************************************************/

/*
 *	NAME
 *		XcmsCIEuvY_ValidSpec
 *
 *	SYNOPSIS
 */
Status
_XcmsCIEuvY_ValidSpec(
    XcmsColor *pColor)
/*
 *	DESCRIPTION
 *		Checks if color specification valid for CIE u'v'Y.
 *
 *	RETURNS
 *		XcmsFailure if invalid,
 *		XcmsSuccess if valid.
 *
 */
{
    if (pColor->format != XcmsCIEuvYFormat
	    ||
	    (pColor->spec.CIEuvY.Y < 0.0 - XMY_DBL_EPSILON)
	    ||
	    (pColor->spec.CIEuvY.Y > 1.0 + XMY_DBL_EPSILON)) {
	return(XcmsFailure);
    }
    return(XcmsSuccess);
}


/*
 *	NAME
 *		XcmsCIEuvYToCIEXYZ - convert CIEuvY to CIEXYZ
 *
 *	SYNOPSIS
 */
Status
XcmsCIEuvYToCIEXYZ(
    XcmsCCC ccc,
    XcmsColor *puvY_WhitePt,
    XcmsColor *pColors_in_out,
    unsigned int nColors)
/*
 *	DESCRIPTION
 *		Converts color specifications in an array of XcmsColor
 *		structures from CIEuvY format to CIEXYZ format.
 *
 *	RETURNS
 *		XcmsFailure if failed,
 *		XcmsSuccess if succeeded.
 *
 */
{
    XcmsCIEXYZ XYZ_return;
    XcmsColor whitePt;
    int i;
    XcmsColor *pColor = pColors_in_out;
    XcmsFloat div, x, y, z, Y;

    /*
     * Check arguments
     *	Postpone checking puvY_WhitePt until it is actually needed
     *	otherwise converting between XYZ and uvY will fail.
     */
    if (pColors_in_out == NULL) {
	return(XcmsFailure);
    }


    /*
     * Now convert each XcmsColor structure to CIEXYZ form
     */
    for (i = 0; i < nColors; i++, pColor++) {

	/* Make sure original format is CIEuvY */
	if (!_XcmsCIEuvY_ValidSpec(pColor)) {
	    return(XcmsFailure);
	}

	/*
	 * Convert to CIEXYZ
	 */

	Y = pColor->spec.CIEuvY.Y;

	/* Convert color u'v' to xyz space */
	div = (6.0 * pColor->spec.CIEuvY.u_prime) - (16.0 * pColor->spec.CIEuvY.v_prime) + 12.0;
	if (div == 0.0) {
	    /* use white point since div == 0 */
	    if (puvY_WhitePt == NULL ) {
		return(XcmsFailure);
	    }
	    /*
	     * Make sure white point is in CIEuvY form
	     */
	    if (puvY_WhitePt->format != XcmsCIEuvYFormat) {
		/* Make copy of the white point because we're going to modify it */
		memcpy((char *)&whitePt, (char *)puvY_WhitePt, sizeof(XcmsColor));
		if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1,
			XcmsCIEuvYFormat)) {
		    return(XcmsFailure);
		}
		puvY_WhitePt = &whitePt;
	    }
	    /* Make sure it is a white point, i.e., Y == 1.0 */
	    if (puvY_WhitePt->spec.CIEuvY.Y != 1.0) {
		return(XcmsFailure);
	    }
	    div = (6.0 * puvY_WhitePt->spec.CIEuvY.u_prime) -
		    (16.0 * puvY_WhitePt->spec.CIEuvY.v_prime) + 12.0;
	    if (div == 0) {
		/* internal error */
		return(XcmsFailure);
	    }
	    x = 9.0 * puvY_WhitePt->spec.CIEuvY.u_prime / div;
	    y = 4.0 * puvY_WhitePt->spec.CIEuvY.v_prime / div;
	} else {
	    x = 9.0 * pColor->spec.CIEuvY.u_prime / div;
	    y = 4.0 * pColor->spec.CIEuvY.v_prime / div;
	}
	z = 1.0 - x - y;

	/* Convert from xyz to XYZ */
	/* Conversion uses color normalized lightness based on Y */
	if (y != 0.0) {
	    XYZ_return.X = x * Y / y;
	} else {
	    XYZ_return.X = x;
	}
	XYZ_return.Y = Y;
	if (y != 0.0) {
	    XYZ_return.Z = z * Y / y;
	} else {
	    XYZ_return.Z = z;
	}

	memcpy((char *)&pColor->spec.CIEXYZ, (char *)&XYZ_return, sizeof(XcmsCIEXYZ));
	/* Identify that format is now CIEXYZ */
	pColor->format = XcmsCIEXYZFormat;
    }

    return(XcmsSuccess);
}


/*
 *	NAME
 *		XcmsCIEXYZToCIEuvY - convert CIEXYZ to CIEuvY
 *
 *	SYNOPSIS
 */
Status
XcmsCIEXYZToCIEuvY(
    XcmsCCC ccc,
    XcmsColor *puvY_WhitePt,
    XcmsColor *pColors_in_out,
    unsigned int nColors)
/*
 *	DESCRIPTION
 *		Converts color specifications in an array of XcmsColor
 *		structures from CIEXYZ format to CIEuvY format.
 *
 *	RETURNS
 *		XcmsFailure if failed,
 *		XcmsSuccess if succeeded.
 *
 */
{
    XcmsCIEuvY uvY_return;
    XcmsColor whitePt;
    int i;
    XcmsColor *pColor = pColors_in_out;
    XcmsFloat div;

    /*
     * Check arguments
     *	Postpone checking puvY_WhitePt until it is actually needed
     *	otherwise converting between XYZ and uvY will fail.
     */
    if (pColors_in_out == NULL) {
	return(XcmsFailure);
    }

    /*
     * Now convert each XcmsColor structure to CIEuvY form
     */
    for (i = 0; i < nColors; i++, pColor++) {

	/* Make sure original format is CIEXYZ */
	if (!_XcmsCIEXYZ_ValidSpec(pColor)) {
	    return(XcmsFailure);
	}

	/* Convert to CIEuvY */
	div = pColor->spec.CIEXYZ.X + (15.0 * pColor->spec.CIEXYZ.Y) +
		(3.0 * pColor->spec.CIEXYZ.Z);
	if (div == 0.0) {
	    /* Use white point since div == 0.0 */
	    if (puvY_WhitePt == NULL ) {
		return(XcmsFailure);
	    }
	    /*
	     * Make sure white point is in CIEuvY form
	     */
	    if (puvY_WhitePt->format != XcmsCIEuvYFormat) {
		/* Make copy of the white point because we're going to modify it */
		memcpy((char *)&whitePt, (char *)puvY_WhitePt, sizeof(XcmsColor));
		if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1,
			XcmsCIEuvYFormat)) {
		    return(XcmsFailure);
		}
		puvY_WhitePt = &whitePt;
	    }
	    /* Make sure it is a white point, i.e., Y == 1.0 */
	    if (puvY_WhitePt->spec.CIEuvY.Y != 1.0) {
		return(XcmsFailure);
	    }
	    uvY_return.Y = pColor->spec.CIEXYZ.Y;
	    uvY_return.u_prime = puvY_WhitePt->spec.CIEuvY.u_prime;
	    uvY_return.v_prime = puvY_WhitePt->spec.CIEuvY.v_prime;
	} else {
	    uvY_return.u_prime = 4.0 * pColor->spec.CIEXYZ.X / div;
	    uvY_return.v_prime = 9.0 * pColor->spec.CIEXYZ.Y / div;
	    uvY_return.Y = pColor->spec.CIEXYZ.Y;
	}

	memcpy((char *)&pColor->spec.CIEuvY, (char *)&uvY_return, sizeof(XcmsCIEuvY));
	/* Identify that format is now CIEuvY */
	pColor->format = XcmsCIEuvYFormat;
    }

    return(XcmsSuccess);
}