diff options
Diffstat (limited to 'libX11/src/xcms/Lab.c')
| -rw-r--r-- | libX11/src/xcms/Lab.c | 862 |
1 files changed, 431 insertions, 431 deletions
diff --git a/libX11/src/xcms/Lab.c b/libX11/src/xcms/Lab.c index 02c8d3b7c..1101754d4 100644 --- a/libX11/src/xcms/Lab.c +++ b/libX11/src/xcms/Lab.c @@ -1,431 +1,431 @@ - -/* - * 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 - * CIELab.c - * - * DESCRIPTION - * This file contains routines that support the CIE L*a*b* - * color space to include conversions to and from the CIE - * XYZ space. These conversions are from Principles of - * Color Technology Second Edition, Fred W. Billmeyer, Jr. - * and Max Saltzman, John Wiley & Sons, Inc., 1981. - * - * Note that the range for L* is 0 to 1. - */ - - -#ifdef HAVE_CONFIG_H -#include <config.h> -#endif -#include <X11/Xos.h> -#include <stdio.h> /* sscanf */ -#include "Xlibint.h" -#include "Xcmsint.h" -#include "Cv.h" - -/* - * 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 -#define DIV16BY116 0.137931 - -/* - * FORWARD DECLARATIONS - */ - -static int CIELab_ParseString(register char *spec, XcmsColor *pColor); -static Status XcmsCIELab_ValidSpec(XcmsColor *pColor); - - -/* - * LOCAL VARIABLES - */ - - - /* - * NULL terminated list of functions applied to get from CIELab to CIEXYZ - */ -static XcmsConversionProc Fl_CIELab_to_CIEXYZ[] = { - XcmsCIELabToCIEXYZ, - NULL -}; - - /* - * NULL terminated list of functions applied to get from CIEXYZ to CIELab - */ -static XcmsConversionProc Fl_CIEXYZ_to_CIELab[] = { - XcmsCIEXYZToCIELab, - NULL -}; - - -/* - * GLOBALS - */ - /* - * CIE Lab Color Space - */ -XcmsColorSpace XcmsCIELabColorSpace = - { - _XcmsCIELab_prefix, /* prefix */ - XcmsCIELabFormat, /* id */ - CIELab_ParseString, /* parseString */ - Fl_CIELab_to_CIEXYZ, /* to_CIEXYZ */ - Fl_CIEXYZ_to_CIELab, /* from_CIEXYZ */ - 1 - }; - - -/************************************************************************ - * * - * PRIVATE ROUTINES * - * * - ************************************************************************/ - -/* - * NAME - * CIELab_ParseString - * - * SYNOPSIS - */ -static int -CIELab_ParseString( - register char *spec, - XcmsColor *pColor) -/* - * DESCRIPTION - * This routines takes a string and attempts to convert - * it into a XcmsColor structure with XcmsCIELabFormat. - * The assumed CIELab string syntax is: - * CIELab:<L>/<a>/<b> - * Where L, a, and b 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, _XcmsCIELab_prefix, n) != 0) { - return(XcmsFailure); - } - - /* - * Attempt to parse the value portion. - */ - if (sscanf(spec + n + 1, "%lf/%lf/%lf", - &pColor->spec.CIELab.L_star, - &pColor->spec.CIELab.a_star, - &pColor->spec.CIELab.b_star) != 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.CIELab.L_star, - &pColor->spec.CIELab.a_star, - &pColor->spec.CIELab.b_star) != 3) { - free(s); - return(XcmsFailure); - } - free(s); - } else - return(XcmsFailure); - } - pColor->format = XcmsCIELabFormat; - pColor->pixel = 0; - - return(XcmsCIELab_ValidSpec(pColor)); -} - - - -/************************************************************************ - * * - * PUBLIC ROUTINES * - * * - ************************************************************************/ - -/* - * NAME - * XcmsCIELab_ValidSpec - * - * SYNOPSIS - */ -static Status -XcmsCIELab_ValidSpec( - XcmsColor *pColor) -/* - * DESCRIPTION - * Checks if color specification valid for CIE L*a*b*. - * - * RETURNS - * XcmsFailure if invalid, - * XcmsSuccess if valid. - * - */ -{ - if (pColor->format != XcmsCIELabFormat - || - (pColor->spec.CIELab.L_star < 0.0 - XMY_DBL_EPSILON) - || - (pColor->spec.CIELab.L_star > 100.0 + XMY_DBL_EPSILON)) { - return(XcmsFailure); - } - return(XcmsSuccess); -} - - -/* - * NAME - * XcmsCIELabToCIEXYZ - convert CIELab to CIEXYZ - * - * SYNOPSIS - */ -Status -XcmsCIELabToCIEXYZ( - XcmsCCC ccc, - XcmsColor *pLab_WhitePt, - XcmsColor *pColors_in_out, - unsigned int nColors) -/* - * DESCRIPTION - * Converts color specifications in an array of XcmsColor - * structures from CIELab format to CIEXYZ format. - * - * WARNING: This routine assumes that Yn = 1.0; - * - * RETURNS - * XcmsFailure if failed, - * XcmsSuccess if succeeded. - * - */ -{ - XcmsCIEXYZ XYZ_return; - XcmsFloat tmpFloat, tmpL; - XcmsColor whitePt; - int i; - XcmsColor *pColor = pColors_in_out; - - /* - * Check arguments - */ - if (pLab_WhitePt == NULL || pColors_in_out == NULL) { - return(XcmsFailure); - } - - /* - * Make sure white point is in CIEXYZ form, if not, convert it. - */ - if (pLab_WhitePt->format != XcmsCIEXYZFormat) { - /* Make a copy of the white point because we're going to modify it */ - memcpy((char *)&whitePt, (char *)pLab_WhitePt, sizeof(XcmsColor)); - if (!_XcmsDIConvertColors(ccc, &whitePt, - (XcmsColor *)NULL, 1, XcmsCIEXYZFormat)) { - return(XcmsFailure); - } - pLab_WhitePt = &whitePt; - } - - /* - * Make sure it is a white point, i.e., Y == 1.0 - */ - if (pLab_WhitePt->spec.CIEXYZ.Y != 1.0) { - return (0); - } - - /* - * Now convert each XcmsColor structure to CIEXYZ form - */ - for (i = 0; i < nColors; i++, pColor++) { - - /* Make sure original format is CIELab */ - if (!XcmsCIELab_ValidSpec(pColor)) { - return(XcmsFailure); - } - - /* Calculate Y: assume that Yn = 1.0 */ - tmpL = (pColor->spec.CIELab.L_star + 16.0) / 116.0; - XYZ_return.Y = tmpL * tmpL * tmpL; - - if (XYZ_return.Y < 0.008856) { - /* Calculate Y: assume that Yn = 1.0 */ - tmpL = pColor->spec.CIELab.L_star / 9.03292; - - /* Calculate X */ - XYZ_return.X = pLab_WhitePt->spec.CIEXYZ.X * - ((pColor->spec.CIELab.a_star / 3893.5) + tmpL); - /* Calculate Y */ - XYZ_return.Y = tmpL; - /* Calculate Z */ - XYZ_return.Z = pLab_WhitePt->spec.CIEXYZ.Z * - (tmpL - (pColor->spec.CIELab.b_star / 1557.4)); - } else { - /* Calculate X */ - tmpFloat = tmpL + (pColor->spec.CIELab.a_star / 5.0); - XYZ_return.X = pLab_WhitePt->spec.CIEXYZ.X * tmpFloat * tmpFloat * tmpFloat; - - /* Calculate Z */ - tmpFloat = tmpL - (pColor->spec.CIELab.b_star / 2.0); - XYZ_return.Z = pLab_WhitePt->spec.CIEXYZ.Z * tmpFloat * tmpFloat * tmpFloat; - } - - memcpy((char *)&pColor->spec.CIEXYZ, (char *)&XYZ_return, - sizeof(XcmsCIEXYZ)); - pColor->format = XcmsCIEXYZFormat; - } - - return (1); -} - - -/* - * NAME - * XcmsCIEXYZToCIELab - convert CIEXYZ to CIELab - * - * SYNOPSIS - */ -Status -XcmsCIEXYZToCIELab( - XcmsCCC ccc, - XcmsColor *pLab_WhitePt, - XcmsColor *pColors_in_out, - unsigned int nColors) -/* - * DESCRIPTION - * Converts color specifications in an array of XcmsColor - * structures from CIEXYZ format to CIELab format. - * - * WARNING: This routine assumes that Yn = 1.0; - * - * RETURNS - * XcmsFailure if failed, - * XcmsSuccess if succeeded. - * - */ -{ - XcmsCIELab Lab_return; - XcmsFloat fX_Xn, fY_Yn, fZ_Zn; - XcmsColor whitePt; - int i; - XcmsColor *pColor = pColors_in_out; - - /* - * Check arguments - */ - if (pLab_WhitePt == NULL || pColors_in_out == NULL) { - return(XcmsFailure); - } - - /* - * Make sure white point is in CIEXYZ form, if not, convert it. - */ - if (pLab_WhitePt->format != XcmsCIEXYZFormat) { - /* Make a copy of the white point because we're going to modify it */ - memcpy((char *)&whitePt, (char *)pLab_WhitePt, sizeof(XcmsColor)); - if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, - 1, XcmsCIEXYZFormat)) { - return(XcmsFailure); - } - pLab_WhitePt = &whitePt; - } - - /* - * Make sure it is a white point, i.e., Y == 1.0 - */ - if (pLab_WhitePt->spec.CIEXYZ.Y != 1.0) { - return(XcmsFailure); - } - - /* - * Now convert each XcmsColor structure to CIEXYZ form - */ - for (i = 0; i < nColors; i++, pColor++) { - - /* Make sure original format is CIELab */ - if (!_XcmsCIEXYZ_ValidSpec(pColor)) { - return(XcmsFailure); - } - - /* Calculate L*: assume Yn = 1.0 */ - if (pColor->spec.CIEXYZ.Y < 0.008856) { - fY_Yn = (0.07787 * pColor->spec.CIEXYZ.Y) + DIV16BY116; - /* note fY_Yn used to compute Lab_return.a below */ - Lab_return.L_star = 116.0 * (fY_Yn - DIV16BY116); - } else { - fY_Yn = (XcmsFloat)XCMS_CUBEROOT(pColor->spec.CIEXYZ.Y); - /* note fY_Yn used to compute Lab_return.a_star below */ - Lab_return.L_star = (116.0 * fY_Yn) - 16.0; - } - - /* Calculate f(X/Xn) */ - if ((fX_Xn = pColor->spec.CIEXYZ.X / pLab_WhitePt->spec.CIEXYZ.X) < 0.008856) { - fX_Xn = (0.07787 * fX_Xn) + DIV16BY116; - } else { - fX_Xn = (XcmsFloat) XCMS_CUBEROOT(fX_Xn); - } - - /* Calculate f(Z/Zn) */ - if ((fZ_Zn = pColor->spec.CIEXYZ.Z / pLab_WhitePt->spec.CIEXYZ.Z) < 0.008856) { - fZ_Zn = (0.07787 * fZ_Zn) + DIV16BY116; - } else { - fZ_Zn = (XcmsFloat) XCMS_CUBEROOT(fZ_Zn); - } - - Lab_return.a_star = 5.0 * (fX_Xn - fY_Yn); - Lab_return.b_star = 2.0 * (fY_Yn - fZ_Zn); - - memcpy((char *)&pColor->spec.CIELab, (char *)&Lab_return, - sizeof(XcmsCIELab)); - pColor->format = XcmsCIELabFormat; - } - - return(XcmsSuccess); -} +
+/*
+ * 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
+ * CIELab.c
+ *
+ * DESCRIPTION
+ * This file contains routines that support the CIE L*a*b*
+ * color space to include conversions to and from the CIE
+ * XYZ space. These conversions are from Principles of
+ * Color Technology Second Edition, Fred W. Billmeyer, Jr.
+ * and Max Saltzman, John Wiley & Sons, Inc., 1981.
+ *
+ * Note that the range for L* is 0 to 1.
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <X11/Xos.h>
+#include <stdio.h> /* sscanf */
+#include "Xlibint.h"
+#include "Xcmsint.h"
+#include "Cv.h"
+
+/*
+ * 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
+#define DIV16BY116 0.137931
+
+/*
+ * FORWARD DECLARATIONS
+ */
+
+static int CIELab_ParseString(register char *spec, XcmsColor *pColor);
+static Status XcmsCIELab_ValidSpec(XcmsColor *pColor);
+
+
+/*
+ * LOCAL VARIABLES
+ */
+
+
+ /*
+ * NULL terminated list of functions applied to get from CIELab to CIEXYZ
+ */
+static XcmsConversionProc Fl_CIELab_to_CIEXYZ[] = {
+ XcmsCIELabToCIEXYZ,
+ NULL
+};
+
+ /*
+ * NULL terminated list of functions applied to get from CIEXYZ to CIELab
+ */
+static XcmsConversionProc Fl_CIEXYZ_to_CIELab[] = {
+ XcmsCIEXYZToCIELab,
+ NULL
+};
+
+
+/*
+ * GLOBALS
+ */
+ /*
+ * CIE Lab Color Space
+ */
+XcmsColorSpace XcmsCIELabColorSpace =
+ {
+ _XcmsCIELab_prefix, /* prefix */
+ XcmsCIELabFormat, /* id */
+ CIELab_ParseString, /* parseString */
+ Fl_CIELab_to_CIEXYZ, /* to_CIEXYZ */
+ Fl_CIEXYZ_to_CIELab, /* from_CIEXYZ */
+ 1
+ };
+
+
+/************************************************************************
+ * *
+ * PRIVATE ROUTINES *
+ * *
+ ************************************************************************/
+
+/*
+ * NAME
+ * CIELab_ParseString
+ *
+ * SYNOPSIS
+ */
+static int
+CIELab_ParseString(
+ register char *spec,
+ XcmsColor *pColor)
+/*
+ * DESCRIPTION
+ * This routines takes a string and attempts to convert
+ * it into a XcmsColor structure with XcmsCIELabFormat.
+ * The assumed CIELab string syntax is:
+ * CIELab:<L>/<a>/<b>
+ * Where L, a, and b 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, _XcmsCIELab_prefix, n) != 0) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Attempt to parse the value portion.
+ */
+ if (sscanf(spec + n + 1, "%lf/%lf/%lf",
+ &pColor->spec.CIELab.L_star,
+ &pColor->spec.CIELab.a_star,
+ &pColor->spec.CIELab.b_star) != 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.CIELab.L_star,
+ &pColor->spec.CIELab.a_star,
+ &pColor->spec.CIELab.b_star) != 3) {
+ free(s);
+ return(XcmsFailure);
+ }
+ free(s);
+ } else
+ return(XcmsFailure);
+ }
+ pColor->format = XcmsCIELabFormat;
+ pColor->pixel = 0;
+
+ return(XcmsCIELab_ValidSpec(pColor));
+}
+
+
+
+/************************************************************************
+ * *
+ * PUBLIC ROUTINES *
+ * *
+ ************************************************************************/
+
+/*
+ * NAME
+ * XcmsCIELab_ValidSpec
+ *
+ * SYNOPSIS
+ */
+static Status
+XcmsCIELab_ValidSpec(
+ XcmsColor *pColor)
+/*
+ * DESCRIPTION
+ * Checks if color specification valid for CIE L*a*b*.
+ *
+ * RETURNS
+ * XcmsFailure if invalid,
+ * XcmsSuccess if valid.
+ *
+ */
+{
+ if (pColor->format != XcmsCIELabFormat
+ ||
+ (pColor->spec.CIELab.L_star < 0.0 - XMY_DBL_EPSILON)
+ ||
+ (pColor->spec.CIELab.L_star > 100.0 + XMY_DBL_EPSILON)) {
+ return(XcmsFailure);
+ }
+ return(XcmsSuccess);
+}
+
+
+/*
+ * NAME
+ * XcmsCIELabToCIEXYZ - convert CIELab to CIEXYZ
+ *
+ * SYNOPSIS
+ */
+Status
+XcmsCIELabToCIEXYZ(
+ XcmsCCC ccc,
+ XcmsColor *pLab_WhitePt,
+ XcmsColor *pColors_in_out,
+ unsigned int nColors)
+/*
+ * DESCRIPTION
+ * Converts color specifications in an array of XcmsColor
+ * structures from CIELab format to CIEXYZ format.
+ *
+ * WARNING: This routine assumes that Yn = 1.0;
+ *
+ * RETURNS
+ * XcmsFailure if failed,
+ * XcmsSuccess if succeeded.
+ *
+ */
+{
+ XcmsCIEXYZ XYZ_return;
+ XcmsFloat tmpFloat, tmpL;
+ XcmsColor whitePt;
+ int i;
+ XcmsColor *pColor = pColors_in_out;
+
+ /*
+ * Check arguments
+ */
+ if (pLab_WhitePt == NULL || pColors_in_out == NULL) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Make sure white point is in CIEXYZ form, if not, convert it.
+ */
+ if (pLab_WhitePt->format != XcmsCIEXYZFormat) {
+ /* Make a copy of the white point because we're going to modify it */
+ memcpy((char *)&whitePt, (char *)pLab_WhitePt, sizeof(XcmsColor));
+ if (!_XcmsDIConvertColors(ccc, &whitePt,
+ (XcmsColor *)NULL, 1, XcmsCIEXYZFormat)) {
+ return(XcmsFailure);
+ }
+ pLab_WhitePt = &whitePt;
+ }
+
+ /*
+ * Make sure it is a white point, i.e., Y == 1.0
+ */
+ if (pLab_WhitePt->spec.CIEXYZ.Y != 1.0) {
+ return (0);
+ }
+
+ /*
+ * Now convert each XcmsColor structure to CIEXYZ form
+ */
+ for (i = 0; i < nColors; i++, pColor++) {
+
+ /* Make sure original format is CIELab */
+ if (!XcmsCIELab_ValidSpec(pColor)) {
+ return(XcmsFailure);
+ }
+
+ /* Calculate Y: assume that Yn = 1.0 */
+ tmpL = (pColor->spec.CIELab.L_star + 16.0) / 116.0;
+ XYZ_return.Y = tmpL * tmpL * tmpL;
+
+ if (XYZ_return.Y < 0.008856) {
+ /* Calculate Y: assume that Yn = 1.0 */
+ tmpL = pColor->spec.CIELab.L_star / 9.03292;
+
+ /* Calculate X */
+ XYZ_return.X = pLab_WhitePt->spec.CIEXYZ.X *
+ ((pColor->spec.CIELab.a_star / 3893.5) + tmpL);
+ /* Calculate Y */
+ XYZ_return.Y = tmpL;
+ /* Calculate Z */
+ XYZ_return.Z = pLab_WhitePt->spec.CIEXYZ.Z *
+ (tmpL - (pColor->spec.CIELab.b_star / 1557.4));
+ } else {
+ /* Calculate X */
+ tmpFloat = tmpL + (pColor->spec.CIELab.a_star / 5.0);
+ XYZ_return.X = pLab_WhitePt->spec.CIEXYZ.X * tmpFloat * tmpFloat * tmpFloat;
+
+ /* Calculate Z */
+ tmpFloat = tmpL - (pColor->spec.CIELab.b_star / 2.0);
+ XYZ_return.Z = pLab_WhitePt->spec.CIEXYZ.Z * tmpFloat * tmpFloat * tmpFloat;
+ }
+
+ memcpy((char *)&pColor->spec.CIEXYZ, (char *)&XYZ_return,
+ sizeof(XcmsCIEXYZ));
+ pColor->format = XcmsCIEXYZFormat;
+ }
+
+ return (1);
+}
+
+
+/*
+ * NAME
+ * XcmsCIEXYZToCIELab - convert CIEXYZ to CIELab
+ *
+ * SYNOPSIS
+ */
+Status
+XcmsCIEXYZToCIELab(
+ XcmsCCC ccc,
+ XcmsColor *pLab_WhitePt,
+ XcmsColor *pColors_in_out,
+ unsigned int nColors)
+/*
+ * DESCRIPTION
+ * Converts color specifications in an array of XcmsColor
+ * structures from CIEXYZ format to CIELab format.
+ *
+ * WARNING: This routine assumes that Yn = 1.0;
+ *
+ * RETURNS
+ * XcmsFailure if failed,
+ * XcmsSuccess if succeeded.
+ *
+ */
+{
+ XcmsCIELab Lab_return;
+ XcmsFloat fX_Xn, fY_Yn, fZ_Zn;
+ XcmsColor whitePt;
+ int i;
+ XcmsColor *pColor = pColors_in_out;
+
+ /*
+ * Check arguments
+ */
+ if (pLab_WhitePt == NULL || pColors_in_out == NULL) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Make sure white point is in CIEXYZ form, if not, convert it.
+ */
+ if (pLab_WhitePt->format != XcmsCIEXYZFormat) {
+ /* Make a copy of the white point because we're going to modify it */
+ memcpy((char *)&whitePt, (char *)pLab_WhitePt, sizeof(XcmsColor));
+ if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL,
+ 1, XcmsCIEXYZFormat)) {
+ return(XcmsFailure);
+ }
+ pLab_WhitePt = &whitePt;
+ }
+
+ /*
+ * Make sure it is a white point, i.e., Y == 1.0
+ */
+ if (pLab_WhitePt->spec.CIEXYZ.Y != 1.0) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Now convert each XcmsColor structure to CIEXYZ form
+ */
+ for (i = 0; i < nColors; i++, pColor++) {
+
+ /* Make sure original format is CIELab */
+ if (!_XcmsCIEXYZ_ValidSpec(pColor)) {
+ return(XcmsFailure);
+ }
+
+ /* Calculate L*: assume Yn = 1.0 */
+ if (pColor->spec.CIEXYZ.Y < 0.008856) {
+ fY_Yn = (0.07787 * pColor->spec.CIEXYZ.Y) + DIV16BY116;
+ /* note fY_Yn used to compute Lab_return.a below */
+ Lab_return.L_star = 116.0 * (fY_Yn - DIV16BY116);
+ } else {
+ fY_Yn = (XcmsFloat)XCMS_CUBEROOT(pColor->spec.CIEXYZ.Y);
+ /* note fY_Yn used to compute Lab_return.a_star below */
+ Lab_return.L_star = (116.0 * fY_Yn) - 16.0;
+ }
+
+ /* Calculate f(X/Xn) */
+ if ((fX_Xn = pColor->spec.CIEXYZ.X / pLab_WhitePt->spec.CIEXYZ.X) < 0.008856) {
+ fX_Xn = (0.07787 * fX_Xn) + DIV16BY116;
+ } else {
+ fX_Xn = (XcmsFloat) XCMS_CUBEROOT(fX_Xn);
+ }
+
+ /* Calculate f(Z/Zn) */
+ if ((fZ_Zn = pColor->spec.CIEXYZ.Z / pLab_WhitePt->spec.CIEXYZ.Z) < 0.008856) {
+ fZ_Zn = (0.07787 * fZ_Zn) + DIV16BY116;
+ } else {
+ fZ_Zn = (XcmsFloat) XCMS_CUBEROOT(fZ_Zn);
+ }
+
+ Lab_return.a_star = 5.0 * (fX_Xn - fY_Yn);
+ Lab_return.b_star = 2.0 * (fY_Yn - fZ_Zn);
+
+ memcpy((char *)&pColor->spec.CIELab, (char *)&Lab_return,
+ sizeof(XcmsCIELab));
+ pColor->format = XcmsCIELabFormat;
+ }
+
+ return(XcmsSuccess);
+}
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