diff options
Diffstat (limited to 'libX11/src/xcms/Luv.c')
| -rw-r--r-- | libX11/src/xcms/Luv.c | 802 |
1 files changed, 401 insertions, 401 deletions
diff --git a/libX11/src/xcms/Luv.c b/libX11/src/xcms/Luv.c index 82bc2946a..0b1325252 100644 --- a/libX11/src/xcms/Luv.c +++ b/libX11/src/xcms/Luv.c @@ -1,401 +1,401 @@ - -/* - * 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 - * CIELuv.c - * - * DESCRIPTION - * This file contains routines that support the CIE L*u*v* - * color space to include conversions to and from the CIE - * XYZ space. - * - * DOCUMENTATION - * "TekColor Color Management System, System Implementor's Manual" - * and - * Fred W. Billmeyer & Max Saltzman, "Principles of Color - * Technology", John Wily & Sons, Inc, 1981. - */ - -#ifdef HAVE_CONFIG_H -#include <config.h> -#endif -#include <X11/Xos.h> -#include "Xlibint.h" -#include "Xcmsint.h" -#include "Cv.h" - -#include <stdio.h> /* sscanf */ - - -/* - * FORWARD DECLARATIONS - */ - -static int CIELuv_ParseString(register char *spec, XcmsColor *pColor); -static Status XcmsCIELuv_ValidSpec(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 CIELuv to CIEXYZ - */ -static XcmsConversionProc Fl_CIELuv_to_CIEXYZ[] = { - XcmsCIELuvToCIEuvY, - XcmsCIEuvYToCIEXYZ, - NULL -}; - - /* - * NULL terminated list of functions applied to get from CIEXYZ to CIELuv - */ -static XcmsConversionProc Fl_CIEXYZ_to_CIELuv[] = { - XcmsCIEXYZToCIEuvY, - XcmsCIEuvYToCIELuv, - NULL -}; - -/* - * GLOBALS - */ - - /* - * CIE Luv Color Space - */ -XcmsColorSpace XcmsCIELuvColorSpace = - { - _XcmsCIELuv_prefix, /* prefix */ - XcmsCIELuvFormat, /* id */ - CIELuv_ParseString, /* parseString */ - Fl_CIELuv_to_CIEXYZ, /* to_CIEXYZ */ - Fl_CIEXYZ_to_CIELuv, /* from_CIEXYZ */ - 1 - }; - - -/************************************************************************ - * * - * PRIVATE ROUTINES * - * * - ************************************************************************/ - -/* - * NAME - * CIELuv_ParseString - * - * SYNOPSIS - */ -static int -CIELuv_ParseString( - register char *spec, - XcmsColor *pColor) -/* - * DESCRIPTION - * This routines takes a string and attempts to convert - * it into a XcmsColor structure with XcmsCIELuvFormat. - * The assumed CIELuv string syntax is: - * CIELuv:<L>/<u>/<v> - * Where L, u, and v 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, _XcmsCIELuv_prefix, n) != 0) { - return(XcmsFailure); - } - - /* - * Attempt to parse the value portion. - */ - if (sscanf(spec + n + 1, "%lf/%lf/%lf", - &pColor->spec.CIELuv.L_star, - &pColor->spec.CIELuv.u_star, - &pColor->spec.CIELuv.v_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.CIELuv.L_star, - &pColor->spec.CIELuv.u_star, - &pColor->spec.CIELuv.v_star) != 3) { - free(s); - return(XcmsFailure); - } - free(s); - } else - return(XcmsFailure); - } - pColor->format = XcmsCIELuvFormat; - pColor->pixel = 0; - return(XcmsCIELuv_ValidSpec(pColor)); -} - - -/************************************************************************ - * * - * PUBLIC ROUTINES * - * * - ************************************************************************/ - -/* - * NAME - * XcmsCIELuv_ValidSpec - * - * SYNOPSIS - */ -static Status -XcmsCIELuv_ValidSpec( - XcmsColor *pColor) -/* - * DESCRIPTION - * Checks if color specification valid for CIE L*u*v*. - * - * RETURNS - * XcmsFailure if invalid, - * XcmsSuccess if valid. - * - */ -{ - if (pColor->format != XcmsCIELuvFormat - || - (pColor->spec.CIELuv.L_star < 0.0 - XMY_DBL_EPSILON) - || - (pColor->spec.CIELuv.L_star > 100.0 + XMY_DBL_EPSILON)) { - return(XcmsFailure); - } - return(XcmsSuccess); -} - - -/* - * NAME - * XcmsCIELuvToCIEuvY - convert CIELuv to CIEuvY - * - * SYNOPSIS - */ -Status -XcmsCIELuvToCIEuvY( - XcmsCCC ccc, - XcmsColor *pLuv_WhitePt, - XcmsColor *pColors_in_out, - unsigned int nColors) -/* - * DESCRIPTION - * Converts color specifications in an array of XcmsColor - * structures from CIELuv format to CIEuvY format. - * - * RETURNS - * XcmsFailure if failed, - * XcmsSuccess if succeeded. - * - */ -{ - XcmsColor *pColor = pColors_in_out; - XcmsColor whitePt; - XcmsCIEuvY uvY_return; - XcmsFloat tmpVal; - register int i; - - /* - * Check arguments - */ - if (pLuv_WhitePt == NULL || pColors_in_out == NULL) { - return(XcmsFailure); - } - - /* - * Make sure white point is in CIEuvY form - */ - if (pLuv_WhitePt->format != XcmsCIEuvYFormat) { - /* Make copy of the white point because we're going to modify it */ - memcpy((char *)&whitePt, (char *)pLuv_WhitePt, sizeof(XcmsColor)); - if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, - 1, XcmsCIEuvYFormat)) { - return(XcmsFailure); - } - pLuv_WhitePt = &whitePt; - } - /* Make sure it is a white point, i.e., Y == 1.0 */ - if (pLuv_WhitePt->spec.CIEuvY.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 CIELuv and is valid */ - if (!XcmsCIELuv_ValidSpec(pColor)) { - return(XcmsFailure); - } - - if (pColor->spec.CIELuv.L_star < 7.99953624) { - uvY_return.Y = pColor->spec.CIELuv.L_star / 903.29; - } else { - tmpVal = (pColor->spec.CIELuv.L_star + 16.0) / 116.0; - uvY_return.Y = tmpVal * tmpVal * tmpVal; /* tmpVal ** 3 */ - } - - - - if (pColor->spec.CIELuv.L_star == 0.0) { - uvY_return.u_prime = pLuv_WhitePt->spec.CIEuvY.u_prime; - uvY_return.v_prime = pLuv_WhitePt->spec.CIEuvY.v_prime; - } else { - tmpVal = 13.0 * (pColor->spec.CIELuv.L_star / 100.0); - uvY_return.u_prime = pColor->spec.CIELuv.u_star/tmpVal + - pLuv_WhitePt->spec.CIEuvY.u_prime; - uvY_return.v_prime = pColor->spec.CIELuv.v_star/tmpVal + - pLuv_WhitePt->spec.CIEuvY.v_prime; - } - /* Copy result to pColor */ - memcpy((char *)&pColor->spec, (char *)&uvY_return, sizeof(XcmsCIEuvY)); - - /* Identify that the format is now CIEuvY */ - pColor->format = XcmsCIEuvYFormat; - } - return(XcmsSuccess); -} - - -/* - * NAME - * XcmsCIEuvYToCIELuv - convert CIEuvY to CIELuv - * - * SYNOPSIS - */ -Status -XcmsCIEuvYToCIELuv( - XcmsCCC ccc, - XcmsColor *pLuv_WhitePt, - XcmsColor *pColors_in_out, - unsigned int nColors) -/* - * DESCRIPTION - * Converts color specifications in an array of XcmsColor - * structures from CIEuvY format to CIELab format. - * - * RETURNS - * XcmsFailure if failed, - * XcmsSuccess if succeeded. - * - */ -{ - XcmsColor *pColor = pColors_in_out; - XcmsColor whitePt; - XcmsCIELuv Luv_return; - XcmsFloat tmpVal; - register int i; - - /* - * Check arguments - */ - if (pLuv_WhitePt == NULL || pColors_in_out == NULL) { - return(XcmsFailure); - } - - /* - * Make sure white point is in CIEuvY form - */ - if (pLuv_WhitePt->format != XcmsCIEuvYFormat) { - /* Make copy of the white point because we're going to modify it */ - memcpy((char *)&whitePt, (char *)pLuv_WhitePt, sizeof(XcmsColor)); - if (!_XcmsDIConvertColors(ccc, &whitePt, - (XcmsColor *)NULL, 1, XcmsCIEuvYFormat)) { - return(XcmsFailure); - } - pLuv_WhitePt = &whitePt; - } - /* Make sure it is a white point, i.e., Y == 1.0 */ - if (pLuv_WhitePt->spec.CIEuvY.Y != 1.0) { - return(XcmsFailure); - } - - /* - * Now convert each XcmsColor structure to CIEXYZ form - */ - for (i = 0; i < nColors; i++, pColor++) { - - if (!_XcmsCIEuvY_ValidSpec(pColor)) { - return(XcmsFailure); - } - - /* Now convert the uvY to Luv */ - Luv_return.L_star = - (pColor->spec.CIEuvY.Y < 0.008856) - ? - (pColor->spec.CIEuvY.Y * 903.29) - : - ((XcmsFloat)(XCMS_CUBEROOT(pColor->spec.CIEuvY.Y) * 116.0) - 16.0); - tmpVal = 13.0 * (Luv_return.L_star / 100.0); - Luv_return.u_star = tmpVal * - (pColor->spec.CIEuvY.u_prime - pLuv_WhitePt->spec.CIEuvY.u_prime); - Luv_return.v_star = tmpVal * - (pColor->spec.CIEuvY.v_prime - pLuv_WhitePt->spec.CIEuvY.v_prime); - - /* Copy result to pColor */ - memcpy((char *)&pColor->spec, (char *)&Luv_return, sizeof(XcmsCIELuv)); - - /* Identify that the format is now CIEuvY */ - pColor->format = XcmsCIELuvFormat; - } - 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
+ * CIELuv.c
+ *
+ * DESCRIPTION
+ * This file contains routines that support the CIE L*u*v*
+ * color space to include conversions to and from the CIE
+ * XYZ space.
+ *
+ * DOCUMENTATION
+ * "TekColor Color Management System, System Implementor's Manual"
+ * and
+ * Fred W. Billmeyer & Max Saltzman, "Principles of Color
+ * Technology", John Wily & Sons, Inc, 1981.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <X11/Xos.h>
+#include "Xlibint.h"
+#include "Xcmsint.h"
+#include "Cv.h"
+
+#include <stdio.h> /* sscanf */
+
+
+/*
+ * FORWARD DECLARATIONS
+ */
+
+static int CIELuv_ParseString(register char *spec, XcmsColor *pColor);
+static Status XcmsCIELuv_ValidSpec(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 CIELuv to CIEXYZ
+ */
+static XcmsConversionProc Fl_CIELuv_to_CIEXYZ[] = {
+ XcmsCIELuvToCIEuvY,
+ XcmsCIEuvYToCIEXYZ,
+ NULL
+};
+
+ /*
+ * NULL terminated list of functions applied to get from CIEXYZ to CIELuv
+ */
+static XcmsConversionProc Fl_CIEXYZ_to_CIELuv[] = {
+ XcmsCIEXYZToCIEuvY,
+ XcmsCIEuvYToCIELuv,
+ NULL
+};
+
+/*
+ * GLOBALS
+ */
+
+ /*
+ * CIE Luv Color Space
+ */
+XcmsColorSpace XcmsCIELuvColorSpace =
+ {
+ _XcmsCIELuv_prefix, /* prefix */
+ XcmsCIELuvFormat, /* id */
+ CIELuv_ParseString, /* parseString */
+ Fl_CIELuv_to_CIEXYZ, /* to_CIEXYZ */
+ Fl_CIEXYZ_to_CIELuv, /* from_CIEXYZ */
+ 1
+ };
+
+
+/************************************************************************
+ * *
+ * PRIVATE ROUTINES *
+ * *
+ ************************************************************************/
+
+/*
+ * NAME
+ * CIELuv_ParseString
+ *
+ * SYNOPSIS
+ */
+static int
+CIELuv_ParseString(
+ register char *spec,
+ XcmsColor *pColor)
+/*
+ * DESCRIPTION
+ * This routines takes a string and attempts to convert
+ * it into a XcmsColor structure with XcmsCIELuvFormat.
+ * The assumed CIELuv string syntax is:
+ * CIELuv:<L>/<u>/<v>
+ * Where L, u, and v 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, _XcmsCIELuv_prefix, n) != 0) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Attempt to parse the value portion.
+ */
+ if (sscanf(spec + n + 1, "%lf/%lf/%lf",
+ &pColor->spec.CIELuv.L_star,
+ &pColor->spec.CIELuv.u_star,
+ &pColor->spec.CIELuv.v_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.CIELuv.L_star,
+ &pColor->spec.CIELuv.u_star,
+ &pColor->spec.CIELuv.v_star) != 3) {
+ free(s);
+ return(XcmsFailure);
+ }
+ free(s);
+ } else
+ return(XcmsFailure);
+ }
+ pColor->format = XcmsCIELuvFormat;
+ pColor->pixel = 0;
+ return(XcmsCIELuv_ValidSpec(pColor));
+}
+
+
+/************************************************************************
+ * *
+ * PUBLIC ROUTINES *
+ * *
+ ************************************************************************/
+
+/*
+ * NAME
+ * XcmsCIELuv_ValidSpec
+ *
+ * SYNOPSIS
+ */
+static Status
+XcmsCIELuv_ValidSpec(
+ XcmsColor *pColor)
+/*
+ * DESCRIPTION
+ * Checks if color specification valid for CIE L*u*v*.
+ *
+ * RETURNS
+ * XcmsFailure if invalid,
+ * XcmsSuccess if valid.
+ *
+ */
+{
+ if (pColor->format != XcmsCIELuvFormat
+ ||
+ (pColor->spec.CIELuv.L_star < 0.0 - XMY_DBL_EPSILON)
+ ||
+ (pColor->spec.CIELuv.L_star > 100.0 + XMY_DBL_EPSILON)) {
+ return(XcmsFailure);
+ }
+ return(XcmsSuccess);
+}
+
+
+/*
+ * NAME
+ * XcmsCIELuvToCIEuvY - convert CIELuv to CIEuvY
+ *
+ * SYNOPSIS
+ */
+Status
+XcmsCIELuvToCIEuvY(
+ XcmsCCC ccc,
+ XcmsColor *pLuv_WhitePt,
+ XcmsColor *pColors_in_out,
+ unsigned int nColors)
+/*
+ * DESCRIPTION
+ * Converts color specifications in an array of XcmsColor
+ * structures from CIELuv format to CIEuvY format.
+ *
+ * RETURNS
+ * XcmsFailure if failed,
+ * XcmsSuccess if succeeded.
+ *
+ */
+{
+ XcmsColor *pColor = pColors_in_out;
+ XcmsColor whitePt;
+ XcmsCIEuvY uvY_return;
+ XcmsFloat tmpVal;
+ register int i;
+
+ /*
+ * Check arguments
+ */
+ if (pLuv_WhitePt == NULL || pColors_in_out == NULL) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Make sure white point is in CIEuvY form
+ */
+ if (pLuv_WhitePt->format != XcmsCIEuvYFormat) {
+ /* Make copy of the white point because we're going to modify it */
+ memcpy((char *)&whitePt, (char *)pLuv_WhitePt, sizeof(XcmsColor));
+ if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL,
+ 1, XcmsCIEuvYFormat)) {
+ return(XcmsFailure);
+ }
+ pLuv_WhitePt = &whitePt;
+ }
+ /* Make sure it is a white point, i.e., Y == 1.0 */
+ if (pLuv_WhitePt->spec.CIEuvY.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 CIELuv and is valid */
+ if (!XcmsCIELuv_ValidSpec(pColor)) {
+ return(XcmsFailure);
+ }
+
+ if (pColor->spec.CIELuv.L_star < 7.99953624) {
+ uvY_return.Y = pColor->spec.CIELuv.L_star / 903.29;
+ } else {
+ tmpVal = (pColor->spec.CIELuv.L_star + 16.0) / 116.0;
+ uvY_return.Y = tmpVal * tmpVal * tmpVal; /* tmpVal ** 3 */
+ }
+
+
+
+ if (pColor->spec.CIELuv.L_star == 0.0) {
+ uvY_return.u_prime = pLuv_WhitePt->spec.CIEuvY.u_prime;
+ uvY_return.v_prime = pLuv_WhitePt->spec.CIEuvY.v_prime;
+ } else {
+ tmpVal = 13.0 * (pColor->spec.CIELuv.L_star / 100.0);
+ uvY_return.u_prime = pColor->spec.CIELuv.u_star/tmpVal +
+ pLuv_WhitePt->spec.CIEuvY.u_prime;
+ uvY_return.v_prime = pColor->spec.CIELuv.v_star/tmpVal +
+ pLuv_WhitePt->spec.CIEuvY.v_prime;
+ }
+ /* Copy result to pColor */
+ memcpy((char *)&pColor->spec, (char *)&uvY_return, sizeof(XcmsCIEuvY));
+
+ /* Identify that the format is now CIEuvY */
+ pColor->format = XcmsCIEuvYFormat;
+ }
+ return(XcmsSuccess);
+}
+
+
+/*
+ * NAME
+ * XcmsCIEuvYToCIELuv - convert CIEuvY to CIELuv
+ *
+ * SYNOPSIS
+ */
+Status
+XcmsCIEuvYToCIELuv(
+ XcmsCCC ccc,
+ XcmsColor *pLuv_WhitePt,
+ XcmsColor *pColors_in_out,
+ unsigned int nColors)
+/*
+ * DESCRIPTION
+ * Converts color specifications in an array of XcmsColor
+ * structures from CIEuvY format to CIELab format.
+ *
+ * RETURNS
+ * XcmsFailure if failed,
+ * XcmsSuccess if succeeded.
+ *
+ */
+{
+ XcmsColor *pColor = pColors_in_out;
+ XcmsColor whitePt;
+ XcmsCIELuv Luv_return;
+ XcmsFloat tmpVal;
+ register int i;
+
+ /*
+ * Check arguments
+ */
+ if (pLuv_WhitePt == NULL || pColors_in_out == NULL) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Make sure white point is in CIEuvY form
+ */
+ if (pLuv_WhitePt->format != XcmsCIEuvYFormat) {
+ /* Make copy of the white point because we're going to modify it */
+ memcpy((char *)&whitePt, (char *)pLuv_WhitePt, sizeof(XcmsColor));
+ if (!_XcmsDIConvertColors(ccc, &whitePt,
+ (XcmsColor *)NULL, 1, XcmsCIEuvYFormat)) {
+ return(XcmsFailure);
+ }
+ pLuv_WhitePt = &whitePt;
+ }
+ /* Make sure it is a white point, i.e., Y == 1.0 */
+ if (pLuv_WhitePt->spec.CIEuvY.Y != 1.0) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Now convert each XcmsColor structure to CIEXYZ form
+ */
+ for (i = 0; i < nColors; i++, pColor++) {
+
+ if (!_XcmsCIEuvY_ValidSpec(pColor)) {
+ return(XcmsFailure);
+ }
+
+ /* Now convert the uvY to Luv */
+ Luv_return.L_star =
+ (pColor->spec.CIEuvY.Y < 0.008856)
+ ?
+ (pColor->spec.CIEuvY.Y * 903.29)
+ :
+ ((XcmsFloat)(XCMS_CUBEROOT(pColor->spec.CIEuvY.Y) * 116.0) - 16.0);
+ tmpVal = 13.0 * (Luv_return.L_star / 100.0);
+ Luv_return.u_star = tmpVal *
+ (pColor->spec.CIEuvY.u_prime - pLuv_WhitePt->spec.CIEuvY.u_prime);
+ Luv_return.v_star = tmpVal *
+ (pColor->spec.CIEuvY.v_prime - pLuv_WhitePt->spec.CIEuvY.v_prime);
+
+ /* Copy result to pColor */
+ memcpy((char *)&pColor->spec, (char *)&Luv_return, sizeof(XcmsCIELuv));
+
+ /* Identify that the format is now CIEuvY */
+ pColor->format = XcmsCIELuvFormat;
+ }
+ return(XcmsSuccess);
+}
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