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+
+/*
+ * 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 <nx-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.
+ */
+{
+ size_t n;
+ char *pchar;
+
+ if ((pchar = strchr(spec, ':')) == NULL) {
+ return(XcmsFailure);
+ }
+ n = (size_t)(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;
+ unsigned 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;
+ unsigned 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);
+}
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