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+/* $XConsortium: xyY.c,v 1.10 93/09/07 21:33:40 rws Exp $ */
+
+/*
+ * 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
+ * CIExyY.c
+ *
+ * DESCRIPTION
+ * This file contains routines that support the CIE xyY
+ * color space to include conversions to and from the CIE
+ * XYZ space.
+ *
+ * DOCUMENTATION
+ * "TekColor Color Management System, System Implementor's Manual"
+ */
+/* $XFree86: xc/lib/X11/xyY.c,v 1.2 1999/05/09 10:50:43 dawes Exp $ */
+
+#include <stdio.h>
+#include <X11/Xos.h>
+#include "Xlibint.h"
+#include "Xcmsint.h"
+
+/*
+ * DEFINES
+ */
+#define EPS 0.00001 /* some extremely small number */
+#ifdef DBL_EPSILON
+# define XMY_DBL_EPSILON DBL_EPSILON
+#else
+# define XMY_DBL_EPSILON 0.00001
+#endif
+
+/*
+ * EXTERNS
+ */
+
+extern char _XcmsCIExyY_prefix[];
+
+/* CvCols.c */
+extern Status _XcmsDIConvertColors();
+
+/* XYZ.c */
+extern Status _XcmsCIEXYZ_ValidSpec();
+
+/*
+ * FORWARD DECLARATIONS
+ */
+
+static int CIExyY_ParseString();
+static Status XcmsCIExyY_ValidSpec();
+
+
+/*
+ * LOCAL VARIABLES
+ */
+
+ /*
+ * NULL terminated list of functions applied to get from CIExyY to CIEXYZ
+ */
+static XcmsConversionProc Fl_CIExyY_to_CIEXYZ[] = {
+ XcmsCIExyYToCIEXYZ,
+ NULL
+};
+
+ /*
+ * NULL terminated list of functions applied to get from CIEXYZ to CIExyY
+ */
+static XcmsConversionProc Fl_CIEXYZ_to_CIExyY[] = {
+ XcmsCIEXYZToCIExyY,
+ NULL
+};
+
+
+/*
+ * GLOBALS
+ */
+
+ /*
+ * CIE xyY Color Space
+ */
+XcmsColorSpace XcmsCIExyYColorSpace =
+ {
+ _XcmsCIExyY_prefix, /* prefix */
+ XcmsCIExyYFormat, /* id */
+ CIExyY_ParseString, /* parseString */
+ Fl_CIExyY_to_CIEXYZ, /* to_CIEXYZ */
+ Fl_CIEXYZ_to_CIExyY, /* from_CIEXYZ */
+ 1
+ };
+
+
+
+/************************************************************************
+ * *
+ * PRIVATE ROUTINES *
+ * *
+ ************************************************************************/
+
+/*
+ * NAME
+ * CIExyY_ParseString
+ *
+ * SYNOPSIS
+ */
+static int
+CIExyY_ParseString(spec, pColor)
+ register char *spec;
+ XcmsColor *pColor;
+/*
+ * DESCRIPTION
+ * This routines takes a string and attempts to convert
+ * it into a XcmsColor structure with XcmsCIExyYFormat.
+ * The assumed CIExyY string syntax is:
+ * CIExyY:<x>/<y>/<Y>
+ * Where x, y, 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, _XcmsCIExyY_prefix, n) != 0) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Attempt to parse the value portion.
+ */
+ if (sscanf(spec + n + 1, "%lf/%lf/%lf",
+ &pColor->spec.CIExyY.x,
+ &pColor->spec.CIExyY.y,
+ &pColor->spec.CIExyY.Y) != 3) {
+ return(XcmsFailure);
+ }
+ pColor->format = XcmsCIExyYFormat;
+ pColor->pixel = 0;
+ return(XcmsCIExyY_ValidSpec(pColor));
+}
+
+
+
+/************************************************************************
+ * *
+ * PUBLIC ROUTINES *
+ * *
+ ************************************************************************/
+
+/*
+ * NAME
+ * CIExyY_ValidSpec()
+ *
+ * SYNOPSIS
+ */
+static Status
+XcmsCIExyY_ValidSpec(pColor)
+ XcmsColor *pColor;
+/*
+ * DESCRIPTION
+ * Checks a valid CIExyY color specification.
+ *
+ * RETURNS
+ * XcmsFailure if invalid.
+ * XcmsSuccess if valid.
+ *
+ */
+{
+ if (pColor->format != XcmsCIExyYFormat
+ ||
+ (pColor->spec.CIExyY.x < 0.0 - XMY_DBL_EPSILON)
+ ||
+ (pColor->spec.CIExyY.x > 1.0 + XMY_DBL_EPSILON)
+ ||
+ (pColor->spec.CIExyY.y < 0.0 - XMY_DBL_EPSILON)
+ ||
+ (pColor->spec.CIExyY.y > 1.0 + XMY_DBL_EPSILON)
+ ||
+ (pColor->spec.CIExyY.Y < 0.0 - XMY_DBL_EPSILON)
+ ||
+ (pColor->spec.CIExyY.Y > 1.0 + XMY_DBL_EPSILON)) {
+ return(XcmsFailure);
+ }
+ return(XcmsSuccess);
+}
+
+
+/*
+ * NAME
+ * XcmsCIExyYToCIEXYZ - convert CIExyY to CIEXYZ
+ *
+ * SYNOPSIS
+ */
+Status
+XcmsCIExyYToCIEXYZ(ccc, pxyY_WhitePt, pColors_in_out, nColors)
+ XcmsCCC ccc;
+ XcmsColor *pxyY_WhitePt;
+ XcmsColor *pColors_in_out;
+ unsigned int nColors;
+/*
+ * DESCRIPTION
+ * Converts color specifications in an array of XcmsColor
+ * structures from CIExyY format to CIEXYZ format.
+ *
+ * RETURNS
+ * XcmsFailure if failed,
+ * XcmsSuccess if succeeded.
+ */
+{
+ XcmsColor *pColor = pColors_in_out;
+ XcmsColor whitePt;
+ XcmsCIEXYZ XYZ_return;
+ XcmsFloat div; /* temporary storage in case divisor is zero */
+ XcmsFloat u, v, x, y, z; /* temporary storage */
+ register int i;
+
+ /*
+ * Check arguments
+ */
+ if (pxyY_WhitePt == NULL || 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 CIExyY and valid */
+ if (!XcmsCIExyY_ValidSpec(pColor)) {
+ return(XcmsFailure);
+ }
+
+ if ((div = (-2 * pColor->spec.CIExyY.x) + (12 * pColor->spec.CIExyY.y) + 3) == 0.0) {
+ /* Note that the divisor is zero */
+ /* This return is abitrary. */
+ XYZ_return.X = 0;
+ XYZ_return.Y = 0;
+ XYZ_return.Z = 0;
+ } else {
+ /*
+ * Make sure white point is in CIEXYZ form
+ */
+ if (pxyY_WhitePt->format != XcmsCIEXYZFormat) {
+ /* Make copy of the white point because we're going to modify it */
+ memcpy((char *)&whitePt, (char *)pxyY_WhitePt, sizeof(XcmsColor));
+ if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1,
+ XcmsCIEXYZFormat)) {
+ return(XcmsFailure);
+ }
+ pxyY_WhitePt = &whitePt;
+ }
+
+ /* Make sure it is a white point, i.e., Y == 1.0 */
+ if (pxyY_WhitePt->spec.CIEXYZ.Y != 1.0) {
+ return(XcmsFailure);
+ }
+
+ /* Convert from xyY to uvY to XYZ */
+ u = (4 * pColor->spec.CIExyY.x) / div;
+ v = (9 * pColor->spec.CIExyY.y) / div;
+ div = (6.0 * u) - (16.0 * v) + 12.0;
+ if (div == 0.0) {
+ /* Note that the divisor is zero */
+ /* This return is abitrary. */
+ if ((div = (6.0 * whitePt.spec.CIEuvY.u_prime) -
+ (16.0 * whitePt.spec.CIEuvY.v_prime) + 12.0) == 0.0) {
+ div = EPS;
+ }
+ x = 9.0 * whitePt.spec.CIEuvY.u_prime / div;
+ y = 4.0 * whitePt.spec.CIEuvY.u_prime / div;
+ } else {
+ /* convert u, v to small xyz */
+ x = 9.0 * u / div;
+ y = 4.0 * v / div;
+ }
+ z = 1.0 - x - y;
+ if (y == 0.0) y = EPS; /* Have to worry about divide by 0 */
+ XYZ_return.Y = pColor->spec.CIExyY.Y;
+ XYZ_return.X = x * XYZ_return.Y / y;
+ XYZ_return.Z = z * XYZ_return.Y / y;
+ }
+
+ /* Copy result to pColor */
+ memcpy ((char *)&pColor->spec, (char *)&XYZ_return, sizeof(XcmsCIEXYZ));
+
+ /* Identify that the format is now CIEXYZ */
+ pColor->format = XcmsCIEXYZFormat;
+ }
+ return(XcmsSuccess);
+}
+
+
+/*
+ * NAME
+ * XcmsCIEXYZToCIExyY - convert CIEXYZ to CIExyY
+ *
+ * SYNOPSIS
+ */
+/* ARGSUSED */
+Status
+XcmsCIEXYZToCIExyY(ccc, pxyY_WhitePt, pColors_in_out, nColors)
+ XcmsCCC ccc;
+ XcmsColor *pxyY_WhitePt;
+ XcmsColor *pColors_in_out;
+ unsigned int nColors;
+/*
+ * DESCRIPTION
+ * Converts color specifications in an array of XcmsColor
+ * structures from CIEXYZ format to CIExyY format.
+ *
+ * RETURNS
+ * XcmsFailure if failed,
+ * XcmsSuccess if succeeded.
+ *
+ */
+{
+ XcmsColor *pColor = pColors_in_out;
+ XcmsCIExyY xyY_return;
+ XcmsFloat div; /* temporary storage in case divisor is zero */
+ register int i;
+
+ /*
+ * Check arguments
+ * pxyY_WhitePt ignored
+ */
+ if (pColors_in_out == NULL) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Now convert each XcmsColor structure to CIEXYZ form
+ */
+ for (i = 0; i < nColors; i++, pColor++) {
+
+ if (!_XcmsCIEXYZ_ValidSpec(pColor)) {
+ return(XcmsFailure);
+ }
+ /* Now convert for XYZ to xyY */
+ if ((div = pColor->spec.CIEXYZ.X + pColor->spec.CIEXYZ.Y + pColor->spec.CIEXYZ.Z) == 0.0) {
+ div = EPS;
+ }
+ xyY_return.x = pColor->spec.CIEXYZ.X / div;
+ xyY_return.y = pColor->spec.CIEXYZ.Y / div;
+ xyY_return.Y = pColor->spec.CIEXYZ.Y;
+
+ /* Copy result to pColor */
+ memcpy ((char *)&pColor->spec, (char *)&xyY_return, sizeof(XcmsCIExyY));
+
+ /* Identify that the format is now CIEXYZ */
+ pColor->format = XcmsCIExyYFormat;
+ }
+ return(XcmsSuccess);
+}
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