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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. TekColor is a
+ * trademark of Tektronix, Inc. The term "TekHVC" designates a particular
+ * color space that is the subject of U.S. Patent No. 4,985,853 (equivalent
+ * foreign patents pending). 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:
+ *
+ * 1. This copyright, permission, and disclaimer notice is reproduced in
+ * all copies of this software and any modification thereof and in
+ * supporting documentation;
+ * 2. Any color-handling application which displays TekHVC color
+ * cooordinates identifies these as TekHVC color coordinates in any
+ * interface that displays these coordinates and in any associated
+ * documentation;
+ * 3. The term "TekHVC" is always used, and is only used, in association
+ * with the mathematical derivations of the TekHVC Color Space,
+ * including those provided in this file and any equivalent pathways and
+ * mathematical derivations, regardless of digital (e.g., floating point
+ * or integer) representation.
+ *
+ * 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
+ * TekHVC.c
+ *
+ * DESCRIPTION
+ * This file contains routines that support the TekHVC
+ * 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 "Xlibint.h"
+#include "Xcmsint.h"
+#include <nx-X11/Xos.h>
+#include <math.h>
+#include "Cv.h"
+
+#include <stdio.h>
+
+/*
+ * DEFINES
+ */
+#define u_BR 0.7127 /* u' Best Red */
+#define v_BR 0.4931 /* v' Best Red */
+#define EPS 0.001
+#define CHROMA_SCALE_FACTOR 7.50725
+#ifndef PI
+# ifdef M_PI
+# define PI M_PI
+# else
+# define PI 3.14159265358979323846264338327950
+# endif
+#endif
+#ifndef degrees
+# define degrees(r) ((XcmsFloat)(r) * 180.0 / PI)
+#endif /* degrees */
+#ifndef radians
+# define radians(d) ((XcmsFloat)(d) * PI / 180.0)
+#endif /* radians */
+
+/*************************************************************************
+ * Note: The DBL_EPSILON for ANSI is 1e-5 so my checks need to take
+ * this into account. If your DBL_EPSILON is different then
+ * adjust this define.
+ *
+ * Also note that EPS is the error factor in the calculations
+ * This may need to be the same as XMY_DBL_EPSILON in
+ * some implementations.
+ **************************************************************************/
+#ifdef DBL_EPSILON
+# define XMY_DBL_EPSILON DBL_EPSILON
+#else
+# define XMY_DBL_EPSILON 0.00001
+#endif
+
+/*
+ * FORWARD DECLARATIONS
+ */
+static int TekHVC_ParseString(register char *spec, XcmsColor *pColor);
+static Status XcmsTekHVC_ValidSpec(XcmsColor *pColor);
+
+/*
+ * LOCAL VARIABLES
+ */
+
+ /*
+ * NULL terminated list of functions applied to get from TekHVC to CIEXYZ
+ */
+static XcmsConversionProc Fl_TekHVC_to_CIEXYZ[] = {
+ XcmsTekHVCToCIEuvY,
+ XcmsCIEuvYToCIEXYZ,
+ NULL
+};
+
+ /*
+ * NULL terminated list of functions applied to get from CIEXYZ to TekHVC
+ */
+static XcmsConversionProc Fl_CIEXYZ_to_TekHVC[] = {
+ XcmsCIEXYZToCIEuvY,
+ XcmsCIEuvYToTekHVC,
+ NULL
+};
+
+/*
+ * GLOBALS
+ */
+
+ /*
+ * TekHVC Color Space
+ */
+XcmsColorSpace XcmsTekHVCColorSpace =
+ {
+ _XcmsTekHVC_prefix, /* prefix */
+ XcmsTekHVCFormat, /* id */
+ TekHVC_ParseString, /* parseString */
+ Fl_TekHVC_to_CIEXYZ, /* to_CIEXYZ */
+ Fl_CIEXYZ_to_TekHVC, /* from_CIEXYZ */
+ 1
+ };
+
+
+
+
+/************************************************************************
+ * *
+ * PRIVATE ROUTINES *
+ * *
+ ************************************************************************/
+
+/*
+ * NAME
+ * TekHVC_ParseString
+ *
+ * SYNOPSIS
+ */
+static int
+TekHVC_ParseString(
+ register char *spec,
+ XcmsColor *pColor)
+/*
+ * DESCRIPTION
+ * This routines takes a string and attempts to convert
+ * it into a XcmsColor structure with XcmsTekHVCFormat.
+ * The assumed TekHVC string syntax is:
+ * TekHVC:<H>/<V>/<C>
+ * Where H, V, and C 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
+ * XcmsFailure if invalid;
+ * XcmsSuccess if valid.
+ */
+{
+ size_t n;
+ char *pchar;
+
+ if ((pchar = strchr(spec, ':')) == NULL) {
+ return(XcmsFailure);
+ }
+ n = (size_t)(pchar - spec);
+
+ /*
+ * Check for proper prefix.
+ */
+ if (strncmp(spec, _XcmsTekHVC_prefix, n) != 0) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Attempt to parse the value portion.
+ */
+ if (sscanf(spec + n + 1, "%lf/%lf/%lf",
+ &pColor->spec.TekHVC.H,
+ &pColor->spec.TekHVC.V,
+ &pColor->spec.TekHVC.C) != 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.TekHVC.H,
+ &pColor->spec.TekHVC.V,
+ &pColor->spec.TekHVC.C) != 3) {
+ free(s);
+ return(XcmsFailure);
+ }
+ free(s);
+ } else
+ return(XcmsFailure);
+ }
+ pColor->format = XcmsTekHVCFormat;
+ pColor->pixel = 0;
+ return(XcmsTekHVC_ValidSpec(pColor));
+}
+
+
+/*
+ * NAME
+ * ThetaOffset -- compute thetaOffset
+ *
+ * SYNOPSIS
+ */
+static int
+ThetaOffset(
+ XcmsColor *pWhitePt,
+ XcmsFloat *pThetaOffset)
+/*
+ * DESCRIPTION
+ * This routine computes the theta offset of a given
+ * white point, i.e. XcmsColor. It is used in both this
+ * conversion and the printer conversions.
+ *
+ * RETURNS
+ * 0 if failed.
+ * 1 if succeeded with no modifications.
+ *
+ * ASSUMPTIONS
+ * Assumes:
+ * pWhitePt != NULL
+ * pWhitePt->format == XcmsCIEuvYFormat
+ *
+ */
+{
+ double div, slopeuv;
+
+ if (pWhitePt == NULL || pWhitePt->format != XcmsCIEuvYFormat) {
+ return(0);
+ }
+
+ if ((div = u_BR - pWhitePt->spec.CIEuvY.u_prime) == 0.0) {
+ return(0);
+ }
+ slopeuv = (v_BR - pWhitePt->spec.CIEuvY.v_prime) / div;
+ *pThetaOffset = degrees(XCMS_ATAN(slopeuv));
+ return(1);
+}
+
+
+
+/************************************************************************
+ * *
+ * PUBLIC ROUTINES *
+ * *
+ ************************************************************************/
+
+/*
+ * NAME
+ * XcmsTekHVC_ValidSpec()
+ *
+ * SYNOPSIS
+ */
+static int
+XcmsTekHVC_ValidSpec(
+ XcmsColor *pColor)
+/*
+ * DESCRIPTION
+ * Checks if values in the color specification are valid.
+ * Also brings hue into the range 0.0 <= Hue < 360.0
+ *
+ * RETURNS
+ * 0 if not valid.
+ * 1 if valid.
+ *
+ */
+{
+ if (pColor->format != XcmsTekHVCFormat) {
+ return(XcmsFailure);
+ }
+ if (pColor->spec.TekHVC.V < (0.0 - XMY_DBL_EPSILON)
+ || pColor->spec.TekHVC.V > (100.0 + XMY_DBL_EPSILON)
+ || (pColor->spec.TekHVC.C < 0.0 - XMY_DBL_EPSILON)) {
+ return(XcmsFailure);
+ }
+
+ if (pColor->spec.TekHVC.V < 0.0) {
+ pColor->spec.TekHVC.V = 0.0 + XMY_DBL_EPSILON;
+ } else if (pColor->spec.TekHVC.V > 100.0) {
+ pColor->spec.TekHVC.V = 100.0 - XMY_DBL_EPSILON;
+ }
+
+ if (pColor->spec.TekHVC.C < 0.0) {
+ pColor->spec.TekHVC.C = 0.0 - XMY_DBL_EPSILON;
+ }
+
+ while (pColor->spec.TekHVC.H < 0.0) {
+ pColor->spec.TekHVC.H += 360.0;
+ }
+ while (pColor->spec.TekHVC.H >= 360.0) {
+ pColor->spec.TekHVC.H -= 360.0;
+ }
+ return(XcmsSuccess);
+}
+
+/*
+ * NAME
+ * XcmsTekHVCToCIEuvY - convert TekHVC to CIEuvY
+ *
+ * SYNOPSIS
+ */
+Status
+XcmsTekHVCToCIEuvY(
+ XcmsCCC ccc,
+ XcmsColor *pHVC_WhitePt,
+ XcmsColor *pColors_in_out,
+ unsigned int nColors)
+/*
+ * DESCRIPTION
+ * Transforms an array of TekHVC color specifications, given
+ * their associated white point, to CIECIEuvY.color
+ * specifications.
+ *
+ * RETURNS
+ * XcmsFailure if failed, XcmsSuccess otherwise.
+ *
+ */
+{
+ XcmsFloat thetaOffset;
+ XcmsColor *pColor = pColors_in_out;
+ XcmsColor whitePt;
+ XcmsCIEuvY uvY_return;
+ XcmsFloat tempHue, u, v;
+ XcmsFloat tmpVal;
+ unsigned int i;
+
+ /*
+ * Check arguments
+ */
+ if (pHVC_WhitePt == NULL || pColors_in_out == NULL) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Make sure white point is in CIEuvY form
+ */
+ if (pHVC_WhitePt->format != XcmsCIEuvYFormat) {
+ /* Make copy of the white point because we're going to modify it */
+ memcpy((char *)&whitePt, (char *)pHVC_WhitePt, sizeof(XcmsColor));
+ if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1,
+ XcmsCIEuvYFormat)) {
+ return(XcmsFailure);
+ }
+ pHVC_WhitePt = &whitePt;
+ }
+ /* Make sure it is a white point, i.e., Y == 1.0 */
+ if (pHVC_WhitePt->spec.CIEuvY.Y != 1.0) {
+ return(XcmsFailure);
+ }
+
+ /* Get the thetaOffset */
+ if (!ThetaOffset(pHVC_WhitePt, &thetaOffset)) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Now convert each XcmsColor structure to CIEXYZ form
+ */
+ for (i = 0; i < nColors; i++, pColor++) {
+
+ /* Make sure original format is TekHVC and is valid */
+ if (!XcmsTekHVC_ValidSpec(pColor)) {
+ return(XcmsFailure);
+ }
+
+ if (pColor->spec.TekHVC.V == 0.0 || pColor->spec.TekHVC.V == 100.0) {
+ if (pColor->spec.TekHVC.V == 100.0) {
+ uvY_return.Y = 1.0;
+ } else { /* pColor->spec.TekHVC.V == 0.0 */
+ uvY_return.Y = 0.0;
+ }
+ uvY_return.u_prime = pHVC_WhitePt->spec.CIEuvY.u_prime;
+ uvY_return.v_prime = pHVC_WhitePt->spec.CIEuvY.v_prime;
+ } else {
+
+ /* Find the hue based on the white point offset */
+ tempHue = pColor->spec.TekHVC.H + thetaOffset;
+
+ while (tempHue < 0.0) {
+ tempHue += 360.0;
+ }
+ while (tempHue >= 360.0) {
+ tempHue -= 360.0;
+ }
+
+ tempHue = radians(tempHue);
+
+ /* Calculate u'v' for the obtained hue */
+ u = (XcmsFloat) ((XCMS_COS(tempHue) * pColor->spec.TekHVC.C) /
+ (pColor->spec.TekHVC.V * (double)CHROMA_SCALE_FACTOR));
+ v = (XcmsFloat) ((XCMS_SIN(tempHue) * pColor->spec.TekHVC.C) /
+ (pColor->spec.TekHVC.V * (double)CHROMA_SCALE_FACTOR));
+
+ /* Based on the white point get the offset from best red */
+ uvY_return.u_prime = u + pHVC_WhitePt->spec.CIEuvY.u_prime;
+ uvY_return.v_prime = v + pHVC_WhitePt->spec.CIEuvY.v_prime;
+
+ /* Calculate the Y value based on the L* = V. */
+ if (pColor->spec.TekHVC.V < 7.99953624) {
+ uvY_return.Y = pColor->spec.TekHVC.V / 903.29;
+ } else {
+ tmpVal = (pColor->spec.TekHVC.V + 16.0) / 116.0;
+ uvY_return.Y = tmpVal * tmpVal * tmpVal; /* tmpVal ** 3 */
+ }
+ }
+
+ /* 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
+ * XcmsCIEuvYToTekHVC - convert CIEuvY to TekHVC
+ *
+ * SYNOPSIS
+ */
+Status
+XcmsCIEuvYToTekHVC(
+ XcmsCCC ccc,
+ XcmsColor *pHVC_WhitePt,
+ XcmsColor *pColors_in_out,
+ unsigned int nColors)
+/*
+ * DESCRIPTION
+ * Transforms an array of CIECIEuvY.color specifications, given
+ * their assiciated white point, to TekHVC specifications.
+ *
+ * RETURNS
+ * XcmsFailure if failed, XcmsSuccess otherwise.
+ *
+ */
+{
+ XcmsFloat theta, L2, u, v, nThetaLow, nThetaHigh;
+ XcmsFloat thetaOffset;
+ XcmsColor *pColor = pColors_in_out;
+ XcmsColor whitePt;
+ XcmsTekHVC HVC_return;
+ unsigned int i;
+
+ /*
+ * Check arguments
+ */
+ if (pHVC_WhitePt == NULL || pColors_in_out == NULL) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Make sure white point is in CIEuvY form
+ */
+ if (pHVC_WhitePt->format != XcmsCIEuvYFormat) {
+ /* Make copy of the white point because we're going to modify it */
+ memcpy((char *)&whitePt, (char *)pHVC_WhitePt, sizeof(XcmsColor));
+ if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL, 1,
+ XcmsCIEuvYFormat)) {
+ return(XcmsFailure);
+ }
+ pHVC_WhitePt = &whitePt;
+ }
+ /* Make sure it is a white point, i.e., Y == 1.0 */
+ if (pHVC_WhitePt->spec.CIEuvY.Y != 1.0) {
+ return(XcmsFailure);
+ }
+ if (!ThetaOffset(pHVC_WhitePt, &thetaOffset)) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Now convert each XcmsColor structure to CIEXYZ form
+ */
+ for (i = 0; i < nColors; i++, pColor++) {
+ if (!_XcmsCIEuvY_ValidSpec(pColor)) {
+ return(XcmsFailure);
+ }
+
+ /* Use the white point offset to determine HVC */
+ u = pColor->spec.CIEuvY.u_prime - pHVC_WhitePt->spec.CIEuvY.u_prime;
+ v = pColor->spec.CIEuvY.v_prime - pHVC_WhitePt->spec.CIEuvY.v_prime;
+
+ /* Calculate the offset */
+ if (u == 0.0) {
+ theta = 0.0;
+ } else {
+ theta = v / u;
+ theta = (XcmsFloat) XCMS_ATAN((double)theta);
+ theta = degrees(theta);
+ }
+
+ nThetaLow = 0.0;
+ nThetaHigh = 360.0;
+ if (u > 0.0 && v > 0.0) {
+ nThetaLow = 0.0;
+ nThetaHigh = 90.0;
+ } else if (u < 0.0 && v > 0.0) {
+ nThetaLow = 90.0;
+ nThetaHigh = 180.0;
+ } else if (u < 0.0 && v < 0.0) {
+ nThetaLow = 180.0;
+ nThetaHigh = 270.0;
+ } else if (u > 0.0 && v < 0.0) {
+ nThetaLow = 270.0;
+ nThetaHigh = 360.0;
+ }
+ while (theta < nThetaLow) {
+ theta += 90.0;
+ }
+ while (theta >= nThetaHigh) {
+ theta -= 90.0;
+ }
+
+ /* calculate the L value from the given Y */
+ L2 = (pColor->spec.CIEuvY.Y < 0.008856)
+ ?
+ (pColor->spec.CIEuvY.Y * 903.29)
+ :
+ ((XcmsFloat)(XCMS_CUBEROOT(pColor->spec.CIEuvY.Y) * 116.0) - 16.0);
+ HVC_return.C = L2 * CHROMA_SCALE_FACTOR * XCMS_SQRT((double) ((u * u) + (v * v)));
+ if (HVC_return.C < 0.0) {
+ theta = 0.0;
+ }
+ HVC_return.V = L2;
+ HVC_return.H = theta - thetaOffset;
+
+ /*
+ * If this is within the error margin let some other routine later
+ * in the chain worry about the slop in the calculations.
+ */
+ while (HVC_return.H < -EPS) {
+ HVC_return.H += 360.0;
+ }
+ while (HVC_return.H >= 360.0 + EPS) {
+ HVC_return.H -= 360.0;
+ }
+
+ /* Copy result to pColor */
+ memcpy((char *)&pColor->spec, (char *)&HVC_return, sizeof(XcmsTekHVC));
+
+ /* Identify that the format is now CIEuvY */
+ pColor->format = XcmsTekHVCFormat;
+ }
+ return(XcmsSuccess);
+}
+
+
+/*
+ * NAME
+ * _XcmsTekHVC_CheckModify
+ *
+ * SYNOPSIS
+ */
+int
+_XcmsTekHVC_CheckModify(
+ XcmsColor *pColor)
+/*
+ * DESCRIPTION
+ * Checks if values in the color specification are valid.
+ * If they are not it modifies the values.
+ * Also brings hue into the range 0.0 <= Hue < 360.0
+ *
+ * RETURNS
+ * 0 if not valid.
+ * 1 if valid.
+ *
+ */
+{
+ int n;
+
+ /* For now only use the TekHVC numbers as inputs */
+ if (pColor->format != XcmsTekHVCFormat) {
+ return(0);
+ }
+
+ if (pColor->spec.TekHVC.V < 0.0) {
+ pColor->spec.TekHVC.V = 0.0 + XMY_DBL_EPSILON;
+ } else if (pColor->spec.TekHVC.V > 100.0) {
+ pColor->spec.TekHVC.V = 100.0 - XMY_DBL_EPSILON;
+ }
+
+ if (pColor->spec.TekHVC.C < 0.0) {
+ pColor->spec.TekHVC.C = 0.0 - XMY_DBL_EPSILON;
+ }
+
+ if (pColor->spec.TekHVC.H < 0.0) {
+ n = -pColor->spec.TekHVC.H / 360.0;
+ pColor->spec.TekHVC.H += (n + 1) * 360.0;
+ if (pColor->spec.TekHVC.H >= 360.0)
+ pColor->spec.TekHVC.H -= 360.0;
+ } else if (pColor->spec.TekHVC.H >= 360.0) {
+ n = pColor->spec.TekHVC.H / 360.0;
+ pColor->spec.TekHVC.H -= n * 360.0;
+ }
+ return(1);
+}
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