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/* $XConsortium: HVCGcVC.c,v 1.11 94/02/07 22:30:20 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. 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
* TekHVCGcVC.c
*
* DESCRIPTION
* Source for XcmsTekHVCClipVC() gamut
* compression function.
*/
#include "Xlibint.h"
#include "Xcmsint.h"
#include <math.h>
/*
* INTERNALS
* Internal defines that need NOT be exported to any package or
* program using this package.
*/
#define MAXBISECTCOUNT 100
/*
* EXTERNS
*/
extern int _XcmsTekHVC_CheckModify();
extern Status _XcmsTekHVCQueryMaxVCRGB();
extern XcmsColorSpace XcmsTekHVCColorSpace;
extern XcmsFunctionSet XcmsLinearRGBFunctionSet;
/************************************************************************
* *
* PUBLIC ROUTINES *
* *
************************************************************************/
/*
* NAME
* XcmsTekHVCClipVC - Return the closest value and chroma
*
* SYNOPSIS
*/
/* ARGSUSED */
Status
XcmsTekHVCClipVC (ccc, pColors_in_out, nColors, i, pCompressed)
XcmsCCC ccc;
XcmsColor *pColors_in_out;
unsigned int nColors;
unsigned int i;
Bool *pCompressed;
/*
* DESCRIPTION
* This routine will find the closest value and chroma
* for a specific hue. The color input is converted to
* HVC format and returned as CIE XYZ format.
*
* Since this routine works with the value within
* pColor_in_out intermediate results may be returned
* even though it may be invalid.
*
* RETURNS
* XcmsFailure - Failure
* XcmsSuccess - Succeeded
*
*/
{
Status retval;
XcmsCCCRec myCCC;
XcmsColor *pColor;
XcmsColor hvc_max;
XcmsRGBi rgb_max;
int nCount, nMaxCount, nI, nILast;
XcmsFloat Chroma, Value, bestChroma, bestValue, nT, saveDist, tmpDist;
/*
* Insure TekHVC installed
*/
if (XcmsAddColorSpace(&XcmsTekHVCColorSpace) == XcmsFailure) {
return(XcmsFailure);
}
/* Use my own CCC */
memcpy ((char *)&myCCC, (char *)ccc, sizeof(XcmsCCCRec));
myCCC.clientWhitePt.format = XcmsUndefinedFormat;/* inherit screen white pt */
myCCC.gamutCompProc = (XcmsCompressionProc)NULL;/* no gamut compression func */
/*
* Color specification passed as input can be assumed to:
* 1. Be in XcmsCIEXYZFormat
* 2. Already be white point adjusted for the Screen White Point.
* This means that the white point now associated with this
* color spec is the Screen White Point (even if the
* ccc->clientWhitePt differs).
*/
pColor = pColors_in_out + i;
if (ccc->visual->class < StaticColor &&
FunctionSetOfCCC(ccc) != (XPointer) &XcmsLinearRGBFunctionSet) {
/*
* GRAY !
*/
_XcmsDIConvertColors(ccc, pColor, &ccc->pPerScrnInfo->screenWhitePt,
1, XcmsTekHVCFormat);
pColor->spec.TekHVC.H = pColor->spec.TekHVC.C = 0.0;
_XcmsDIConvertColors(ccc, pColor, &ccc->pPerScrnInfo->screenWhitePt,
1, XcmsCIEXYZFormat);
if (pCompressed) {
*(pCompressed + i) = True;
}
return(XcmsSuccess);
} else {
/* Convert from CIEXYZ to TekHVC format */
if (_XcmsDIConvertColors(&myCCC, pColor,
&myCCC.pPerScrnInfo->screenWhitePt, 1, XcmsTekHVCFormat)
== XcmsFailure) {
return(XcmsFailure);
}
if (!_XcmsTekHVC_CheckModify(pColor)) {
return (XcmsFailure);
}
/* Step 1: compute the maximum value and chroma for this hue. */
/* This copy may be overkill but it preserves the pixel etc. */
memcpy((char *)&hvc_max, (char *)pColor, sizeof(XcmsColor));
if (_XcmsTekHVCQueryMaxVCRGB (&myCCC, hvc_max.spec.TekHVC.H, &hvc_max,
&rgb_max) == XcmsFailure) {
return (XcmsFailure);
}
/* Now check and return the appropriate value */
if (pColor->spec.TekHVC.V == hvc_max.spec.TekHVC.V) {
/* When the value input is equal to the maximum value */
/* merely return the chroma for that value. */
pColor->spec.TekHVC.C = hvc_max.spec.TekHVC.C;
retval = _XcmsDIConvertColors(&myCCC, pColor,
&myCCC.pPerScrnInfo->screenWhitePt, 1, XcmsCIEXYZFormat);
}
if (pColor->spec.TekHVC.V < hvc_max.spec.TekHVC.V) {
/* return the intersection of the perpindicular line through */
/* the value and chroma given and the line from 0,0 and hvc_max. */
Chroma = pColor->spec.TekHVC.C;
Value = pColor->spec.TekHVC.V;
pColor->spec.TekHVC.C =
(Value + (hvc_max.spec.TekHVC.C / hvc_max.spec.TekHVC.V * Chroma)) /
((hvc_max.spec.TekHVC.V / hvc_max.spec.TekHVC.C) +
(hvc_max.spec.TekHVC.C / hvc_max.spec.TekHVC.V));
if (pColor->spec.TekHVC.C >= hvc_max.spec.TekHVC.C) {
pColor->spec.TekHVC.C = hvc_max.spec.TekHVC.C;
pColor->spec.TekHVC.V = hvc_max.spec.TekHVC.V;
} else {
pColor->spec.TekHVC.V = pColor->spec.TekHVC.C *
hvc_max.spec.TekHVC.V / hvc_max.spec.TekHVC.C;
}
retval = _XcmsDIConvertColors(&myCCC, pColor,
&myCCC.pPerScrnInfo->screenWhitePt, 1, XcmsCIEXYZFormat);
if (retval != XcmsFailure && pCompressed != NULL) {
*(pCompressed + i) = True;
}
return (retval);
}
/* return the closest point on the upper part of the hue leaf. */
/* must do a bisection here to compute the delta e. */
nMaxCount = MAXBISECTCOUNT;
nI = nMaxCount / 2;
bestValue = Value = pColor->spec.TekHVC.V;
bestChroma = Chroma = pColor->spec.TekHVC.C;
saveDist = (XcmsFloat) XCMS_SQRT ((double) (((Chroma - hvc_max.spec.TekHVC.C) *
(Chroma - hvc_max.spec.TekHVC.C)) +
((Value - hvc_max.spec.TekHVC.V) *
(Value - hvc_max.spec.TekHVC.V))));
for (nCount = 0; nCount < nMaxCount; nCount++) {
nT = (XcmsFloat) nI / (XcmsFloat) nMaxCount;
pColor->spec.RGBi.red = rgb_max.red * (1.0 - nT) + nT;
pColor->spec.RGBi.green = rgb_max.green * (1.0 - nT) + nT;
pColor->spec.RGBi.blue = rgb_max.blue * (1.0 - nT) + nT;
pColor->format = XcmsRGBiFormat;
/* Convert from RGBi to HVC */
if (_XcmsConvertColorsWithWhitePt(&myCCC, pColor,
&myCCC.pPerScrnInfo->screenWhitePt, 1, XcmsTekHVCFormat,
(Bool *) NULL)
== XcmsFailure) {
return (XcmsFailure);
}
if (!_XcmsTekHVC_CheckModify(pColor)) {
return (XcmsFailure);
}
tmpDist = (XcmsFloat) XCMS_SQRT ((double)
(((Chroma - pColor->spec.TekHVC.C) *
(Chroma - pColor->spec.TekHVC.C)) +
((Value - pColor->spec.TekHVC.V) *
(Value - pColor->spec.TekHVC.V))));
nILast = nI;
if (tmpDist > saveDist) {
nI /= 2;
} else {
nI = (nMaxCount + nI) / 2;
saveDist = tmpDist;
bestValue = pColor->spec.TekHVC.V;
bestChroma = pColor->spec.TekHVC.C;
}
if (nI == nILast || nI == 0) {
break;
}
}
if (bestChroma >= hvc_max.spec.TekHVC.C) {
pColor->spec.TekHVC.C = hvc_max.spec.TekHVC.C;
pColor->spec.TekHVC.V = hvc_max.spec.TekHVC.V;
} else {
pColor->spec.TekHVC.C = bestChroma;
pColor->spec.TekHVC.V = bestValue;
}
if (!_XcmsTekHVC_CheckModify(pColor)) {
return (XcmsFailure);
}
retval = _XcmsDIConvertColors(&myCCC, pColor,
&myCCC.pPerScrnInfo->screenWhitePt, 1, XcmsCIEXYZFormat);
if (retval != XcmsFailure && pCompressed != NULL) {
*(pCompressed + i) = True;
}
return(retval);
}
}
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