243 lines
7.6 KiB
C
243 lines
7.6 KiB
C
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/*
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* Code and supporting documentation (c) Copyright 1990 1991 Tektronix, Inc.
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* All Rights Reserved
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*
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* This file is a component of an X Window System-specific implementation
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* of Xcms based on the TekColor Color Management System. TekColor is a
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* trademark of Tektronix, Inc. The term "TekHVC" designates a particular
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* color space that is the subject of U.S. Patent No. 4,985,853 (equivalent
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* foreign patents pending). Permission is hereby granted to use, copy,
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* modify, sell, and otherwise distribute this software and its
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* documentation for any purpose and without fee, provided that:
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*
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* 1. This copyright, permission, and disclaimer notice is reproduced in
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* all copies of this software and any modification thereof and in
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* supporting documentation;
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* 2. Any color-handling application which displays TekHVC color
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* cooordinates identifies these as TekHVC color coordinates in any
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* interface that displays these coordinates and in any associated
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* documentation;
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* 3. The term "TekHVC" is always used, and is only used, in association
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* with the mathematical derivations of the TekHVC Color Space,
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* including those provided in this file and any equivalent pathways and
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* mathematical derivations, regardless of digital (e.g., floating point
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* or integer) representation.
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*
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* Tektronix makes no representation about the suitability of this software
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* for any purpose. It is provided "as is" and with all faults.
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*
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* TEKTRONIX DISCLAIMS ALL WARRANTIES APPLICABLE TO THIS SOFTWARE,
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* INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE. IN NO EVENT SHALL TEKTRONIX BE LIABLE FOR ANY
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* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
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* RESULTING FROM LOSS OF USE, DATA, OR PROFITS, WHETHER IN AN ACTION OF
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* CONTRACT, NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR THE PERFORMANCE OF THIS SOFTWARE.
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*
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* NAME
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* TekHVCMxC.c
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*
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* DESCRIPTION
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* Source for the XcmsTekHVCQueryMaxC() gamut boundary
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* querying routine.
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include "Xlibint.h"
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#include "Xcmsint.h"
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#include <math.h>
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#include "Cv.h"
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/*
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* DEFINES
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*/
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#define MAXBISECTCOUNT 100
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#define EPS 0.001
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/************************************************************************
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* *
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* PUBLIC ROUTINES *
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* *
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************************************************************************/
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/*
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* NAME
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* XcmsTekHVCQueryMaxC - Compute the maximum chroma for a hue and value
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*
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* SYNOPSIS
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*/
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Status
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XcmsTekHVCQueryMaxC(
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XcmsCCC ccc,
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XcmsFloat hue,
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XcmsFloat value,
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XcmsColor *pColor_return)
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/*
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* DESCRIPTION
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* Return the maximum chroma for a specific hue and value.
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* The returned format is in XcmsTekHVCFormat.
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*
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*
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* ASSUMPTIONS
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* This routine assumes that the white point associated with
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* the color specification is the Screen White Point. The
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* Screen White Point will also be associated with the
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* returned color specification.
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*
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* RETURNS
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* XcmsFailure - Failure
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* XcmsSuccess - Succeeded
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*
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*/
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{
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XcmsCCCRec myCCC;
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XcmsColor tmp;
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XcmsColor max_vc;
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XcmsRGBi rgb_saved;
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int nCount, nMaxCount;
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XcmsFloat nValue, savedValue, lastValue, lastChroma, prevValue;
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XcmsFloat maxDist, nT, rFactor;
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XcmsFloat ftmp1, ftmp2;
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/*
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* Check Arguments
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*/
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if (ccc == NULL || pColor_return == NULL) {
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return(XcmsFailure);
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}
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/*
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* Insure TekHVC installed
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*/
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if (XcmsAddColorSpace(&XcmsTekHVCColorSpace) == XcmsFailure) {
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return(XcmsFailure);
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}
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/* Use my own CCC */
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memcpy ((char *)&myCCC, (char *)ccc, sizeof(XcmsCCCRec));
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myCCC.clientWhitePt.format = XcmsUndefinedFormat; /* inherit screen white Pt */
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myCCC.gamutCompProc = (XcmsCompressionProc)NULL;/* no gamut comp func */
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tmp.spec.TekHVC.H = hue;
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tmp.spec.TekHVC.V = value;
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tmp.spec.TekHVC.C = 100.0;
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tmp.pixel = pColor_return->pixel;
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tmp.format = XcmsTekHVCFormat;
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/* check to make sure we have a valid TekHVC number */
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if (!_XcmsTekHVC_CheckModify(&tmp)) {
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return(XcmsFailure);
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}
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/* Step 1: compute the maximum value and chroma for this hue. */
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memcpy((char *)&max_vc, (char *)&tmp, sizeof(XcmsColor));
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if (_XcmsTekHVCQueryMaxVCRGB(&myCCC, hue, &max_vc, &rgb_saved)
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== XcmsFailure) {
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return(XcmsFailure);
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}
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/* Step 2: If the value is less than the value for the maximum */
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/* value, chroma point then the chroma is on the line */
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/* from max_vc to 0,0. */
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if (value <= max_vc.spec.TekHVC.V) {
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tmp.spec.TekHVC.C = value
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* max_vc.spec.TekHVC.C / max_vc.spec.TekHVC.V;
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if (_XcmsTekHVC_CheckModify (&tmp)) {
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memcpy((char *)pColor_return, (char *)&tmp, sizeof(XcmsColor));
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return(XcmsSuccess);
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} else {
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return(XcmsFailure);
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}
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} else {
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/* must do a bisection here to compute the maximum chroma */
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/* save the structure input so that any elements that */
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/* are not touched are recopied later in the routine. */
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nValue = savedValue = value;
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lastChroma = -1.0;
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lastValue = -1.0;
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nMaxCount = MAXBISECTCOUNT;
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maxDist = 100.0 - max_vc.spec.TekHVC.V;
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rFactor = 1.0;
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for (nCount = 0; nCount < nMaxCount; nCount++) {
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prevValue = lastValue;
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lastValue = tmp.spec.TekHVC.V;
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lastChroma = tmp.spec.TekHVC.C;
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nT = (nValue - max_vc.spec.TekHVC.V) / maxDist * rFactor;
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tmp.spec.RGBi.red = rgb_saved.red * (1.0 - nT) + nT;
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tmp.spec.RGBi.green = rgb_saved.green * (1.0 - nT) + nT;
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tmp.spec.RGBi.blue = rgb_saved.blue * (1.0 - nT) + nT;
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tmp.format = XcmsRGBiFormat;
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/* convert from RGB to HVC */
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if (_XcmsConvertColorsWithWhitePt(&myCCC, &tmp,
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&myCCC.pPerScrnInfo->screenWhitePt, 1, XcmsTekHVCFormat,
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(Bool *) NULL) == XcmsFailure) {
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return(XcmsFailure);
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}
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/* Now check the return against what is expected */
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if (tmp.spec.TekHVC.V <= savedValue + EPS &&
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tmp.spec.TekHVC.V >= savedValue - EPS) {
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/* make sure to return the input hue */
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tmp.spec.TekHVC.H = hue;
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if (_XcmsTekHVC_CheckModify (&tmp)) {
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memcpy((char *)pColor_return, (char *)&tmp, sizeof(XcmsColor));
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return(XcmsSuccess);
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} else {
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return(XcmsFailure);
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}
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}
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nValue += savedValue - tmp.spec.TekHVC.V;
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if (nValue < max_vc.spec.TekHVC.V) {
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nValue = max_vc.spec.TekHVC.V;
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rFactor *= 0.5; /* selective relaxation employed */
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} else if (nValue > 100.0) {
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/* make sure to return the input hue */
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tmp.spec.TekHVC.H = hue;
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/* avoid using fabs */
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ftmp1 = lastValue - savedValue;
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if (ftmp1 < 0.0)
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ftmp1 = -ftmp1;
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ftmp2 = tmp.spec.TekHVC.V - savedValue;
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if (ftmp2 < 0.0)
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ftmp2 = -ftmp2;
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if (ftmp1 < ftmp2) {
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tmp.spec.TekHVC.V = lastValue;
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tmp.spec.TekHVC.C = lastChroma;
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}
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if (_XcmsTekHVC_CheckModify (&tmp)) {
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memcpy((char *)pColor_return, (char *)&tmp, sizeof(XcmsColor));
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return(XcmsSuccess);
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} else {
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return(XcmsFailure);
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}
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} else if (tmp.spec.TekHVC.V <= prevValue + EPS &&
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tmp.spec.TekHVC.V >= prevValue - EPS) {
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rFactor *= 0.5; /* selective relaxation employed */
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}
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}
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if (nCount >= nMaxCount) {
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/* avoid using fabs */
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ftmp1 = lastValue - savedValue;
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if (ftmp1 < 0.0)
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ftmp1 = -ftmp1;
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ftmp2 = tmp.spec.TekHVC.V - savedValue;
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if (ftmp2 < 0.0)
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ftmp2 = -ftmp2;
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if (ftmp1 < ftmp2) {
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tmp.spec.TekHVC.V = lastValue;
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tmp.spec.TekHVC.C = lastChroma;
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}
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}
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}
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/* make sure to return the input hue */
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tmp.spec.TekHVC.H = hue;
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memcpy((char *)pColor_return, (char *)&tmp, sizeof(XcmsColor));
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return(XcmsSuccess);
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}
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