163 lines
5.2 KiB
C
163 lines
5.2 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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* TekHVCMnV.c
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*
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* DESCRIPTION
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* Source for XcmsTekHVCQueryMinV gamut boundary 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 "Cv.h"
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/*
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* DEFINES
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*/
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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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* XcmsTekHVCQueryMinV - Compute minimum value for hue and chroma
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*
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* SYNOPSIS
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*/
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Status
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XcmsTekHVCQueryMinV (
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XcmsCCC ccc,
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XcmsFloat hue,
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XcmsFloat chroma,
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XcmsColor *pColor_return)
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/*
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* DESCRIPTION
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* Return the minimum value for a specific hue, and the
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* corresponding chroma. The input color specification
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* may be in any format, however output is in XcmsTekHVCFormat.
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*
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* Since this routine works with the value within
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* pColor_return intermediate results may be returned
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* even though it may be invalid.
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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 with no modifications
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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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/*
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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 = 100.0;
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tmp.spec.TekHVC.C = chroma;
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tmp.pixel = pColor_return->pixel;
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tmp.format = XcmsTekHVCFormat;
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/* Check for a valid HVC */
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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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/* This copy may be overkill but it preserves the pixel etc. */
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memcpy((char *)&max_vc, (char *)&tmp, sizeof(XcmsColor));
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if (_XcmsTekHVCQueryMaxVCRGB (&myCCC, max_vc.spec.TekHVC.H, &max_vc,
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(XcmsRGBi *)NULL) == XcmsFailure) {
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return(XcmsFailure);
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}
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/* Step 2: find the intersection with the maximum hvc and chroma line. */
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if (tmp.spec.TekHVC.C > max_vc.spec.TekHVC.C + EPS) {
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/* If the chroma is to large then return maximum hvc. */
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tmp.spec.TekHVC.C = max_vc.spec.TekHVC.C;
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tmp.spec.TekHVC.V = max_vc.spec.TekHVC.V;
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} else {
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tmp.spec.TekHVC.V = tmp.spec.TekHVC.C *
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max_vc.spec.TekHVC.V / max_vc.spec.TekHVC.C;
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if (tmp.spec.TekHVC.V > max_vc.spec.TekHVC.V) {
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tmp.spec.TekHVC.V = max_vc.spec.TekHVC.V;
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} else if (tmp.spec.TekHVC.V < 0.0) {
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tmp.spec.TekHVC.V = tmp.spec.TekHVC.C = 0.0;
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}
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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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}
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