4.4BSD/usr/src/contrib/X11R5-lib/lib/X/TekHVCMxVC.c
/* $XConsortium: TekHVCMxVC.c,v 1.6 91/07/25 01:08:17 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
* TekHVCMxVC.c
*
* DESCRIPTION
* Source for the XcmsTekHVCQueryMaxVC() gamut boundary
* querying routine.
*
*/
#include "Xlibint.h"
#include "Xcmsint.h"
/*
* DEFINES
*/
#define MIN(x,y) ((x) > (y) ? (y) : (x))
#define MIN3(x,y,z) (MIN((x), MIN((y), (z))))
#define MAX(x,y) ((x) > (y) ? (x) : (y))
#define MAX3(x,y,z) (MAX((x), MAX((y), (z))))
#define START_V 40.0
#define START_C 120.0
/*
* EXTERNS
*/
extern Status _XcmsTekHVC_CheckModify();
extern Status _XcmsConvertColorsWithWhitePt();
extern XcmsColorSpace XcmsTekHVCColorSpace;
/*
* FORWARD DECLARATIONS
*/
Status _XcmsTekHVCQueryMaxVCRGB();
/************************************************************************
* *
* API PRIVATE ROUTINES *
* *
************************************************************************/
/*
* NAME
* _XcmsTekHVCQueryMaxVCRGB - Compute maximum value/chroma.
*
* SYNOPSIS
*/
Status
_XcmsTekHVCQueryMaxVCRGB(ccc, hue, pColor_return, pRGB_return)
XcmsCCC ccc;
XcmsFloat hue;
XcmsColor *pColor_return;
XcmsRGBi *pRGB_return;
/*
* DESCRIPTION
* Return the maximum chroma for a specified hue, and the
* corresponding value. This is computed by a binary search of
* all possible chromas. An assumption is made that there are
* no local maxima. Use the unrounded Max Chroma because
* the difference check can be small.
*
* NOTE: No local CCC is used because this is a private
* routine and all routines that call it are expected
* to behave properly, i.e. send a local CCC with
* no white adjust function and no gamut compression
* function.
*
* This routine only accepts hue as input and outputs
* HVC's and RGBi's.
*
* RETURNS
* XcmsFailure - Failure
* XCMS_SUCCUSS - Succeeded
*
*/
{
XcmsFloat nSmall, nLarge;
XcmsColor tmp;
tmp.format = XcmsTekHVCFormat;
tmp.spec.TekHVC.H = hue;
/* Use some unreachable color on the given hue */
tmp.spec.TekHVC.V = START_V;
tmp.spec.TekHVC.C = START_C;
/*
* Convert from HVC to RGB
*
* Note that the CIEXYZ to RGBi conversion routine must stuff the
* out of bounds RGBi values in tmp when the ccc->gamutCompProc
* is NULL.
*/
if ((_XcmsConvertColorsWithWhitePt(ccc, &tmp,
&ccc->pPerScrnInfo->screenWhitePt, 1, XcmsRGBiFormat, (Bool *) NULL)
== XcmsFailure) && tmp.format != XcmsRGBiFormat) {
return (XcmsFailure);
}
/* Now pick the smallest RGB */
nSmall = MIN3(tmp.spec.RGBi.red,
tmp.spec.RGBi.green,
tmp.spec.RGBi.blue);
/* Make the smallest RGB equal to zero */
tmp.spec.RGBi.red -= nSmall;
tmp.spec.RGBi.green -= nSmall;
tmp.spec.RGBi.blue -= nSmall;
/* Now pick the largest RGB */
nLarge = MAX3(tmp.spec.RGBi.red,
tmp.spec.RGBi.green,
tmp.spec.RGBi.blue);
/* Scale the RGB values based on the largest one */
tmp.spec.RGBi.red /= nLarge;
tmp.spec.RGBi.green /= nLarge;
tmp.spec.RGBi.blue /= nLarge;
tmp.format = XcmsRGBiFormat;
/* If the calling routine wants RGB value give them the ones used. */
if (pRGB_return) {
pRGB_return->red = tmp.spec.RGBi.red;
pRGB_return->green = tmp.spec.RGBi.green;
pRGB_return->blue = tmp.spec.RGBi.blue;
}
/* Convert from RGBi to HVC */
if (_XcmsConvertColorsWithWhitePt(ccc, &tmp,
&ccc->pPerScrnInfo->screenWhitePt, 1, XcmsTekHVCFormat, (Bool *) NULL)
== XcmsFailure) {
return (XcmsFailure);
}
/* make sure to return the input hue */
tmp.spec.TekHVC.H = hue;
bcopy((char *)&tmp, (char *)pColor_return, sizeof(XcmsColor));
return (XcmsSuccess);
}
/************************************************************************
* *
* PUBLIC ROUTINES *
* *
************************************************************************/
/*
* NAME
* XcmsTekHVCQueryMaxVC - Compute maximum value and chroma.
*
* SYNOPSIS
*/
Status
XcmsTekHVCQueryMaxVC (ccc, hue, pColor_return)
XcmsCCC ccc;
XcmsFloat hue;
XcmsColor *pColor_return;
/*
* DESCRIPTION
* Return the maximum chroma for the specified hue, and the
* corresponding value.
*
* ASSUMPTIONS
* This routine assumes that the white point associated with
* the color specification is the Screen White Point. The
* Screen White Point will also be associated with the
* returned color specification.
*
* RETURNS
* XcmsFailure - Failure
* XcmsSuccess - Succeeded
*
*/
{
XcmsCCCRec myCCC;
/*
* Check Arguments
*/
if (ccc == NULL || pColor_return == NULL) {
return(XcmsFailure);
}
/*
* Insure TekHVC installed
*/
if (XcmsAddColorSpace(&XcmsTekHVCColorSpace) == XcmsFailure) {
return(XcmsFailure);
}
/* Use my own CCC */
bcopy ((char *)ccc, (char *)&myCCC, sizeof(XcmsCCCRec));
myCCC.clientWhitePt.format = XcmsUndefinedFormat;
myCCC.gamutCompProc = (XcmsCompressionProc)NULL;
while (hue < 0.0) {
hue += 360.0;
}
while (hue >= 360.0) {
hue -= 360.0;
}
return(_XcmsTekHVCQueryMaxVCRGB (&myCCC, hue, pColor_return,
(XcmsRGBi *)NULL));
}