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[unix-history] / usr / src / contrib / X11R5-lib / lib / X / CIELuvGcL.c

/* $XConsortium: CIELuvGcL.c,v 1.2 91/07/25 01:07:33 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.  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 this copyright, permission, and disclaimer notice is reproduced in
* all copies of this software and in supporting documentation.  TekColor
* is a trademark of Tektronix, Inc.
* 
* 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
*              CIELuvGcL.c
*
*      DESCRIPTION
*              Source for XcmsCIELuvClipL() gamut compression routine.
*
*/

#include "Xlibint.h"
#include "Xcmsint.h"

/*
*      EXTERNS
*/
extern Status _XcmsCIELuvQueryMaxLCRGB();

\f
/************************************************************************
*                                                                      *
*                       PUBLIC ROUTINES                                *
*                                                                      *
************************************************************************/

/*
*      NAME
*              XcmsCIELuvClipL - Return the closest L*
*
*      SYNOPSIS
*/
/* ARGSUSED */
Status
XcmsCIELuvClipL (ccc, pColors_in_out, nColors, i, pCompressed)
   XcmsCCC ccc;
   XcmsColor *pColors_in_out;
   unsigned int nColors;
   unsigned int i;
   Bool *pCompressed;
/*
*      DESCRIPTION
*              Return the closest L* for a specific hue and chroma.
*              This routine takes any color as input and outputs 
*              a CIE XYZ color.
*
*              Since this routine works with the L* within
*              pColor_in_out intermediate results may be returned
*              even though it may be invalid.
*
*      RETURNS
*              XcmsFailure - Failure
*              XcmsSuccess - Succeeded
*
*/
{
   XcmsCCCRec  myCCC;
   XcmsColor   *pColor;
   XcmsColor   Luv_max;
   XcmsFloat   hue, chroma, maxChroma;
   Status retval;

   /* Use my own CCC */
   bcopy ((char *)ccc, (char *)&myCCC, sizeof(XcmsCCCRec));
   myCCC.clientWhitePt.format = XcmsUndefinedFormat;/* Inherit Screen WP */
   myCCC.gamutCompProc = (XcmsCompressionProc)NULL;/* no gamut compression */

   /*
    * 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) {
       /*
        * GRAY !
        */
       return(XcmsFailure);
   } else {
       /* Convert from CIEXYZ to CIE L*u*v* format */
       if (_XcmsDIConvertColors(&myCCC, pColor,
               ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIELuvFormat)
               == XcmsFailure) {
           return(XcmsFailure);
       }

       hue = XCMS_CIELUV_PMETRIC_HUE(pColor->spec.CIELuv.u_star,
                                     pColor->spec.CIELuv.v_star);
       chroma = XCMS_CIELUV_PMETRIC_CHROMA(pColor->spec.CIELuv.u_star,
                                           pColor->spec.CIELuv.v_star);
       /* Step 1: compute the maximum L* and chroma for this hue. */
       /*         This copy may be overkill but it preserves the pixel etc. */
       bcopy((char *)pColor, (char *)&Luv_max, sizeof(XcmsColor));
       if (_XcmsCIELuvQueryMaxLCRGB (&myCCC, hue, &Luv_max,
               (XcmsRGBi *)NULL) == XcmsFailure) {
           return (XcmsFailure);
       }
       maxChroma = XCMS_CIELUV_PMETRIC_CHROMA(Luv_max.spec.CIELuv.u_star,
                                              Luv_max.spec.CIELuv.v_star);

       /* Now check and return the appropriate L* */
       if (chroma == maxChroma) {
           /* When the chroma input is equal to the maximum chroma */
           /* merely return the L* for that chroma. */
           bcopy((char *)&Luv_max, (char *)pColor, sizeof(XcmsColor));
           retval = _XcmsDIConvertColors(&myCCC, pColor,
                   ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIEXYZFormat);
       } else if (chroma > maxChroma) {
           /* When the chroma input is greater than the maximum chroma */
           /* merely return the L* and chroma for the given hue. */
           bcopy((char *)&Luv_max, (char *)pColor, sizeof(XcmsColor));
           return (XcmsFailure);
       } else if (pColor->spec.CIELuv.L_star < Luv_max.spec.CIELuv.L_star) {
           /* Find the minimum lightness for the given chroma. */  
           if (pColor->format != XcmsCIELuvFormat) {
               if (_XcmsDIConvertColors(ccc, pColor,
                       ScreenWhitePointOfCCC(ccc), 1, XcmsCIELuvFormat)
                       == XcmsFailure) {
                   return(XcmsFailure);
               }
           }
           if (XcmsCIELuvQueryMinL(&myCCC, degrees(hue), chroma, pColor)
               == XcmsFailure) {
                   return (XcmsFailure);
           }
           retval = _XcmsDIConvertColors(&myCCC, pColor,
                          ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIEXYZFormat);
       } else {
           /* Find the maximum lightness for the given chroma. */
           if (pColor->format != XcmsCIELuvFormat) {
               if (_XcmsDIConvertColors(ccc, pColor,
                             ScreenWhitePointOfCCC(ccc), 1, XcmsCIELuvFormat)
                       == XcmsFailure) {
                   return(XcmsFailure);
               }
           }
           if (XcmsCIELuvQueryMaxL(&myCCC, degrees(hue), chroma, pColor)
               == XcmsFailure) {
                   return (XcmsFailure);
           }
           retval = _XcmsDIConvertColors(&myCCC, pColor,
                          ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIEXYZFormat);
       }
       if (retval != XcmsFailure && pCompressed != NULL) {
           *(pCompressed + i) = True;
       }
       return(retval);
   }
}