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384 lines
9.5 KiB
C
384 lines
9.5 KiB
C
/* $Xorg: Luv.c,v 1.3 2000/08/17 19:44:41 cpqbld Exp $ */
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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. Permission is
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* hereby granted to use, copy, modify, sell, and otherwise distribute this
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* software and its documentation for any purpose and without fee, provided
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* that this copyright, permission, and disclaimer notice is reproduced in
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* all copies of this software and in supporting documentation. TekColor
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* is a trademark of Tektronix, Inc.
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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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*
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* NAME
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* CIELuv.c
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*
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* DESCRIPTION
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* This file contains routines that support the CIE L*u*v*
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* color space to include conversions to and from the CIE
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* XYZ space.
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*
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* DOCUMENTATION
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* "TekColor Color Management System, System Implementor's Manual"
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* and
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* Fred W. Billmeyer & Max Saltzman, "Principles of Color
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* Technology", John Wily & Sons, Inc, 1981.
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*/
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/* $XFree86: xc/lib/X11/Luv.c,v 1.4 2003/04/13 19:22:16 dawes Exp $ */
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#include <X11/Xos.h>
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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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#include <stdio.h> /* sscanf */
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/*
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* FORWARD DECLARATIONS
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*/
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static int CIELuv_ParseString(register char *spec, XcmsColor *pColor);
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static Status XcmsCIELuv_ValidSpec(XcmsColor *pColor);
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/*
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* DEFINES
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* Internal definitions that need NOT be exported to any package
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* or program using this package.
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*/
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#ifdef DBL_EPSILON
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# define XMY_DBL_EPSILON DBL_EPSILON
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#else
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# define XMY_DBL_EPSILON 0.00001
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#endif
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/*
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* LOCAL VARIABLES
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*/
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/*
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* NULL terminated list of functions applied to get from CIELuv to CIEXYZ
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*/
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static XcmsConversionProc Fl_CIELuv_to_CIEXYZ[] = {
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XcmsCIELuvToCIEuvY,
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XcmsCIEuvYToCIEXYZ,
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NULL
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};
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/*
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* NULL terminated list of functions applied to get from CIEXYZ to CIELuv
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*/
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static XcmsConversionProc Fl_CIEXYZ_to_CIELuv[] = {
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XcmsCIEXYZToCIEuvY,
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XcmsCIEuvYToCIELuv,
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NULL
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};
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/*
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* GLOBALS
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*/
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/*
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* CIE Luv Color Space
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*/
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XcmsColorSpace XcmsCIELuvColorSpace =
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{
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_XcmsCIELuv_prefix, /* prefix */
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XcmsCIELuvFormat, /* id */
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CIELuv_ParseString, /* parseString */
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Fl_CIELuv_to_CIEXYZ, /* to_CIEXYZ */
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Fl_CIEXYZ_to_CIELuv, /* from_CIEXYZ */
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1
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};
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/************************************************************************
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* *
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* PRIVATE ROUTINES *
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* *
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************************************************************************/
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/*
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* NAME
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* CIELuv_ParseString
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*
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* SYNOPSIS
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*/
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static int
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CIELuv_ParseString(
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register char *spec,
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XcmsColor *pColor)
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/*
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* DESCRIPTION
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* This routines takes a string and attempts to convert
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* it into a XcmsColor structure with XcmsCIELuvFormat.
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* The assumed CIELuv string syntax is:
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* CIELuv:<L>/<u>/<v>
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* Where L, u, and v are in string input format for floats
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* consisting of:
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* a. an optional sign
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* b. a string of numbers possibly containing a decimal point,
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* c. an optional exponent field containing an 'E' or 'e'
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* followed by a possibly signed integer string.
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*
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* RETURNS
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* 0 if failed, non-zero otherwise.
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*/
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{
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int n;
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char *pchar;
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if ((pchar = strchr(spec, ':')) == NULL) {
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return(XcmsFailure);
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}
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n = (int)(pchar - spec);
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/*
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* Check for proper prefix.
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*/
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if (strncmp(spec, _XcmsCIELuv_prefix, n) != 0) {
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return(XcmsFailure);
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}
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/*
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* Attempt to parse the value portion.
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*/
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if (sscanf(spec + n + 1, "%lf/%lf/%lf",
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&pColor->spec.CIELuv.L_star,
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&pColor->spec.CIELuv.u_star,
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&pColor->spec.CIELuv.v_star) != 3) {
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return(XcmsFailure);
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}
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pColor->format = XcmsCIELuvFormat;
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pColor->pixel = 0;
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return(XcmsCIELuv_ValidSpec(pColor));
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}
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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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* XcmsCIELuv_ValidSpec
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*
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* SYNOPSIS
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*/
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static Status
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XcmsCIELuv_ValidSpec(
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XcmsColor *pColor)
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/*
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* DESCRIPTION
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* Checks if color specification valid for CIE L*u*v*.
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*
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* RETURNS
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* XcmsFailure if invalid,
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* XcmsSuccess if valid.
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*
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*/
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{
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if (pColor->format != XcmsCIELuvFormat
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(pColor->spec.CIELuv.L_star < 0.0 - XMY_DBL_EPSILON)
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(pColor->spec.CIELuv.L_star > 100.0 + XMY_DBL_EPSILON)) {
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return(XcmsFailure);
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}
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return(XcmsSuccess);
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}
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/*
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* NAME
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* XcmsCIELuvToCIEuvY - convert CIELuv to CIEuvY
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*
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* SYNOPSIS
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*/
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Status
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XcmsCIELuvToCIEuvY(ccc, pLuv_WhitePt, pColors_in_out, nColors)
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XcmsCCC ccc;
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XcmsColor *pLuv_WhitePt;
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XcmsColor *pColors_in_out;
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unsigned int nColors;
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/*
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* DESCRIPTION
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* Converts color specifications in an array of XcmsColor
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* structures from CIELuv format to CIEuvY format.
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*
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* RETURNS
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* XcmsFailure if failed,
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* XcmsSuccess if succeeded.
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*
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*/
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{
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XcmsColor *pColor = pColors_in_out;
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XcmsColor whitePt;
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XcmsCIEuvY uvY_return;
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XcmsFloat tmpVal;
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register int i;
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/*
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* Check arguments
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*/
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if (pLuv_WhitePt == NULL || pColors_in_out == NULL) {
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return(XcmsFailure);
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}
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/*
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* Make sure white point is in CIEuvY form
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*/
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if (pLuv_WhitePt->format != XcmsCIEuvYFormat) {
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/* Make copy of the white point because we're going to modify it */
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memcpy((char *)&whitePt, (char *)pLuv_WhitePt, sizeof(XcmsColor));
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if (!_XcmsDIConvertColors(ccc, &whitePt, (XcmsColor *)NULL,
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1, XcmsCIEuvYFormat)) {
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return(XcmsFailure);
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}
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pLuv_WhitePt = &whitePt;
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}
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/* Make sure it is a white point, i.e., Y == 1.0 */
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if (pLuv_WhitePt->spec.CIEuvY.Y != 1.0) {
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return(XcmsFailure);
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}
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/*
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* Now convert each XcmsColor structure to CIEXYZ form
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*/
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for (i = 0; i < nColors; i++, pColor++) {
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/* Make sure original format is CIELuv and is valid */
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if (!XcmsCIELuv_ValidSpec(pColor)) {
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return(XcmsFailure);
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}
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if (pColor->spec.CIELuv.L_star < 7.99953624) {
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uvY_return.Y = pColor->spec.CIELuv.L_star / 903.29;
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} else {
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tmpVal = (pColor->spec.CIELuv.L_star + 16.0) / 116.0;
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uvY_return.Y = tmpVal * tmpVal * tmpVal; /* tmpVal ** 3 */
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}
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if (pColor->spec.CIELuv.L_star == 0.0) {
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uvY_return.u_prime = pLuv_WhitePt->spec.CIEuvY.u_prime;
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uvY_return.v_prime = pLuv_WhitePt->spec.CIEuvY.v_prime;
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} else {
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tmpVal = 13.0 * (pColor->spec.CIELuv.L_star / 100.0);
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uvY_return.u_prime = pColor->spec.CIELuv.u_star/tmpVal +
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pLuv_WhitePt->spec.CIEuvY.u_prime;
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uvY_return.v_prime = pColor->spec.CIELuv.v_star/tmpVal +
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pLuv_WhitePt->spec.CIEuvY.v_prime;
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}
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/* Copy result to pColor */
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memcpy((char *)&pColor->spec, (char *)&uvY_return, sizeof(XcmsCIEuvY));
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/* Identify that the format is now CIEuvY */
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pColor->format = XcmsCIEuvYFormat;
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}
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return(XcmsSuccess);
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}
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/*
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* NAME
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* XcmsCIEuvYToCIELuv - convert CIEuvY to CIELuv
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*
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* SYNOPSIS
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*/
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Status
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XcmsCIEuvYToCIELuv(ccc, pLuv_WhitePt, pColors_in_out, nColors)
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XcmsCCC ccc;
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XcmsColor *pLuv_WhitePt;
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XcmsColor *pColors_in_out;
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unsigned int nColors;
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/*
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* DESCRIPTION
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* Converts color specifications in an array of XcmsColor
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* structures from CIEuvY format to CIELab format.
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*
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* RETURNS
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* XcmsFailure if failed,
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* XcmsSuccess if succeeded.
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*
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*/
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{
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XcmsColor *pColor = pColors_in_out;
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XcmsColor whitePt;
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XcmsCIELuv Luv_return;
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XcmsFloat tmpVal;
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register int i;
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/*
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* Check arguments
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*/
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if (pLuv_WhitePt == NULL || pColors_in_out == NULL) {
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return(XcmsFailure);
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}
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/*
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* Make sure white point is in CIEuvY form
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*/
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if (pLuv_WhitePt->format != XcmsCIEuvYFormat) {
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/* Make copy of the white point because we're going to modify it */
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memcpy((char *)&whitePt, (char *)pLuv_WhitePt, sizeof(XcmsColor));
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if (!_XcmsDIConvertColors(ccc, &whitePt,
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(XcmsColor *)NULL, 1, XcmsCIEuvYFormat)) {
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return(XcmsFailure);
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}
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pLuv_WhitePt = &whitePt;
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}
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/* Make sure it is a white point, i.e., Y == 1.0 */
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if (pLuv_WhitePt->spec.CIEuvY.Y != 1.0) {
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return(XcmsFailure);
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}
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/*
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* Now convert each XcmsColor structure to CIEXYZ form
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*/
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for (i = 0; i < nColors; i++, pColor++) {
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if (!_XcmsCIEuvY_ValidSpec(pColor)) {
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return(XcmsFailure);
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}
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/* Now convert the uvY to Luv */
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Luv_return.L_star =
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(pColor->spec.CIEuvY.Y < 0.008856)
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?
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(pColor->spec.CIEuvY.Y * 903.29)
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:
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((XcmsFloat)(XCMS_CUBEROOT(pColor->spec.CIEuvY.Y) * 116.0) - 16.0);
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tmpVal = 13.0 * (Luv_return.L_star / 100.0);
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Luv_return.u_star = tmpVal *
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(pColor->spec.CIEuvY.u_prime - pLuv_WhitePt->spec.CIEuvY.u_prime);
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Luv_return.v_star = tmpVal *
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(pColor->spec.CIEuvY.v_prime - pLuv_WhitePt->spec.CIEuvY.v_prime);
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/* Copy result to pColor */
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memcpy((char *)&pColor->spec, (char *)&Luv_return, sizeof(XcmsCIELuv));
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/* Identify that the format is now CIEuvY */
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pColor->format = XcmsCIELuvFormat;
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}
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return(XcmsSuccess);
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}
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