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Diffstat (limited to 'libX11/src/xcms/LabMxL.c')
| -rw-r--r-- | libX11/src/xcms/LabMxL.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/libX11/src/xcms/LabMxL.c b/libX11/src/xcms/LabMxL.c new file mode 100644 index 000000000..fbc39eef3 --- /dev/null +++ b/libX11/src/xcms/LabMxL.c @@ -0,0 +1,218 @@ +/* $Xorg: LabMxL.c,v 1.3 2000/08/17 19:44:40 cpqbld 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 + * CIELabMxL.c + * + * DESCRIPTION + * Source for the XcmsCIELabQueryMaxL() gamut boundary + * querying routine. + * + */ +/* $XFree86: xc/lib/X11/LabMxL.c,v 1.3 2001/01/17 19:41:39 dawes Exp $ */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif +#include "Xlibint.h" +#include "Xcmsint.h" +#include <math.h> +#include "Cv.h" + +/* + * DEFINES + */ +#define MAXBISECTCOUNT 100 +#define EPS (XcmsFloat)0.001 +#define START_L_STAR (XcmsFloat)40 + + +/************************************************************************ + * * + * PUBLIC ROUTINES * + * * + ************************************************************************/ + +/* + * NAME + * XcmsCIELabQueryMaxL - Compute max Lstar for a hue and chroma + * + * SYNOPSIS + */ +Status +XcmsCIELabQueryMaxL( + XcmsCCC ccc, + XcmsFloat hue_angle, /* hue in degrees */ + XcmsFloat chroma, + XcmsColor *pColor_return) +/* + * DESCRIPTION + * Return the maximum Lstar for a specified hue_angle and chroma. + * + * 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 with no modifications + * + */ +{ + XcmsCCCRec myCCC; + XcmsColor max_lc, tmp, prev; + XcmsFloat max_chroma, tmp_chroma; + XcmsFloat hue, nT, nChroma, lastChroma, prevChroma; + XcmsFloat rFactor; + XcmsRGBi rgb_saved; + int nCount, nMaxCount; + + /* + * Check Arguments + */ + if (ccc == NULL || pColor_return == NULL) { + return(XcmsFailure); + } + + /* setup the CCC to use for the conversions. */ + memcpy ((char *) &myCCC, (char *) ccc, sizeof(XcmsCCCRec)); + myCCC.clientWhitePt.format = XcmsUndefinedFormat; + myCCC.gamutCompProc = (XcmsCompressionProc) NULL; + + while (hue_angle < 0.0) { + hue_angle += 360.0; + } + while (hue_angle >= 360.0) { + hue_angle -= 360.0; + } + + hue = radians(hue_angle); + tmp.spec.CIELab.L_star = START_L_STAR; + tmp.spec.CIELab.a_star = XCMS_CIEASTAROFHUE(hue, chroma); + tmp.spec.CIELab.b_star = XCMS_CIEBSTAROFHUE(hue, chroma); + tmp.pixel = pColor_return->pixel; + tmp.format = XcmsCIELabFormat; + + /* Step 1: Obtain the maximum L_star and chroma for this hue. */ + if (_XcmsCIELabQueryMaxLCRGB(&myCCC, hue, &max_lc, &rgb_saved) + == XcmsFailure) { + return(XcmsFailure); + } + + max_chroma = XCMS_CIELAB_PMETRIC_CHROMA(max_lc.spec.CIELab.a_star, + max_lc.spec.CIELab.b_star); + + if (max_chroma <= chroma) { + /* + * If the chroma is greater than the chroma for the + * maximum L/chroma point then the L_star is the + * the L_star for the maximum L_star/chroma point. + * This is an error but I return the best approximation I can. + * Thus the inconsistency. + */ + memcpy ((char *) pColor_return, (char *) &max_lc, sizeof (XcmsColor)); + return(XcmsSuccess); + } + + /* + * If the chroma is equal to the chroma for the + * maximum L_star/chroma point then the L_star is the + * the L_star for the maximum L* and chroma point. + */ + /* if (max_chroma == chroma) { + * memcpy ((char *) pColor_return, (char *) &max_lc, sizeof (XcmsColor)); + * return(XcmsSuccess); + * } + */ + + /* must do a bisection here to compute the maximum L* */ + /* save the structure input so that any elements that */ + /* are not touched are recopied later in the routine. */ + nChroma = chroma; + tmp_chroma = max_chroma; + lastChroma = -1.0; + nMaxCount = MAXBISECTCOUNT; + rFactor = 1.0; + + for (nCount = 0; nCount < nMaxCount; nCount++) { + prevChroma = lastChroma; + lastChroma = tmp_chroma; + nT = (1.0 - (nChroma / max_chroma)) * rFactor; + memcpy ((char *)&prev, (char *)&tmp, sizeof(XcmsColor)); + tmp.spec.RGBi.red = rgb_saved.red * (1.0 - nT) + nT; + tmp.spec.RGBi.green = rgb_saved.green * (1.0 - nT) + nT; + tmp.spec.RGBi.blue = rgb_saved.blue * (1.0 - nT) + nT; + tmp.format = XcmsRGBiFormat; + + /* convert from RGB to CIELab */ + if (_XcmsConvertColorsWithWhitePt(&myCCC, &tmp, + ScreenWhitePointOfCCC(&myCCC), 1, XcmsCIELabFormat, + (Bool *) NULL) == XcmsFailure) { + return(XcmsFailure); + } + + /* Now check the return against what is expected */ + tmp_chroma = XCMS_CIELAB_PMETRIC_CHROMA(tmp.spec.CIELab.a_star, + tmp.spec.CIELab.b_star); + if (tmp_chroma <= chroma + EPS && tmp_chroma >= chroma - EPS) { + /* Found It! */ + memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor)); + return(XcmsSuccess); + } + nChroma += chroma - tmp_chroma; + if (nChroma > max_chroma) { + nChroma = max_chroma; + rFactor *= 0.5; /* selective relaxation employed */ + } else if (nChroma < 0.0) { + if (XCMS_FABS(lastChroma - chroma) < + XCMS_FABS(tmp_chroma - chroma)) { + memcpy ((char *)pColor_return, (char *)&prev, + sizeof(XcmsColor)); + } else { + memcpy ((char *)pColor_return, (char *)&tmp, + sizeof(XcmsColor)); + } + return(XcmsSuccess); + } else if (tmp_chroma <= prevChroma + EPS && + tmp_chroma >= prevChroma - EPS) { + rFactor *= 0.5; /* selective relaxation employed */ + } + } + + if (nCount >= nMaxCount) { + if (XCMS_FABS(lastChroma - chroma) < + XCMS_FABS(tmp_chroma - chroma)) { + memcpy ((char *)pColor_return, (char *)&prev, + sizeof(XcmsColor)); + } else { + memcpy ((char *)pColor_return, (char *)&tmp, + sizeof(XcmsColor)); + } + } + memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor)); + return(XcmsSuccess); +} |