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+/* $Xorg: HVCMxV.c,v 1.3 2000/08/17 19:44:37 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. 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
+ * TekHVCMxV.c
+ *
+ * DESCRIPTION
+ * Source for the XcmsTekHVCQueryMaxV() gamut boundary
+ * querying routine.
+ *
+ */
+/* $XFree86: xc/lib/X11/HVCMxV.c,v 1.4 2003/04/13 19:22:16 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 0.001
+
+
+/************************************************************************
+ * *
+ * PUBLIC ROUTINES *
+ * *
+ ************************************************************************/
+
+/*
+ * NAME
+ * XcmsTekHVCQueryMaxV - Compute maximum value for a hue and chroma
+ *
+ * SYNOPSIS
+ */
+Status
+XcmsTekHVCQueryMaxV(
+ XcmsCCC ccc,
+ XcmsFloat hue,
+ XcmsFloat chroma,
+ XcmsColor *pColor_return)
+/*
+ * DESCRIPTION
+ * Return the maximum value for a specified hue 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 tmp;
+ XcmsColor max_vc;
+ XcmsRGBi rgb_saved;
+ int nCount, nMaxCount;
+ XcmsFloat nT, nChroma, savedChroma, lastValue, lastChroma, prevChroma;
+ XcmsFloat rFactor;
+ XcmsFloat ftmp1, ftmp2;
+
+ /*
+ * Check Arguments
+ */
+ if (ccc == NULL || pColor_return == NULL) {
+ return(XcmsFailure);
+ }
+
+ /*
+ * Insure TekHVC installed
+ */
+ if (XcmsAddColorSpace(&XcmsTekHVCColorSpace) == XcmsFailure) {
+ 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;
+
+ tmp.spec.TekHVC.H = hue;
+ tmp.spec.TekHVC.V = 0.0;
+ tmp.spec.TekHVC.C = chroma;
+ tmp.pixel = pColor_return->pixel;
+ tmp.format = XcmsTekHVCFormat;
+
+ if (!_XcmsTekHVC_CheckModify (&tmp)) {
+ return(XcmsFailure);
+ }
+
+ /* Step 1: compute the maximum value and chroma for this hue. */
+ /* This copy may be overkill but it preserves the pixel etc. */
+ memcpy((char *)&max_vc, (char *)&tmp, sizeof(XcmsColor));
+ hue = max_vc.spec.TekHVC.H;
+ if (_XcmsTekHVCQueryMaxVCRGB(&myCCC, max_vc.spec.TekHVC.H, &max_vc, &rgb_saved)
+ == XcmsFailure) {
+ return(XcmsFailure);
+ }
+
+ if (max_vc.spec.TekHVC.C < tmp.spec.TekHVC.C) {
+ /*
+ * If the chroma is greater than the chroma for the
+ * maximum value/chroma point then the value is the
+ * the value for the maximum value, chroma point.
+ * This is an error but it I return the best approximation I can.
+ * Thus the inconsistency.
+ */
+ tmp.spec.TekHVC.C = max_vc.spec.TekHVC.C;
+ tmp.spec.TekHVC.V = max_vc.spec.TekHVC.V;
+ memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor));
+ return(XcmsSuccess);
+ } else if (max_vc.spec.TekHVC.C == tmp.spec.TekHVC.C) {
+ /*
+ * If the chroma is equal to the chroma for the
+ * maximum value/chroma point then the value is the
+ * the value for the maximum value, chroma point.
+ */
+ tmp.spec.TekHVC.V = max_vc.spec.TekHVC.V;
+ memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor));
+ return(XcmsSuccess);
+ } else {
+ /* must do a bisection here to compute the maximum value */
+ /* save the structure input so that any elements that */
+ /* are not touched are recopied later in the routine. */
+ nChroma = savedChroma = tmp.spec.TekHVC.C;
+ tmp.spec.TekHVC.C = max_vc.spec.TekHVC.C;
+ tmp.spec.TekHVC.V = max_vc.spec.TekHVC.V;
+ lastChroma = -1.0;
+ lastValue = -1.0;
+ nMaxCount = MAXBISECTCOUNT;
+ rFactor = 1.0;
+
+ for (nCount = 0; nCount < nMaxCount; nCount++) {
+ prevChroma = lastChroma;
+ lastValue = tmp.spec.TekHVC.V;
+ lastChroma = tmp.spec.TekHVC.C;
+ nT = (1.0 - (nChroma / max_vc.spec.TekHVC.C)) * rFactor;
+ 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 HVC */
+ if (_XcmsConvertColorsWithWhitePt(&myCCC, &tmp,
+ &myCCC.pPerScrnInfo->screenWhitePt, 1, XcmsTekHVCFormat,
+ (Bool *) NULL) == XcmsFailure) {
+ return(XcmsFailure);
+ }
+
+ /* Now check the return against what is expected */
+ if (tmp.spec.TekHVC.C <= savedChroma + EPS &&
+ tmp.spec.TekHVC.C >= savedChroma - EPS) {
+ tmp.spec.TekHVC.H = hue; /* use the saved hue */
+ memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor));
+ return(XcmsSuccess);
+ }
+ nChroma += savedChroma - tmp.spec.TekHVC.C;
+ if (nChroma > max_vc.spec.TekHVC.C) {
+ nChroma = max_vc.spec.TekHVC.C;
+ rFactor *= 0.5; /* selective relaxation employed */
+ } else if (nChroma < 0.0) {
+ /* avoid using fabs */
+ ftmp1 = lastChroma - savedChroma;
+ if (ftmp1 < 0.0)
+ ftmp1 = -ftmp1;
+ ftmp2 = tmp.spec.TekHVC.C - savedChroma;
+ if (ftmp2 < 0.0)
+ ftmp2 = -ftmp2;
+ if (ftmp1 < ftmp2) {
+ tmp.spec.TekHVC.V = lastValue;
+ tmp.spec.TekHVC.C = lastChroma;
+ }
+ /* make sure to return the input hue */
+ tmp.spec.TekHVC.H = hue;
+ if (!_XcmsTekHVC_CheckModify(&tmp)) {
+ return(XcmsFailure);
+ }
+ memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor));
+ return(XcmsSuccess);
+ } else if (tmp.spec.TekHVC.C <= prevChroma + EPS &&
+ tmp.spec.TekHVC.C >= prevChroma - EPS) {
+ rFactor *= 0.5; /* selective relaxation employed */
+ }
+ }
+ if (nCount >= nMaxCount) {
+ /* avoid using fabs */
+ ftmp1 = lastChroma - savedChroma;
+ if (ftmp1 < 0.0)
+ ftmp1 = -ftmp1;
+ ftmp2 = tmp.spec.TekHVC.C - savedChroma;
+ if (ftmp2 < 0.0)
+ ftmp2 = -ftmp2;
+ if (ftmp1 < ftmp2) {
+ tmp.spec.TekHVC.V = lastValue;
+ tmp.spec.TekHVC.C = lastChroma;
+ }
+ }
+ }
+
+ /* make sure to return the input hue */
+ tmp.spec.TekHVC.H = hue;
+ memcpy ((char *) pColor_return, (char *) &tmp, sizeof (XcmsColor));
+ return(XcmsSuccess);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-01 21:44:48 +0000