--- ray/src/common/falsecolor.c	2005/11/18 22:50:20	3.5
+++ ray/src/common/falsecolor.c	2008/07/03 03:30:21	3.8
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: falsecolor.c,v 3.5 2005/11/18 22:50:20 greg Exp $";
+static const char RCSid[] = "$Id: falsecolor.c,v 3.8 2008/07/03 03:30:21 greg Exp $";
 #endif
 /*
  * False color mapping functions.
@@ -88,9 +88,9 @@ fcLinearMapping(FCstruct *fcs, TMstruct *tms, double p
 	if ((fcs == NULL) | (tms == NULL) || (tms->histo == NULL) |
 			(0 > pctile) | (pctile >= 50))
 		return(TM_E_ILLEGAL);
-	i = (tms->hbrmin-MINBRT)/HISTEP;
+	i = HISTI(tms->hbrmin);
 	brt0 = MINBRT + HISTEP/2 + i*HISTEP;
-	histlen = (tms->hbrmax-MINBRT)/HISTEP + 1 - i;
+	histlen = HISTI(tms->hbrmax) + 1 - i;
 	histot = 0;
 	for (i = histlen; i--; )
 		histot += tms->histo[i];
@@ -112,22 +112,22 @@ fcLogMapping(FCstruct *fcs, TMstruct *tms, double pcti
 	int		brt0, wbrmin, wbrmax;
 
 	if ((fcs == NULL) | (tms == NULL) || (tms->histo == NULL) |
-			(0 > pctile) | (pctile >= 50))
+			(.0 > pctile) | (pctile >= 50.))
 		return(TM_E_ILLEGAL);
-	i = (tms->hbrmin-MINBRT)/HISTEP;
+	i = HISTI(tms->hbrmin);
 	brt0 = MINBRT + HISTEP/2 + i*HISTEP;
-	histlen = (tms->hbrmax-MINBRT)/HISTEP + 1 - i;
+	histlen = HISTI(tms->hbrmax) + 1 - i;
 	histot = 0;
 	for (i = histlen; i--; )
 		histot += tms->histo[i];
-	cnt = histot * pctile / 100;
+	cnt = histot * pctile * .01;
 	for (i = 0; i < histlen; i++)
 		if ((cnt -= tms->histo[i]) < 0)
 			break;
 	if (i >= histlen)
 		return(TM_E_TMFAIL);
 	wbrmin = brt0 + i*HISTEP;
-	cnt = histot * pctile / 100;
+	cnt = histot * pctile * .01;
 	for (i = histlen; i--; )
 		if ((cnt -= tms->histo[i]) < 0)
 			break;
@@ -165,12 +165,16 @@ fcMapPixels(FCstruct *fcs, BYTE *ps, TMbright *ls, int
 int
 fcIsLogMap(FCstruct *fcs)
 {
-	int	midval;
+	int	miderr;
 
 	if (fcs == NULL || fcs->lumap == NULL)
 		return(-1);
-	midval = fcs->lumap[(fcs->mbrmax - fcs->mbrmin)/2];
-	return((127 <= midval) & (midval <= 129));
+	
+	miderr = (fcs->mbrmax - fcs->mbrmin)/2;
+	miderr = fcs->lumap[miderr] -
+			256L * miderr / (fcs->mbrmax - fcs->mbrmin + 1);
+
+	return((-1 <= miderr) & (miderr <= 1));
 }
 
 /* Duplicate a false color structure */