--- ray/src/px/ra_gif.c	1994/03/30 14:24:52	2.1
+++ ray/src/px/ra_gif.c	1995/04/03 15:29:43	2.6
@@ -33,11 +33,14 @@ extern long  ftell();
 
 long  picstart;
 
-extern BYTE  clrtab[][3];
+BYTE  clrtab[256][3];
 
+extern int  samplefac;
+
 extern int  getgifpix();
 
 COLR	*scanln;
+BYTE	*pixscan;
 
 int  xmax, ymax;			/* picture size */
 
@@ -45,8 +48,12 @@ double	gamv = 2.2;			/* gamma correction */
 
 int  greyscale = 0;			/* convert to B&W? */
 
+int  dither = 1;			/* dither colors? */
+
 int  bradj = 0;				/* brightness adjustment */
 
+int  ncolors = 0;			/* number of colors requested */
+
 char  *progname;
 
 
@@ -54,7 +61,6 @@ main(argc, argv)
 int  argc;
 char  *argv[];
 {
-	int  ncolors = 0;
 	int  bitsperpix;
 	int  i;
 #ifdef MSDOS
@@ -64,6 +70,7 @@ char  *argv[];
 	setmode(fileno(stdout), O_BINARY);
 #endif
 	progname = argv[0];
+	samplefac = 0;
 
 	for (i = 1; i < argc; i++)
 		if (argv[i][0] == '-')
@@ -74,6 +81,9 @@ char  *argv[];
 			case 'b':
 				greyscale = 1;
 				break;
+			case 'd':
+				dither = !dither;
+				break;
 			case 'c':
 				ncolors = atoi(argv[++i]);
 				break;
@@ -82,6 +92,9 @@ char  *argv[];
 					goto userr;
 				bradj = atoi(argv[++i]);
 				break;
+			case 'n':
+				samplefac = atoi(argv[++i]);
+				break;
 			default:
 				goto userr;
 			}
@@ -130,7 +143,7 @@ char  *argv[];
 	exit(0);
 userr:
 	fprintf(stderr,
-	"Usage: %s [-b][-c ncolors][-g gamv][-e +/-stops] input [output]\n",
+	"Usage: %s [-b][-d][-n samp][-c ncolors][-g gamv][-e +/-stops] input [output]\n",
 			progname);
 	exit(1);
 }
@@ -149,11 +162,17 @@ int  y;
 		if (freadcolrs(scanln, xmax, stdin) < 0) {
 			fprintf(stderr, "%s: error reading picture (y==%d)\n",
 					progname, ymax-1-y);
+			exit(1);
 		}
 	while (++currow < y);
 	if (bradj)
 		shiftcolrs(scanln, xmax, bradj);
 	colrs_gambs(scanln, xmax);
+	if (pixscan != NULL)
+		if (samplefac)
+			neu_dith_colrs(pixscan, scanln, xmax);
+		else
+			dith_colrs(pixscan, scanln, xmax);
 }
 
 
@@ -162,17 +181,30 @@ int	nc;
 {
 	register int	i;
 
-	new_histo();
+	if ((samplefac ? neu_init(xmax*ymax) : new_histo(xmax*ymax)) == -1)
+		goto memerr;
 	for (i = 0; i < ymax; i++) {
 		getrow(i);
-		cnt_colrs(scanln, xmax);
+		if (samplefac)
+			neu_colrs(scanln, xmax);
+		else
+			cnt_colrs(scanln, xmax);
 	}
-	new_clrtab(nc);
+	if (samplefac)
+		neu_clrtab(nc);
+	else
+		new_clrtab(nc);
 	for (i = 0; i < nc; i++) {
 		rmap[i] = clrtab[i][RED];
 		gmap[i] = clrtab[i][GRN];
 		bmap[i] = clrtab[i][BLU];
 	}
+	if (dither && (pixscan = (BYTE *)malloc(xmax)) == NULL)
+		goto memerr;
+	return;
+memerr:
+	fprintf(stderr, "%s: out of memory\n", progname);
+	exit(1);
 }
 
 
@@ -197,8 +229,10 @@ int  x, y;
 
 	getrow(y);
 	if (greyscale)
-		return(normbright(scanln[x]));
-	return(map_pixel(scanln[x]));
+		return((normbright(scanln[x])*ncolors)>>8);
+	if (pixscan != NULL)
+		return(pixscan[x]);
+	return(samplefac ? neu_map_pixel(scanln[x]) : map_pixel(scanln[x]));
 }