--- ray/src/common/color.c	1989/05/11 22:15:57	1.4
+++ ray/src/common/color.c	1991/08/28 08:39:47	1.15
@@ -1,4 +1,4 @@
-/* Copyright (c) 1986 Regents of the University of California */
+/* Copyright (c) 1991 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -14,147 +14,127 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include  "color.h"
 
-#ifdef  SPEC_RGB
-/*
- *	The following table contains the CIE tristimulus integrals
- *  for X, Y, and Z.  The table is cumulative, so that
- *  each color coordinate integrates to 1.
- */
+#define  MINELEN	8	/* minimum scanline length for encoding */
+#define  MINRUN		4	/* minimum run length */
 
-#define  STARTWL	380		/* starting wavelength (nanometers) */
-#define  INCWL		10		/* wavelength increment */
-#define  NINC		40		/* # of values */
 
-static BYTE  chroma[3][NINC] = {
-	{							/* X */
-		0,   0,   0,   2,   6,   13,  22,  30,  36,  41,
-		42,  43,  43,  44,  46,  52,  60,  71,  87,  106,
-		128, 153, 178, 200, 219, 233, 243, 249, 252, 254,
-		255, 255, 255, 255, 255, 255, 255, 255, 255, 255
-	}, {							/* Y */
-		0,   0,   0,   0,   0,   1,   2,   4,   7,   11,
-		17,  24,  34,  48,  64,  84,  105, 127, 148, 169,
-		188, 205, 220, 232, 240, 246, 250, 253, 254, 255,
-		255, 255, 255, 255, 255, 255, 255, 255, 255, 255
-	}, {							/* Z */
-		0,   0,   2,   10,  32,  66,  118, 153, 191, 220,
-		237, 246, 251, 253, 254, 255, 255, 255, 255, 255,
-		255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
-		255, 255, 255, 255, 255, 255, 255, 255, 255, 255
-	}
-};
-
-
-spec_rgb(col, s, e)		/* comput RGB color from spectral range */
-COLOR  col;
-int  s, e;
+char *
+tempbuffer(len)			/* get a temporary buffer */
+unsigned  len;
 {
-	COLOR  ciecolor;
+	extern char  *malloc(), *realloc();
+	static char  *tempbuf = NULL;
+	static int  tempbuflen = 0;
 
-	spec_cie(ciecolor, s, e);
-	cie_rgb(col, ciecolor);
+	if (len > tempbuflen) {
+		if (tempbuflen > 0)
+			tempbuf = realloc(tempbuf, len);
+		else
+			tempbuf = malloc(len);
+		tempbuflen = tempbuf==NULL ? 0 : len;
+	}
+	return(tempbuf);
 }
 
 
-spec_cie(col, s, e)		/* compute a color from a spectral range */
-COLOR  col;		/* returned color */
-int  s, e;		/* starting and ending wavelengths */
+fwritecolrs(scanline, len, fp)		/* write out a colr scanline */
+register COLR  *scanline;
+int  len;
+register FILE  *fp;
 {
-	register int  i, d, r;
+	register int  i, j, beg, cnt;
+	int  c2;
 	
-	s -= STARTWL;
-	if (s < 0)
-		s = 0;
-
-	e -= STARTWL;
-	if (e >= INCWL*(NINC - 1))
-		e = INCWL*(NINC - 1) - 1;
-
-	d = e / INCWL;			/* interpolate values */
-	r = e % INCWL;
-	for (i = 0; i < 3; i++)
-		col[i] = chroma[i][d]*(INCWL - r) + chroma[i][d + 1]*r;
-
-	d = s / INCWL;
-	r = s % INCWL;
-	for (i = 0; i < 3; i++)
-		col[i] -= chroma[i][d]*(INCWL - r) - chroma[i][d + 1]*r;
-
-	col[RED] = (col[RED] + 0.5) / (256*INCWL);
-	col[GRN] = (col[GRN] + 0.5) / (256*INCWL);
-	col[BLU] = (col[BLU] + 0.5) / (256*INCWL);
-}
-
-
-cie_rgb(rgbcolor, ciecolor)		/* convert CIE to RGB (NTSC) */
-register COLOR  rgbcolor, ciecolor;
-{
-	static float  cmat[3][3] = {
-		1.73, -.48, -.26,
-		-.81, 1.65, -.02,
-		 .08, -.17, 1.28,
-	};
-	register int  i;
-
-	for (i = 0; i < 3; i++) {
-		rgbcolor[i] =	cmat[i][0]*ciecolor[0] +
-				cmat[i][1]*ciecolor[1] +
-				cmat[i][2]*ciecolor[2] ;
-		if (rgbcolor[i] < 0.0)
-			rgbcolor[i] = 0.0;
+	if (len < MINELEN)		/* too small to encode */
+		return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
+	if (len > 32767)		/* too big! */
+		return(-1);
+	putc(2, fp);			/* put magic header */
+	putc(2, fp);
+	putc(len>>8, fp);
+	putc(len&255, fp);
+					/* put components seperately */
+	for (i = 0; i < 4; i++) {
+	    for (j = 0; j < len; j += cnt) {	/* find next run */
+		for (beg = j; beg < len; beg += cnt) {
+		    for (cnt = 1; cnt < 127 && beg+cnt < len &&
+			    scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
+			;
+		    if (cnt >= MINRUN)
+			break;			/* long enough */
+		}
+		if (beg-j > 1 && beg-j < MINRUN) {
+		    c2 = j+1;
+		    while (scanline[c2++][i] == scanline[j][i])
+			if (c2 == beg) {	/* short run */
+			    putc(128+beg-j, fp);
+			    putc(scanline[j][i], fp);
+			    j = beg;
+			    break;
+			}
+		}
+		while (j < beg) {		/* write out non-run */
+		    if ((c2 = beg-j) > 128) c2 = 128;
+		    putc(c2, fp);
+		    while (c2--)
+			putc(scanline[j++][i], fp);
+		}
+		if (cnt >= MINRUN) {		/* write out run */
+		    putc(128+cnt, fp);
+		    putc(scanline[beg][i], fp);
+		} else
+		    cnt = 0;
+	    }
 	}
+	return(ferror(fp) ? -1 : 0);
 }
-#endif
 
 
-fwritecolrs(scanline, len, fp)		/* write out a colr scanline */
+freadcolrs(scanline, len, fp)		/* read in an encoded colr scanline */
 register COLR  *scanline;
 int  len;
 register FILE  *fp;
 {
-	COLR  lastcolr;
-	int  rept;
-	
-	lastcolr[RED] = lastcolr[GRN] = lastcolr[BLU] = 1;
-	lastcolr[EXP] = 0;
-	rept = 0;
-	
-	while (len > 0) {
-		if (scanline[0][EXP] == lastcolr[EXP] &&
-				scanline[0][RED] == lastcolr[RED] &&
-				scanline[0][GRN] == lastcolr[GRN] &&
-				scanline[0][BLU] == lastcolr[BLU])
-			rept++;
-		else {
-			while (rept) {		/* write out count */
-				putc(1, fp);
-				putc(1, fp);
-				putc(1, fp);
-				putc(rept & 255, fp);
-				rept >>= 8;
-			}
-			putc(scanline[0][RED], fp);	/* new color */
-			putc(scanline[0][GRN], fp);
-			putc(scanline[0][BLU], fp);
-			putc(scanline[0][EXP], fp);
-			copycolr(lastcolr, scanline[0]);
-			rept = 0;
-		}
-		scanline++;
-		len--;
+	register int  i, j;
+	int  code;
+					/* determine scanline type */
+	if (len < MINELEN)
+		return(oldreadcolrs(scanline, len, fp));
+	if ((i = getc(fp)) == EOF)
+		return(-1);
+	if (i != 2) {
+		ungetc(i, fp);
+		return(oldreadcolrs(scanline, len, fp));
 	}
-	while (rept) {		/* write out count */
-		putc(1, fp);
-		putc(1, fp);
-		putc(1, fp);
-		putc(rept & 255, fp);
-		rept >>= 8;
+	scanline[0][GRN] = getc(fp);
+	scanline[0][BLU] = getc(fp);
+	if ((i = getc(fp)) == EOF)
+		return(-1);
+	if (scanline[0][GRN] != 2 || scanline[0][BLU] & 128) {
+		scanline[0][RED] = 2;
+		scanline[0][EXP] = i;
+		return(oldreadcolrs(scanline+1, len-1, fp));
 	}
-	return(ferror(fp) ? -1 : 0);
+	if ((scanline[0][BLU]<<8 | i) != len)
+		return(-1);		/* length mismatch! */
+					/* read each component */
+	for (i = 0; i < 4; i++)
+	    for (j = 0; j < len; ) {
+		if ((code = getc(fp)) == EOF)
+		    return(-1);
+		if (code > 128) {	/* run */
+		    scanline[j++][i] = getc(fp);
+		    for (code &= 127; --code; j++)
+			scanline[j][i] = scanline[j-1][i];
+		} else			/* non-run */
+		    while (code--)
+			scanline[j++][i] = getc(fp);
+	    }
+	return(feof(fp) ? -1 : 0);
 }
 
 
-freadcolrs(scanline, len, fp)		/* read in a colr scanline */
+oldreadcolrs(scanline, len, fp)		/* read in an old colr scanline */
 register COLR  *scanline;
 int  len;
 register FILE  *fp;
@@ -193,86 +173,50 @@ register FILE  *fp;
 fwritescan(scanline, len, fp)		/* write out a scanline */
 register COLOR  *scanline;
 int  len;
-register FILE  *fp;
+FILE  *fp;
 {
-	COLR  lastcolr, thiscolr;
-	int  rept;
-	
-	lastcolr[RED] = lastcolr[GRN] = lastcolr[BLU] = 1;
-	lastcolr[EXP] = 0;
-	rept = 0;
-	
-	while (len > 0) {
-		setcolr(thiscolr, scanline[0][RED],
+	COLR  *clrscan;
+	int  n;
+	register COLR  *sp;
+					/* get scanline buffer */
+	if ((sp = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
+		return(-1);
+	clrscan = sp;
+					/* convert scanline */
+	n = len;
+	while (n-- > 0) {
+		setcolr(sp[0], scanline[0][RED],
 				  scanline[0][GRN],
 				  scanline[0][BLU]);
-		if (thiscolr[EXP] == lastcolr[EXP] &&
-				thiscolr[RED] == lastcolr[RED] &&
-				thiscolr[GRN] == lastcolr[GRN] &&
-				thiscolr[BLU] == lastcolr[BLU])
-			rept++;
-		else {
-			while (rept) {		/* write out count */
-				putc(1, fp);
-				putc(1, fp);
-				putc(1, fp);
-				putc(rept & 255, fp);
-				rept >>= 8;
-			}
-			putc(thiscolr[RED], fp);	/* new color */
-			putc(thiscolr[GRN], fp);
-			putc(thiscolr[BLU], fp);
-			putc(thiscolr[EXP], fp);
-			copycolr(lastcolr, thiscolr);
-			rept = 0;
-		}
 		scanline++;
-		len--;
+		sp++;
 	}
-	while (rept) {		/* write out count */
-		putc(1, fp);
-		putc(1, fp);
-		putc(1, fp);
-		putc(rept & 255, fp);
-		rept >>= 8;
-	}
-	return(ferror(fp) ? -1 : 0);
+	return(fwritecolrs(clrscan, len, fp));
 }
 
 
 freadscan(scanline, len, fp)		/* read in a scanline */
 register COLOR  *scanline;
 int  len;
-register FILE  *fp;
+FILE  *fp;
 {
-	COLR  thiscolr;
-	int  rshift;
-	register int  i;
-	
-	rshift = 0;
-	
-	while (len > 0) {
-		thiscolr[RED] = getc(fp);
-		thiscolr[GRN] = getc(fp);
-		thiscolr[BLU] = getc(fp);
-		thiscolr[EXP] = getc(fp);
-		if (feof(fp) || ferror(fp))
-			return(-1);
-		if (thiscolr[RED] == 1 &&
-				thiscolr[GRN] == 1 &&
-				thiscolr[BLU] == 1) {
-			for (i = thiscolr[EXP] << rshift; i > 0; i--) {
-				copycolor(scanline[0], scanline[-1]);
-				scanline++;
-				len--;
-			}
-			rshift += 8;
-		} else {
-			colr_color(scanline[0], thiscolr);
-			scanline++;
-			len--;
-			rshift = 0;
-		}
+	register COLR  *clrscan;
+
+	if ((clrscan = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
+		return(-1);
+	if (freadcolrs(clrscan, len, fp) < 0)
+		return(-1);
+					/* convert scanline */
+	colr_color(scanline[0], clrscan[0]);
+	while (--len > 0) {
+		scanline++; clrscan++;
+		if (clrscan[0][RED] == clrscan[-1][RED] &&
+			    clrscan[0][GRN] == clrscan[-1][GRN] &&
+			    clrscan[0][BLU] == clrscan[-1][BLU] &&
+			    clrscan[0][EXP] == clrscan[-1][EXP])
+			copycolor(scanline[0], scanline[-1]);
+		else
+			colr_color(scanline[0], clrscan[0]);
 	}
 	return(0);
 }
@@ -308,7 +252,7 @@ colr_color(col, clr)		/* convert short to float color 
 register COLOR  col;
 register COLR  clr;
 {
-	double  ldexp(), f;
+	double  f;
 	
 	if (clr[EXP] == 0)
 		col[RED] = col[GRN] = col[BLU] = 0.0;
@@ -318,4 +262,18 @@ register COLR  clr;
 		col[GRN] = (clr[GRN] + 0.5)*f;
 		col[BLU] = (clr[BLU] + 0.5)*f;
 	}
+}
+
+
+bigdiff(c1, c2, md)			/* c1 delta c2 > md? */
+register COLOR  c1, c2;
+double  md;
+{
+	register int  i;
+
+	for (i = 0; i < 3; i++)
+		if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) ||
+			colval(c2,i)-colval(c1,i) > md*colval(c1,i))
+			return(1);
+	return(0);
 }