--- a/Depth8Image.st	Sun Jul 02 18:18:17 1995 +0200
+++ b/Depth8Image.st	Sun Jul 02 22:48:08 1995 +0200
@@ -21,7 +21,7 @@
 COPYRIGHT (c) 1993 by Claus Gittinger
 	      All Rights Reserved
 
-$Header: /cvs/stx/stx/libview/Depth8Image.st,v 1.23 1995-07-02 16:15:33 claus Exp $
+$Header: /cvs/stx/stx/libview/Depth8Image.st,v 1.24 1995-07-02 20:48:08 claus Exp $
 '!
 
 !Depth8Image class methodsFor:'documentation'!
@@ -42,7 +42,7 @@
 
 version
 "
-$Header: /cvs/stx/stx/libview/Depth8Image.st,v 1.23 1995-07-02 16:15:33 claus Exp $
+$Header: /cvs/stx/stx/libview/Depth8Image.st,v 1.24 1995-07-02 20:48:08 claus Exp $
 "
 !
 
@@ -692,19 +692,13 @@
 
     |pseudoBits f has8BitImage deviceDepth
      redBytes greenBytes blueBytes
-"/     eR    "{Class: SmallInteger }"
-"/     eG    "{Class: SmallInteger }"
-"/     eB    "{Class: SmallInteger }"
-"/     wantR "{Class: SmallInteger }"
-"/     wantG "{Class: SmallInteger }"
-"/     wantB "{Class: SmallInteger }"
      w     "{Class: SmallInteger }"
      h     "{Class: SmallInteger }"
      index "{Class: SmallInteger }"
      fixR  "{Class: SmallInteger }"
      fixG  "{Class: SmallInteger }"
      fixB  "{Class: SmallInteger }"
-     fixIds failed|
+     fixIds failed map|
 
     aDevice ~~ Display ifTrue:[^ nil].
 
@@ -762,10 +756,8 @@
 %{
     int __x, __y;
     int __eR, __eG, __eB;
-    int __wantR, __wantG, __wantB;
     unsigned char *srcP, *dstP;
     unsigned char *redP, *greenP, *blueP;
-    int pix;
     unsigned char *idP;
     int __fR, __fG, __fB;
     int iR, iG, iB;
@@ -794,8 +786,9 @@
 	for (__y=_intVal(h); __y>0; __y--) {
 	    __eR = __eG = __eB = 0;
 	    for (__x=_intVal(w); __x>0; __x--) {
-		int t;
 		int __want;
+		int pix;
+		int __wantR, __wantG, __wantB;
 
 		pix = *srcP++;
 
@@ -814,28 +807,37 @@
 		else if (__wantR < 0) __want = 0;
 		else __want = __wantR;
 
-		iR = __want * __fR / 128;
-		iR = (iR / 2) + (iR & 1);
+		iR = (__want * __fR + 128) / 255; /* red index rounded */
+#ifdef OLD
+		iR = __want * __fR / 128;  /* red index * 2 */
+		iR = (iR / 2) + (iR & 1);  /* red index rounded */
+#endif
 		idx = iR * (__fG+1);
 
 		if (__wantG > 255) __want = 255;
 		else if (__wantG < 0) __want = 0;
 		else __want = __wantG;
 
+		iG = (__want * __fG + 128) / 255; /* green index rounded */
+#ifdef OLD
 		iG = __want * __fG / 128;
 		iG = (iG / 2) + (iG & 1);
+#endif
 		idx = (idx + iG) * (__fB+1);
 
 		if (__wantB > 255) __want = 255;
 		else if (__wantB < 0) __want = 0;
 		else __want = __wantB;
 
+		iB = (__want * __fB + 128) / 255; /* blue index rounded */
+#ifdef OLD
 		iB = __want * __fB / 128;
 		iB = (iB / 2) + (iB & 1);
+#endif
 		idx = idx + iB;
 
 		/*
-		 * store the corresponding dither colorId
+		 * store the corresponding dither colors colorId
 		 */
 		*dstP++ = idP[idx];
 
@@ -852,57 +854,21 @@
     failed ifTrue:[
 	self primitiveFailed.
 	^ nil
-
-"/ for non-C programmers:
-"/   the above code is (roughly) equivalent to:
-"/
-"/    index := 1.
-"/    1 to:h do:[:y |
-"/        eR := eG := eB := 0.
-"/        1 to:w do:[:x |
-"/            |pixel "{ Class: SmallInteger }"
-"/             clr 
-"/             wR    "{ Class: SmallInteger }"
-"/             wG    "{ Class: SmallInteger }"
-"/             wB    "{ Class: SmallInteger }" |
-"/
-"/            pixel := (bytes at:index) + 1.
-"/
-"/            wantR := ((redBytes at:pixel) + eR).
-"/            wantG := ((greenBytes at:pixel) + eG).
-"/            wantB := ((blueBytes at:pixel) + eB).
-"/            wR := wantR.
-"/            wR > 200 ifTrue:[wR := 200] ifFalse:[wR < 0 ifTrue:[wR := 0]].
-"/            wG := wantG.
-"/            wG > 200 ifTrue:[wG := 200] ifFalse:[wG < 0 ifTrue:[wG := 0]].
-"/            wB := wantB.
-"/            wB > 200 ifTrue:[wB := 200] ifFalse:[wB < 0 ifTrue:[wB := 0]].
-"/
-"/            iR := wR * (fixR-1) / 128.
-"/            iR := (iR / 2) + (iR bitAnd:1).
-"/            iG := wG * (fixG-1) / 128.
-"/            iG := (iG / 2) + (iG bitAnd:1).
-"/            iB := wB * (fixB-1) / 128.
-"/            iB := (iB / 2) + (iB bitAnd:1).
-"/            idx := (iR * fixR + iG) * fixB + iB.
-"/            clr := fixColors at:idx. 
-"/
-"/            eR := wantR - (clr red * 2) asInteger.
-"/            eG := wantG - (clr green * 2) asInteger.
-"/            eB := wantB - (clr blue * 2) asInteger.
-"/
-"/            pixel := clr colorId.
-"/            pseudoBits at:index put:pixel.
-"/
-"/            index := index + 1
-"/        ].
-"/    ].
     ].
 
     f := Form width:width height:height depth:deviceDepth on:aDevice.
     f isNil ifTrue:[^ nil].
-    f colorMap:fixColors. 
+    "/
+    "/ have to create a funny colorMap, where
+    "/ color at:index == color colorId:index
+    "/
+    map := Array new:256.
+    fixColors do:[:clr |
+	map at:clr colorId + 1 put:clr
+    ].
+    f colorMap:map. 
     f initGC.
+    f bits:pseudoBits.
     aDevice drawBits:pseudoBits bitsPerPixel:8 depth:deviceDepth  
 	       width:width height:height
 		   x:0 y:0
@@ -911,9 +877,10 @@
     ^ f
 
     "
-     example: color reduction from Depth8 to Depth4 can be done by:
+     example: 
+	color reduction from Depth8 to Depth4 (dithering) can be done by:
 
-     |img8 reducedImg8 img4 map|
+     |img8 reducedImg8 img4 map form|
 
      map := #( 
 		  (0     0   0)
@@ -937,7 +904,7 @@
 			nRed:2
 		      nGreen:3
 		       nBlue:2.
-     img8 := Depth8Image fromForm:form.
+     img8 := Depth8Image fromForm:form.    'dithered version of original image'.
      img4 := Depth4Image fromImage:img8.
     "
 !