AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

1994.09.16 04:17 "TIFF Bit Ordering Versus Fill Order", by John M Davison
1994.09.19 17:34 "Now that you mention bit order...", by Craig Jackson
1994.09.19 19:04 "Bit order revisited ...", by Scott Wagner
1994.09.19 22:46 "Re: Now that you mention bit order...", by Sam Leffler
1994.09.20 13:25 "RE: Now that you mention bit order...", by Scott Wagner
[...]

1994.09.19 19:04 "Bit order revisited ...", by Scott Wagner

However, there are times when a MSB-to-LSB order is convenient for processing, especially on big-endian machines. There are other times when a LSB-to-MSB order is more convenient. These cases may be more frequent on little-endian machines, but not restricted to them.

Since big-endian or MSB-to-LSB bit order is most commonly used, and since this issue tends to create LOTS of confusion, I maintain that the preferred course is to read (and frown upon) LSB-to-MSB order, read (and prefer) MSB-to-LSB order, and ALWAYS write MSB-to-LSB order. When performance issues arise, choose best berformance for big-endian or MSB-to-LSB bit order, and take the hit on LSB-to-MSB order.

Scott Wagner (wagner@itek.com)
Senior Engineer
Itek Graphix
Rochester, NY USA