Newsgroups: sci.image.processing
From: Steve@dstrip.demon.co.uk (Steve Rencontre)
Path: cantaloupe.srv.cs.cmu.edu!das-news2.harvard.edu!news2.near.net!news.mathworks.com!uunet!news.sprintlink.net!peernews.demon.co.uk!dstrip.demon.co.uk!Steve
Subject: Re: THe 'libtiff' library & Intel TIFF support
References: <oleaD4H5M2.F69@netcom.com> <sbrogden.30.000C21FB@derwent.co.uk> <331159955wnr@dstrip.demon.co.uk>
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Date: Fri, 24 Feb 1995 20:05:51 +0000
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In article: <oleaD4H5M2.F69@netcom.com>  olea@netcom.com (Michael Olea) writes:
> 
> Steve@dstrip.demon.co.uk (Steve Rencontre) writes:
> >...you don't have to *understand* any of the TIFF tags, just swap 
> >bytes around.

> 	Swapping bytes in the tags is in general not sufficient.
> For example, the "stripOffsets" and "stripByteCounts" tags may point
> to data that would also need to be swapped to be consistent - or
> they may point to data that should be left alone.

I didn't mean (or say, IMO) that you should only swap bytes in the tags. 

> A program cannot
> distinguish such cases without *understanding* at least some of the
> tags.

No, the program must understand the TIFF rules, which say that a tag 
may *contain* or *point to* data, but in all cases, the format of the data 
(byte, word, longword, etc) is defined by the tag. However, the 
meaning of the data is irrelevant. I can define my own tag called 
privateNumberOfElephantsInScene and if I follow the rules, somebody 
else should be able to byte-swap my data correctly.


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Steve Rencontre               |  steve@dstrip.demon.co.uk (business) 
If it works, it's obsolete.   |  steveren@cix.compulink.co.uk (private)
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