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September 2007

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2007.09.23 16:42 "G3 fax: EOL needed at the beginning of each strip?", by Comsquare Martin Osieka
2007.09.24 01:27 "Re: G3 fax: EOL needed at the beginning of each strip?", by Bob Friesenhahn
2007.09.24 05:56 "Re: G3 fax: EOL needed at the beginning of each strip?", by Joris Van Damme
2007.09.24 07:24 "Re: G3 fax: EOL needed at the beginning of each strip?", by Comsquare Martin Osieka
2007.09.24 07:51 "Re: G3 fax: EOL needed at the beginning of each strip?", by Joris Van Damme
2007.09.24 08:01 "Re: G3 fax: EOL needed at the beginning of each strip?", by Andy Cave
2007.09.24 08:32 "Re: G3 fax: EOL needed at the beginning of each strip?", by Joris Van Damme
2007.09.24 08:52 "Re: G3 fax: EOL needed at the beginning of each strip?", by Comsquare Martin Osieka
2007.09.24 08:58 "Re: G3 fax: EOL needed at the beginning of each strip?", by Andy Cave
2007.09.24 08:45 "Re: G3 fax: EOL needed at the beginning of each strip?", by Andy Cave
2007.09.24 09:03 "Re: G3 fax: EOL needed at the beginning of each strip?", by Joris Van Damme

2007.09.24 08:01 "Re: G3 fax: EOL needed at the beginning of each strip?", by Andy Cave

Hi Joris,

I'm curious - where in the spec does it indicate strips have to start with 
EOL? I don't remember it saying so, and checking quickly, I can't find a 
reference to that.

Thanks,

Andy.

----- Original Message ----- 
From: "Joris" <joris.at.lebbeke@skynet.be>
To: "ComSquare Martin Osieka" <martin.osieka@comsquare.ch>; 
<tiff@lists.maptools.org>
Sent: Monday, September 24, 2007 6:56 AM
Subject: Re: [Tiff] G3 fax: EOL needed at the beginning of each strip?


> Martin,
> ...
> The spec clearly indicates strips have to start with EOL. Unfortunately, 
> I've a reasonable amount (i.e. not just a fluke) of testimages where 
> garbage data preceeds the G3 block. LibTiff succeeds on these images by 
> skipping to the first EOL. If we were to change LibTiff to start decoding 
> right away, more unexpected stuff will happen on these images with 
> preceeding garbage data that might just be more frequent.
>
> In AsTiff, what I do if the strip or tile doesn't start with an EOL, is 
> actually test and see if a line of desired length can successfully be 
> decoded from the preceeding data, and if that data then is followed by an 
> EOL. If so, I regard that the first line. If not, the code starts at the 
> first EOL instead. This works on both the testimages with random 
> preceeding data, and the testimages that just lack the first EOL. But the 
> LibTiff fax decoder being as it is, a heap of macro's with embedded 
> macro's that nobody at this stage can easilly decipher, it may be hard to 
> make it behave equally intelligent.
> ...