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TIFF and LibTiff Mail List Archive

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2001.03.21 15:19 "Wang tiff", by Neil Durant
2001.03.21 16:10 "Re: Wang tiff", by Helge Blischke
2001.03.21 16:20 "Re: Wang tiff", by Neil Durant
2001.03.21 17:21 "Re: Wang tiff", by Nenad Rijavec
2001.03.21 17:33 "Re: Wang tiff", by Neil Durant
2001.03.21 16:44 "Re: Wang tiff", by Neil Durant
2001.03.21 17:14 "Re: Wang tiff", by Helge Blischke
2001.03.21 17:02 "Re: Wang tiff", by Nenad Rijavec
2001.03.21 17:13 "Re: Wang tiff", by Neil Durant
2001.03.21 18:33 "Re: Wang tiff", by Rex Jolliff
2001.03.21 18:45 "Re: Wang tiff", by Neil Durant
2001.03.21 19:46 "Re: Wang tiff", by Dave Abercrombie
2001.03.21 19:46 "Re: Wang tiff", by Yaron Kober
2001.03.23 13:09 "Re: Wang tiff", by Ross

2001.03.21 17:21 "Re: Wang tiff", by Nenad Rijavec

Neil,

I looked at the sample file. This is a single-page Wang TIFF, which means that it can be treated as a TIFF file with an unknown tag. Wang private tag, 0x80a6, contains an offset to the page control structure. In your file, this value is 0, which means the page contains a single page only. I should note, though, that the Wang files I've seen so far use 0x80a7 tag, so I am conjecturing a bit.

I think the problem you face is not Wang format, but rather your JPEG compression. The file uses the old-style compression 6 (JPEG). And uses it with vengeance - the Huffman and quantization tables are scattered throughout, and each block row is compressed in a separate strip. It's well known that this type of compression is ill-defined and should not be used, which is why you are having trouble finding the readers for your file.

Assuming all your files have the same format, you might use the data in your file to reassemble a proper JFIF file without actually decompressing your bitmap.

Regards,

Nenad

Neil Durant <neil@sphere3.demon.co.uk>@olympiakos.com on 03/21/2001 09:20:21 AM

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Subject: Re: Wang tiff