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From: "Joris" <joris.at.lebbeke@skynet.be>
To: <pwatkins@crawfordtech.com>, <tiff@lists.maptools.org>
References: <20060313153515.361DAB203@mail.business.allstream.net>
Subject: Re: [Tiff] CCITT Group 4 images
Date: Mon, 13 Mar 2006 17:19:17 +0100
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Status:   

Philip,

Philip Watkinson wrote:
> I have CCITT Group 4 compressed images that are not contained
> within TIFF files. Can I use Libtiff to decompress the images?

It is possible, but it is not easy.

You can redefine the LibTiff IO routines. Thus, you can make 'm such
that they 'read' a fake valid TIFF file header, a fake valid TIFF IFD,
and your real CCITT group 4 data, all combined into a valid TIFF.
LibTiff's output then is the decompressed data.

Similar techniques are used in the tiff2pdf contribution.

Joris Van Damme
info@awaresystems.be
http://www.awaresystems.be/
Download your free TIFF tag viewer for windows here:
http://www.awaresystems.be/imaging/tiff/astifftagviewer.html

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