Description:
tiffany 0.6.7
Tiffany - Read/Write Multipage-Tiff with PIL without PIL========================================================Tiffany stands for any tiff. The tiny module solves a large set ofproblems, has no dependencies and just works wherever Python works.Tiffany was developed in the course of the *Pydica* project and willnow appear on PyPi.Abstract========During the development of *Pydica* (Python Distributed Capture) we wereconfronted with the problem to read multipage Tiff scans. The GUI toolkit*PySide (Qt)* does support Tiff, but only shows the first page. We also hadto support Fax compression (CCITT G3/G4), but *Qt* supports this.As a first approach we copied single pages out of multi-page tiff filesusing *tiffcp* or *tiffutil* (OS X) as a temp file for display. A sub-optimumsolution, especially for data security reasons.The second approach replaced this by a tiny modification of the linkage ofthe tiff directories (IFD). This way, a tiff file could be patched in memorywith the wanted page offset and then be shown without any files involved.Unfortunately also this solution was not satisfactory:- our tiff files have anomalies in their tiff tags like too many null-bytes and wrong tag order,- Qt's implementation of tiff is over-pedantic and ignores all tags after the smallest error. Being a good friend of *Fredrik Lundh* and his *PIL* since years, I tried toattack the problem using this. Sadly Fredrik hasn't worked much on this since2006, and the situation is slightly messed up:*PIL* has a clean-up of tiff tags, but cannot cope with fax compression by default.There exists a patch since many years, but this complicates the build processand pulls with *libtiff* a lot of dependencies in.Furthermore, *PIL* is unable to write fax compressed files, but blows the dataup to the full size, making this approach only a half solution as well.After a longer odyssey I saw then the light of a Tiffany lamp:I use only a hand-full of *PIL*s files, without any modification, pretend to unpacka tiff file, but actually cheating. Only the tiff tags are nicely processed andstreamlined, but the compressed data is taken unmodified as-is.When writing a tiff page out, the existing data is just assembled in the correctorder.For many projects like *Pydica* that are processing tiff files without editingtheir contents, this is a complete solution of their tiff problem. The dependenciesof the project stay minimal, there are no binaries required, and Tiffany is withless than 300 lines remarkably small.Because just 5 files from *PIL* are used and the _imaging module is not compiledat all, I'm talking about "PIL without PIL" ;-)Tiffany is a stand-alone module and has no interference with *PIL*.You can see this by looking at ``import_mapper.py``. This module modifies ``__import__``so that the *PIL* modules appear as top-level internally, but become sub-modules oftiffany in ``sys.modules``.Please let me know if this stuff works for you, and send requests to<tismer@stackless.com> or use the links in the bitbucket website:https://bitbucket.org/pydica/tiffanyeasiest way to install tiffany: ``$ pip install tiffany``# EOF
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