Skip to main content

Tiffany -- read/write/arrange any multi-page Tiff, any compression

Project description

Tiffany - Read/Write Multipage-Tiff with PIL without PIL
========================================================

Tiffany stands for any tiff. The tiny module solves a large set of
problems, has no dependencies and just works wherever Python works.
Tiffany was developed in the course of the *Pydica* project and will
now appear on PyPi.

Abstract
========

During the development of *Pydica* (Python Distributed Capture) we were
confronted with the problem to read multipage Tiff scans. The GUI toolkit
*PySide (Qt)* does support Tiff, but only shows the first page. We also had
to support Fax compression (CCITT G3/G4), but *Qt* supports this.

As a first approach we copied single pages out of multi-page tiff files
using *tiffcp* or *tiffutil* (OS X) as a temp file for display. A sub-optimum
solution, especially for data security reasons.

The second approach replaced this by a tiny modification of the linkage of
the tiff directories (IFD). This way, a tiff file could be patched in memory
with 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 to
attack the problem using this. Sadly Fredrik hasn't worked much on this since
2006, 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 process
and pulls with *libtiff* a lot of dependencies in.

Furthermore, *PIL* is unable to write fax compressed files, but blows the data
up 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 unpack
a tiff file, but actually cheating. Only the tiff tags are nicely processed and
streamlined, but the compressed data is taken unmodified as-is.
When writing a tiff page out, the existing data is just assembled in the correct
order.

For many projects like *Pydica* that are processing tiff files without editing
their contents, this is a complete solution of their tiff problem. The dependencies
of the project stay minimal, there are no binaries required, and Tiffany is with
less than 300 lines remarkably small.

Because just 5 files from *PIL* are used and the _imaging module is not compiled
at 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 of
tiffany 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/tiffany

easiest way to install tiffany:

``$ pip install tiffany``

# EOF

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

tiffany-0.6.7.tar.gz (197.4 kB view hashes)

Uploaded Source

Built Distributions

tiffany-0.6.7-py3-none-any.whl (202.0 kB view hashes)

Uploaded Python 3

tiffany-0.6.7-py2-none-any.whl (202.0 kB view hashes)

Uploaded Python 2

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page