OASA is a python library for manipulation of chemical formats that forms the base of BKChem.
Until very recently, it was used solely by BKChem and some of my private projects. However because there seems to be some demand for a library that can draw chemical structures to PNG, I decided to publish OASA separately from BKChem from time to time.
Even though OASA is already some 4 years old project, its API may be unstable. This is mainly because it was never before released outside of BKChem and I followed all significant API changes there. Therefore please do not expect a highly polished, well documented library. OASA is probably rather the opposite. You have been warned.
- reading and writing of SMILES, InChI, Molfile
- atom coordinate generation
- molecule rendering into PNG, PDF and SVG using cairo
- full streochemistry support (only cis/trans double bond stereochemistry is supported)
- many more I cannot remember now
The latest release is oasa-0.13.1.
Older releases are available here.
A kind of ChangeLog is available here.
There is also a special package for Windows systems available. It is no sophisticated auto-installer, but it contains a working copy of cairo for Windows, which might come handy.
To install this version, just copy the two directories
cairo from the package directory either inside your projects directory or into a system wide location, such as
C:\Python25\Lib\site-packages\. You can test if it works for you by running the
test.py script from the distribution directory. It should create an image file called
The windows package is created for Python 2.5 (or 2.6, see below), however the only version dependent part of the package is the file
cairo\_cairo.pyd. Replacing this file by the included
cairo\_cairo.pyd2.4 should make the package work with Python 2.4.