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Python Wrapper

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Revision as of 18:16, 28 November 2010 by Brandyn (talk | contribs) (About)
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"Python API, Documents and Stuff"


The Python wrapper is written in Cython Ctypes. This is the Cython-based libfreenect Python wrappers. This provides async (e.g., using callbacks) and sync (e.g., simple function calls) interfaces to libfreenect. The majority of the runloop is abstracted so that later upstream modifications will have minimal impact on your code; however, you are free to implement your own runloop and access all available functionality. The interface is designed to mimic the C library except where 1.) It is impractical or 2.) It would be "Un-Pythonic" to do so. See "Differences with C Library" for specific instances of this. The exposed interface supports both asynchronous (e.g., callback) and synchronous (e.g., call and block) functions which is enabled by the C_Sync_Wrapper.

We have been through several iterations of these wrappers in Pure C, Ctypes, and Cython. Cython is by far the easiest to maintain (as the main lib changes regularly) while maintaining C-like speed. It does require Cython to install the C code; however, this is available for all supported platforms. If this becomes a burden we can easily include the generated C code in the repo. The other dependencies are the same for pure C python extensions.

A variety of demos are provided using all available kinect features with examples for Matplotlib and OpenCV display.

Who is involved

Search for Python in People

However (Brandyn) and (amiller) are trying to organize things for Python.

Differences with C Library

Functions in the C library of the form freenect_blah are accessed as freenect.blah. The reason for this is Python has good module level namespace support and the function name's differ by 1 character. This also goes for enumerated constants that have the FREENECT_ prefix.

The init functions all return the initialized value as opposed to using the C-style of passing a double pointer.

In C:

 freenect_init(&ctx, 0)


 ctx = init()

How to compile


Example Python Scripts

(amiller) has a few Python demo scripts at