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qimage2ndarray is a small python extension for quickly converting between QImages and numpy.ndarrays (in both directions). These are very common tasks when programming e.g. scientific visualizations in Python using PyQt4 as the GUI library.
Similar code was found in Qwt and floating around on mailing lists, but qimage2ndarray has the following unique feature set:
Supports conversion of scalar and RGB data, with arbitrary dtypes and memory layout, with and without alpha channels, into QImages (e.g. for display or saving using Qt).
Using a tiny C++ extension, qimage2ndarray makes it possible to create ndarrays that are views into a given QImage's memory.
This allows for very efficient data handling and makes it possible to modify Qt image data in-place (e.g. for brightness/gamma or alpha mask modifications).
qimage2ndarray is stable and unit-tested:
- proper reference counting even with views (ndarray.base points to the underlying QImage)
- handles non-standard widths and respects QImage's 32-bit row alignment
Masked arrays are also supported and are converted into QImages with transparent pixels.
Supports recarrays (and comes with an appropriate dtype) for convenient access to RGB(A) channels.
Supports value scaling / normalization to 0..255 for convenient display of arbitrary NumPy arrays.
Documentation
API documentation can be found in the doc/ subdirectory.
Code
The extension is open source, BSD-licensed, and the mercurial repository can be browsed online or cloned using Mercurial:
hg clone http://www.informatik.uni-hamburg.de/~meine/hg/qimage2ndarray/
Installation
The current release (version 1.0) is available for download below or via PyPI, i.e. you might just issue:
easy_install qimage2ndarray
to compile and install the extension.
Hint: If you want to specify another compiler, e.g. in order to use MinGW instead of the Microsoft compiler on Windows, you can do it like this:
python setup.py build -c mingw32 install
Latest Stable Release
| File: qimage2ndarray-1.0.tar.gz | (48.01 kb; Wed, Jun/09/2010) |  |
| File: qimage2ndarray-1.0.tar.gz.asc | (198 bytes; Wed, Jun/09/2010) | |
| File: qimage2ndarray-1.0.win32-py2.5.exe | (69.37 kb; Wed, Jun/09/2010) | |
| File: qimage2ndarray-1.0.win32-py2.5.exe.asc | (198 bytes; Wed, Jun/09/2010) | |
| File: qimage2ndarray-1.0.zip | (54.38 kb; Wed, Jun/09/2010) | |
| File: qimage2ndarray-1.0.zip.asc | (198 bytes; Wed, Jun/09/2010) | |
Changelog
- Version 1.0:
- Let array2qimage support 2 channels (gray + alpha)
- Fixed installation on OS X (where Qt libs come as "Frameworks")
- Version 0.2:
- Fixed endianness issues (tested on PowerPC arch)
- Simplified installation on Windows (e.g. with Qt DLLs bundled with PyQt)
- Version 0.1:
- Initial Relase
