Installation

The libdmtx DLLs are included with the Windows Python wheels. On other operating systems, you will need to install the libdmtx shared library.

On Mac OS X:

brew install libdmtx

On Linux:

sudo apt-get install libdmtx0a

Install this Python wrapper; use the second form to install dependencies of the read_datamatrix command-line script:

pip install pylibdmtx
pip install pylibdmtx[scripts]

Example usage

The decode function accepts instances of PIL.Image.

>>> from pylibdmtx.pylibdmtx import decode
>>> from PIL import Image
>>> decode(Image.open('pylibdmtx/tests/datamatrix.png'))
[Decoded(data='Stegosaurus', rect=Rect(left=5, top=6, width=96, height=95)),
 Decoded(data='Plesiosaurus', rect=Rect(left=298, top=6, width=95, height=95))]

It also accepts instances of numpy.ndarray, which might come from loading images using OpenCV.

>>> import cv2
>>> decode(cv2.imread('pylibdmtx/tests/datamatrix.png'))
[Decoded(data='Stegosaurus', rect=Rect(left=5, top=6, width=96, height=95)),
 Decoded(data='Plesiosaurus', rect=Rect(left=298, top=6, width=95, height=95))]

You can also provide a tuple (pixels, width, height)

>>> image = cv2.imread('pylibdmtx/tests/datamatrix.png')
>>> height, width = image.shape[:2]
>>> decode((image.tobytes(), width, height))
[Decoded(data='Stegosaurus', rect=Rect(left=5, top=6, width=96, height=95)),
 Decoded(data='Plesiosaurus', rect=Rect(left=298, top=6, width=95, height=95))]

Limitations

Feel free to submit a PR to address any of these.

• decoding only - no encoding

• I took the bone-headed approach of copying the logic in pydmtx’s decode function (in pydmtxmodule.c); there might be more of libdmtx’s functionality that could be used to read barcodes

• I exposed the bare minimum of functions, defines, enums and typedefs neede to reimplement pydmtx’s decode function

License

pylibdmtx is distributed under the MIT license (see LICENCE.txt). The libdmtx shared library is distributed under the Simplified BSD license (see libdmtx-LICENCE.txt).