Read and write Data Matrix barcodes from Python 2 and 3 using the libdmtx library.
- Pure python
- Works with PIL / Pillow images, OpenCV / imageio / numpy
ndarray
s, and raw bytes - Decodes locations of barcodes
- No dependencies, other than the libdmtx library itself
- Tested on Python 2.7, and Python 3.5 to 3.10
The older pydmtx package is stuck in Python 2.x-land.
The libdmtx
DLL
s are included with the Windows Python wheels. On other operating systems, you will need to install the libdmtx
shared library.
Mac OS X:
brew install libdmtx
Linux:
sudo apt-get install libdmtx0a
The PyPI package is currently out-of-date; to install the latest version, use:
pip install git+https://github.com/NaturalHistoryMuseum/pylibdmtx.git
To use the read_datamatrix
and write_datamatrix
command-line scripts, you will also need to install Pillow >= 3.2.0:
pip install "Pillow>=3.2.0"
If you want to install the outdated package from PyPI:
pip install pylibdmtx
pip install pylibdmtx[scripts]
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))]
The encode
function generates an image containing a Data Matrix barcode:
>>> from pylibdmtx.pylibdmtx import encode
>>> encoded = encode('hello world'.encode('utf8'))
>>> img = Image.frombytes('RGB', (encoded.width, encoded.height), encoded.pixels)
>>> img.save('dmtx.png')
>>> print(decode(Image.open('dmtx.png')))
[Decoded(data=b'hello world', rect=Rect(left=9, top=10, width=80, height=79))]
If you see an ugly ImportError
when importing pylibdmtx
on Windows you will most likely need the Visual C++ Redistributable Packages for Visual Studio 2013. Install vcredist_x64.exe
if using 64-bit Python, vcredist_x86.exe
if using 32-bit Python.
Feel free to submit a PR to address any of these.
- I took the bone-headed approach of copying the logic in
pydmtx
’sdecode
function (in pydmtxmodule.c); there might be more oflibdmtx
’s functionality that could usefully be exposed - I exposed the bare minimum of functions, defines, enums and typedefs neede to reimplement
pydmtx
’sdecode
function
- Vinicius Kursancew (@kursancew) - first implementation of barcode writing
- Joseph Weston (@jbweston) - support for
libdmtx
0.7.5
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
).