NaturalHistoryMuseum/pylibdmtx

Name: pylibdmtx

Owner: Natural History Museum

Description: Read Data Matrix barcodes from Python 2 and 3.

Created: 2016-11-01 08:32:59.0

Updated: 2018-05-17 01:29:41.0

Pushed: 2018-05-10 19:11:35.0

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Size: 87

Language: Python

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README

pylibdmtx

Read Data Matrix barcodes from Python 2 and 3 using the libdmtx library.

• Pure python
• Works with PIL / Pillow images, OpenCV / numpy ndarrays, and raw bytes
• Decodes locations of barcodes
• No dependencies, other than the libdmtx library itself
• Tested on Python 2.7, and Python 3.4 to 3.6

The older pydmtx package is stuck in Python 2.x-land.

Installation

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

Mac OS X:

 install libdmtx

Linux:

 apt-get install libdmtx0a

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

install pylibdmtx
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'))
oded(data='Stegosaurus', rect=Rect(left=5, top=6, width=96, height=95)),
oded(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'))
oded(data='Stegosaurus', rect=Rect(left=5, top=6, width=96, height=95)),
oded(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))
oded(data='Stegosaurus', rect=Rect(left=5, top=6, width=96, height=95)),
oded(data='Plesiosaurus', rect=Rect(left=298, top=6, width=95, height=95))]

Windows error message

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.

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).