pyzbar 0.1.4

A ctypes-based wrapper around the zbar barcode reader.

A ctypes-based Python wrapper around the zbar barcode reader.

The zbar wrapper is stuck in Python 2.x-land. The zbarlight wrapper doesn’t provide support for Windows and depends upon Pillow. This ctypes-based wrapper brings zbar to Python 2.7 and to Python 3.4 or greater.

Installation

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

On Mac OS X:

brew install zbar

On Linux:

sudo apt-get install libzbar0

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

pip install pyzbar
pip install pyzbar[scripts]

Example usage

The decode function accepts instances of PIL.Image.

>>> from pyzbar.pyzbar import decode
>>> from PIL import Image
>>> decode(Image.open('pyzbar/tests/code128.png'))
[Decoded(data=b'Foramenifera', type='CODE128'),
 Decoded(data=b'Rana temporaria', type='CODE128')]

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

>>> import cv2
>>> decode(cv2.imread('pyzbar/tests/code128.png'))
[Decoded(data=b'Foramenifera', type='CODE128'),
 Decoded(data=b'Rana temporaria', type='CODE128')]

You can also provide a tuple (pixels, width, height), where the image data is eight bits-per-pixel.

>>> image = cv2.imread('pyzbar/tests/code128.png')
>>> height, width = image.shape[:2]

>>> # 8 bpp by considering just the blue channel
>>> decode((image[:, :, 0].astype('uint8').tobytes(), width, height))
[Decoded(data=b'Foramenifera', type='CODE128'),
 Decoded(data=b'Rana temporaria', type='CODE128')]

>>> # 8 bpp by converting image to greyscale
>>> grey = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
>>> decode((grey.tobytes(), width, height))
[Decoded(data=b'Foramenifera', type='CODE128'),
 Decoded(data=b'Rana temporaria', type='CODE128')]

>>> # If you don't provide 8 bpp
>>> decode((image.tobytes(), width, height))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/lawh/projects/pyzbar/pyzbar/pyzbar.py", line 102, in decode
    raise PyZbarError('Unsupported bits-per-pixel [{0}]'.format(bpp))
pyzbar.pyzbar_error.PyZbarError: Unsupported bits-per-pixel [24]

zbar’s default behaviour is (I think) to decode all symbol types. You can ask zbar to look for just your symbol types (I have no idea of the effect of this on performance)

>>> from pyzbar.pyzbar import ZBarSymbol
>>> # Look for just qrcode
>>> decode(Image.open('pyzbar/tests/qrcode.png'), symbols=[ZBarSymbol.QRCODE])
[Decoded(data=b'Thalassiodracon', type='QRCODE')]

>>> # If we look for just code128, the qrcodes in the image will not be detected
>>> decode(Image.open('pyzbar/tests/qrcode.png'), symbols=[ZBarSymbol.CODE128])
[]

License

pyzbar is distributed under the MIT license (see LICENCE.txt). The zbar shared library is distributed under the GNU Lesser General Public License, version 2.1 (see zbar-LICENCE.txt).