pylibdmtx

0.1.10 verified Mon Apr 27 auth: no python

Python library for reading and writing Data Matrix barcodes, wrapping the libdmtx C library. Current version 0.1.10, low release cadence.

pip install pylibdmtx

Common errors

error OSError: libdmtx.so: cannot open shared object file ↓

cause libdmtx shared library not installed on Linux/macOS.

fix

Install libdmtx via system package manager: apt-get install libdmtx0 (Debian/Ubuntu) or brew install libdmtx (macOS).

error ImportError: cannot import name 'decode' from 'pylibdmtx' ↓

cause Importing from the top-level package instead of the submodule.

fix

Use: from pylibdmtx.pylibdmtx import decode

error AttributeError: 'NoneType' object has no attribute 'decode' ↓

cause decode() returned None (no barcode found).

fix

Check result is not None before accessing .data.

error TypeError: expected str, bytes or os.PathLike object, not BytesIO ↓

cause Passing a BytesIO object directly instead of a PIL Image.

fix

Open with Image.open(BytesIO(...)) to create PIL Image.

Warnings

breaking On Windows, libdmtx.dll must be in PATH. Use conda or manually add DLL directory. ↓

fix Install via conda-forge (includes bundled DLL) or copy libdmtx.dll to a PATH directory.

gotcha decode() returns bytes, not str. Must call .decode('utf-8') on data. ↓

fix Use result.data.decode('utf-8') or appropriate encoding.

gotcha Input image must be PIL Image, not file path. Open with Image.open() first. ↓

fix Always pass a PIL Image object to decode().

deprecated Python 2 support is deprecated; library still installs but may break on Python 2 EOL. ↓

fix Use Python 3.6+.

Install

conda install -c conda-forge pylibdmtx

Imports

decode
wrong
```
import pylibdmtx
```
correct
```
from pylibdmtx.pylibdmtx import decode
```
Top-level import does not expose decode; must import from submodule.
encode
```
from pylibdmtx.pylibdmtx import encode
```

Quickstart

Decode a Data Matrix barcode from an image file.

from PIL import Image
from pylibdmtx.pylibdmtx import decode

image = Image.open('datamatrix.png')
results = decode(image)
for result in results:
    print(result.data.decode('utf-8'))