python-barcode

0.16.1 · active · verified Sat Apr 11

python-barcode provides a simple way to create standard barcodes in Python. It requires no external dependencies for generating SVG files. For outputting image formats like PNGs, the optional Pillow library is needed. The current version is 0.16.1, supporting Python 3.9 up to 3.13. The library maintains an active development status with regular updates addressing Python compatibility and bug fixes.

Warnings

breaking Older versions introduced significant API changes, such as moving writer classes from subpackages to modules (v0.5.0) and modifying the `render` method's API (v0.2.1). Version 0.14.0 changed default dimensions for better PNG/SVG consistency, and v0.15.x dropped support for Python 3.6. Always consult the changelog for major version upgrades.
Fix: Review the official changelog when upgrading, especially for major and minor version bumps, to adapt to API changes or deprecated Python versions. For Python 3.6, upgrade your Python environment to 3.9 or newer.
gotcha Barcode checksums are automatically calculated by the library for most standard formats (e.g., EAN13, ISBN13). Providing an input number that already includes a checksum, or one with an incorrect length, can lead to invalid barcodes or errors. For EAN13, provide a 12-digit number; the 13th check digit is added automatically.
Fix: Always provide the base number without the check digit for barcode types where the library calculates it. Refer to the documentation for the specific length requirements of each barcode format.
gotcha Generating image formats (like PNG, JPEG) using `ImageWriter` requires the `Pillow` library to be installed. Without `Pillow`, attempts to use `ImageWriter` will result in an `ImportError` or other runtime errors related to missing image processing capabilities.
Fix: Install `Pillow` using the extra: `pip install "python-barcode[images]"`. Ensure Pillow is available in your environment when using `ImageWriter`.
gotcha When bundling applications with PyInstaller (or similar tools), `python-barcode` may fail to find its internal font files (`DejaVuSansMono.ttf`) for rendering text on barcodes, leading to `IOError` or similar exceptions.
Fix: One common workaround is to modify the `writer.py` file within your `site-packages/barcode` directory (or a copied version for your project) to explicitly set `self.font_path = 'arial.ttf'` or embed `DejaVuSansMono.ttf` and adjust the path accordingly for your PyInstaller bundle. This often involves ensuring 'arial.ttf' is available in the system or bundled.

Install

pip install python-barcode Base installation (SVG output)
pip install "python-barcode[images]" Installation with Pillow for image output (e.g., PNG, JPEG)

Imports

EAN13
```
from barcode import EAN13
```
Common barcode type, directly importable from the top-level package.
SVGWriter
```
from barcode.writer import SVGWriter
```
The writer class for generating SVG format barcodes.
ImageWriter
```
from barcode.writer import ImageWriter
```
The writer class for generating image formats (requires Pillow).
Code128
```
from barcode.codex import Code128
```
In older versions, some barcode types like Code128 might have been directly importable from `barcode`. Since version 0.10.0 and above, most codex-based barcode types (like Code128, Code39) are located under `barcode.codex`.

Quickstart

This quickstart demonstrates generating an EAN13 barcode as an SVG file and a Code128 barcode as a PNG image. The PNG generation specifically highlights the dependency on Pillow and shows how to handle potential `ImportError`. It includes both direct file writing and in-memory byte stream handling for images.

import os
from io import BytesIO
from barcode import EAN13, Code128
from barcode.writer import SVGWriter, ImageWriter

# Example 1: Generate EAN13 as SVG
number_ean13 = '590123412345' # 12 digits, 13th (checksum) is calculated
ean = EAN13(number_ean13, writer=SVGWriter())
with open('ean13_barcode.svg', 'wb') as f:
    ean.write(f)
print('Generated ean13_barcode.svg')

# Example 2: Generate Code128 as PNG (requires Pillow)
try:
    # Use a dummy number for Code128, it supports alphanumeric data
    code128_data = 'MY-PRODUCT-ABC-123'
    code = Code128(code128_data, writer=ImageWriter())
    # To write to a file directly, ensure the output path is writable
    # code.write(open('code128_barcode.png', 'wb'))

    # Or, to an in-memory byte stream, then save
    # This pattern is good for web apps or if you don't want to save to disk immediately
    fp = BytesIO()
    code.write(fp)

    # Simulate saving from BytesIO if Pillow is available
    from PIL import Image
    fp.seek(0) # Rewind to the beginning of the stream
    img = Image.open(fp)
    img.save('code128_barcode.png')
    print('Generated code128_barcode.png (requires Pillow)')

except ImportError:
    print("Pillow not installed. Skipping PNG generation. Install with: pip install \"python-barcode[images]\".")
except Exception as e:
    print(f"Error generating Code128 PNG: {e}")

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