python-barcode

python-barcode is a pure-python library for generating barcodes in various formats.

Dependencies:

• SVG generation: No external dependencies required.
• Image generation (e.g., PNG): Requires the Pillow library to be installed in your environment.

You can implement custom rendering logic by inheriting from barcode.writer.BaseWriter. To work correctly, your custom writer must implement the following callbacks within its __init__ method:

1. initialize(raw_code)
2. paint_module(xpos, ypos, width, color)
3. paint_text(xpos, ypos)
4. finish()

To use it, instantiate your custom writer and pass it as an argument when creating a barcode instance. When render() is called on the barcode, your implementation's callbacks will be triggered.

You can install python-barcode via PyPI.

Note on dependencies:

• SVG generation: No external dependencies required.
• Image generation (e.g., PNG): Requires the Pillow library to be installed.

pip install python-barcode
# If you need to generate PNGs, also install Pillow:
pip install Pillow

Install the core library using pip:

pip install python-barcode

If you need to export barcodes as images (e.g., PNG, JPEG) instead of just SVG, you must install the images extra, which includes the necessary dependencies like Pillow:

pip install "python-barcode[images]"

Note: Use quotes around the package name in most shells to prevent issues with square brackets.

To generate SVG barcodes, use a barcode class (like EAN13) and provide an SVGWriter. You can write the output to a file-like object (e.g., BytesIO) or directly to a file.

Checksums are calculated automatically. For systems like Code 39 where checksums are optional, you can pass add_checksum=False as a keyword argument.

from io import BytesIO
from barcode import EAN13
from barcode.writer import SVGWriter

# Write to a file-like object:
rv = BytesIO()
EAN13("100000902922", writer=SVGWriter()).write(rv)

# Or to an actual file:
with open("somefile.svg", "wb") as f:
    EAN13(str(100000011111), writer=SVGWriter()).write(f)

To output a compressed SVG file, use the SVGWriter and set the compress option to True in the options dictionary passed to the save method.

import barcode

ean = barcode.get('ean13', '123456789102')
# Checksum is automatically added
print(ean.get_fullcode())

# Save standard SVG
filename = ean.save('ean13')
print(filename)  # 'ean13.svg'

# Save compressed SVGZ
options = dict(compress=True)
filename = ean.save('ean13', options)
print(filename)  # 'ean13.svgz'

To generate raster images, use ImageWriter. This requires the [images] extra to be installed.

Note: SVG files are vectorized and scale better than images. Use images only if your target medium does not support SVG.

from io import BytesIO
from barcode import EAN13
from barcode.writer import ImageWriter

# Write to a file-like object:
rv = BytesIO()
EAN13(str(100000902922), writer=ImageWriter()).write(rv)

# Or to an actual file:
with open("somefile.jpeg", "wb") as f:
    EAN13("100000011111", writer=ImageWriter()).write(f)

The generate() function provides a high-level way to create barcodes without manually instantiating classes. You specify the barcode type, the data, and optionally the writer and output destination.

from barcode import generate
from barcode.writer import ImageWriter
from io import BytesIO

# Generate an SVG file
name = generate('EAN13', '590123457', output='barcode_svg')

# Generate an image to a file-like object
fp = BytesIO()
generate('EAN13', '590123457', writer=ImageWriter(), output=fp)

The ImageWriter renders barcodes as images and supports any format compatible with the Pillow library. It supports all common writer options plus specific options for format and resolution.

Special Options:

• format: str. The image file format (e.g., 'PNG', 'JPEG', 'BMP'). Default: 'PNG'.
• dpi: int. Dots per inch used to calculate image size in pixels from mm values. Default: 300.

import barcode

ean = barcode.get('ean13', '123456789102')
# Save as a high-resolution JPEG
ean.save('ean13', options={'format': 'JPEG', 'dpi': 600})

You can retrieve a barcode class by its string identifier using barcode.get_barcode_class(). This is useful for selecting types dynamically at runtime.

Available barcode types can be found in barcode.PROVIDED_BARCODES.

import barcode

# List available types
print(barcode.PROVIDED_BARCODES)

# Get a specific class
EAN = barcode.get_barcode_class('ean13')
my_ean = EAN('590123457')

# Save to a file (automatically adds extension)
fullname = my_ean.save('ean13_barcode')