Treepoem
A cleverly named, but very simple python barcode renderer wrapping the
BWIPP library and ghostscript
command line tool.
Installation
Install from pip:
python -m pip install treepoem
Python 3.8 to 3.12 supported.
You'll also need Ghostscript installed. On Ubuntu/Debian this can be installed with:
apt-get install ghostscript
On Mac OS X use:
brew install ghostscript
Otherwise refer to your distribution's package manager, though it's likely to
be called ghostscript
too.
There's a known issue with rendering on Ghostscript 9.22+ where images are smeared. See GitHub Issue #124 and its associated links for more details. Ghostscript merged a fix in version 9.26 and common barcodes seem to work from then on, though still with some smearing.
You can check your Ghostscript version with:
gs --version
Working on a Django project? Improve your skills with one of my books.
API
generate_barcode(barcode_type: str, data: str | bytes, options: dict[str, str | bool] | None=None) -> EpsImageFile
Generates a barcode and returns it as a PIL image file object (specifically, a
PIL.EpsImagePlugin.EpsImageFile
).
barcode_type
is the name of the barcode type to generate (see below).
data
is a str
or bytes
of data to embed in the barcode - the amount
that can be embedded varies by type.
options
is a dictionary of strings-to-strings of extra options to be passed
to BWIPP, as per its docs.
For example, this generates a QR code image, and saves it to a file using
standard PIL Image.save()
:
>>> import treepoem
>>> image = treepoem.generate_barcode(
... barcode_type="qrcode", # One of the BWIPP supported codes.
... data="barcode payload",
... )
>>> image.convert("1").save("barcode.png")
If your barcode image is monochrome, with no additional text or
coloring, converting the Image
object to monochrome as shown above
(image.convert('1')
) will likely reduce its file size.
barcode_types: dict[str, BarcodeType]
This is a dict
of the ~100 names of the barcode types that the vendored
version of BWIPP supports: its keys are str
s of the barcode type encoder
names, and the values are instances of BarcodeType
.
BarcodeType
A class representing meta information on the types. It has two attributes:
type_code
- the value needed for thebarcode_type
argument ofgenerate_barcode()
to use this type.description
- the human level description of the type which has twostr
.
Only these common types are used in the test suite:
qrcode
- QR Codeazteccode
- Aztec Codepdf417
- PDF417interleaved2of5
- Interleaved 2 of 5code128
- Code 128code39
- Code 39
Command-line interface
Treepoem also includes a simple command-line interface to the
functionality of generate_barcode
. For example, these commands
will generate two QR codes with identical contents, but different levels
of error correction (see QR Code Options):
$ treepoem -o barcode1.png -t qrcode "This is a test" eclevel=H
$ treepoem -o barcode2.png -t qrcode "^084his is a test" eclevel=L parse
Complete usage instructions are shown with treepoem --help
.
What's so clever about the name?
Barcode.
Bark ode.
Tree poem.
Updating BWIPP
For development of treepoem, when there's a new BWIPP release:
- Download the latest monolithic zip file from https://github.com/bwipp/postscriptbarcode/releases
- Unzip the files into src/treepoem/postscriptbarcode
- Remove the unneded docs subdirectory.
- Run make_data.py from the root of the repo to update the barcode types that treepoem knows about.
- Add a CHANGELOG note about the upgrade.
- Commit and make a pull request, for examples see https://github.com/adamchainz/treepoem/pulls?utf8=%E2%9C%93&q=is%3Apr+is%3Aclosed+upgrade+bwipp