Writing plugins for Segno

segno.QRCode provides a plugin architecture which utilizes egg entry points.

All plugins must use the segno.plugin.converter entry point to be recognized. If a plugin is detected, the user may use the the plugin by calling to_XXX where XXX refers to the plugin name.

The specific plugin is invoked by providing the segno.QRCode instance and any further arguments or keywords.

Simple plugin

This section explains how to write a plugin which writes to stdout and uses X for dark modules and _ for light modules.

Content of simple_plugin.py:

import sys

def write(qrcode):
    write = sys.stdout.write
    for row in qrcode.matrix:
        for col in row:
            write('X' if col else '_')
        write('\n')

setup.py:

setup(
    name='simple-plugin',
    version='1.0',
    license='BSD',
    author='John Doe',
    author_email='[email protected]',
    platforms=['any'],
    py_modules=['simple_plugin'],
    entry_points="""
    [segno.plugin.converter]
    simple = simple_plugin:write
    """,
    install_requires=['segno'],
)

Once installed, it’s possible to call this plugin via:

>>> import segno
>>> qr = segno.make('Chelsea Hotel No. 2')
>>> qr.to_simple()
XXXXXXX_XXXX_XX_X_XXXXXXX
X_____X___________X_____X
X_XXX_X_XX__XXX___X_XXX_X
X_XXX_X__X_XXX_X__X_XXX_X
X_XXX_X__XX_XX__X_X_XXX_X
X_____X_X__XXX__X_X_____X
XXXXXXX_X_X_X_X_X_XXXXXXX
__________X_X__XX________
X_X___XX__XXXXX_X__X__X_X
_XX__X_XXXXXX__XX_XX_X__X
_X____X____X_XXXX__XX_X_X
_XX__X_XX_XXX__XXXX_XX___
__X_XXXX_XXX_XX_X_XXXX_X_
_____X_X_X___X__XXXX_XX_X
XXXXX_X_X_XX___XX_XXXXX_X
____XX__XXX__X_______X_XX
XX_X__X__XXXXX_XXXXXX__XX
________X_X_X___X___X____
XXXXXXX_X___XXX_X_X_X___X
X_____X__X_XX_X_X___XX_XX
X_XXX_X___X__XXXXXXXXX_XX
X_XXX_X______XX__X__XX_X_
X_XXX_X_XXXX_____X_XX_XXX
X_____X___X__X__XX_X_X___
XXXXXXX_XXXXXX__X_XXXX__X