How to develop a plugin

The following sections describe the 4 major rules to respect in order to create your python package you want to use as a Pandora plugin.

  1. Instantiate a subclass

Each subpackage of Pandora, representing one particular step, defines an abstract base classes

@matching_cost.AbstractMatchingCost.register_subclass('my_matching_cost_method')
class MYMATCHINGCOST(matching_cost.AbstractMatchingCost):

  1. Provide definitions of abstract methods

def desc(self):
    """
    Describes the matching cost method
    """
    print('My similarity measure')

def compute_cost_volume(self, img_left, img_right, disp_min, disp_max, **cfg)
    """
    """
    print ("Just an example")

  1. Implement a configuration checking method for parameters checking

def __init__(self, **cfg):

    self.cfg = self.check_config(**cfg)
    self._my_matching_cost_param = str(self.cfg['my_matching_cost_param'])
    self._window_size = self.cfg['window_size']
    self._subpix = self.cfg['subpix']

def check_config(self, **cfg):
    """
    Add default values to the dictionary if there are missing elements and check if the dictionary is correct

    :param cfg: matching_cost configuration
    :type cfg: dict
    :return cfg: matching_cost configuration updated
    :rtype: dict
    """
    # Give the default value if the required element is not in the configuration
    if 'window_size' not in cfg:
        cfg['window_size'] = self._WINDOW_SIZE
    if 'subpix' not in cfg:
        cfg['subpix'] = self._SUBPIX

    schema = {
        "matching_cost_method": And(str, lambda x: x == 'my_matching_cost_method'),
        "window_size": And(int, lambda x: x == 11),
        "subpix": And(int, lambda x: x == 1),
        "my_matching_cost_param": int,
    }

    checker = Checker(schema)
    checker.validate(cfg)
    return cfg desc(self):

  1. Make your plugin avalaible

Pandora works with entry point specification and can load all plugin refered in the “pandora.plugin” group.

So, you must declare, on your setup.cfg file, an entry point:

[metadata]
name = plugin_my_matching_cost_method
description = Pandora plugin to compute cost volume with my new matching cost algorithm

[options]
setup_requires =
    very-good-setuptools-git-version

[options.entry_points]
pandora.plugin =
    plugin_my_matching_cost_method = plugin_my_matching_cost_method.my_matching_cost_method:MYMATCHINGCOST