mirror of
https://github.com/wassname/scikit-image.git
synced 2026-07-01 07:27:48 +08:00
Stefan van der Walt
144 lines
3.8 KiB
Python
144 lines
3.8 KiB
Python
"""Handle image reading, writing and plotting plugins.
|
|
|
|
"""
|
|
|
|
__all__ = ['register', 'use']
|
|
|
|
import warnings
|
|
|
|
plugin_store = {'read': [],
|
|
'save': [],
|
|
'show': []}
|
|
|
|
def register(name, **kwds):
|
|
"""Register an image I/O plugin.
|
|
|
|
Parameters
|
|
----------
|
|
name : str
|
|
Name of this plugin.
|
|
read : callable, optional
|
|
Function with signature
|
|
``read(filename, as_grey=False, dtype=None, **plugin_specific_args)``
|
|
that reads images.
|
|
save : callable, optional
|
|
Function with signature
|
|
``write(filename, arr, **plugin_specific_args)``
|
|
that writes an image to disk.
|
|
show : callable, optional
|
|
Function with signature
|
|
``show(X, **plugin_specific_args)`` that displays an image.
|
|
|
|
"""
|
|
for kind in kwds:
|
|
if kind not in plugin_store.keys():
|
|
raise ValueError('Tried to register invalid plugin method.')
|
|
|
|
func = kwds[kind]
|
|
if not callable(func):
|
|
raise ValueError('Can only register functions as plugins.')
|
|
|
|
plugin_store[kind].append((name, func))
|
|
|
|
|
|
def call(kind, *args, **kwargs):
|
|
"""Find the appropriate plugin of 'kind' and execute it.
|
|
|
|
Parameters
|
|
----------
|
|
kind : {'show', 'save', 'read'}
|
|
Function to look up.
|
|
plugin : str, optional
|
|
Plugin to load. Defaults to None, in which case the first
|
|
matching plugin is used.
|
|
*args, **kwargs : arguments and keyword arguments
|
|
Passed to the plugin function.
|
|
|
|
"""
|
|
if not kind in plugin_store:
|
|
raise ValueError('Invalid function (%s) requested.' % kind)
|
|
|
|
plugin_funcs = plugin_store[kind]
|
|
if len(plugin_funcs) == 0:
|
|
raise RuntimeError('No suitable plugin registered for %s' % kind)
|
|
|
|
plugin = kwargs.pop('plugin', None)
|
|
if plugin is None:
|
|
_, func = plugin_funcs[0]
|
|
else:
|
|
try:
|
|
func = [f for (p,f) in plugin_funcs if p == plugin][0]
|
|
except IndexError:
|
|
raise RuntimeError('Could not find the plugin "%s" for %s.' % \
|
|
(plugin, kind))
|
|
|
|
return func(*args, **kwargs)
|
|
|
|
def use(name, kind=None):
|
|
"""Set the default plugin for a specified operation.
|
|
|
|
Parameters
|
|
----------
|
|
name : str
|
|
Name of plugin.
|
|
kind : {'save', 'read', 'show'}, optional
|
|
Set the plugin for this function. By default,
|
|
the plugin is set for all functions.
|
|
|
|
Examples
|
|
--------
|
|
|
|
Use Python Imaging Library to read images:
|
|
|
|
>>> from scikits.image.io import plugin
|
|
>>> plugin.use('PIL', 'read')
|
|
|
|
"""
|
|
if kind is None:
|
|
kind = plugin_store.keys()
|
|
else:
|
|
kind = [kind]
|
|
|
|
for k in kind:
|
|
if not k in plugin_store:
|
|
raise RuntimeError("Could not find plugin for '%s'" % k)
|
|
|
|
funcs = plugin_store[k]
|
|
|
|
# Shuffle the plugins so that the requested plugin stands first
|
|
# in line
|
|
funcs = [(n, f) for (n, f) in funcs if n == name] + \
|
|
[(n, f) for (n, f) in funcs if n != name]
|
|
|
|
n, f = funcs[0]
|
|
if not n == name:
|
|
warnings.warn(RuntimeWarning('Could not set plugin "%s" for'
|
|
' function "%s".' % (name, k)))
|
|
|
|
plugin_store[k] = funcs
|
|
|
|
def available(kind=None):
|
|
"""List available plugins.
|
|
|
|
Parameters
|
|
----------
|
|
kind : {'show', 'save', 'read'}, optional
|
|
Display the plugin list for the given function type. If not specified,
|
|
return a dictionary with the plugins for all functions.
|
|
|
|
"""
|
|
if kind is None:
|
|
kind = plugin_store.keys()
|
|
else:
|
|
kind = [kind]
|
|
|
|
d = {}
|
|
for k in kind:
|
|
if not k in plugin_store:
|
|
raise ValueError('No function "%s" exists in the plugin registry.'
|
|
% kind)
|
|
|
|
d[k] = [name for (name, func) in plugin_store[k]]
|
|
|
|
return d
|