1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
|
I/O Plugin Infrastructure
-------------------------
A plugin consists of two files, the source and the descriptor ``.ini``. Let's
say we'd like to provide a plugin for ``imshow`` using ``matplotlib``. We'll
call our plugin ``mpl``::
skimage/io/_plugins/mpl.py
skimage/io/_plugins/mpl.ini
The name of the ``.py`` and ``.ini`` files must correspond. Inside the
``.ini`` file, we give the plugin meta-data::
[mpl] <-- name of the plugin, may be anything
description = Matplotlib image I/O plugin
provides = imshow <-- a comma-separated list, one or more of
imshow, imsave, imread, _app_show
The "provides"-line lists all the functions provided by the plugin. Since our
plugin provides ``imshow``, we have to define it inside ``mpl.py``::
# This is mpl.py
import matplotlib.pyplot as plt
def imshow(img):
plt.imshow(img)
Note that, by default, ``imshow`` is non-blocking, so a special function
``_app_show`` must be provided to block the GUI. We can modify our plugin to
provide it as follows::
[mpl]
provides = imshow, _app_show
::
# This is mpl.py
import matplotlib.pyplot as plt
def imshow(img):
plt.imshow(img)
def _app_show():
plt.show()
Any plugin in the ``_plugins`` directory is automatically examined by
``skimage.io`` upon import. You may list all the plugins on your
system::
>>> import skimage as ski
>>> ski.io.find_available_plugins()
{'gtk': ['imshow'],
'matplotlib': ['imshow', 'imread', 'imread_collection'],
'pil': ['imread', 'imsave', 'imread_collection'],
'test': ['imsave', 'imshow', 'imread', 'imread_collection'],}
or only those already loaded::
>>> ski.io.find_available_plugins(loaded=True)
{'matplotlib': ['imshow', 'imread', 'imread_collection'],
'pil': ['imread', 'imsave', 'imread_collection']}
A plugin is loaded using the ``use_plugin`` command::
>>> ski.io.use_plugin('pil') # Use all capabilities provided by PIL
or
::
>>> ski.io.use_plugin('pil', 'imread') # Use only the imread capability of PIL
Note that, if more than one plugin provides certain functionality, the
last plugin loaded is used.
To query a plugin's capabilities, use ``plugin_info``::
>>> ski.io.plugin_info('pil')
>>>
{'description': 'Image reading via the Python Imaging Library',
'provides': 'imread, imsave'}
|
