Enable magicgui decorator on class member functions

Hi Talley @tlambert03 ,

thanks again for your support recently on the forum. I think I have a related feature request. To simplify my code, it would be nice if one could use magicgui on class member functions. In this way, the function could have access to a broader context, which is not handled in the magicgui.

To illustrate what I mean, take a look at this code:

import napari

from magicgui import magicgui
from napari.layers import Image


class MyObject:
    def __init__(self):
        self.counter = 0

    @magicgui(auto_call=True)
    def process_image(self, image : Image, sigma: float = 5):
        self.counter = self.counter + sigma
        print(self)

# load data
from skimage.io import imread
image = imread('https://samples.fiji.sc/blobs.png')

# start up napari
with napari.gui_qt():
    viewer = napari.Viewer()
    viewer.add_image(image, name='blobs')

    # generate a Graphical User Interface from the function above magically
    gui = MyObject().process_image.Gui()
    viewer.window.add_dock_widget(gui)

When executing it and increasing the sigma in the magic user interface, this error is thrown:

ERROR:root:Unhandled exception:
Traceback (most recent call last):
  File "C:\Users\rober\miniconda3\lib\site-packages\magicgui\core.py", line 532, in __call__
    value = self.func(**_kwargs)
  File "C:/structure/code/pyclesperanto_prototype/demo/napari_gui/napari_magicgui.py", line 17, in process_image
    self.counter = self.counter + sigma
AttributeError: 'str' object has no attribute 'counter'

Thus, the self variable is not correctly set in such a context. Do you think this could be implemented? I’m also open to other solutions if you see some.

Thanks!

Cheers, Robert

[tlambert03]

omg! it already works on the current master!! 🎉 (one of those super happy moments when something you’ve worked on for a while just magically fixes a different problem)

Try checking out the master branch here and using this code:

import napari
from napari.layers import Image
from skimage.io import imread

from magicgui import magicgui


class MyObject:
    def __init__(self):
        self.counter = 0.0

    def process_image(self, image: Image, sigma: float = 5):
        self.counter += sigma
        print(self.counter, sigma)


image = imread("https://samples.fiji.sc/blobs.png")

# start up napari
with napari.gui_qt():
    viewer = napari.Viewer()
    viewer.add_image(image, name="blobs")

    m = MyObject()
    gui = magicgui(m.process_image, auto_call=True)
    viewer.window.add_dock_widget(gui)

[tlambert03]

I’m actually going to leave this issue open, since the decorator syntax still won’t work, but it could be made to work and I like the idea.