simple evented model demo in napari

evented_model_demo.py

from typing import Tuple

import napari
import scipy.ndimage as ndi
import numpy as np
from psygnal import EventedModel


viewer = napari.Viewer(ndisplay=3)
mask_layer = viewer.add_image(mask := np.zeros((128, 128, 128)))


class SphericalMaskParameters(EventedModel):
    """simple evented model (dataclass) with parameters for mask creation"""
    sidelength: int
    position: Tuple[int, int, int]
    radius: int


def create_sphere_mask(mask_parameters: SphericalMaskParameters) -> np.ndarray:
    """Create a spherical mask with specific parameters"""
    ones = np.ones((128, 128, 128))
    ones[mask_parameters.position] = 0
    edt = ndi.distance_transform_edt(ones)
    mask = np.logical_and(edt < mask_parameters.radius, edt != 0)
    return mask

# instantiate the mask parameters class
parameters = SphericalMaskParameters(sidelength=128, position=(64, 64, 64), radius=20)

# define a callback which will be called whenever field values on the model change
def update_viewer():
    """callback to update mask data in the viewer"""
    global parameters, mask_layer
    mask = create_sphere_mask(parameters)
    mask_layer.data = mask

# connect events from evented model so that GUI is updated
parameters.events.sidelength.connect(update_viewer)
parameters.events.position.connect(update_viewer)
parameters.events.radius.connect(update_viewer)

# put local variables in the napari console so they can be played with from napari
viewer.window._qt_viewer.console.push(locals())

napari.run()