Hi to all

I'm new in scikit-image, and i develop algorithms for medical applications.

Sometimes is very very useful to have user interaction, in particular Region of Interest (ROI) selection over an image. I found in skimage the RectangleTool and i'm trying to write a simple ROI selector in order to use the rectangle coords in successive computations.

unfortunately i can't be able to handle mouse events: for example if i've:

#import
import skimage as sk
from skimage import data
import matplotlib.pyplot as plt
from skimage.viewer.canvastools import RectangleTool
import numpy as np
from skimage.draw import polygon
from skimage.draw import line

im = data.lena()
f, ax = plt.subplots()
plt.imshow(im)

def cable(img):
    
   # is here usable "extents?"


rect_tool = RectangleTool(ax,on_enter=cable(im))

i simply want to see "extents" which is the attribute that store coords for user-selected rectangle according to

http://scikit-image.org/docs/dev/api/skimage.viewer.canvastools.html?highlight=rectangle#skimage.viewer.canvastools.RectangleTool

i hope this is clear and if it's possible i think is useful to embed this example in docs.

thanks in advance