hover_part_5.py

def hover(event):
    # if the mouse is over the scatter points
    if line.contains(event)[0]:
        # find out the index within the array from the event
        ind, = line.contains(event)[1]["ind"]
        # get the figure size
        w,h = fig.get_size_inches()*fig.dpi
        ws = (event.x > w/2.)*-1 + (event.x <= w/2.) 
        hs = (event.y > h/2.)*-1 + (event.y <= h/2.)
        # if event occurs in the top or right quadrant of the figure,
        # change the annotation box position relative to mouse.
        ab.xybox = (xybox[0]*ws, xybox[1]*hs)
        # make annotation box visible
        ab.set_visible(True)
        # place it at the position of the hovered scatter point
        ab.xy =(x[ind], y[ind])
        # set the image corresponding to that point
        im.set_data(arr[ind,:,:])
    else:
        #if the mouse is not over a scatter point
        ab.set_visible(False)
    fig.canvas.draw_idle()