Update positions of masked scatter points when updated - #558

import plopp as pp
import scipp as sc
import ipywidgets as ipw

%matplotlib widget

a = pp.Node(pp.data.scatter())
b = pp.data.scatter(seed=2) * 10.0
b.masks['m'] = b.coords['y'] > sc.scalar(10, unit='m')
b = pp.Node(b)

slider = ipw.FloatSlider(
    min=0,
    max=60,
    value=30,
    description='Position of orange group',
    style={'description_width': 'initial'},
    layout={'width': '500px'},
)
slider_node = pp.widget_node(slider)


@pp.node
def move(da, x):
    out = da.copy(deep=False)
    out.coords['x'] = da.coords['x'] + sc.scalar(x, unit=da.coords['x'].unit)
    return out


move_node = move(da=b, x=slider_node)

f = pp.scatterfigure(a, move_node, cbar=False, autoscale=False)
f.bottom_bar.add(slider)
f.canvas.xrange = [-40, 100]
f