Add a mask to an image from ImageData item

[payno]

I would like to provide a mask to an image. So either displaying or hiding the pixels of the image.

But the following code seems not to take into account the mask:

import numpy
from silx import sx

w = sx.plot()
item = w.addImage(numpy.arange(1024**2).reshape(1024, 1024))

mask = numpy.ones((1024, 1024))
mask[400:800] = 0

item.setMaskData(mask)