updating matshow

I like the new matshow function. Is it possible to update

    > the data? I was looking for the equivalent of an imshow
    > object's set_data method, but it is not exposed to
    > matshow.

matshow returns the image object, so you should be able to call
set_data on this instance. Of course, the new array needs to have the
same aspect ratio as the original if you want the aspect preserving
features of matshow.

    > This is a nice function for plotting microscopy images,
    > since the aspect ratio is fixed. Is there any object to
    > allowing the origin kwarg to do reorient the origin of the
    > image? --

I don't think so. Take a look at the implementation of matshow in
pylab.py. It is broken into two pieces. The hard part is being done
in matplotlib.figure.figaspect, which creates the figure with the
right aspect ratio -- as long as you create an axes with equal width
and height, your axes will have the right aspect too.

You can use this figaspect yourself, and then simply call imshow with
the args you want.

  from matplotlib.figure import figaspect
  w,h = figaspect(arr)
  fig = figure(figsize=(w,h))
  ax = fig.add_axes([0.15, 0.09, 0.775, 0.775])
  ax.imshow(arr, origin='upper', interpolation='nearest')