[magick-users] image panning from the commandline using `display'

[Dean S. Messing]

Suppose I have a 1000x1000 image named im.png.

If I execute `display -geometry 200x200 im.png' I get
a 200x200 "viewport" of the image aligned at the top left corner.

How do I move the viewport on the command line?

Add offests, say `display -geometry 200x200+150+300 im.png', just
moves the X-window on the desktop but the contents are the same.  Basically
I'd like to "pan" the image from the commandline. 

How do I do it?

Dean