ZOOM_VP scales the specified viewport by a factor.
---->(ZOOM_VP)----|viewport|----|factor|---->
This action has no options. The contents of the specified
viewport are magnified by the given factor.
Use this action to modify your view of a viewport.
A zoom factor greater than 1 will zoom in. A zoom factor of
less than 1 will zoom out. For example, the zoom factors -2
and 0.5 both zoom out by a factor of 2.
Note that the viewport is zoomed about a central point which
remains in place.
To zoom in by a factor of two on a viewport named "vport1":
ZOOM_VP "vport1" 2
DYNAMIC_VP interrupt action
PAN_VP interrupt action
WINDOW_VP interrupt action