Display area coords/zoomfactor

[Anonymous]

I have a routine that measures the distance that an object is located along
a polyline. In it, I draw an arrow with (grvecs) to indicate which
direction the polyline is pointing. I'd like to make that arrow draw the
same size irregardless of what scale the drawing is currently scaled at.
Right now I'm using

(/ (getvar "viewsize") size) ;'size' being the length of the arrow.

This works, unless the user is in a viewport in the layout tab. Then it
scales the arrow to the current viewport. If the user is zoomed in pretty
close (we lock our viewports), the arrow appears huge, if they're zoomed
out, its small--exactly what I'm trying to avoid.

So does anyone have any ideas on how to get the zoom factor or the
coordinates of the display area in a layout tab?

--
Ben Maki
NDC Inc.