[texhax] TeX Query 7: measuring the real height and width

[Paul Stanley]

Hi folks,
How does one draw a `virtical' line to a specified length in order to 
measure the height of box or boxes in the output?

For example, a virtical line to get an idea of the `real' height of 
the following structure:
%start code
{\hsize = 5cm \settabs 3 \columns
\+column 1&column 2&column 3\cr
\+one&cattle&herd\cr
\+two&fish&school\cr
\+three&lions&pride\cr}
%end code

There may be other ways of getting the real height and width of boxes 
and compound structures, if so, i'd be grateful for more info.

many thanks,
Paul