Is there an easy way to determine the number of lines which will print on a report page. Obviously based on font size, page size, etc.

I need to design a report which will have a snaking 3 column index at the end (after a page break).

It is relatively easy to create the index data in the columns, but I want to make sure that the index colums snake across the current page before moving to the next.

Any suggestions would be appreciated.