>>BTW what You define as Line? All text that ends with CRLF or a text that is fitted in one line of the editbox w/o wraping on the next line?
>All text the user can see in the editbox. This text will be printed, and the space available is for seven rows only. I need to advice the user if this number is over. The fontname is Arial Narrow and set Memowidth is not useful

You don't care about the font for the screen display, you care about the font that will be used by the printer.