Tally Genicom Matrix Printer - Manual (Page 38)

7265 Programmer’s Manual 34
Copyright © 2004 TallyGenicom Chapter 3 ANSI Bar Codes
Before You Begin - Set the Form Length
Programmers tend not to trust form feeds and sometimes use line feeds instead to move from
one form to another. If there is any advantage to that approach, it is that the vertical move will not
depend on the current form length. When printing bar codes on labels, you can greatly simplify
your task by setting a form length that exactly matches the length of your physical form and then
using form feeds to make vertical moves between labels or rows of labels.
If you print nothing but text, then the vertical position following each line feed lies on a grid that is
evenly spaced according to the line feed increment. If you print a bar code symbol, then positions
established by subsequent line feeds may not be on that grid. The vertical position following a bar
code symbol becomes the origin for a subsequent line feed; this new origin must be computed
based on bar code height, and the status of the human-readable line.
If you do not initialize your vertical position with a form feed for each row of labels, then printed
objects may creep cumulatively up or down with respect to the top of your physical form.