User Guide

FontLab 4
508
F o n t P ar a m e t e r s
Because within each font it’s very important that all characters have a
consistent appearance, some font-level information is necessary for
hinting. There are two kinds of such information: alignment zones and
stem widths.
Alignment zones set the positions of the most important vertical positions,
such as the sizes of uppercase characters, the position of middle-lines, and
the top and bottom overshoot positions.
To minimize rounding error and to make better baseline alignment you
have to suppress overshoots and maintain the same size of overshoot and
regular characters at small PPMs. This is very easy to do if you position and
size the bottoms and tops of these characters and “stick” the bottom and
top points to these values.
Stem widths define the most important stems in the font and control the
rounding of these stems. Here you must control the PPM at which the stem
width changes from one to two pixels and from two to three pixels.
Refer to page 482 for more information about alignment zones and
standard stem widths.