User Guide

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Device-Dependent Metrics
The [hdmx] control lets you customize the sizes for which FontLab will
generate records in the hdmx TrueType table. This table is used to pre-
calculate pixel metrics of font glyphs so it will not be necessary to run a
hinting program to get the correct width.
If you don’t want FontLab to generate a hdmx table for your font, empty
this editing field.
Use a colon to separate entries and ‘-’ to define ranges of PPM.
Use the Create VDMX Table control to ask FontLab to automatically
calculate a VDMX (Vertical Device Metrics) table. This is necessary if some
characters in the font are hinted in the vertical direction, so that at some
resolutions they can extend above or below the scaled Win/Mac Ascender
or Win/Mac Descender values and unwanted dropouts do not appear. We
strongly recommend you always have this option switched on.
Using CacheTT to Build Device Metrics Tables
There are two ways to make a device metrics tables. You can use FontLab
to calculate these values or you can use the CacheTT program made by
Microsoft. FontLab’s own algorithm is very fast but is not as precise as
CacheTT. We recommend you use FontLab’s calculation while you are
working on the font and use CacheTT when you prepare your font for
release.