ot2kpx - Online in the Cloud

PROGRAM:

NAME

ot2kpx - extract kerning information from OpenType fonts

SYNOPSIS

ot2kpx fontfile

DESCRIPTION

ot2kpx extract the kerning data from OpenType fonts (both otf and ttf formats) and prints
it (in afm format) to "stdout".

OPTIONS AND ARGUMENTS

fontfile
The OpenType font (in either otf or ttf format).

RESTRICTIONS

- ot2kpx doesn't implement all of the OpenType specification. Things that are missing
include: support for font files containing multiple fonts, LookupTables with
LookupTypes other than 2, "kern" tables with format other than 0 and ValueRecords with
other types of data than just XAdvance data.

Most of these limitations won't matter, since the missing features are rare (the only
fonts I know of that use them are the non-western fonts that come with Adobe Reader).
Furthermore, many of these features define (according to the OpenType specification)
"subtle, device-dependent adjustments at specific font sizes or device resolutions";
since there's no way to express such adjustments in afm format, ignoring them seems to
be the only option anyway.

- ot2kpx collects kerning data first from the "kern" table, then from all LookupTables
associated with the "kern" feature; if a kerning pair occurs multiple times, the first
value seen is chosen. There are (or may be) several issues with this approach:

- The OpenType specification says that fonts in otf format shouldn't use the "kern"
table at all, just the lookups from the "GPOS" table. Many such fonts do,
however, contain a "kern" table, but no "GPOS" table; so we use the "kern" table
anyway.

- Instead of reading all LookupTables, it might be better to let the user specify a
script and language and process only the LookupTables for those values. However,
at least in the fonts I checked, all script/language combinations eventually point
to the same "kern" LookupTables, so this approach wouldn't make any difference
(apart from further complicating the code).

Use ot2kpx online using onworks.net services