FW: [OpenType] Kerning

[Michelle Perham]

Forwarding Simon's response posted to the other list.

-----Original Message-----
From: listmaster at indx.co.uk [mailto:listmaster at indx.co.uk] On Behalf Of Simon Daniels 
Sent: Wednesday, March 10, 2010 10:58 AM
To: multiple recipients of OpenType - sent by
Subject: [OpenType] Kerning

Message from OpenType list:


Hi,

Responding to earlier questions regarding OpenType Kerning and TrueType kern table co-existing in some of our fonts. 

There are two reasons some of our fonts contain both styles of kerning…

1.	During the development of Office 2007 we made the case for PowerPoint turning on kerning by default. When they followed our advice they found that the new C* fonts were not kerning, we knew we really had to do something, and that was adding in the kern table. This happened at the last minute during Windows Vista/Office 2007, by converting OT-kerning to kern and removing all pairs that contained unmapped glyphs.  

2.	Some Windows apps, and Mac OS, assumed that any font with GPOS table would contain OpenType kerning, so kern table was being ignored in fonts like TNR which had mark positioning. For this reason we had to add OpenType kerning to some of the legacy fonts which we’d licensed to Apple as well as those commonly used in the OT-savvy Windows apps. 

I don’t know if the spec needs to talk about what to do if a font contains both. One would expect that both sets are compatible, and that the app would use the OpenType kerning first, and only use kern if there were no GPOS kerning. 

Cheers, Si  




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