Preprocessing and tool source tables

The discussion about recognised table tags has me wondering whether 
stripping of recognised tool source tables might be a reasonable 
preprocessing step? There are a few font tools that use the sfnt 
structure as a source format and store custom tables in the font; when 
the font is 'shipped' from these tools, the source data is compiled to 
standard font tables and the custom source tables are stripped. 
Obviously web fonts should properly be made from shipped fonts, and not 
from sfnt files containing source tables, and in a sane world we'd be 
able to rely on the makers of WOFF files and/or WOFF creation tools to 
ensure that this is the case. However, since these custom source tables 
can be of very significant size, and clearly inappropriate to include in 
any web font, I wonder if it would make sense to identify known source 
table tags in the spec as invalid for inclusion in a WOFF?

Offhand, I would include the following VTT and VOLT source table tags in 
such a list:

 TSI0
 TSI1
 TSI2
 TSI3
 TSI4
 TSI5
 TSIV

[If Microsoft can confirm the convention of beginning all custom source 
table names with 'TSI', we could presumably declare any such tag invalid 
for inclusion in a WOFF.]


JH

Received on Thursday, 27 March 2014 21:20:47 UTC