RE: [Devel] validation of TrueType fonts, particularly embedded Type 42 fonts

[Graham Asher]

David,

one important change I would like to make to your new SFNT validation code
is this: ignore tables called 'glyx' and 'locx' when sanity-checking the
table directory.. These will (probably) never be valid in Type 42 fonts with
external glyph recipes, that is, with the glyph recipes not in the TrueType
file image but in a PostScript GlyphDirectory array. It seems that some
programs that generate PostScript files with embedded Type 42 fonts 'hack
out' the 'glyf' and 'loca' tables by changing their tags to 'glyx' and
'locx', and truncating the file image before them, so that the offsets to
their starts will be outside the file. See the thread started by Igor
Melichev, now a colleague of mine working for Artifex, Inc., at

http://www.ghostscript.com/pipermail/gs-devel/2001-October/000713.html

for more information.

Best regards,

Graham