[XeTeX] using Didot.dfont in Linux

[Adam Twardoch]

 > It seems that the Didot ttf fonts cmap table with Mac Unicode
 > enconding (I was told). And I don't know whether xdvipdfmx
 > can handle this or it requires a Windows encoding.

TrueType and OpenType fonts typically contain two Unicode subtables: 
0.3, which is used on Mac OS X, and 3.1, which is used on Windows. If 
0.3 is absent from a font, Mac OS X will use 3.1 instead, but if 3.1 is 
absent from a font, Windows can’t use the font at all.

I believe Apple’s .dfonts only contain the 0.3 subtables since fonts in 
the .dfont
packaging don’t work anywhere except on Mac OS X, so inclusion of the 
3.1 subtable wouldn’t do anything except bloat the font file.

Jonathan,
which subtables does XeTeX use? Does the behavior differ on Mac and 
Linux/Windows? It would be good to harmonize these behaviors. Note that 
if, say, Mac XeTeX uses 0.3 and the Linux/Windows XeTeX uses 3.1, this 
can potentially lead to incompatible cross-platform renderings. After 
all, it’s possible to have OT/TT fonts that have different contents of 
the 0.3 and 3.1 subtables (I have built such fonts for a client).

Adam

-- 

Adam Twardoch
http://www.twardoch.com/