# [XeTeX] LaTeX Font Warning: Encoding `OT1' has changed to `U' for symbol font

Will Robertson wspr81 at gmail.com
Sat May 13 09:49:08 CEST 2006

```On 13/05/2006, at 5:53 , William Adams wrote:
> On May 12, 2006, at 2:43 PM, Will Robertson wrote:
>
>> No, this is going down the wrong track.
>
> I would beg to differ given that....

:)
Sorry, I was a bit curt there.

>> I think the current Mac XeTeX installer must include an older version
>> of fontspec -- I fixed this annoying warning up (well, hid it) in the
>> last released version.
>
> Rather than hiding it, wouldn't doing a proper utfenc.def file fix
> it? Would it afford any other advantages? Perhaps address some other
> of the encoding difficulties we've been having?

I haven't pushed for the creation of our very own font encoding for
XeTeX+fontspec for the reason that "font encoding" doesn't mean the
same thing when you're using unicode fonts. In LaTeX proper, I font
encoding is supposed to mean (although doesn't always, to their
chagrin) that the font contains *exactly* some set of glyphs. Then,
if a character is requested that cannot be typeset with this font,
corrective measures are taken.

But consider what this means: every non-ascii character is active and
assigned a "LaTeX Input Character Representation" (or something,
can't ever remember what the acronym stands for). E.g. "é" -> \eacute
-> slot XXX in font with encoding YYY. With XeTeX, we know we're
always using unicode fonts. So this step is largely unnecessary. "é"
in the source will be typeset directly by XeTeX.

In order to fulfil the LaTeX paradigm, we'd need to set up a mapping
for every character in unicode to a control sequence, back to a glyph
in a unicode font. We'd then need to start representing fonts by
which subset of unicode they contain, and this will never be fully
consistent across fonts.

In the scheme above, you could perform error checking in the stage
from going from command name to unicode glyph, but it would be
terribly inefficient (consider that Jonathan Kew hasn't wanted to
implement this *in the source*. This would be much slower.)

Finally :) this wouldn't fix the stupid warning that LaTeX gives when
changing the encoding of the maths fonts. You can see Robin
Fairbairn's thoughts on the matter here: