[XeTeX] OpenType features

[Jonathan Kew]

On 1 Oct 2004, at 4:57 pm, Yves Codet wrote:

> Hello.
>
> If I run "OpenType-info.tex" on a font I get something like this:
>
> OpenType features found in Sanskrit 2003:
> script ='deva'
> language = <default>
> features ='abvs' 'akhn' 'blwf' 'blws' 'half' 'nukt' 'psts' 'pres' 
> 'rphf' 'vatu' 'abvm' 'blwm'
>
> Is there a table somewhere which would allow to know what all this 
> means, and does when selected?
>

Details of the OT feature tags defined/registered by Microsoft can be 
found somewhere under:

	http://www.microsoft.com/typography/

(look for "Specifications"), and I'm sure Adobe has documentation 
relevant to their fonts somewhere on their site.

Note that for complex scripts, XeTeX does not currently support 
user-specified optional features; it always applies the features that 
the script-specific "shaping engine" determines are appropriate. So for 
a font such as your Sanskrit example, there's no real need for you to 
know what the individual features do; you just specify "script=deva" to 
get Devanagari shaping.

For Latin fonts, however, XeTeX does allow you to enable/disable 
individual features, so you may want to look up the available tags in 
MS or Adobe documentation to check what they're supposed to do. (Note 
that what they *actually* do depends on the font developer!)

Hope this helps,

Jonathan