[XeTeX] fontspec and Nikosh font

[Jonathan Kew]

On 20/6/16 23:22, maxwell wrote:
> Not sure if Will is on this mailing list, but I'm cc'ing him using his
> email address on the fontspec document.  (The doc doesn't have the
> co-author's email, Khaled Hosny, but I think I've seen him here.)
>
> On 2016-06-20 17:55, Jonathan Kew wrote:
>> My guess is that this might be a bug in the TL'16 version of fontspec,
>> which looks like it is intended to support both the "new Indic spec"
>> OpenType tags such as 'dev2', 'bng2', etc, as well as the "old Indic"
>> versions 'deva', 'beng', etc, with preference being given to the v.2
>> tags. Perhaps that feature is broken?
>> ...
>>
>> One way to check what's wrong would be to search for the
>>
>>   \newfontscript{Devanagari}{dev2,deva}
>>
>> declaration around line 2247 in fontspec-xetex.sty, and remove "dev2,"
>> from it so that it only looks for the old-style 'deva' tag. If that
>> makes Gargi work without complaint (using [Script=Devanagari] as
>> before), then you've identified a bug in fontspec and should report it
>> to Will.
>
> I confirm that omitting 'dev2,' from that declaration causes fontspec
> not to emit a warning when I do
>     \newfontfamily\sanskritfont[Script=Devanagari]{gargi}
> and similarly for the Nikosh font, fontspec gives a warning when I do
>     \newfontfamily\bengalifont[Script=Bengali]{Nikosh}
> unless I change
>     \newfontscript{Bengali}{bng2,beng}
> to
>     \newfontscript{Bengali}{beng}
> in fontspec-xetex.sty.
>
> Thanks for the pointer, Jonathan!

The other question I have is whether this is a "harmless" (if alarming) 
warning, meaning that fontspec warns when it fails to find the v.2 tag, 
but then proceeds to use the old tag and the text is shaped correctly. 
Or does it mean that fontspec is failing to use the second tag, so that 
the proper Indic shaping does not get applied?

It should be easy to test this with a word like हिन्दी, using the Gargi 
font with [Script=Devanagari]. Does the short-i matra ि appear to the 
left of the ह, or after it? If it appears to the left (despite the 
fontspec warning), then it's correctly falling back to 'deva' when 
'dev2' is not found.

JK