Re: how reliable is rendering of complex scripts?

[Werner LEMBERG <wl@gnu.org>]

>> This essentially means that Emacs developers wait for users to
>> report bad renderings, right?
> 
> No, it means Emacs developers lack resources, knowledge, and
> motivated individuals aboard to do that.  If you or someone else
> volunteers, that'd be great.

I can only indirectly volunteer, namely by maintaining FreeType :-/

>> Well, this makes Emacs on MS-Windows really superior to other
>> platforms in this area, which is less than ideal...  I mean
>> `superior' in the sense that the rendering results on MS-Windows
>> are well tested and can be trusted in general, something that is
>> missing otherwise.
> 
> That's not entirely true, because, as I said, part of the data and
> algorithms needed for complex script layout is in Emacs, and is used
> on all supported platforms, not just by the Windows build.

OK.

>>   https://github.com/behdad/harfbuzz/tree/master/test/shaping
>>   https://github.com/behdad/harfbuzz/tree/master/util
> 
> I will see if we can extract something from there to see how Emacs
> displays those scripts.

The nice thing about `hb-shape' is that it doesn't output graphics but
a textual representation of the GSUB and GPOS manipulation results
(including reordering of the input).  In other words, Emacs could use
the same output format in a special test mode, making comparisons very
simple – and automated!


    Werner