bug#22786: 25.1.50; eww arabic rendering

[Lars Ingebrigtsen <larsi@gnus.org>]

Eli Zaretskii <eliz@gnu.org> writes:

> So I think for best results we should add support for the remaining
> bidi directives.  Adding support for "dir=auto" in the HTML tag is
> almost trivial.  To support the rest of the directives you need to add
> bidirectional formatting control characters before and/or around the
> text that is marked with these directives.  (If needed, I can provide
> the details about the controls you need to insert in each case.)

Actually, I think I need help, anyway.  :-)

Adding support for BDO was easy enough -- I slap LRO/RLO at the start en
PDF at the end of the phrase.  This works fine:

<p>This goes <bdo dir=rtl>the wrong way</bdo>, doesn't it?

However, I'm not quite sure how the BDI is supposed to work.  With this
example:

<p><bdo dir=ltr>Here's something with <bdi>العربيّ</bdi> lri.</bdo>

I would have expected that slapping FSI/PDI pairs around the Arabic text
would isolate it from the LRO that the <bdo> introduced.  But it
doesn't.  Should it?  Using LRI/RLI instead works, but then I would have
to keep track of what direction the text is already in?  So I think
there's something I don't quite understand here.

Or perhaps I should have used LRM/RLM instead of LRO/RLO?

Anyway, this reminds me: Do we have a literal char syntax for these
control characters?  I know about ?\u2068, but that's not very...
clear...  Having something like ?\ucLRM (or... something) would make the
code a lot easier to read.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no