Re: Valid UTF-8 text mangled up in GtkLabel

[Behdad Esfahbod <behdad cs toronto edu>]

On Fri, 5 Aug 2005, Jonathan Ben Avraham wrote:

> Hi Behdad, Gaurav,
> IMHO this is *the* classic example of misapplied "bidi algorithm", that
> is, the heuristic for determining base direction based on the first
> strong directional. There is no reason ever to use this heuristic in any
> normal GUI application. In almost all Arabic, Farsi and Hebrew apps you
> know the base direction from the outset or else you want to be able to set
> is specifically.

I use gedit on a daily basis to type text with Persian and
English paragraphs, and I want my Persian paragraphs to be set ar
RTL and aligned to right, and English paragraphs LTR and aligned
to left.  If you have a patch that does this better than the
current code, I would be happy to review it.  I should not have
to do any configuration, no matter what.  It should Just Work.

> For example, email addresses are always LTR,

No.  I want my email addresses with Persian name to be set RTL,
something like:

                                                               |
                     <something somewhere org> DOBHAFSE DADHEB |
                                                               |

> text editing must always be user-selectable.

Yes, in a broken design, yes.  fortunately GNOME has left that
philosophy behind since around 2000 when the HIG work started.
Users should be able to just use applications, not teach them how
to do tasks.  Teaching computers is what developers should do.

> It would be good to implement the same
> directional model in Gtk that Sun implemented in Java Swing TextComponent,
> though I appreciate that this would require a lot of work.

I don't know what Swing does, though I've heard it turned off
automatic direction handling.  But as far as I'm concerned,
automatic direction is here to stay in GNOME.

The whole point you and other people advertising in the direction
that you do is that applications can be taught to be smart, to
handle _marked-up_ text.  The bidi algorithm currently only
handles plain text, and with my definition, email addresses are
not plain text.  I've already sketched a solution, you are more
than welcome to go and implement that, otherwise, please keep the
negative energy to a minimum:

  http://bugzilla.gnome.org/show_bug.cgi?id=168108

Thanks
behdad


> My 2c,
>
>   - yba
>
>
>
> On Fri, 5 Aug 2005, Behdad Esfahbod wrote:
>
> > On Fri, 5 Aug 2005, Gaurav Jain wrote:
> >
> > > Hi,
> > >
> > > I'm trying to set the text in a GtkLabel to a UTF-8 string, which
> > > contains some arabic characters first, followed by my email address in
> > > angle brackets, followed by my name in round brackets.  For e.g., a
> > > sample value is:
> > >
> > > X <gaurav somewhere com> (Gaurav Jain)
> > >
> > > In the above, 'X' represents a valid sequence of arabic UTF-8
> > > characters.  The problem that I see is that when I run this program
> > > (appended to this mail), the output shown is something like this:
> > >
> > > (gaurav somewhere com> (Gaurav Jain> X
> > >
> > > Note that the angle and round brackets are all messed up, and that
> > > order of arabic and ascii words is also wrong.
> >
> > Apparently our milages do vary ;).
> >
> >
> > > Does anyone know WHY this is happening?
> >
> > Yes, because Arabic is written from right to left, unlike Latin.
> > And this behavior is part of the Unicode standard.
> >
> > > Just for information, I'm using GTK 2.4.14.  Also,
> > > I was surprised to discover that this works fine with an older version
> > > of GTK (2.0.9).
> >
> > Right.  Because /bidi/ was not implemented completely in that
> > version.  This specific part of bidi that is causing problems for
> > you is called automatic paragraph direction.
> >
> > > Does something special need to be done so I can get
> > > it to work with GTK >= 2.4?
> >
> > It /is/ working.  If you like to get the behavior similar to the
> > old one, you need ot insert a U+200E LEFT-TO-RIGHT MARK character
> > at the beginning of the buffer.
> >
> >
> > > Thanks,
> > > Gaurav
> >
> > --behdad
> > http://behdad.org/
> > _______________________________________________
> > gtk-i18n-list mailing list
> > gtk-i18n-list gnome org
> > http://mail.gnome.org/mailman/listinfo/gtk-i18n-list

--behdad
http://behdad.org/