http://ik.homelinux.org/
Hans-Peter Diettrich wrote 37 lines
Zaher Dirkey schrieb:
Some time i feel the same, but all open source project have the same
> problem for add official Right To Left, and many of them refuse to add the
> BIDI to it, i have old experience with some PHP forum, the core team of
> Lazaurs make it offical bidi and always accept my patches and that enough
> to, may be take a long time, but all features need the same time.
>
One problem may be the extent of BiDi support, that is unknown to most
(western) developers. E.g. I even don't know how to enter RTL text, so that
all related code should be implemented and checked by people that are
familiar with RTL applications and environment.
Does there exist a list of things that should change in RTL mode?
Newer Windows systems have an API for rendering full Unicode text,
including an mix of LTR and RTL parts. Do there exist similar libraries for
other platforms or widgetsets (Qt???)? If yes, these libraries should be
explored and a compatible wrapper (class) should be constructed, for
immediate use in most components (SynEdit may be an exception). If not, an
API must be defined first, and then the platform specific libraries must be
implemented accordingly.
But there seem to exist more issues with RTL, like the rows in a grid
running from right to left? Such behaviour can be tested by everybody, at
least by faking RTL mode to make the different appearance occur.
Sorry for my poor English, i am writing in English as like writing
> programming code :)
>
Does there exist a Wiki (Wikipedia?) entry, that describes *all* required
changes in BiDi/RTL mode?
Let's seperate things into two groups:
1. Text
2. UI
For text, both Qt and GTK 2x support right to left languages. When there are also non right to left chars (such as "arabic numbers" [the number used in the arabic language are actually hindu numbers :)], and latin letters etc) .
Even on non BiDi system, you can write right to left languages. The problem starts when you need to use non Right To Left chars inside a Right To Left paragraph, or the other way around, when you have a Left To Right language and you add there Right To Left chars. That called Bi-Directional or BiDi for short. You have a full algorithm description for it in unicode,org ( http://www.unicode.org/reports/tr9/), including FAQ on the matter ( http://www.unicode.org/faq/bidi.html).
One more sophisticated problem in BiDi is the Arabic language. Many letters in the Arabic language have several ways to be presented, because the Arabic written language combine all (almost) letters like the lattin script language. So Letters that at the beginning, middle or end of a word (depends on few other rules) are different letter shapes.
My native language -> Hebrew does not have this have in the Open Source few implementation of BiDi support such as FreeBiDi, and the IBM's unicode library, but also with GTK2 and Qt3 and above.
The Right To Left UI, is a whole different approach that actually everyone here can help with. On Latin based languages, everything starts from Left To Right, on Right To Left UI, everything starts from the Right.
So point 0,0 on Latin bases system should be on the top left, and on the Right to left languages starts from the top right. Some UI such as GTK2 (up to a point, it does not support all of what we require in Lazarus) support it, and so does Qt, and Windows API (on a native/enabled/unicode versions).
I hope Bidi and Right To Left is more clearer now :)
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Ido
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