Re: Bidirectional Bugs in hebrew

[Chookij Vanatham <chookij vanatham eng sun com>]

Hi Owen, Robert, Uri, Omer, Pablo,

] 
] Kaixo!
] 
] On Fri, Oct 27, 2000 at 01:33:51PM +0200, Omer Zak wrote:
] 
] > > Problem: when writing in hebrew (and RTL direction) a letter and then "-"
] > > and a number, I should receive the right image (right.gif attached).
] > > Instead I get wrong.gif (attached).
] > > My hypothesis for the problem: when pressing "-" Pango returns to english,
] > > and then it is logical to write "-8". However, in cases like this the
] > > layout should stay in hebrew until I type space or something.
This is because of Bidirection algorithm which doesn't define "minus sign"
as the R type (Right to Left) which is a strong type. This is because "minus
sign" in hebrew will have different direction than Left-to-Right script, like
english. The bidirection algorihm is used with multi-scripts and not just
specific to hebrew.

] 
] > The problem is not due to Pango.
]  
] > I am not sure of this, but it seems to be according to the Unicode
] > bidirectionality algorithm.
] > 
] > The rationale behind the algorithm:  to make it possible to type negative
] > numbers in "natural" order.  If it were not for this "problem", it would
] > have been awkward to type negative numbers in bidirectional text.
] 
] That makes sense.
] 
] And if we use soft hyphen (0xad, available in iso-8859-6 (Arabic),
] iso-8859-8 (Hebrew), cp1255 (Hebrew + Yiddish), cp1256 (Arabic+Farsi+Urdu))
] would it produce a rtl string ?
] If so then the problem is solved, and users just must be isntructed to
] use the minus only as a minus, and the hyphen when a "-" sign is needed
] in words. 
I haven't tried this but I think, you should get the same result because
"soft hyphen" would not be the R type like hebrew alphabet.

Because you are using this in unicode locale, so, you can try typing
RLO or RLE before typing "minus sign" to force the direction to be Right to
left, and then typing 8 and other number untill you done with Right to left
direction then typing PDF to finish the direction. Another word,...

	RLO ..... PDF
	
This would be one way to control the direction you want for running Pango
in Unicode locale which deals with multi-scripts.

I haven't tried it but I think fribidi should work with RLO,RLE,PDF as well.
For the keyboard input, not too sure if gtk+1.3 is enabled to allow users
to input those RLO, RLE, PDF codes.

Chookij V.

] 
] -- 
] Ki ça vos våye bén,
] Pablo Saratxaga
] 
] http://www.srtxg.easynet.be/		PGP Key available, key ID: 0x8F0E4975
] 
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