Use Kashida for full justification in Arabic scripts

• Component: Layout and Rendering
• Status: NEW ---

Kashidas should be used when fully justifying text in Arabic scripts.

The CSS3 Text Effects Module working draft at http://www.w3.org/TR/css3-text/ specifies advanced 
Kashida behavior.

[Ahmad]

Created attachment 5526 [details]
Full justification using Kashidas implemented in I.E 6 (Windows) compared to Webkit2006-01-06

Full justification using Kashidas implemented in I.E 6 (Windows) compared to
Webkit2006-01-06

[Glenn Adams]

(In reply to comment #1)
> Created an attachment (id=5526) [details]
> Full justification using Kashidas implemented in I.E 6 (Windows) compared to
> Webkit2006-01-06
> 
> Full justification using Kashidas implemented in I.E 6 (Windows) compared to
> Webkit2006-01-06

The only clear evidence of Kashida usage in this example is in the emboldened title of the second item shown (i.e., to the right of the picture). The title of the first item (at top) does not exhibit Kashida in either IE or WebKit.

Regarding the second item, it is not clear from the example attachment whether the content author manually inserted TATWEEL (U+0640) [= kashida] in order to produce the shown justification or if IE performed Kashida insertion.

I suspect the former, which if true, would mean that WebKit was ignoring or mapping TATWEEL to the empty set when performing character to glyph mapping.

It would have been useful if you had included the original HTML that produced this example.

[Ebrahim Byagowi]

Unfortunately I couldn't find that page on the net and I have not IE6 in order to test that what was behavior of IE6 but as in am seeing on IE10 on Windows8, text-align: justify; is not enough for doing kashida justification and text-justify: kashida; is also needed but I guess in IE6 quirk mode text-justify: kashida was enabled by default (that is not important for us I guess).
Here is my test http://fa.wikipedia.org/w/index.php?oldid=8341664#Justification that you can see on IE in doing text-justify 

I want to propose changing this bug as a CSS3 feature ( http://www.w3.org/TR/css3-text/#text-justify ) request on text-justify: kashida; but I don't think this is a blocker for Bug 76173 as it was not on Firefox counterpart bug ( https://bugzilla.mozilla.org/show_bug.cgi?id=536557 ).

[Ebrahim Byagowi]

Kashida justification is removed from CSS3 (http://www.w3.org/TR/css3-text/) and deferred to CSS4 (http://dev.w3.org/csswg/css-text-4/).

See also:
* http://stackoverflow.com/a/20790740
* http://www.microsoft.com/middleeast/msdn/JustifyingText-CSS.aspx