[XeTeX] Fontspec Bug

[Jonathan Kew]

On 20 Nov 2008, at 07:26, Heba Soliman wrote:

> Dear All:
>
> Thank you all for your replies, I prepared some samples with free  
> fonts.
>
> Please find the attached PDFs with the names of the fonts.
>
> I used:
>
> 1-Arial

It looks like Arial (or at least the version you're using) does not  
support proper diacritic positioning at all, it simply places them at  
fixed positions.

>
> 2-Andalso

This seems to have some diacritic positioning, but it's not very  
carefully controlled. I wonder if it's using an older, substitution- 
based approach rather than GPOS and attachment points.

Also, there appears to be a glitch in the display of one of the base  
characters (in the third from last sample word).

>
> 3-LateefRegOT

Here, the diacritic positioning is working as it should. But Lateef  
doesn't have ligatures such as the initial lam-meem, so it's not  
really comparable to your original sample.

>
>
> I observed that they are different in the bugs places.
>

Yes, they are, because they have varying levels of support for  
ligatures and diacritic positioning. I don't think any of these shows  
the same problem as you have with the Linotype font in your original  
sample; in these cases, I think xetex is correctly handling the font,  
to the extent that the font itself is designed to work. I still think  
the original problem may be a bug in the support for diacritic  
positioning with ligatures, but none of these examples shows that  
exact situation.

JK

> thanks,
>
> Heba
>
> Heba Soliman wrote:
>> Dear Mr Will:
>> First of all thank you for your hard efforts in improving the  
>> fontspec package.
>> Second I have a big problem that is related to my work so I need  
>> please a quick answer.
>> The problem is that I am writing an arabic article and the  
>> diacritics in some places are collapsed with the letters and I  
>> don't know why this problem generated and how to fix it, the only  
>> thing I am sure of is that the font has no problem as I checked  
>> with other programs as Adobe illustrator and this problem doesn't  
>> exist:
>> This is my sample file:
>> \documentclass{amsart}
>> \usepackage{fontspec}
>> \usepackage{xltxtra}
>> \usepackage{xunicode}
>> \usepackage{bidi}
>> \setmainfont[Script=Arabic]{YakoutLinotypeLight-Regularxx.ttf}
>> \begin{document}
>> لمّا ألّا لمًّا آلّلًة لمُا
>> \end{document}
>> Please find attached the generated PDF file.
>> I will appreciate your quick reply. Thank you again for your efforts.
>> Best regards,
>> Heba
> < 
> LateefRegOT 
> .pdf 
> > 
> < 
> andalso.pdf><arial.pdf>_______________________________________________
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