[XeTeX] Arabic and line spacing

[Musa Furber]

On Jun 4, 2005, at 1:19 PM, Stephen Moye wrote:

>  On Friday, June 03, 2005, at 11:40PM, Musa Furber <musaf at runbox.com> 
> wrote:
>
>> On Jun 3, 2005, at 5:44 PM, Jonathan Kew wrote:
>>
>>> On 3 Jun 2005, at 3:39 pm, Musa Furber wrote:
>>>
>>>> The line height between lines of Arabic text always a bit large. Is
>>>> there any way to reduce this? I have tried
>>>> \fontsize{point-size}{on-line-size}\selectfont, but it doesn't 
>>>> change
>>>> anything.
>>>>
>>>> Any ideas?
>>>
>>> In plain TeX terms, you need to override \lineskiplimit so as to 
>>> allow
>>> the nominal height and depth of adjacent lines to overlap slightly, 
>>> as
>>> the ascent and descent metrics of most Arabic fonts are such that
>>> otherwise you get quite generous spacing.
>>>
>>> Not being much of a LaTeX user, I don't know what the appropriate
>>> LaTeX idiom would be, but I expect one of the experts here can help.
>>
>> I created three LaTeX files where I make a novice's attempt to change
>> the leading with Times. There is one file for pdfLaTeX, another for
>> XeLaTeX loading fonts with fontspec, and another for XeLaTeX using 
>> NFSS
>> (\DeclareFont...).
>>
>> The pdfLaTeX and XeLaTex/NFSS versions show a slight change in 
>> leading.
>>
>> The XeLaTeX/fontspec leading remains constant. Is this something that
>> should be changed in Will's wonderful fontspec?
>>
>> I wasn't able to produce an example where leading is small enough that
>> consecutive lines start to overlap - something that will be useful to
>> compensate for the x-height of Arabic without vowels.
>>
>> Regards,
>> Musa
>
> I looked at your samples and what you did not do is follow JK's advice 
> about \lineskiplimit.
>
> Somewhere in the preamble of your document you must type something 
> like \lineskiplimit=-20pt (or whatever negative figure works for you).
>
> This works -- I tried it in your samples.

Thanks for the suggestion. I did try it, both within the preamble and 
within the document; the samples I sent include a variation. 
Unfortunately, it didn't seem to change anything... for me, at least.

What did work with the baselines-xelatex-latex example was
<<
\baselineskip=10pt
\setlength{\lineskiplimit}{-1.5in}
\normalfont
\mysample
 >>

This appears to be dynamically changeable, something useful for 
documents where fonts have disagreeable leading.

Regards,
Musa