[XeTeX] Reducing ligatures in arabxetex

[Jonathan Kew]

On 15 Feb 2012, at 14:53, Khaled Hosny wrote:

> On Wed, Feb 15, 2012 at 12:21:28AM +0000, Juan Acevedo wrote:
>> Hello,
>> 
>> The package arabtex has a handy switch to reduce the number of Arabic
>> ligatures used: you can alternate between the essential ligatures
>> (\ligsfalse) or having additionally stacking letters (\ligstrue).
>> 
>> Now I'm working with arabxetex. I have to set some pages of Persian, I
>> realise that Persian typesetting is sparing in its use of ligatures
>> and I would like to reduce them to a minimum, like avoiding stacking
>> letters. Is there any way to achieve that \ligsfalse effect in
>> arabxetex, or any dirty trick to that effect someone might like to
>> share?
>> 
>> I have searched all over and I have been trying unsuccessfully the
>> different combinations of fontspec Ligatures settings. 
> 
> Depending on the style of the font, “ligature” can be essential to get
> proper rendering and disabling them would result in suboptimal (or even
> illegible) rendering. If you think the font is too fancy for your needs,
> then it is better to choose a different, simplified font.
> 
> Regards,
> Khaled

The xetex features (which fontspec accesses via settings such as Ligatures) for enabling/disabling specific OpenType features are only supported for "simple" scripts (such as Latin). For scripts such as Arabic that involve complex "shaping" behavior, the script-specific shaping engine controls which features are applied at each character. It would be nice to have the ability to *also* apply (or disable) optional features, in addition to the script-required ones, but that's not supported at the moment.

I'd recommend choosing a font that was explicitly designed for Persian, which may have slightly different stylistic preferences than typical Arabic usage.

JK