Re: Use Core Text for Cocoa Emacs

[Adrian Robert <adrian.b.robert@gmail.com>]

On May 18, 2010, at 11:28 PM, covici@ccs.covici.com wrote:

> Adrian Robert <Adrian.B.Robert@gmail.com> wrote:
> 
>> Wang Ling <an00na <at> gmail.com> writes:
>> 
>>> 
>>> Is it possible and advantageous to use Core Text for Cocoa Emacs?
>>> I'm just wondering whether it is a practical and meaningful thing to do for
>> Mac Emacsers.
>> 
>> Hi,
>> 
>> Overall it's probably a wash at the present time.  Using it would not result in
>> any immediate user-visible changes by itself and might make supporting Tiger
>> difficult.  (The framework is there on Tiger, but it's private, and I'm not sure
>> how mature compared to the CG APIs.)  But on the other hand, it exposes a bit
>> more of the guts of the Text system than earlier APIs, which should make support
>> of advanced font backend features easier.  The cost here would be forking this
>> code to keep GNUstep supported.  (Right now CG (vs. DPS on GNUstep) is only used
>> at the very lowest level for emacs rendering, so the split code is small.)
>> 
> 
> What about accessibility -- which of these would work better with
> Voiceover?

I haven't looked at this particular issue, but the main problem no matter which API were used for rendering would be getting the text onto the Cocoa side.  In the Emacs model all high-level control of the text resides in the generic code, so the Cocoa side just sees small pieces as they need to be rendered, not the whole buffer.