Re: Pixel-based display functions

[Stefan Monnier]

Why are we re-implementing the display code in Elisp, again?


        Stefan


>>>>> "Eli" == Eli Zaretskii <address@hidden> writes:

>> Date: Fri, 30 Jan 2015 13:56:21 +0200
>> From: Eli Zaretskii <address@hidden>
>> Cc: address@hidden
>> 
>> (In the display engine, there's a thing called the "face ID" that is
>> computed as part of displaying text, which takes the characters into
>> consideration, which is why I suggested 'face' in the first place.
>> I will try to see how to do the same in Lisp.)

> Not really the same, but how about using

>   (aref char-script-table (char-after POS))

> to find where in the text you have characters from a different script?
> If this is fast enough, it should give you a conservative estimation
> of where to call font-at again.  (It's conservative because the same
> font can, and usually does, cover more than a single script.)

> One more issue that I think needs to be handled are characters for
> which there's no font installed on the user's system.  We display them
> as defined by glyphless-char-display-control.  Or maybe you should
> allow the text to overflow in this case: after all, it's not really
> legible, is it?