Re: How to know if a key is pressed without getting it?

[Vinicius Jose Latorre <viniciusjl@ig.com.br>]

>
>> The problem that I'm trying to fix is an specific slow down in whitespace
>> when user holds space key pressed at end of a line. The slow down is caused
>> by whitespace which call jit-font-lock-refontify each time the user press
>> a space at end of line. If it is possible to detect that user is still
>> pressing a key, I could fix the slow down by not calling
>> jit-font-lock-refontify while user is pressing a key.
>>      
> Calling it without any BEG and END args is a bad idea for something that
> can run at each key press.
>    

Despite jit-font-lock-refontify args, this was not a problem in Emacs 22.

In Emacs 22, jit-font-lock-refontify was called at each end of line with 
or without trailing spaces.

I had to modify this because since Emacs 23, calling 
jit-font-lock-refontify causes a slow down in whitespace-mode.

> You could try to check input-pending-p, but note that the pending input
> may end up not running any command, so you may end up with a display in
> an incorrect state for an unlimited amount of time, since the next
> post-command-hook may not be run for the same unlimited amount of time.
>    

Yes, you're right.


>> BTW, calling jit-font-lock-refontify in Emacs 22 didn't cause any slow down,
>> but this happens in Emacs 23 and 24. Probably jit-font-lock-refontify or
>> some part of font-lock was modified in Emacs 23.
>>      
> I can't think of what that slowdown may come from, so it might be
> worth investigating.

I agree.