bug#46155: 28.0.50; Regression: buffer contents flicker on macOS frames when

[Alan Third]

On Thu, Jan 28, 2021 at 09:48:25AM -0600, Aaron Jensen wrote:
> From emacs -Q:
> 
> (dotimes (n 10)
>   (set-frame-parameter nil 'width (+ 80 n))
>   (sit-for 0.1))
> 
> This was previously fixed in bug#30699
> 
> I don't know if it was reverted at some point and I didn't notice, or it
> was started flickering again after Alan's recent (fantastic) performance
> improvements.
> 
> This reproduces on master (non-native-comp) as of ac102bb966 as well.

Apple deprecated the functions we were using to block screen drawing.

It's possible we can have a neater work-around now since we're drawing
to an offscreen buffer and therefore have greater control over what's
displayed. I'll have to look into it again.
-- 
Alan Third