Re: Change to NS drawing routines

[charles@aurox.ch (Charles A. Roelli)]

> Date: Sat, 11 Aug 2018 15:06:20 +0100
> From: Alan Third <alan@idiocy.org>
> 
> The next version of macOS deprecates the method we use in the NS port
> to draw to the screen, specifically marking an NSView as ‘focused’ and
> then drawing to it. The ‘modern’ way is to only draw from within the
> ‘drawRect:’ method where ‘focusing’ is already done for you. There is
> some previous discussion here:
> 
> https://lists.gnu.org/archive/html/emacs-devel/2018-07/msg00799.html
> 
> I’ve created a new branch called scratch/ns-drawing which only draws
> from within drawRect by marking areas that are to be drawn as ‘dirty’
> and then, at the end of redisplay, forcing an update, which uses
> drawRect and expose_frame to redraw the relevant bits of the frame.
> 
> I believe this is a somewhat controversial approach.

Why's that?

> My experience so far is that performance is not noticeably slower than
> master, however if someone with a slower Mac could try it that would
> be helpful.

I don't notice a speed difference compared to master on my slow box
running macOS 10.6.  Do we have any benchmarks that we could use to
check?