Re: NS Port drawing, again

[Alan Third <alan@idiocy.org>]

On Sat, Nov 10, 2018 at 07:47:35PM -0800, Keith David Bershatsky wrote:
> With respect to cursors being left behind when scrolling, I have dealt with that in playing with feature requests #22873 (multiple fake cursors) and #17684 (crosshairs) by removing the cursors at the outset of redisplay in various locations.  For example, see the locations where I have:
> 
>   mc_remove_multiple_cursors (w);
>   mc_remove_crosshairs (w);
> 
> See proof concept patch version 015 (11_10_2018__18_53_09_703.diff):

The problem we’re having with cursors is that when we ask for a cursor
to be removed it doesn’t actually happen on the bitmap until Cocoa
gets round to running drawRect. We can force it to run but that
invariably results in blank frames and things. On Mojave at least.

The current code works in most situations. There’s no longer any
random blanking of the screen (I think), so it’s perfectly usable, it
just has some weird issues with cursors. (I believe there are still
issues with the menus though? Nobody’s mentioned that for a while.)

I tried implementing drawing to a buffer, and that works perfectly on
High Sierra (except for some bits I know how to fix), but Aaron
reports that it doesn’t work at all on Mojave. I don’t know what I’ve
done wrong.

-- 
Alan Third