Re: macOS metal rendering engine in mac port

[Alan Third]

On Thu, Sep 16, 2021 at 06:59:33PM +0300, Y. E. wrote:
> 
> >> > It's infrequent, but I've seen a number of rendering artifacts in 28
> >> > in the last month or so. Typically it is a line of group of lines that
> >> > are painted twice (i.e. in the wrong place). I may see line 33
> >> > duplicated so there is no 34, just two 33 in a row. Scrolling to
> >> > change the position does not fix it. I have to scroll the buggy line
> >> > out of view entirely and scroll it back to get it to be right.
> >> >
> >> > I do not have a repro for this unfortunately.
> >>
> >> I can confirm that I have been having this exact issue for quite some
> >> time now. It is very infrequent and mild so I never bothered to report
> >> it.
> >>
> >> I also don't have any ideas what's causing it and how to reproduce it,
> >> but M-x redraw-display RET fixes it straight away.
> 
> I saw this (or extremely similar) issue 2-3 times during the past month
> on an oldish MacOS with vanilla Emacs, in buffers with ELisp code.
> 
> I looked as if chunk of the text (from this buffer) overlayed
> another (correct) text. And it was impossible to remove that overlaying
> text without reverting (AFAIR) the buffer.
> 
> Unfortunately, I also have no idea on how to reproduce the issue so far.

Nobody has any idea what they were doing when it happened? Scrolling
or typing or resizing windows or anything?

Someone in an unrelated bug report suggested something similar
happened after they created a new frame (which doesn't make much
sense, unless Emacs is drawing to the wrong frame). Was anyone doing
anything like that? Child frames popping up for use with, I don't
know, company mode or something?

Where on the frame do these things happen? If it happens again please
send a screenshot of the whole frame.
-- 
Alan Third