Subject: Re: bug#77039: 31.0.50; Flickering on macOS

From: Aaron Jensen <[email-masked]>
Date: Sun, 16 Mar 2025 17:19:47 +0000

On Sun, Mar 16, 2025 at 10:15 AM, Aaron Jensen <[email-masked]>
wrote:

> Hi,
>
> I've narrowed it down to the addition to frame in the glyph comparison. As
> far as I can tell, the attached patch removes the flickering for me. I saw
> the cursor blink once, but I couldn't reproduce that and I couldn't get it
> to do it again.
>
> The patch is not suitable for applying to master as it certainly breaks
> something int he tty child frame code, but hopefully it gives you an idea
> of what the problem might be. I'm going to experiment with accounting for
> the NULL frame in the space glyph and see if that helps.
>
> Aaron
>

Actually, while I don't fully understand the code, it seems suspect to me
that there is a global `space_glyph` glyph struct that gets initialized
with a NULL frame but the frame is mutated over time. I wonder if my not
removing the frame check inside of CHAR_GLYPH_SPACE_P is why I saw the
cursor flicker once.

> On Sun, Mar 16, 2025 at 2:00 AM, Gerd Möllmann <[email-masked]>
> wrote:
>
>> Aaron Jensen <[email-masked]> writes:
>>
>> One other thing, it may be related to tab-bar mode. It seems to be
>> connected to when I switch tabs — one tab has a vterm buffer scrolling
>> output and the other just has a grep output, for example. If I don't get
>> the flicker in the grep output, I can switch back and forth between the two
>> tabs a couple times and I'll start to get it.
>>
>> Doesn't ring a bell, I'm afraid. Tab bar, AFAIU it, is "just playing with
>> window configurations". Why that would lead to flickering, I can't imagine
>> ATM.
>>
>