bug#57434: 28.1.91; Terminal Emacs Mac OS flickering.

[Dmitrii Kuragin via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

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Hello,

Sorry I made you wait. I tried the patch (see attachments) and everything
worked perfectly. No flickering.

I tried to implement the second spec, but it didn't work (at least in
Alacritty). But, I can try to add support for both.

BTW, tmux uses the sync update for their own TUI and they check "Sync"
terminal capability. Do we need to do the same or we can just send the
escapes and hope the unsupported terminal would just recover?

Side note: I still have the issue when I run emacs inside of tmux, but it
is due to lack of support from tmux side. I created a bug and will try to
implement the functionality in tmux sooner or later. See
https://github.com/tmux/tmux/issues/3325 foe details. I assume, in the case
of tmux, the multiplexer just consumes the escape codes and doesn't send
them to the parent terminal.


On Tue, Sep 6, 2022 at 9:59 PM Gerd Möllmann <gerd.moellmann@gmail.com>
wrote:

> Gerd Möllmann <gerd.moellmann@gmail.com> writes:
>
> > Dmitrii Kuragin <kuragin@google.com> writes:
> >
> >> Also, I tried to enable syncing and it works like a charm.
> >
> > So I take it that you fixed the problem that you originally reported
> > with Alacritty.
> >
> > Could you please show a diff of what you did?
> >
> > Also, did you try both synchronized update proposols?
> >
> > https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec
> >
> https://gist.github.com/christianparpart/d8a62cc1ab659194337d73e399004036
> >
> > If you didn't try both, could you please do and report back?
> >
> >> The next problem is I need to configure tmux to somehow respect it.
> >
> > Sorry, can't help with that, I don't know tmux.
>
> Ping.
>


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From df63c2616d99b8d9162c9c422c50dc3c8de65d25 Mon Sep 17 00:00:00 2001
From: Dmitrii Kuragin <kuragin@chromium.org>
Date: Sat, 3 Sep 2022 09:30:48 -0700
Subject: [PATCH] Implement Synchrnized Update for frame rendering in TTY.

Spec: https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec

* src/term.c (set_tty_hooks, tty_update_end, tty_update_begin): Put
  escape sequence at the beginning and end of the fram update in order
  to inform terminal about synchonization points.
---
 src/term.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/term.c b/src/term.c
index 2e43d89232..5f7c07b2cf 100644
--- a/src/term.c
+++ b/src/term.c
@@ -227,6 +227,14 @@ tty_reset_terminal_modes (struct terminal *terminal)
     }
 }
 
+static void
+tty_update_begin (struct frame *f)
+{
+  struct tty_display_info *tty = FRAME_TTY (f);
+
+  fputs ("\033P=1s\033\\", tty->output);
+}
+
 /* Flag the end of a display update on a termcap terminal. */
 
 static void
@@ -238,6 +246,7 @@ tty_update_end (struct frame *f)
     tty_show_cursor (tty);
   tty_turn_off_insert (tty);
   tty_background_highlight (tty);
+  fputs ("\033P=2s\033\\", tty->output);
   fflush (tty->output);
 }
 
@@ -3880,6 +3889,7 @@ set_tty_hooks (struct terminal *terminal)
   terminal->ring_bell_hook = &tty_ring_bell;
   terminal->reset_terminal_modes_hook = &tty_reset_terminal_modes;
   terminal->set_terminal_modes_hook = &tty_set_terminal_modes;
+  terminal->update_begin_hook = &tty_update_begin;
   terminal->update_end_hook = &tty_update_end;
 #ifdef MSDOS
   terminal->menu_show_hook = &x_menu_show;
-- 
2.37.2.789.g6183377224-goog