Re: Implementing image support for kitty terminal

[Gerd Möllmann]

On 22-09-09 16:20 , Eli Zaretskii wrote:
> > Date: Fri, 9 Sep 2022 16:10:07 +0200
> > Cc: emacs-devel@gnu.org
> > From: Gerd Möllmann <gerd.moellmann@gmail.com>
> >
> > It wouldn't be hard to buffer the writes until the update is done, I
> > think.
>
> I think we already do, see this part of update_frame_1:
>
>    /* Now update the rest of the lines.  */
>    for (i = 0; i < desired_matrix->nrows - 1 && (force_p || !input_pending); 
> i++)
>      {
>        if (MATRIX_ROW_ENABLED_P (desired_matrix, i))
>         {
>           if (FRAME_TERMCAP_P (f))
>             {
>               /* Flush out every so many lines.
>                  Also flush out if likely to have more than 1k buffered
>                  otherwise.   I'm told that some telnet connections get
>                  really screwed by more than 1k output at once.  */
>               FILE *display_output = FRAME_TTY (f)->output;
>               if (display_output)
>                 {
>                   ptrdiff_t outq = __fpending (display_output);
>                   if (outq > 900
>                       || (outq > 20 && ((i - 1) % preempt_count == 0)))
>                     fflush (display_output);
>                 }
>             }

Oh, right.

The comment there is also interesting.  Looks like some connections 
don't like larger buffers, some benefit from it, some don't care. 
Whatever we do, it's always wrong :-).