Re: [Qemu-devel] [PATCH] Reduce curses escdelay from 1s to 0.2s

[Warner Losh <imp@bsdimp.com>]

On Sun, Mar 3, 2019, 12:45 AM Samuel Thibault <samuel.thibault@ens-lyon.org>
wrote:

> By default, curses will only report single ESC key event after 1s delay,
> since ESC is also used for keypad escape sequences. This however makes
> users
> believe that ESC is not working. Reducing to 0.2s provides good enough user
> experience, while still allowing 200ms for keypad sequences to get in,
> which
> should be more than enough.
>

How did you come up with this number? Still seems a bit long for the ESC
ESC case where the user hits ESC twice in quick succession. Even back in
the day, terminals would send the characters back to back at 1200 baud,
which is 8ms per character. 32ms is 4x that, 32x 9600 baud rates. 25 or
50ms is suggested from these figures.

Warner

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
> ---
>  ui/curses.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/ui/curses.c b/ui/curses.c
> index 6e0091c3b2..700315bc09 100644
> --- a/ui/curses.c
> +++ b/ui/curses.c
> @@ -231,7 +231,7 @@ static void curses_refresh(DisplayChangeListener *dcl)
>          keycode = curses2keycode[chr];
>          keycode_alt = 0;
>
> -        /* alt key */
> +        /* alt or esc key */
>          if (keycode == 1) {
>              int nextchr = getch();
>
> @@ -361,6 +361,7 @@ static void curses_setup(void)
>      initscr(); noecho(); intrflush(stdscr, FALSE);
>      nodelay(stdscr, TRUE); nonl(); keypad(stdscr, TRUE);
>      start_color(); raw(); scrollok(stdscr, FALSE);
> +    set_escdelay(200);
>
>      /* Make color pair to match color format (3bits bg:3bits fg) */
>      for (i = 0; i < 64; i++) {
> --
> 2.20.1
>
>
>