Re: The new text-mode menu and the cursor in -nw mode

[Mario Lang <mlang@delysid.org>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Mario Lang <mlang@delysid.org>
>> Date: Mon, 28 Apr 2014 21:14:35 +0200
>> 
>> >> However, as mention in this thread, what is important to both
>> >> groups, is that the hardware cursor position is update if the
>> >> currently "highlighted" area of the screen changes, so that the
>> >> screen reader can "follow" the hightlight around on the screen.
>> >
>> > That's exactly what bothers me: updating a menu might, and generally
>> > will, change more than one place on the screen.  As a trivial example,
>> > moving to the next menu item will redraw both the one which was
>> > highlighted before and the one that is to be highlighted now.  Screen
>> > readers will probably read both (and the help echo in between them),
>> > and I'm not sure the user will understand what is going on, not
>> > without some training.
>> 
>> I am not really sure about speech based screen readers, but some have
>> ways to cope with very fast screen updates, and present the changes in a
>> "meaningful" way.  All I know, as a braille user, is that the hardware
>> cursor position is essential to indicate the highlighted area.  Screen
>> update ordering is totally irrelevant to me, since the screen updates
>> happen way to fast to actually "see" them.  However, what I need is the
>> hardware cursor on the highlighted item, such that my screen reader
>> shows the text "around" the highlight area, instead of going stuck in
>> the middle of the currently active window.
>
> Please try the patch below.  If it gives good results, I will install
> it.

That is exactly what I was looking for, thank you!
Tested on trunk.  While I can see that this might be counted as a
feature by some, I'd like to argue that this change should be installed
to the release branch as well.  Thanks for a very quick response.

> Thanks.
>
> --- src/term.c~0	2014-03-21 08:34:40 +0200
> +++ src/term.c	2014-04-29 17:20:24 +0300
> @@ -2897,6 +2897,13 @@ tty_menu_display (tty_menu *menu, int x,
>  	  menu_help_paneno = pn - 1;
>  	  menu_help_itemno = j;
>  	}
> +      /* Take note of the coordinates of the active menu item, to
> +	 display the cursor there.  */
> +      if (mousehere)
> +	{
> +	  row = y + i;
> +	  col = x;
> +	}
>        display_tty_menu_item (menu->text[j], max_width, face, x, y + i,
>  			     menu->submenu[j] != NULL);
>      }
> @@ -3177,6 +3184,7 @@ tty_menu_activate (tty_menu *menu, int *
>    bool first_time;
>    Lisp_Object selectface;
>    int first_item = 0;
> +  int col, row;
>
>    /* Don't allow non-positive x0 and y0, lest the menu will wrap
>       around the display.  */
> @@ -3364,6 +3372,11 @@ tty_menu_activate (tty_menu *menu, int *
>  			    faces, x, y, first_item, 1);
>  	  tty_hide_cursor (tty);
>  	  fflush (tty->output);
> +	  /* The call to display help-echo below will move the cursor,
> +	     so remember its current position as computed by
> +	     tty_menu_display.  */
> +	  col = cursorX (tty);
> +	  row = cursorY (tty);
>  	}
>
>        /* Display the help-echo message for the currently-selected menu
> @@ -3373,6 +3386,10 @@ tty_menu_activate (tty_menu *menu, int *
>  	{
>  	  help_callback (menu_help_message,
>  			 menu_help_paneno, menu_help_itemno);
> +	  /* Move the cursor to the beginning of the current menu
> +	     item, so that screen readers and other accessibility aids
> +	     know where the active region is.  */
> +	  cursor_to (sf, row, col);
>  	  tty_hide_cursor (tty);
>  	  fflush (tty->output);
>  	  prev_menu_help_message = menu_help_message;

-- 
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