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

[Eli Zaretskii <eliz@gnu.org>]

> 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.

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;