Re: suggested feature -- console-mode frame title sets Xterm title

[Martin Pool]

On  1 Oct 2003, Richard Stallman <address@hidden> wrote:
>     Perhaps this patch ought to add Lisp variables to set the escape
>     codes, but there is already a (slightly obscure) way to set them
>     through the termcap file or $TERMCAP.
> 
> I think we should have both interfaces.  It is good to look in the
> termcap entry, but xterm is important and we can't expect its termcap
> entry to be fixed soon.  So we should create a mechanism that
> lisp/term/xterm.el can use to supply the correct information.
> 
> Can you do that?

Here's a new patch.

I have set tty-frame-use-title on by default, because it won't do
anything unless we're on a terminal where it can work.  

This works well in xterms and under GNU screen.  It's quite nice to
see the title update as you flip between buffers or screens.  Before
this can be committed we need a term/screen.el as well.

I think the only remaining problem is that this has changed the way
select-buffer-by-name works.  For multi-frame text terminals the names
used to be F%d, but now they're "full" names, probably including the
name of the buffer.  This is inconsistent with how it was documented
to work in the 21.3 manual, but on the other hand it is consistent
with how this function works on windowing system frames.  I'm not sure
how to resolve this.  

To avoid messing up the modeline I have disabled the %F character when
tty-frame-use-title is set.  This is perhaps a bit ugly but I think a
proper resolution would require something like adding a 'short name'
for the frame as distinct from its title.


diff -dru emacs-21.3/lisp/cus-start.el emacs-21.3-title/lisp/cus-start.el
--- emacs-21.3/lisp/cus-start.el        2001-10-29 03:24:54.000000000 +1100
+++ emacs-21.3-title/lisp/cus-start.el  2003-10-02 16:16:15.000000000 +1000
@@ -244,6 +244,9 @@
                                        (choice integer
                                                (const :tag "No limit" nil)))
             (highlight-nonselected-windows display boolean)
+             (tty-frame-use-title display boolean)
+             (tty-frame-title-start display string)
+             (tty-frame-title-end display end)
             (message-log-max debug (choice (const :tag "Disable" nil)
                                            (integer :menu-tag "lines"
                                                     :format "%v")
diff -dru emacs-21.3/lisp/term/xterm.el emacs-21.3-title/lisp/term/xterm.el
--- emacs-21.3/lisp/term/xterm.el       2001-07-16 21:39:42.000000000 +1000
+++ emacs-21.3-title/lisp/term/xterm.el 2003-10-02 16:24:37.000000000 +1000
@@ -48,4 +48,7 @@
 (define-key function-key-map "\e[24~" [f12])
 (define-key function-key-map "\e[29~" [print])
 
+(set-variable 'tty-frame-title-start "\e]2;")
+(set-variable 'tty-frame-title-end "\007")
+
 ;;; xterm.el ends here
diff -dru emacs-21.3/src/dispextern.h emacs-21.3-title/src/dispextern.h
--- emacs-21.3/src/dispextern.h 2002-11-15 00:15:46.000000000 +1100
+++ emacs-21.3-title/src/dispextern.h   2003-10-02 16:02:18.000000000 +1000
@@ -2224,6 +2224,9 @@
 extern int current_mode_line_height, current_header_line_height;
 extern int cursor_in_non_selected_windows;
 
+extern int tty_frame_use_title;
+extern Lisp_Object Vtty_frame_title_start, Vtty_frame_title_end;
+
 /* Defined in sysdep.c */
 
 void get_frame_size P_ ((int *, int *));
@@ -2365,6 +2368,7 @@
 /* Defined in term.c */
 
 extern void ring_bell P_ ((void));
+extern void terminal_set_frame_title P_ ((char *, int));
 extern void set_terminal_modes P_ ((void));
 extern void reset_terminal_modes P_ ((void));
 extern void update_begin P_ ((struct frame *));
diff -dru emacs-21.3/src/term.c emacs-21.3-title/src/term.c
--- emacs-21.3/src/term.c       2001-05-31 18:56:32.000000000 +1000
+++ emacs-21.3-title/src/term.c 2003-10-02 11:56:47.000000000 +1000
@@ -285,6 +285,9 @@
 char *TS_set_window;           /* "wi" (4 params, start and end of window,
                                   each as vpos and hpos) */
 
+char *TS_to_status;             /* "ts", go to status line */
+char *TS_from_status;           /* "fs", go back from status line */
+
 /* Value of the "NC" (no_color_video) capability, or 0 if not
    present.  */
 
@@ -369,9 +372,13 @@
                           TN_standout_width == 0, it means don't bother
                           to write any end-standout cookies.  */
 
+int TF_status;              /* termcap hs flag: has a status line
+                               (title for xterms) */
+
 int TN_standout_width; /* termcap sg number: width occupied by standout
                           markers */
 
+
 static int RPov;       /* # chars to start a TS_repeat */
 
 static int delete_in_insert_mode;      /* delete mode == insert mode */
@@ -472,6 +479,30 @@
 }
 
 void
+terminal_set_frame_title (line, len)
+     char *line;
+     int len;
+{
+  /* XXX: Are there any terminals where we need to explicitly clear
+     the status line after jumping to it? */
+
+  if (!NILP (Vtty_frame_title_start)
+      && !NILP (Vtty_frame_title_end))
+    {
+      fputs (XSTRING (Vtty_frame_title_start)->data, stdout);
+      fwrite (line, 1, len, stdout);
+      fputs (XSTRING (Vtty_frame_title_end)->data, stdout);
+    }
+  else if (TF_status && TS_to_status && TS_from_status)
+    {
+      /* defined by termcap */    
+      OUTPUT1 (TS_to_status);
+      fwrite (line, 1, len, stdout);
+      OUTPUT1 (TS_from_status);
+    }
+}
+
+void
 set_terminal_modes ()
 {
   if (FRAME_TERMCAP_P (XFRAME (selected_frame)))
@@ -2334,6 +2365,9 @@
   TS_cursor_visible = tgetstr ("vs", address);
   TS_cursor_invisible = tgetstr ("vi", address);
   TS_set_window = tgetstr ("wi", address);
+  TS_to_status = tgetstr ("ts", address);
+  TS_from_status = tgetstr ("fs", address);
+  TF_status = tgetflag ("hs");
   
   TS_enter_underline_mode = tgetstr ("us", address);
   TS_exit_underline_mode = tgetstr ("ue", address);
diff -dru emacs-21.3/src/xdisp.c emacs-21.3-title/src/xdisp.c
--- emacs-21.3/src/xdisp.c      2003-01-18 00:45:13.000000000 +1100
+++ emacs-21.3-title/src/xdisp.c        2003-10-02 16:24:52.000000000 +1000
@@ -1,5 +1,5 @@
 /* Display generation from window structure and buffer text.
-   Copyright (C) 1985, 86, 87, 88, 93, 94, 95, 97, 98, 99, 2000, 2001, 2002
+   Copyright (C) 1985, 86, 87, 88, 93, 94, 95, 97, 98, 99, 2000, 01, 02, 03
    Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
@@ -296,6 +296,13 @@
 
 static int message_log_need_newline;
 
+/* Non-nil means to try to show frame titles on tty frames.  Whether
+   we can actually do so depends on whether the termcap definition has
+   hardstatus capabilities. */
+int tty_frame_use_title;
+
+Lisp_Object Vtty_frame_title_start, Vtty_frame_title_end;
+
 
 /* The buffer position of the first character appearing entirely or
    partially on the line of the selected window which contains the
@@ -688,7 +695,7 @@
 static int text_outside_line_unchanged_p P_ ((struct window *, int, int));
 static void store_frame_title_char P_ ((char));
 static int store_frame_title P_ ((unsigned char *, int, int));
-static void x_consider_frame_title P_ ((Lisp_Object));
+static void consider_frame_title P_ ((Lisp_Object));
 static void handle_stop P_ ((struct it *));
 static int tool_bar_lines_needed P_ ((struct frame *));
 static int single_display_prop_intangible_p P_ ((Lisp_Object));
@@ -7142,7 +7149,6 @@
  ***********************************************************************/
 
 
-#ifdef HAVE_WINDOW_SYSTEM
 
 /* A buffer for constructing frame titles in it; allocated from the
    heap in init_xdisp and resized as needed in store_frame_title_char.  */
@@ -7211,17 +7217,19 @@
 }
 
 
+
 /* Set the title of FRAME, if it has changed.  The title format is
    Vicon_title_format if FRAME is iconified, otherwise it is
    frame_title_format.  */
 
 static void
-x_consider_frame_title (frame)
+consider_frame_title (frame)
      Lisp_Object frame;
 {
   struct frame *f = XFRAME (frame);
 
   if (FRAME_WINDOW_P (f)
+      || (FRAME_TERMCAP_P (f) && tty_frame_use_title)
       || FRAME_MINIBUF_ONLY_P (f)
       || f->explicit_name)
     {
@@ -7260,24 +7268,41 @@
       frame_title_ptr = NULL;
       set_buffer_internal (obuf);
 
+#ifdef HAVE_WINDOW_SYSTEM
+          /* Even if we're compiled with a window system, we might not be
+             using it for this frame... */
+
       /* Set the title only if it's changed.  This avoids consing in
         the common case where it hasn't.  (If it turns out that we've
         already wasted too much time by walking through the list with
         display_mode_element, then we might need to optimize at a
         higher level than this.)  */
-      if (! STRINGP (f->name) 
-         || STRING_BYTES (XSTRING (f->name)) != len
-         || bcmp (frame_title_buf, XSTRING (f->name)->data, len) != 0)
-       x_implicitly_set_name (f, make_string (frame_title_buf, len), Qnil);
-    }
-}
+      if (FRAME_WINDOW_P (f))
+        if (! STRINGP (f->name) 
+            || STRING_BYTES (XSTRING (f->name)) != len
+            || bcmp (frame_title_buf, XSTRING (f->name)->data, len) != 0)
+          {
+            /* TODO: There is some common logic across all terminal
+               types that could be factored out of
+               x_implicitly_set_name() */
+            x_implicitly_set_name (f, make_string (frame_title_buf, len), 
Qnil);
+          }
+#endif
 
-#else /* not HAVE_WINDOW_SYSTEM */
+      /* For termcap windows, we always reset the title when we
+         reconsider it, because this may not have been the
+         previously-visible frame. */
+      if (FRAME_TERMCAP_P (f)  &&  f == SELECTED_FRAME ())
+        {
+          terminal_set_frame_title (frame_title_buf, len);
+          f->name =  make_string (frame_title_buf, len);
+        }
 
-#define frame_title_ptr ((char *)0)
-#define store_frame_title(str, mincol, maxcol) 0
+      /* There are other possibilities, e.g. a nongraphical window
+         on Windows NT.  We don't handle that at the moment. */
+    }
+}
 
-#endif /* not HAVE_WINDOW_SYSTEM */
 
 
 
@@ -7307,7 +7332,6 @@
   /* Update all frame titles based on their buffer names, etc.  We do
      this before the menu bars so that the buffer-menu will show the
      up-to-date frame titles.  */
-#ifdef HAVE_WINDOW_SYSTEM
   if (windows_or_buffers_changed || update_mode_lines)
     {
       Lisp_Object tail, frame;
@@ -7317,10 +7341,9 @@
          f = XFRAME (frame);
          if (!EQ (frame, tooltip_frame)
              && (FRAME_VISIBLE_P (f) || FRAME_ICONIFIED_P (f)))
-           x_consider_frame_title (frame);
+           consider_frame_title (frame);
        }
     }
-#endif /* HAVE_WINDOW_SYSTEM */
 
   /* Update the menu bar item lists, if appropriate.  This has to be
      done before any actual redisplay or generation of display lines.  */
@@ -14068,6 +14091,8 @@
       /* %F displays the frame name.  */
       if (!NILP (f->title))
        return (char *) XSTRING (f->title)->data;
+      if (FRAME_TERMCAP_P (f) && tty_frame_use_title)
+        return "";
       if (f->explicit_name || ! FRAME_WINDOW_P (f))
        return (char *) XSTRING (f->name)->data;
       return "Emacs";
@@ -14955,6 +14980,27 @@
                                                               Qnil)))),
                           Qnil)));
 
+  DEFVAR_BOOL ("tty-frame-use-title", &tty_frame_use_title,
+"*Show frame titles in the title or status line of text terminals.\n\
+The title is set if this variable is non-nil and if either \n\
+`tty-frame-title-start' and `tty-frame-title-end' are set, or if the \n\
+terminal has the `ts' and `fs' termcap capabilities.");
+  tty_frame_use_title = 1;
+
+  DEFVAR_LISP ("tty-frame-title-start", &Vtty_frame_title_start,
+"Start of the escape sequence to set a text terminal's title bar.\n\
+This value is only used if `tty-frame-use-title' is non-nil.\n\
+The default value is suitable for xterms, GNU Screen, and many other\n\
+modern terminal emulators.");
+  Vtty_frame_title_start = Qnil;
+
+  DEFVAR_LISP ("tty-frame-title-end", &Vtty_frame_title_end,
+"End of the escape sequence to set a text terminal's title bar.\n\
+This value is only used if `tty-frame-use-title' is non-nil.\n\
+The default value is suitable for xterms, GNU Screen, and many other\n\
+modern terminal emulators.");
+  Vtty_frame_title_end = Qnil;
+
   DEFVAR_LISP ("message-log-max", &Vmessage_log_max,
     "Maximum number of lines to keep in the message log buffer.\n\
 If nil, disable message logging.  If t, log messages but don't truncate\n\
@@ -15120,7 +15166,6 @@
        default_invis_vector[i] = make_number ('.');
     }
 
-#ifdef HAVE_WINDOW_SYSTEM
   {
     /* Allocate the buffer for frame titles.  */
     int size = 100;
@@ -15128,7 +15173,6 @@
     frame_title_buf_end = frame_title_buf + size;
     frame_title_ptr = NULL;
   }
-#endif /* HAVE_WINDOW_SYSTEM */
   
   help_echo_showing_p = 0;
 }



-- 
Martin