bug#28340: 26.0.50; xterm frame titles

[Mark Oteiza <mvoteiza@udel.edu>]

Wishlist item.

Hi,

I tacked setting window/iconified window titles into term/xterm.el, but
found a quirk I suspect is related to Bug#18137 (which refers to
42fe2e88d and Bug#15025).  Because clients don't always have focus,
opening a new client won't trigger hooks that I would think trigger,
perhaps even after-make-frame-functions or window-size-change-functions.

diff --git a/lisp/term/xterm.el b/lisp/term/xterm.el
index e6d224dd3d..03dd516ebf 100644
--- a/lisp/term/xterm.el
+++ b/lisp/term/xterm.el
@@ -802,6 +802,7 @@ terminal-init-xterm
     (when (memq 'setSelection xterm-extra-capabilities)
       (xterm--init-activate-set-selection)))
 
+  (xterm--init-frame-title)
   ;; Unconditionally enable bracketed paste mode: terminals that don't
   ;; support it just ignore the sequence.
   (xterm--init-bracketed-paste-mode)
@@ -828,6 +829,22 @@ xterm--init-activate-set-selection
   "Terminal initialization for `gui-set-selection'."
   (set-terminal-parameter nil 'xterm--set-selection t))
 
+(defun xterm--init-frame-title ()
+  "Terminal initialization for `gui-set-selection'."
+  (xterm-set-window-title)
+  (add-hook 'post-command-hook 'xterm-set-window-title)
+  (add-hook 'minibuffer-exit-hook 'xterm-set-window-title))
+
+(defun xterm-set-window-title ()
+  "Set the window title of the Xterm with the current Emacs frame."
+  (send-string-to-terminal
+   (format "\e]2;%s\a" (format-mode-line frame-title-format))))
+
+(defun xterm-set-icon-title ()
+  "Set the window title of the Xterm with the current Emacs frame."
+  (send-string-to-terminal
+   (format "\e]1;%s\a" (format-mode-line icon-title-format))))
+
 (defun xterm--selection-char (type)
   (pcase type
     ('PRIMARY "p")