Re: Making TTY menus more visual

[Jared Finder via "Emacs development discussions." <emacs-devel@gnu.org>]

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On 2020-10-03 12:26 pm, Jared Finder wrote:
> On 2020-10-03 1:50 am, Eli Zaretskii wrote:
>>> Date: Fri, 02 Oct 2020 17:16:55 -0700
>>> From: Jared Finder <jared@finder.org>
>>> Cc: emacs-devel@gnu.org
>>> 
>>> Also, a user may click outside of the popped up menu, which they
>>> would expect to dismiss the menu. (this is patch 002 in the root of
>>> the thread, not yet complete)
>> 
>> This should already work; it does in the MS-Windows build when Emacs
>> is invoked with -nw.  Please tell more why you think any changes there
>> are needed.  Perhaps you could take me through the code there and
>> explain what is missing and why.  (And why do you call posn-x-y in the
>> patch when X and Y are already known and used by that code? is that
>> because mouse_get_xy does not yet support xterm-mouse? if so, that
>> support should be added via the terminal's mouse_position_hook.)
> 
> From injecting debug logs into read_menu_input, I can observe that
> tty-menu-mouse-movement is never received so the highlighted item
> never changes except due to keyboard input. And from tracing
> xterm-mouse--read-event-sequence, it appears that Emacs normally does
> not receive xterm mouse motion events unless a button is pressed.
> 
> This appears to be due to xt-mouse sending event code 1002 instead of
> 1003 (see
> https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h2-Mouse-Tracking).
> 
> Just sending 1003 instead doesn't just work, but I do see mouse events
> now coming through. Let me do some more investigation here and I will
> get back to you.

It wasn't that much more work to get xterm-mouse to work. I've attached 
an updated patch.

I have just one question, corresponding to the remaining TODO:

Now there are newly emitted events for mouse-movement that are not 
handled such as "<mode-line> <mouse-movement>" or "<vertical-line> 
<mouse-movement>". It'd be easy enough to bind all of these to ignore 
and further update tty-menu-navigation-map to have more cases, but is 
that the right solution? I'm surprised that only xterm-mouse would run 
into this case.

   -- MJF

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From 2b71048614be65eb9c4267224a0606bfcd86cc8a Mon Sep 17 00:00:00 2001
From: Jared Finder <jared@finder.org>
Date: Sat, 3 Oct 2020 14:46:30 -0700
Subject: [PATCH 2/2] Making TTY menus work with xterm-mouse-mode.

* Update xt-mouse.el to use SET_ANY_EVENT_MOUSE (1003) so mouse movement is
  always reported.
* Hook up mouse_get_xy to mouse-position so it works with xterm mouse.
* (WIP) Properly handle mouse-movement events in all the possible
  prefixes, such as menu-bar or mode-line.
---
 lisp/menu-bar.el | 10 ++++++++++
 lisp/xt-mouse.el | 10 +++++-----
 src/term.c       | 28 ++++++++++++++++++----------
 3 files changed, 33 insertions(+), 15 deletions(-)

diff --git a/lisp/menu-bar.el b/lisp/menu-bar.el
index 9021be8eff..44de6e7c32 100644
--- a/lisp/menu-bar.el
+++ b/lisp/menu-bar.el
@@ -2758,6 +2758,16 @@ tty-menu-navigation-map
     (define-key map [C-down-mouse-2] 'tty-menu-ignore)
     (define-key map [C-down-mouse-3] 'tty-menu-ignore)
     (define-key map [mouse-movement] 'tty-menu-mouse-movement)
+
+    ;; These are needed because xterm-mouse always sends events with
+    ;; special prefixes.
+    ;;
+    ;; TODO -- either make xterm-mouse not use the special prefixes or
+    ;; fix all "prefix-thingy mouse-movement is undefined" with
+    ;; special prefixes.
+    (define-key map [header-line mouse-movement] 'tty-menu-mouse-movement)
+    (define-key map [menu-bar mouse-movement] 'tty-menu-mouse-movement)
+    (define-key map [mode-line mouse-movement] 'tty-menu-mouse-movement)
     map)
   "Keymap used while processing TTY menus.")
 
diff --git a/lisp/xt-mouse.el b/lisp/xt-mouse.el
index 362d29b943..ae6f85f1f7 100644
--- a/lisp/xt-mouse.el
+++ b/lisp/xt-mouse.el
@@ -339,7 +339,7 @@ xterm-mouse-tracking-enable-sequence
             position (<= 223), which can be reported in this
             basic mode.
 
-\"\\e[?1002h\" \"Mouse motion mode\": Enables reports for mouse
+\"\\e[?1003h\" \"Mouse motion mode\": Enables reports for mouse
             motion events during dragging operations.
 
 \"\\e[?1005h\" \"UTF-8 coordinate extension\": Enables an
@@ -360,7 +360,7 @@ xterm-mouse-tracking-enable-sequence
   (apply #'concat (xterm-mouse--tracking-sequence ?h)))
 
 (defconst xterm-mouse-tracking-enable-sequence
-  "\e[?1000h\e[?1002h\e[?1005h\e[?1006h"
+  "\e[?1000h\e[?1003h\e[?1005h\e[?1006h"
   "Control sequence to enable xterm mouse tracking.
 Enables basic mouse tracking, mouse motion events and finally
 extended tracking on terminals that support it. The following
@@ -371,7 +371,7 @@ xterm-mouse-tracking-enable-sequence
             position (<= 223), which can be reported in this
             basic mode.
 
-\"\\e[?1002h\" \"Mouse motion mode\": Enables reports for mouse
+\"\\e[?1003h\" \"Mouse motion mode\": Enables reports for mouse
             motion events during dragging operations.
 
 \"\\e[?1005h\" \"UTF-8 coordinate extension\": Enables an extension
@@ -400,7 +400,7 @@ xterm-mouse-tracking-disable-sequence
   (apply #'concat (nreverse (xterm-mouse--tracking-sequence ?l))))
 
 (defconst xterm-mouse-tracking-disable-sequence
-  "\e[?1006l\e[?1005l\e[?1002l\e[?1000l"
+  "\e[?1006l\e[?1005l\e[?1003l\e[?1000l"
   "Reset the modes set by `xterm-mouse-tracking-enable-sequence'.")
 
 (make-obsolete-variable
@@ -414,7 +414,7 @@ xterm-mouse--tracking-sequence
 enable, ?l to disable)."
   (mapcar
    (lambda (code) (format "\e[?%d%c" code suffix))
-   `(1000 1002 ,@(when xterm-mouse-utf-8 '(1005)) 1006)))
+   `(1000 1003 ,@(when xterm-mouse-utf-8 '(1005)) 1006)))
 
 (defun turn-on-xterm-mouse-tracking-on-terminal (&optional terminal)
   "Enable xterm mouse tracking on TERMINAL."
diff --git a/src/term.c b/src/term.c
index 3677644845..1196609047 100644
--- a/src/term.c
+++ b/src/term.c
@@ -2481,6 +2481,16 @@ term_mouse_position (struct frame **fp, int insist, Lisp_Object *bar_window,
   *bar_window = Qnil;
   *part = scroll_bar_above_handle;
 
+  // xterm-mouse always stores the mouse positions in terminal
+  // parameters. Existing code path (GPM?) does not.
+  //
+  // TODO: Figure out the right way to unify these code paths.
+  if (true)
+    {
+      last_mouse_x = XFIXNUM (Fterminal_parameter (Qnil, intern ("xterm-mouse-x")));
+      last_mouse_y = XFIXNUM (Fterminal_parameter (Qnil, intern ("xterm-mouse-y")));
+    }
+
   XSETINT (*x, last_mouse_x);
   XSETINT (*y, last_mouse_y);
   *timeptr = current_Time ();
@@ -2804,16 +2814,14 @@ tty_menu_calc_size (tty_menu *menu, int *width, int *height)
 static void
 mouse_get_xy (int *x, int *y)
 {
-  struct frame *sf = SELECTED_FRAME ();
-  Lisp_Object lmx = Qnil, lmy = Qnil, lisp_dummy;
-  enum scroll_bar_part part_dummy;
-  Time time_dummy;
-
-  if (FRAME_TERMINAL (sf)->mouse_position_hook)
-    (*FRAME_TERMINAL (sf)->mouse_position_hook) (&sf, -1,
-                                                 &lisp_dummy, &part_dummy,
-						 &lmx, &lmy,
-						 &time_dummy);
+  Lisp_Object lmx = Qnil, lmy = Qnil, mouse_position = Fmouse_position ();
+
+  if (EQ (selected_frame, XCAR(mouse_position)))
+    {
+      lmx = XCAR (XCDR (mouse_position));
+      lmy = XCDR (XCDR (mouse_position));
+    }
+
   if (!NILP (lmx))
     {
       *x = XFIXNUM (lmx);
-- 
2.20.1