Re: Mouse-hovering over 'mouse-face' overlays/regions on a TTY Emacs

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

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On 2020-12-01 10:20 am, Eli Zaretskii wrote:
>> Date: Mon, 30 Nov 2020 23:10:54 -0800
>> From: Jared Finder <jared@finder.org>
>> Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel@gnu.org
>> 
>> I found the following two suspect lines that sound related, but it's
>> unclear to me what they're for.  Does anyone know what functionality
>> they enable?  (Note: I have some local changes, so my line numbers may
>> be slightly off.)
>> 
>> term.c:4253
>>    tty->mouse_highlight.mouse_face_window = Qnil;
>> 
>> xdisp.c:20783
>> 	  gui_clear_window_mouse_face (w);
> 
> They are necessary parts of mouse-highlight implementation, and should
> be indeed enabled in all builds nowadays.
> 
>> Additionally, it looks like set-mouse-position and
>> set-mouse-pixel-position in frame.c does not behave consistently on 
>> TTYs
>> if Emacs is compiled with window system support vs without.
> 
> You mean, if Emacs is compiled with X _and_ with GPM?  Otherwise I
> don't think I see the issue.

Yes that.  Also if none of the flags are defined, then Fselect_frame is 
not called.  This is independent of if GPM is enabled or not.


Attached is a patch that addresses the above issues.  I was able to 
verify that this make set-mouse-position and set-mouse-pixel-position 
select frames if HAS_GPM is not defined.  I was not able to notice any 
difference when always setting mouse_face_window.

I'd appreciate if someone could test the changes to set-mouse-position 
on MSDOS and with window systems enabled as I can not test that 
environment.

   -- MJF

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From 41fa47d4315a998ea1116f0d9f898eeaaad51c0b Mon Sep 17 00:00:00 2001
From: Jared Finder <jared@finder.org>
Date: Wed, 2 Dec 2020 00:05:59 -0800
Subject: [PATCH] Remove incorrect usage of HAVE_GPM.

* src/frame.c (Fset_mouse_position, Fset_mouse_pixel_position): Call
Fselect_frame in all terminals, independent of defines.
* src/term.c (init_tty): Initialize mouse_face_window for all
terminals.
* src/xdisp.c (try_window_id): Call gui_clear_window_mouse_face in all
cases.
---
 src/frame.c | 36 ++++++++++++++++++++++++------------
 src/term.c  |  2 +-
 src/xdisp.c |  3 +--
 3 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/src/frame.c b/src/frame.c
index 17ec455d2d..4bbcb74667 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -2574,22 +2574,28 @@ DEFUN ("set-mouse-position", Fset_mouse_position, Sset_mouse_position, 3, 3, 0,
   /* I think this should be done with a hook.  */
 #ifdef HAVE_WINDOW_SYSTEM
   if (FRAME_WINDOW_P (XFRAME (frame)))
-    /* Warping the mouse will cause enternotify and focus events.  */
-    frame_set_mouse_position (XFRAME (frame), xval, yval);
-#elif defined MSDOS
+    {
+      /* Warping the mouse will cause enternotify and focus events.  */
+      frame_set_mouse_position (XFRAME (frame), xval, yval);
+      return Qnil;
+    }
+#endif /* HAVE_WINDOW_SYSTEM */
+#ifdef MSDOS
   if (FRAME_MSDOS_P (XFRAME (frame)))
     {
       Fselect_frame (frame, Qnil);
       mouse_moveto (xval, yval);
+      return Qnil;
     }
-#elif defined HAVE_GPM
+#endif /* MSDOS */
+
   Fselect_frame (frame, Qnil);
+#if defined (HAVE_GPM) && ! defined (HAVE_WINDOW_SYSTEM)
   term_mouse_moveto (xval, yval);
 #else
   (void) xval;
   (void) yval;
-#endif
-
+#endif /* HAVE_GPM && ! HAVE_WINDOW_SYSTEM */
   return Qnil;
 }
 
@@ -2612,22 +2618,28 @@ DEFUN ("set-mouse-pixel-position", Fset_mouse_pixel_position,
   /* I think this should be done with a hook.  */
 #ifdef HAVE_WINDOW_SYSTEM
   if (FRAME_WINDOW_P (XFRAME (frame)))
-    /* Warping the mouse will cause enternotify and focus events.  */
-    frame_set_mouse_pixel_position (XFRAME (frame), xval, yval);
-#elif defined MSDOS
+    {
+      /* Warping the mouse will cause enternotify and focus events.  */
+      frame_set_mouse_pixel_position (XFRAME (frame), xval, yval);
+      return Qnil;
+    }
+#endif /* HAVE_WINDOW_SYSTEM */
+#ifdef MSDOS
   if (FRAME_MSDOS_P (XFRAME (frame)))
     {
       Fselect_frame (frame, Qnil);
       mouse_moveto (xval, yval);
+      return Qnil;
     }
-#elif defined HAVE_GPM
+#endif /* MSDOS */
+
   Fselect_frame (frame, Qnil);
+#if defined (HAVE_GPM) && ! defined (HAVE_WINDOW_SYSTEM)
   term_mouse_moveto (xval, yval);
 #else
   (void) xval;
   (void) yval;
-#endif
-
+#endif /* HAVE_GPM && ! HAVE_WINDOW_SYSTEM */
   return Qnil;
 }
 \f
diff --git a/src/term.c b/src/term.c
index fee3b55575..dfdc3bce7e 100644
--- a/src/term.c
+++ b/src/term.c
@@ -4246,8 +4246,8 @@ init_tty (const char *name, const char *terminal_type, bool must_succeed)
 
 #ifdef HAVE_GPM
   terminal->mouse_position_hook = term_mouse_position;
-  tty->mouse_highlight.mouse_face_window = Qnil;
 #endif
+  tty->mouse_highlight.mouse_face_window = Qnil;
 
   terminal->kboard = allocate_kboard (Qnil);
   terminal->kboard->reference_count++;
diff --git a/src/xdisp.c b/src/xdisp.c
index 76ef420a36..498e6f1065 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -20779,9 +20779,8 @@ #define GIVE_UP(X) return 0
 		     + window_wants_header_line (w)
 		     + window_internal_height (w));
 
-#if defined (HAVE_GPM) || defined (MSDOS)
 	  gui_clear_window_mouse_face (w);
-#endif
+
 	  /* Perform the operation on the screen.  */
 	  if (dvpos > 0)
 	    {
-- 
2.20.1