Subject: bug#75931: 31.0.50; mouse-face and pointer properties make pointer change back and forth

From: Eli Zaretskii <[email-masked]>
Date: Thu, 30 Jan 2025 21:19:56 +0200

> Date: Thu, 30 Jan 2025 09:33:37 -0300
> Cc: [email-masked], [email-masked]
> From: Mauro Aranda <[email-masked]>
> 
> On 30/1/25 09:25, Eli Zaretskii wrote:
>  >>
>  >> I've no idea how to do that.  So, I did something silly:
>  >> In show_mouse_face, when draw is DRAW_MOUSE_FACE, I changed:
>  >> FRAME_OUTPUT_DATA (f)->hand_cursor
>  >> to:
>  >> FRAME_OUTPUT_DATA (f)->current_cursor
>  >
>  > That's what I had in mind, thanks.
> 
> Great!
> 
>  >> But I'm way out of my league here, so I don't know if the change is
>  >> correct, most probably not.  What seems correct is not specifying
>  >> hand_cursor, but rather find out which cursor do we need to draw when
>  >> redrawing it...
>  >
>  > That'd be the fallback plan, but it would require to refactor the code
>  > in note_mouse_highlight, and in particular move the code which
>  > determines the pointer shape into show_mouse_face (which will make it
>  > more expensive), and also other changes, since show_mouse_face is
>  > called from several places.  Let's hope this will not be necessary.
> 
> OK.  I'll keep my fingers crossed.

Please try the patch below.

diff --git a/src/xdisp.c b/src/xdisp.c
index a801caa..a047035 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -1229,7 +1229,7 @@ #define face_after_it_pos(IT)  face_before_or_after_it_pos (IT, false)
 
 static void produce_special_glyphs (struct it *, enum display_element_type);
 static void pad_mode_line (struct it *, bool);
-static void show_mouse_face (Mouse_HLInfo *, enum draw_glyphs_face);
+static void show_mouse_face (Mouse_HLInfo *, enum draw_glyphs_face, bool);
 static bool coords_in_mouse_face_p (struct window *, int, int);
 static void reset_box_start_end_flags (struct it *);
 
@@ -15052,14 +15052,14 @@ handle_tab_bar_click (struct frame *f, int x, int y, bool down_p,
     {
       /* Show the clicked button in pressed state.  */
       if (!NILP (Vmouse_highlight))
-	show_mouse_face (hlinfo, DRAW_IMAGE_SUNKEN);
+	show_mouse_face (hlinfo, DRAW_IMAGE_SUNKEN, true);
       f->last_tab_bar_item = prop_idx; /* record the pressed tab */
     }
   else
     {
       /* Show item in released state.  */
       if (!NILP (Vmouse_highlight))
-	show_mouse_face (hlinfo, DRAW_IMAGE_RAISED);
+	show_mouse_face (hlinfo, DRAW_IMAGE_RAISED, true);
       f->last_tab_bar_item = -1;
     }
 
@@ -15157,7 +15157,7 @@ note_tab_bar_highlight (struct frame *f, int x, int y)
       hlinfo->mouse_face_face_id = TAB_BAR_FACE_ID;
 
       /* Display it as active.  */
-      show_mouse_face (hlinfo, draw);
+      show_mouse_face (hlinfo, draw, true);
     }
 
  set_help_echo:
@@ -16074,7 +16074,7 @@ handle_tool_bar_click_with_device (struct frame *f, int x, int y, bool down_p,
     {
       /* Show item in pressed state.  */
       if (!NILP (Vmouse_highlight))
-	show_mouse_face (hlinfo, DRAW_IMAGE_SUNKEN);
+	show_mouse_face (hlinfo, DRAW_IMAGE_SUNKEN, true);
       f->last_tool_bar_item = prop_idx;
     }
   else
@@ -16085,7 +16085,7 @@ handle_tool_bar_click_with_device (struct frame *f, int x, int y, bool down_p,
 
       /* Show item in released state.  */
       if (!NILP (Vmouse_highlight))
-	show_mouse_face (hlinfo, DRAW_IMAGE_RAISED);
+	show_mouse_face (hlinfo, DRAW_IMAGE_RAISED, true);
 
       key = AREF (f->tool_bar_items, prop_idx + TOOL_BAR_ITEM_KEY);
 
@@ -16181,7 +16181,7 @@ note_tool_bar_highlight (struct frame *f, int x, int y)
       hlinfo->mouse_face_face_id = TOOL_BAR_FACE_ID;
 
       /* Display it as active.  */
-      show_mouse_face (hlinfo, draw);
+      show_mouse_face (hlinfo, draw, true);
     }
 
  set_help_echo:
@@ -34196,12 +34196,13 @@ erase_phys_cursor (struct window *w)
   /* Since erasing the phys cursor will probably lead to corruption of
      the mouse face display if the glyph's pixel_width is not kept up
      to date with the :box property of the mouse face, just redraw the
-     mouse face.  */
+     mouse face, but leave the mouse cursor as it was.  */
   if (FRAME_WINDOW_P (WINDOW_XFRAME (w)) && mouse_face_here_p)
     {
       w->phys_cursor_on_p = false;
       w->phys_cursor_type = NO_CURSOR;
-      show_mouse_face (MOUSE_HL_INFO (WINDOW_XFRAME (w)), DRAW_MOUSE_FACE);
+      show_mouse_face (MOUSE_HL_INFO (WINDOW_XFRAME (w)), DRAW_MOUSE_FACE,
+		       false);
       return;
     }
 #endif
@@ -34462,7 +34463,8 @@ draw_row_with_mouse_face (struct window *w, int start_x, struct glyph_row *row,
 /* Display the active region described by mouse_face_* according to DRAW.  */
 
 static void
-show_mouse_face (Mouse_HLInfo *hlinfo, enum draw_glyphs_face draw)
+show_mouse_face (Mouse_HLInfo *hlinfo, enum draw_glyphs_face draw,
+		 bool define_mouse_cursor)
 {
   /* Don't bother doing anything if the mouse-face window is not set
      up.  */
@@ -34604,7 +34606,7 @@ show_mouse_face (Mouse_HLInfo *hlinfo, enum draw_glyphs_face draw)
 
 #ifdef HAVE_WINDOW_SYSTEM
   /* Change the mouse cursor.  */
-  if (FRAME_WINDOW_P (f) && NILP (track_mouse))
+  if (FRAME_WINDOW_P (f) && NILP (track_mouse) && define_mouse_cursor)
     {
       if (draw == DRAW_NORMAL_TEXT
 #ifndef HAVE_EXT_TOOL_BAR
@@ -34612,8 +34614,7 @@ show_mouse_face (Mouse_HLInfo *hlinfo, enum draw_glyphs_face draw)
 #endif
 	  && !EQ (hlinfo->mouse_face_window, f->tab_bar_window))
 	FRAME_RIF (f)->define_frame_cursor (f, FRAME_OUTPUT_DATA (f)->text_cursor);
-      else
-      if (draw == DRAW_MOUSE_FACE)
+      else if (draw == DRAW_MOUSE_FACE)
 	FRAME_RIF (f)->define_frame_cursor (f, FRAME_OUTPUT_DATA (f)->hand_cursor);
       else
 	FRAME_RIF (f)->define_frame_cursor (f, FRAME_OUTPUT_DATA (f)->nontext_cursor);
@@ -34632,7 +34633,7 @@ clear_mouse_face (Mouse_HLInfo *hlinfo)
   bool cleared
     = !hlinfo->mouse_face_hidden && !NILP (hlinfo->mouse_face_window);
   if (cleared)
-    show_mouse_face (hlinfo, DRAW_NORMAL_TEXT);
+    show_mouse_face (hlinfo, DRAW_NORMAL_TEXT, true);
   hlinfo->mouse_face_beg_row = hlinfo->mouse_face_beg_col = -1;
   hlinfo->mouse_face_end_row = hlinfo->mouse_face_end_col = -1;
   hlinfo->mouse_face_window = Qnil;
@@ -35199,7 +35200,7 @@ mouse_face_from_buffer_pos (Lisp_Object window,
     = face_at_buffer_position (w, mouse_charpos, &ignore,
 			       mouse_charpos + 1,
                                !hlinfo->mouse_face_hidden, -1, 0);
-  show_mouse_face (hlinfo, DRAW_MOUSE_FACE);
+  show_mouse_face (hlinfo, DRAW_MOUSE_FACE, true);
 }
 
 /* The following function is not used anymore (replaced with
@@ -35909,7 +35910,7 @@ note_mode_line_or_margin_highlight (Lisp_Object window, int x, int y,
 	    face_at_string_position (w, string, charpos, 0, &ignore,
 	                             glyph->face_id, true, 0);
 
-	  show_mouse_face (hlinfo, DRAW_MOUSE_FACE);
+	  show_mouse_face (hlinfo, DRAW_MOUSE_FACE, true);
 	  mouse_face_shown = true;
 
 	  if (NILP (pointer))
@@ -36448,7 +36449,7 @@ note_mouse_highlight (struct frame *f, int x, int y)
 	      hlinfo->mouse_face_face_id
 		= face_at_string_position (w, object, pos, 0, &ignore,
 		                           glyph->face_id, true, 0);
-	      show_mouse_face (hlinfo, DRAW_MOUSE_FACE);
+	      show_mouse_face (hlinfo, DRAW_MOUSE_FACE, true);
 	      cursor = No_Cursor;
 	    }
 	  else