Optionally reuse tooltip frames instead of deleting/recreating them.

* src/frame.c (tooltip_reuse_hidden_frame): New option.
* src/w32fns.c (x_create_tip_frame): Remove argument TEXT.  Fix
handling of dividers.
(x_hide_tip): New function.
(Fx_show_tip): Try to reuse old tooltip frame when
`tooltip-reuse-hidden-frame' is non-nil and frame parameters
have not changed.  Insert STRING here instead of passing it to
x_create_tip_frame.  Compute size of tooltip window with
Fwindow_text_pixel_size.  Obey Vw32_tooltip_extra_pixels when
padding tooltip window.
(Fx_hide_tip): Call x_hide_tip.
(Vw32_tooltip_extra_pixels): New variable.
* src/xdisp.c (Fwindow_text_pixel_size): Don't return negative y
value.  Fix doc-string.
* src/xfns.c (x_create_tip_frame): Remove argument TEXT.  Call
make_frame with mini_p argument false.
(x_hide_tip): New function.
(Fx_show_tip): Try to reuse old tooltip frame when
`tooltip-reuse-hidden-frame' is non-nil and frame parameters
have not changed.  Insert STRING here instead of passing it to
x_create_tip_frame.  Compute size of tooltip window with
Fwindow_text_pixel_size.
(Fx_hide_tip): Call x_hide_tip.
* lisp/cus-start.el (tooltip-reuse-hidden-frame): Add
customization entry.

4 files changed, 475 insertions, 491 deletions

diff --git a/src/frame.c b/src/frame.c
index fd9f3ce0203..d5364682f61 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -5262,6 +5262,21 @@ The function `frame--size-history' displays the value of this variable
 in a more readable form.  */);
     frame_size_history = Qnil;
 
+  DEFVAR_BOOL ("tooltip-reuse-hidden-frame", tooltip_reuse_hidden_frame,
+               doc: /* Non-nil means reuse hidden tooltip frames.
+When this is nil, delete a tooltip frame when hiding the associated
+tooltip.  When this is non-nil, make the tooltip frame invisible only,
+so it can be reused when the next tooltip is shown.
+
+Setting this to non-nil may drastically reduce the consing overhead
+incurred by creating new tooltip frames.  However, a value of non-nil
+means also that intermittent changes of faces or `default-frame-alist'
+are not applied when showing a tooltip in a reused frame.
+
+This variable is effective only with the X toolkit (and there only when
+Gtk+ tooltips are not used) and on Windows.  */);
+  tooltip_reuse_hidden_frame = false;
+
   staticpro (&Vframe_list);
 
   defsubr (&Sframep);
diff --git a/src/w32fns.c b/src/w32fns.c
index 0fe6a6fd2b3..568a45a3114 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -6422,8 +6422,6 @@ no value of TYPE (always string in the MS Windows case).  */)
                                 Tool tips
  ***********************************************************************/
 
-static Lisp_Object x_create_tip_frame (struct w32_display_info *,
-                                       Lisp_Object, Lisp_Object);
 static void compute_tip_xy (struct frame *, Lisp_Object, Lisp_Object,
                             Lisp_Object, int, int, int *, int *);
 
@@ -6458,8 +6456,7 @@ unwind_create_tip_frame (Lisp_Object frame)
 
 
 /* Create a frame for a tooltip on the display described by DPYINFO.
-   PARMS is a list of frame parameters.  TEXT is the string to
-   display in the tip frame.  Value is the frame.
+   PARMS is a list of frame parameters.  Value is the frame.
 
    Note that functions called here, esp. x_default_parameter can
    signal errors, for instance when a specified color name is
@@ -6467,8 +6464,7 @@ unwind_create_tip_frame (Lisp_Object frame)
    when this happens.  */
 
 static Lisp_Object
-x_create_tip_frame (struct w32_display_info *dpyinfo,
-                    Lisp_Object parms, Lisp_Object text)
+x_create_tip_frame (struct w32_display_info *dpyinfo, Lisp_Object parms)
 {
   struct frame *f;
   Lisp_Object frame;
@@ -6477,8 +6473,6 @@ x_create_tip_frame (struct w32_display_info *dpyinfo,
   ptrdiff_t count = SPECPDL_INDEX ();
   struct kboard *kb;
   bool face_change_before = face_change;
-  Lisp_Object buffer;
-  struct buffer *old_buffer;
   int x_width = 0, x_height = 0;
 
   /* Use this general default value to start with until we know if
@@ -6502,23 +6496,9 @@ x_create_tip_frame (struct w32_display_info *dpyinfo,
   frame = Qnil;
   /* Make a frame without minibuffer nor mode-line.  */
   f = make_frame (false);
-  f->wants_modeline = 0;
+  f->wants_modeline = false;
   XSETFRAME (frame, f);
 
-  AUTO_STRING (tip, " *tip*");
-  buffer = Fget_buffer_create (tip);
-  /* Use set_window_buffer instead of Fset_window_buffer (see
-     discussion of bug#11984, bug#12025, bug#12026).  */
-  set_window_buffer (FRAME_ROOT_WINDOW (f), buffer, false, false);
-  old_buffer = current_buffer;
-  set_buffer_internal_1 (XBUFFER (buffer));
-  bset_truncate_lines (current_buffer, Qnil);
-  specbind (Qinhibit_read_only, Qt);
-  specbind (Qinhibit_modification_hooks, Qt);
-  Ferase_buffer ();
-  Finsert (1, &text);
-  set_buffer_internal_1 (old_buffer);
-
   record_unwind_protect (unwind_create_tip_frame, frame);
 
   /* By setting the output method, we're essentially saying that
@@ -6552,7 +6532,7 @@ x_create_tip_frame (struct w32_display_info *dpyinfo,
     {
       fset_name (f, name);
       f->explicit_name = true;
-      /* use the frame's title when getting resources for this frame.  */
+      /* Use the frame's title when getting resources for this frame.  */
       specbind (Qx_resource_name, name);
     }
 
@@ -6582,14 +6562,10 @@ x_create_tip_frame (struct w32_display_info *dpyinfo,
         parms = Fcons (Fcons (Qinternal_border_width, value),
                        parms);
     }
+
   x_default_parameter (f, parms, Qinternal_border_width, make_number (1),
                        "internalBorderWidth", "internalBorderWidth",
                        RES_TYPE_NUMBER);
-  x_default_parameter (f, parms, Qright_divider_width, make_number (0),
-                       NULL, NULL, RES_TYPE_NUMBER);
-  x_default_parameter (f, parms, Qbottom_divider_width, make_number (0),
-                       NULL, NULL, RES_TYPE_NUMBER);
-
   /* Also do the stuff which must be set before the window exists.  */
   x_default_parameter (f, parms, Qforeground_color, build_string ("black"),
                        "foreground", "Foreground", RES_TYPE_STRING);
@@ -6616,6 +6592,9 @@ x_create_tip_frame (struct w32_display_info *dpyinfo,
   f->fringe_cols = 0;
   f->left_fringe_width = 0;
   f->right_fringe_width = 0;
+  /* No dividers on tip frame.  */
+  f->right_divider_width = 0;
+  f->bottom_divider_width = 0;
 
   block_input ();
   my_create_tip_window (f);
@@ -6642,7 +6621,6 @@ x_create_tip_frame (struct w32_display_info *dpyinfo,
   SET_FRAME_LINES (f, 0);
   adjust_frame_size (f, width * FRAME_COLUMN_WIDTH (f),
                      height * FRAME_LINE_HEIGHT (f), 0, true, Qtip_frame);
-
   /* Add `tooltip' frame parameter's default value. */
   if (NILP (Fframe_parameter (frame, Qtooltip)))
     Fmodify_frame_parameters (frame, Fcons (Fcons (Qtooltip, Qt), Qnil));
@@ -6660,8 +6638,6 @@ x_create_tip_frame (struct w32_display_info *dpyinfo,
     Lisp_Object fg = Fframe_parameter (frame, Qforeground_color);
     Lisp_Object colors = Qnil;
 
-    /* Set tip_frame here, so that */
-    tip_frame = frame;
     call2 (Qface_set_after_frame_default, frame, Qnil);
 
     if (!EQ (bg, Fframe_parameter (frame, Qbackground_color)))
@@ -6793,6 +6769,48 @@ compute_tip_xy (struct frame *f,
     *root_x = min_x;
 }
 
+/* Hide tooltip.  Delete its frame if DELETE is true.  */
+static Lisp_Object
+x_hide_tip (bool delete)
+{
+  if (!NILP (tip_timer))
+    {
+      call1 (Qcancel_timer, tip_timer);
+      tip_timer = Qnil;
+    }
+
+  if (NILP (tip_frame)
+      || (!delete && FRAMEP (tip_frame)
+          && !FRAME_VISIBLE_P (XFRAME (tip_frame))))
+    return Qnil;
+  else
+    {
+      ptrdiff_t count;
+      Lisp_Object was_open = Qnil;
+
+      count = SPECPDL_INDEX ();
+      specbind (Qinhibit_redisplay, Qt);
+      specbind (Qinhibit_quit, Qt);
+
+      if (FRAMEP (tip_frame))
+        {
+          if (delete)
+            {
+              delete_frame (tip_frame, Qnil);
+              tip_frame = Qnil;
+            }
+          else
+            x_make_frame_invisible (XFRAME (tip_frame));
+
+          was_open = Qt;
+        }
+      else
+        tip_frame = Qnil;
+
+      return unbind_to (count, was_open);
+    }
+}
+
 
 DEFUN ("x-show-tip", Fx_show_tip, Sx_show_tip, 1, 6, 0,
        doc: /* Show STRING in a \"tooltip\" window on frame FRAME.
@@ -6826,15 +6844,16 @@ A tooltip's maximum size is specified by `x-max-tooltip-size'.
 Text larger than the specified size is clipped.  */)
   (Lisp_Object string, Lisp_Object frame, Lisp_Object parms, Lisp_Object timeout, Lisp_Object dx, Lisp_Object dy)
 {
-  struct frame *f;
+  struct frame *f, *tip_f;
   struct window *w;
   int root_x, root_y;
   struct buffer *old_buffer;
   struct text_pos pos;
   int i, width, height;
-  bool seen_reversed_p;
   int old_windows_or_buffers_changed = windows_or_buffers_changed;
   ptrdiff_t count = SPECPDL_INDEX ();
+  ptrdiff_t count_1;
+  Lisp_Object window, size;
 
   specbind (Qinhibit_redisplay, Qt);
 
@@ -6858,91 +6877,155 @@ Text larger than the specified size is clipped.  */)
   if (NILP (last_show_tip_args))
     last_show_tip_args = Fmake_vector (make_number (3), Qnil);
 
-  if (!NILP (tip_frame))
+  if (FRAMEP (tip_frame) && FRAME_LIVE_P (XFRAME (tip_frame)))
     {
       Lisp_Object last_string = AREF (last_show_tip_args, 0);
       Lisp_Object last_frame = AREF (last_show_tip_args, 1);
       Lisp_Object last_parms = AREF (last_show_tip_args, 2);
 
-      if (EQ (frame, last_frame)
-          && !NILP (Fequal (last_string, string))
+      if (FRAME_VISIBLE_P (XFRAME (tip_frame))
+          && EQ (frame, last_frame)
+          && !NILP (Fequal_including_properties (last_string, string))
           && !NILP (Fequal (last_parms, parms)))
         {
-          struct frame *f = XFRAME (tip_frame);
-
           /* Only DX and DY have changed.  */
+          tip_f = XFRAME (tip_frame);
           if (!NILP (tip_timer))
             {
               Lisp_Object timer = tip_timer;
+
               tip_timer = Qnil;
               call1 (Qcancel_timer, timer);
             }
 
           block_input ();
-          compute_tip_xy (f, parms, dx, dy, FRAME_PIXEL_WIDTH (f),
-                          FRAME_PIXEL_HEIGHT (f), &root_x, &root_y);
+          compute_tip_xy (tip_f, parms, dx, dy, FRAME_PIXEL_WIDTH (tip_f),
+                          FRAME_PIXEL_HEIGHT (tip_f), &root_x, &root_y);
 
           /* Put tooltip in topmost group and in position.  */
-          SetWindowPos (FRAME_W32_WINDOW (f), HWND_TOPMOST,
+          SetWindowPos (FRAME_W32_WINDOW (tip_f), HWND_TOPMOST,
                         root_x, root_y, 0, 0,
                         SWP_NOSIZE | SWP_NOACTIVATE | SWP_NOOWNERZORDER);
 
           /* Ensure tooltip is on top of other topmost windows (eg menus).  */
-          SetWindowPos (FRAME_W32_WINDOW (f), HWND_TOP,
+          SetWindowPos (FRAME_W32_WINDOW (tip_f), HWND_TOP,
                         0, 0, 0, 0,
                         SWP_NOMOVE | SWP_NOSIZE
                         | SWP_NOACTIVATE | SWP_NOOWNERZORDER);
 
+          /* Let redisplay know that we have made the frame visible already.  */
+          SET_FRAME_VISIBLE (tip_f, 1);
+          ShowWindow (FRAME_W32_WINDOW (tip_f), SW_SHOWNOACTIVATE);
           unblock_input ();
+
           goto start_timer;
         }
-    }
+      else if (tooltip_reuse_hidden_frame && EQ (frame, last_frame))
+        {
+          bool delete = false;
+          Lisp_Object tail, elt, parm, last;
 
-  /* Hide a previous tip, if any.  */
-  Fx_hide_tip ();
+          /* Check if every parameter in PARMS has the same value in
+             last_parms.  This may destruct last_parms which, however,
+             will be recreated below.  */
+          for (tail = parms; CONSP (tail); tail = XCDR (tail))
+            {
+              elt = XCAR (tail);
+              parm = Fcar (elt);
+              /* The left, top, right and bottom parameters are handled
+                 by compute_tip_xy so they can be ignored here.  */
+              if (!EQ (parm, Qleft) && !EQ (parm, Qtop)
+                  && !EQ (parm, Qright) && !EQ (parm, Qbottom))
+                {
+                  last = Fassq (parm, last_parms);
+                  if (NILP (Fequal (Fcdr (elt), Fcdr (last))))
+                    {
+                      /* We lost, delete the old tooltip.  */
+                      delete = true;
+                      break;
+                    }
+                  else
+                    last_parms = call2 (Qassq_delete_all, parm, last_parms);
+                }
+              else
+                last_parms = call2 (Qassq_delete_all, parm, last_parms);
+            }
+
+          /* Now check if there's a parameter left in last_parms with a
+             non-nil value.  */
+          for (tail = last_parms; CONSP (tail); tail = XCDR (tail))
+            {
+              elt = XCAR (tail);
+              parm = Fcar (elt);
+              if (!EQ (parm, Qleft) && !EQ (parm, Qtop) && !EQ (parm, Qright)
+                  && !EQ (parm, Qbottom) && !NILP (Fcdr (elt)))
+                {
+                  /* We lost, delete the old tooltip.  */
+                  delete = true;
+                  break;
+                }
+            }
+
+          x_hide_tip (delete);
+        }
+      else
+        x_hide_tip (true);
+    }
+  else
+    x_hide_tip (true);
 
   ASET (last_show_tip_args, 0, string);
   ASET (last_show_tip_args, 1, frame);
   ASET (last_show_tip_args, 2, parms);
 
-  /* Add default values to frame parameters.  */
-  if (NILP (Fassq (Qname, parms)))
-    parms = Fcons (Fcons (Qname, build_string ("tooltip")), parms);
-  if (NILP (Fassq (Qinternal_border_width, parms)))
-    parms = Fcons (Fcons (Qinternal_border_width, make_number (3)), parms);
-  if (NILP (Fassq (Qright_divider_width, parms)))
-    parms = Fcons (Fcons (Qright_divider_width, make_number (0)), parms);
-  if (NILP (Fassq (Qbottom_divider_width, parms)))
-    parms = Fcons (Fcons (Qbottom_divider_width, make_number (0)), parms);
-  if (NILP (Fassq (Qborder_width, parms)))
-    parms = Fcons (Fcons (Qborder_width, make_number (1)), parms);
-  if (NILP (Fassq (Qborder_color, parms)))
-    parms = Fcons (Fcons (Qborder_color, build_string ("lightyellow")), parms);
-  if (NILP (Fassq (Qbackground_color, parms)))
-    parms = Fcons (Fcons (Qbackground_color, build_string ("lightyellow")),
-                   parms);
-
   /* Block input until the tip has been fully drawn, to avoid crashes
      when drawing tips in menus.  */
   block_input ();
 
-  /* Create a frame for the tooltip, and record it in the global
-     variable tip_frame.  */
-  frame = x_create_tip_frame (FRAME_DISPLAY_INFO (f), parms, string);
-  f = XFRAME (frame);
+  if (!FRAMEP (tip_frame) || !FRAME_LIVE_P (XFRAME (tip_frame)))
+    {
+      /* Add default values to frame parameters.  */
+      if (NILP (Fassq (Qname, parms)))
+        parms = Fcons (Fcons (Qname, build_string ("tooltip")), parms);
+      if (NILP (Fassq (Qinternal_border_width, parms)))
+        parms = Fcons (Fcons (Qinternal_border_width, make_number (3)), parms);
+      if (NILP (Fassq (Qborder_width, parms)))
+        parms = Fcons (Fcons (Qborder_width, make_number (1)), parms);
+      if (NILP (Fassq (Qborder_color, parms)))
+        parms = Fcons (Fcons (Qborder_color, build_string ("lightyellow")), parms);
+      if (NILP (Fassq (Qbackground_color, parms)))
+        parms = Fcons (Fcons (Qbackground_color, build_string ("lightyellow")),
+                       parms);
+
+      /* Create a frame for the tooltip, and record it in the global
+         variable tip_frame.  */
+      if (NILP (tip_frame = x_create_tip_frame (FRAME_DISPLAY_INFO (f), parms)))
+        {
+          /* Creating the tip frame failed.  */
+          unblock_input ();
+          return unbind_to (count, Qnil);
+        }
+    }
+
+  tip_f = XFRAME (tip_frame);
+  window = FRAME_ROOT_WINDOW (tip_f);
+  AUTO_STRING (tip, " *tip*");
+  set_window_buffer (window, Fget_buffer_create (tip), false, false);
+  w = XWINDOW (window);
+  w->pseudo_window_p = true;
 
-  /* Set up the frame's root window.  */
-  w = XWINDOW (FRAME_ROOT_WINDOW (f));
+  /* Set up the frame's root window.  Note: The following code does not
+     try to size the window or its frame correctly.  Its only purpose is
+     to make the subsequent text size calculations work.  The right
+     sizes should get installed when the toolkit gets back to us.  */
   w->left_col = 0;
   w->top_line = 0;
   w->pixel_left = 0;
   w->pixel_top = 0;
 
   if (CONSP (Vx_max_tooltip_size)
-      && INTEGERP (XCAR (Vx_max_tooltip_size))
-      && XINT (XCAR (Vx_max_tooltip_size)) > 0
-      && INTEGERP (XCDR (Vx_max_tooltip_size))
-      && XINT (XCDR (Vx_max_tooltip_size)) > 0)
+      && RANGED_INTEGERP (1, XCAR (Vx_max_tooltip_size), INT_MAX)
+      && RANGED_INTEGERP (1, XCDR (Vx_max_tooltip_size), INT_MAX))
     {
       w->total_cols = XFASTINT (XCAR (Vx_max_tooltip_size));
       w->total_lines = XFASTINT (XCDR (Vx_max_tooltip_size));
@@ -6953,164 +7036,71 @@ Text larger than the specified size is clipped.  */)
       w->total_lines = 40;
     }
 
-  w->pixel_width = w->total_cols * FRAME_COLUMN_WIDTH (f);
-  w->pixel_height = w->total_lines * FRAME_LINE_HEIGHT (f);
-
-  FRAME_TOTAL_COLS (f) = WINDOW_TOTAL_COLS (w);
-  adjust_frame_glyphs (f);
-  w->pseudo_window_p = true;
+  w->pixel_width = w->total_cols * FRAME_COLUMN_WIDTH (tip_f);
+  w->pixel_height = w->total_lines * FRAME_LINE_HEIGHT (tip_f);
+  FRAME_TOTAL_COLS (tip_f) = WINDOW_TOTAL_COLS (w);
+  adjust_frame_glyphs (tip_f);
 
-  /* Display the tooltip text in a temporary buffer.  */
+  /* Insert STRING into the root window's buffer and fit the frame to
+     the buffer.  */
+  count_1 = SPECPDL_INDEX ();
   old_buffer = current_buffer;
-  set_buffer_internal_1 (XBUFFER (XWINDOW (FRAME_ROOT_WINDOW (f))->contents));
+  set_buffer_internal_1 (XBUFFER (w->contents));
   bset_truncate_lines (current_buffer, Qnil);
+  specbind (Qinhibit_read_only, Qt);
+  specbind (Qinhibit_modification_hooks, Qt);
+  specbind (Qinhibit_point_motion_hooks, Qt);
+  Ferase_buffer ();
+  Finsert (1, &string);
   clear_glyph_matrix (w->desired_matrix);
   clear_glyph_matrix (w->current_matrix);
   SET_TEXT_POS (pos, BEGV, BEGV_BYTE);
-  try_window (FRAME_ROOT_WINDOW (f), pos, TRY_WINDOW_IGNORE_FONTS_CHANGE);
-
-  /* Compute width and height of the tooltip.  */
-  width = height = 0;
-  seen_reversed_p = false;
-  for (i = 0; i < w->desired_matrix->nrows; ++i)
-    {
-      struct glyph_row *row = &w->desired_matrix->rows[i];
-      struct glyph *last;
-      int row_width;
-
-      /* Stop at the first empty row at the end.  */
-      if (!row->enabled_p || !MATRIX_ROW_DISPLAYS_TEXT_P (row))
-        break;
-
-      /* Let the row go over the full width of the frame.  */
-      row->full_width_p = true;
-
-      row_width = row->pixel_width;
-      if (row->used[TEXT_AREA])
-        {
-          if (!row->reversed_p)
-            {
-              /* There's a glyph at the end of rows that is used to
-                 place the cursor there.  Don't include the width of
-                 this glyph.  */
-              last = &row->glyphs[TEXT_AREA][row->used[TEXT_AREA] - 1];
-              if (NILP (last->object))
-                row_width -= last->pixel_width;
-            }
-          else
-            {
-              /* There could be a stretch glyph at the beginning of R2L
-                 rows that is produced by extend_face_to_end_of_line.
-                 Don't count that glyph.  */
-              struct glyph *g = row->glyphs[TEXT_AREA];
-
-              if (g->type == STRETCH_GLYPH && NILP (g->object))
-                {
-                  row_width -= g->pixel_width;
-                  seen_reversed_p = true;
-                }
-            }
-        }
-
-      height += row->height;
-      width = max (width, row_width);
-    }
-
-  /* If we've seen partial-length R2L rows, we need to re-adjust the
-     tool-tip frame width and redisplay it again, to avoid over-wide
-     tips due to the stretch glyph that extends R2L lines to full
-     width of the frame.  */
-  if (seen_reversed_p)
-    {
-      /* PXW: Why do we do the pixel-to-cols conversion only if
-         seen_reversed_p holds?  Don't we have to set other fields of
-         the window/frame structure?
-
-         w->total_cols and FRAME_TOTAL_COLS want the width in columns,
-         not in pixels.  */
-      w->pixel_width = width;
-      width /= WINDOW_FRAME_COLUMN_WIDTH (w);
-      w->total_cols = width;
-      FRAME_TOTAL_COLS (f) = width;
-      SET_FRAME_WIDTH (f, width);
-      adjust_frame_glyphs (f);
-      w->pseudo_window_p = 1;
-      clear_glyph_matrix (w->desired_matrix);
-      clear_glyph_matrix (w->current_matrix);
-      try_window (FRAME_ROOT_WINDOW (f), pos, TRY_WINDOW_IGNORE_FONTS_CHANGE);
-      width = height = 0;
-      /* Recompute width and height of the tooltip.  */
-      for (i = 0; i < w->desired_matrix->nrows; ++i)
-        {
-          struct glyph_row *row = &w->desired_matrix->rows[i];
-          struct glyph *last;
-          int row_width;
-
-          if (!row->enabled_p || !MATRIX_ROW_DISPLAYS_TEXT_P (row))
-            break;
-          row->full_width_p = true;
-          row_width = row->pixel_width;
-          if (row->used[TEXT_AREA] && !row->reversed_p)
-            {
-              last = &row->glyphs[TEXT_AREA][row->used[TEXT_AREA] - 1];
-              if (NILP (last->object))
-                row_width -= last->pixel_width;
-            }
-
-          height += row->height;
-          width = max (width, row_width);
-        }
-    }
-
-  /* Add the frame's internal border to the width and height the w32
-     window should have.  */
-  height += 2 * FRAME_INTERNAL_BORDER_WIDTH (f);
-  width += 2 * FRAME_INTERNAL_BORDER_WIDTH (f);
-
-  /* Move the tooltip window where the mouse pointer is.  Resize and
-     show it.
-
-     PXW: This should use the frame's pixel coordinates.  */
-  compute_tip_xy (f, parms, dx, dy, width, height, &root_x, &root_y);
-
+  try_window (window, pos, TRY_WINDOW_IGNORE_FONTS_CHANGE);
+  /* Calculate size of tooltip window.  */
+  size = Fwindow_text_pixel_size (window, Qnil, Qnil, Qnil,
+                                  make_number (w->pixel_height), Qnil);
+  /* Add the frame's internal border to calculated size.  */
+  width = XINT (Fcar (size)) + 2 * FRAME_INTERNAL_BORDER_WIDTH (tip_f);
+  height = XINT (Fcdr (size)) + 2 * FRAME_INTERNAL_BORDER_WIDTH (tip_f);
+  /* Calculate position of tooltip frame.  */
+  compute_tip_xy (tip_f, parms, dx, dy, width, height, &root_x, &root_y);
+
+  /* Show tooltip frame.  */
   {
-    /* Adjust Window size to take border into account.  */
     RECT rect;
+    int pad = (NUMBERP (Vw32_tooltip_extra_pixels)
+               ? max (0, XINT (Vw32_tooltip_extra_pixels))
+               : FRAME_COLUMN_WIDTH (tip_f));
+
     rect.left = rect.top = 0;
     rect.right = width;
     rect.bottom = height;
-    AdjustWindowRect (&rect, f->output_data.w32->dwStyle, false);
-
-    /* Position and size tooltip, and put it in the topmost group.
-       The add-on of FRAME_COLUMN_WIDTH to the 5th argument is a
-       peculiarity of w32 display: without it, some fonts cause the
-       last character of the tip to be truncated or wrapped around to
-       the next line.  */
-    SetWindowPos (FRAME_W32_WINDOW (f), HWND_TOPMOST,
+    AdjustWindowRect (&rect, tip_f->output_data.w32->dwStyle,
+                      FRAME_EXTERNAL_MENU_BAR (tip_f));
+
+    /* Position and size tooltip and put it in the topmost group.  */
+    SetWindowPos (FRAME_W32_WINDOW (tip_f), HWND_TOPMOST,
                   root_x, root_y,
-                  rect.right - rect.left + FRAME_COLUMN_WIDTH (f),
+                  rect.right - rect.left + pad,
                   rect.bottom - rect.top, SWP_NOACTIVATE | SWP_NOOWNERZORDER);
 
     /* Ensure tooltip is on top of other topmost windows (eg menus).  */
-    SetWindowPos (FRAME_W32_WINDOW (f), HWND_TOP,
+    SetWindowPos (FRAME_W32_WINDOW (tip_f), HWND_TOP,
                   0, 0, 0, 0,
                   SWP_NOMOVE | SWP_NOSIZE
                   | SWP_NOACTIVATE | SWP_NOOWNERZORDER);
 
     /* Let redisplay know that we have made the frame visible already.  */
-    SET_FRAME_VISIBLE (f, 1);
+    SET_FRAME_VISIBLE (tip_f, 1);
 
-    ShowWindow (FRAME_W32_WINDOW (f), SW_SHOWNOACTIVATE);
+    ShowWindow (FRAME_W32_WINDOW (tip_f), SW_SHOWNOACTIVATE);
   }
 
-  /* Draw into the window.  */
   w->must_be_updated_p = true;
   update_single_window (w);
-
-  unblock_input ();
-
-  /* Restore original current buffer.  */
   set_buffer_internal_1 (old_buffer);
+  unbind_to (count_1, Qnil);
+  unblock_input ();
   windows_or_buffers_changed = old_windows_or_buffers_changed;
 
  start_timer:
@@ -7127,31 +7117,7 @@ DEFUN ("x-hide-tip", Fx_hide_tip, Sx_hide_tip, 0, 0, 0,
 Value is t if tooltip was open, nil otherwise.  */)
   (void)
 {
-  ptrdiff_t count;
-  Lisp_Object deleted, frame, timer;
-
-  /* Return quickly if nothing to do.  */
-  if (NILP (tip_timer) && NILP (tip_frame))
-    return Qnil;
-
-  frame = tip_frame;
-  timer = tip_timer;
-  tip_frame = tip_timer = deleted = Qnil;
-
-  count = SPECPDL_INDEX ();
-  specbind (Qinhibit_redisplay, Qt);
-  specbind (Qinhibit_quit, Qt);
-
-  if (!NILP (timer))
-    call1 (Qcancel_timer, timer);
-
-  if (FRAMEP (frame))
-    {
-      delete_frame (frame, Qnil);
-      deleted = Qt;
-    }
-
-  return unbind_to (count, deleted);
+  return x_hide_tip (!tooltip_reuse_hidden_frame);
 }
 
 /***********************************************************************
@@ -9751,6 +9717,7 @@ syms_of_w32fns (void)
   DEFSYM (Qmm_size, "mm-size");
   DEFSYM (Qframes, "frames");
   DEFSYM (Qtip_frame, "tip-frame");
+  DEFSYM (Qassq_delete_all, "assq-delete-all");
   DEFSYM (Qunicode_sip, "unicode-sip");
 #if defined WINDOWSNT && !defined HAVE_DBUS
   DEFSYM (QCicon, ":icon");
@@ -10063,6 +10030,18 @@ Default is nil.
 This variable has effect only on Windows Vista and later.  */);
   w32_disable_new_uniscribe_apis = 0;
 
+  DEFVAR_LISP ("w32-tooltip-extra-pixels",
+               Vw32_tooltip_extra_pixels,
+               doc: /* Number of pixels added after tooltip text.
+On Windows some fonts may cause the last character of a tooltip be
+truncated or wrapped around to the next line.  Adding some extra space
+at the end of the toooltip works around this problem.
+
+This variable specifies the number of pixels that shall be added.  The
+default value t means to add the width of one canonical character of the
+tip frame.  */);
+  Vw32_tooltip_extra_pixels = Qt;
+
 #if 0 /* TODO: Port to W32 */
   defsubr (&Sx_change_window_property);
   defsubr (&Sx_delete_window_property);
diff --git a/src/xdisp.c b/src/xdisp.c
index b9d496ed556..5b961444384 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -9794,26 +9794,28 @@ the maximum pixel-height of all text lines.
 
 The optional argument FROM, if non-nil, specifies the first text
 position and defaults to the minimum accessible position of the buffer.
-If FROM is t, use the minimum accessible position that is not a newline
-character.  TO, if non-nil, specifies the last text position and
+If FROM is t, use the minimum accessible position that starts a
+non-empty line.  TO, if non-nil, specifies the last text position and
 defaults to the maximum accessible position of the buffer.  If TO is t,
-use the maximum accessible position that is not a newline character.
+use the maximum accessible position that ends a non-empty line.
 
 The optional argument X-LIMIT, if non-nil, specifies the maximum text
 width that can be returned.  X-LIMIT nil or omitted, means to use the
-pixel-width of WINDOW's body; use this if you do not intend to change
-the width of WINDOW.  Use the maximum width WINDOW may assume if you
-intend to change WINDOW's width.  In any case, text whose x-coordinate
-is beyond X-LIMIT is ignored.  Since calculating the width of long lines
-can take some time, it's always a good idea to make this argument as
-small as possible; in particular, if the buffer contains long lines that
-shall be truncated anyway.
+pixel-width of WINDOW's body; use this if you want to know how high
+WINDOW should be become in order to fit all of its buffer's text with
+the width of WINDOW unaltered.  Use the maximum width WINDOW may assume
+if you intend to change WINDOW's width.  In any case, text whose
+x-coordinate is beyond X-LIMIT is ignored.  Since calculating the width
+of long lines can take some time, it's always a good idea to make this
+argument as small as possible; in particular, if the buffer contains
+long lines that shall be truncated anyway.
 
 The optional argument Y-LIMIT, if non-nil, specifies the maximum text
-height that can be returned.  Text lines whose y-coordinate is beyond
-Y-LIMIT are ignored.  Since calculating the text height of a large
-buffer can take some time, it makes sense to specify this argument if
-the size of the buffer is unknown.
+height (exluding the height of the mode- or header-line, if any) that
+can be returned.  Text lines whose y-coordinate is beyond Y-LIMIT are
+ignored.  Since calculating the text height of a large buffer can take
+some time, it makes sense to specify this argument if the size of the
+buffer is large or unknown.
 
 Optional argument MODE-AND-HEADER-LINE nil or omitted means do not
 include the height of the mode- or header-line of WINDOW in the return
@@ -9831,7 +9833,7 @@ include the height of both, if present, in the return value.  */)
   ptrdiff_t start, end, pos;
   struct text_pos startp;
   void *itdata = NULL;
-  int c, max_y = -1, x = 0, y = 0;
+  int c, max_x = 0, max_y = 0, x = 0, y = 0;
 
   CHECK_BUFFER (buffer);
   b = XBUFFER (buffer);
@@ -9876,11 +9878,13 @@ include the height of both, if present, in the return value.  */)
       end = max (start, min (XINT (to), ZV));
     }
 
-  if (!NILP (y_limit))
-    {
-      CHECK_NUMBER (y_limit);
-      max_y = min (XINT (y_limit), INT_MAX);
-    }
+  if (!NILP (x_limit) && RANGED_INTEGERP (0, x_limit, INT_MAX))
+    max_x = XINT (x_limit);
+
+  if (NILP (y_limit))
+    max_y = INT_MAX;
+  else if (RANGED_INTEGERP (0, y_limit, INT_MAX))
+    max_y = XINT (y_limit);
 
   itdata = bidi_shelve_cache ();
   SET_TEXT_POS (startp, start, CHAR_TO_BYTE (start));
@@ -9890,27 +9894,30 @@ include the height of both, if present, in the return value.  */)
     x = move_it_to (&it, end, -1, max_y, -1, MOVE_TO_POS | MOVE_TO_Y);
   else
     {
-      CHECK_NUMBER (x_limit);
-      it.last_visible_x = min (XINT (x_limit), INFINITY);
+      it.last_visible_x = max_x;
       /* Actually, we never want move_it_to stop at to_x.  But to make
          sure that move_it_in_display_line_to always moves far enough,
-         we set it to INT_MAX and specify MOVE_TO_X.  */
-      x = move_it_to (&it, end, INT_MAX, max_y, -1,
-                      MOVE_TO_POS | MOVE_TO_X | MOVE_TO_Y);
+         we set it to INT_MAX and specify MOVE_TO_X.  Also bound width
+         value by X-LIMIT.  */
+      x = min (move_it_to (&it, end, INT_MAX, max_y, -1,
+                           MOVE_TO_POS | MOVE_TO_X | MOVE_TO_Y),
+               max_x);
     }
 
-  y = it.current_y + it.max_ascent + it.max_descent;
+  /* Subtract height of header-line which was counted automatically by
+     start_display.  */
+  y = min (it.current_y + it.max_ascent + it.max_descent
+           - WINDOW_HEADER_LINE_HEIGHT (w),
+           max_y);
 
-  if (!EQ (mode_and_header_line, Qheader_line)
-      && !EQ (mode_and_header_line, Qt))
-    /* Do not count the header-line which was counted automatically by
-       start_display.  */
-    y = y - WINDOW_HEADER_LINE_HEIGHT (w);
+  if (EQ (mode_and_header_line, Qheader_line)
+      || EQ (mode_and_header_line, Qt))
+    /* Re-add height of header-line as requested.  */
+    y = y + WINDOW_HEADER_LINE_HEIGHT (w);
 
   if (EQ (mode_and_header_line, Qmode_line)
       || EQ (mode_and_header_line, Qt))
-    /* Do count the mode-line which is not included automatically by
-       start_display.  */
+    /* Add height of mode-line as requested.  */
     y = y + WINDOW_MODE_LINE_HEIGHT (w);
 
   bidi_unshelve_cache (itdata, false);
diff --git a/src/xfns.c b/src/xfns.c
index 2a50a5a5f99..c1ce1b73a21 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -5303,8 +5303,6 @@ no value of TYPE (always string in the MS Windows case).  */)
                                 Tool tips
  ***********************************************************************/
 
-static Lisp_Object x_create_tip_frame (struct x_display_info *,
-                                       Lisp_Object, Lisp_Object);
 static void compute_tip_xy (struct frame *, Lisp_Object, Lisp_Object,
                             Lisp_Object, int, int, int *, int *);
 
@@ -5348,9 +5346,7 @@ unwind_create_tip_frame (Lisp_Object frame)
    when this happens.  */
 
 static Lisp_Object
-x_create_tip_frame (struct x_display_info *dpyinfo,
-                    Lisp_Object parms,
-                    Lisp_Object text)
+x_create_tip_frame (struct x_display_info *dpyinfo, Lisp_Object parms)
 {
   struct frame *f;
   Lisp_Object frame;
@@ -5359,7 +5355,6 @@ x_create_tip_frame (struct x_display_info *dpyinfo,
   ptrdiff_t count = SPECPDL_INDEX ();
   bool face_change_before = face_change;
   Lisp_Object buffer;
-  struct buffer *old_buffer;
   int x_width = 0, x_height = 0;
 
   if (!dpyinfo->terminal->name)
@@ -5375,23 +5370,9 @@ x_create_tip_frame (struct x_display_info *dpyinfo,
     error ("Invalid frame name--not a string or nil");
 
   frame = Qnil;
-  f = make_frame (true);
+  f = make_frame (false);
+  f->wants_modeline = false;
   XSETFRAME (frame, f);
-
-  AUTO_STRING (tip, " *tip*");
-  buffer = Fget_buffer_create (tip);
-  /* Use set_window_buffer instead of Fset_window_buffer (see
-     discussion of bug#11984, bug#12025, bug#12026).  */
-  set_window_buffer (FRAME_ROOT_WINDOW (f), buffer, false, false);
-  old_buffer = current_buffer;
-  set_buffer_internal_1 (XBUFFER (buffer));
-  bset_truncate_lines (current_buffer, Qnil);
-  specbind (Qinhibit_read_only, Qt);
-  specbind (Qinhibit_modification_hooks, Qt);
-  Ferase_buffer ();
-  Finsert (1, &text);
-  set_buffer_internal_1 (old_buffer);
-
   record_unwind_protect (unwind_create_tip_frame, frame);
 
   f->terminal = dpyinfo->terminal;
@@ -5633,8 +5614,6 @@ x_create_tip_frame (struct x_display_info *dpyinfo,
   {
     Lisp_Object bg = Fframe_parameter (frame, Qbackground_color);
 
-    /* Set tip_frame here, so that */
-    tip_frame = frame;
     call2 (Qface_set_after_frame_default, frame, Qnil);
 
     if (!EQ (bg, Fframe_parameter (frame, Qbackground_color)))
@@ -5773,6 +5752,85 @@ compute_tip_xy (struct frame *f, Lisp_Object parms, Lisp_Object dx, Lisp_Object
 }
 
 
+/* Hide tooltip.  Delete its frame if DELETE is true.  */
+static Lisp_Object
+x_hide_tip (bool delete)
+{
+  if (!NILP (tip_timer))
+    {
+      call1 (Qcancel_timer, tip_timer);
+      tip_timer = Qnil;
+    }
+
+
+  if (NILP (tip_frame)
+      || (!delete && FRAMEP (tip_frame)
+          && !FRAME_VISIBLE_P (XFRAME (tip_frame))))
+    return Qnil;
+  else
+    {
+      ptrdiff_t count;
+      Lisp_Object was_open = Qnil;
+
+      count = SPECPDL_INDEX ();
+      specbind (Qinhibit_redisplay, Qt);
+      specbind (Qinhibit_quit, Qt);
+
+#ifdef USE_GTK
+      {
+        /* When using system tooltip, tip_frame is the Emacs frame on
+           which the tip is shown.  */
+        struct frame *f = XFRAME (tip_frame);
+
+        if (FRAME_LIVE_P (f) && xg_hide_tooltip (f))
+          {
+            tip_frame = Qnil;
+            was_open = Qt;
+          }
+      }
+#endif
+
+      if (FRAMEP (tip_frame))
+        {
+          if (delete)
+            {
+              delete_frame (tip_frame, Qnil);
+              tip_frame = Qnil;
+            }
+          else
+            x_make_frame_invisible (XFRAME (tip_frame));
+
+          was_open = Qt;
+
+#ifdef USE_LUCID
+          /* Bloodcurdling hack alert: The Lucid menu bar widget's
+             redisplay procedure is not called when a tip frame over
+             menu items is unmapped.  Redisplay the menu manually...  */
+          {
+            Widget w;
+            struct frame *f = SELECTED_FRAME ();
+            if (FRAME_X_P (f) && FRAME_LIVE_P (f))
+              {
+                w = f->output_data.x->menubar_widget;
+
+                if (!DoesSaveUnders (FRAME_DISPLAY_INFO (f)->screen)
+                    && w != NULL)
+                  {
+                    block_input ();
+                    xlwmenu_redisplay (w);
+                    unblock_input ();
+                  }
+              }
+          }
+#endif /* USE_LUCID */
+        }
+      else
+        tip_frame = Qnil;
+
+      return unbind_to (count, was_open);
+    }
+}
+
 DEFUN ("x-show-tip", Fx_show_tip, Sx_show_tip, 1, 6, 0,
        doc: /* Show STRING in a "tooltip" window on frame FRAME.
 A tooltip window is a small X window displaying a string.
@@ -5805,15 +5863,16 @@ A tooltip's maximum size is specified by `x-max-tooltip-size'.
 Text larger than the specified size is clipped.  */)
   (Lisp_Object string, Lisp_Object frame, Lisp_Object parms, Lisp_Object timeout, Lisp_Object dx, Lisp_Object dy)
 {
-  struct frame *f;
+  struct frame *f, *tip_f;
   struct window *w;
   int root_x, root_y;
   struct buffer *old_buffer;
   struct text_pos pos;
-  int i, width, height;
-  bool seen_reversed_p;
+  int width, height;
   int old_windows_or_buffers_changed = windows_or_buffers_changed;
   ptrdiff_t count = SPECPDL_INDEX ();
+  ptrdiff_t count_1;
+  Lisp_Object window, size;
 
   specbind (Qinhibit_redisplay, Qt);
 
@@ -5862,22 +5921,23 @@ Text larger than the specified size is clipped.  */)
   if (NILP (last_show_tip_args))
     last_show_tip_args = Fmake_vector (make_number (3), Qnil);
 
-  if (!NILP (tip_frame))
+  if (FRAMEP (tip_frame) && FRAME_LIVE_P (XFRAME (tip_frame)))
     {
       Lisp_Object last_string = AREF (last_show_tip_args, 0);
       Lisp_Object last_frame = AREF (last_show_tip_args, 1);
       Lisp_Object last_parms = AREF (last_show_tip_args, 2);
 
-      if (EQ (frame, last_frame)
-          && !NILP (Fequal (last_string, string))
+      if (FRAME_VISIBLE_P (XFRAME (tip_frame))
+          && EQ (frame, last_frame)
+          && !NILP (Fequal_including_properties (last_string, string))
           && !NILP (Fequal (last_parms, parms)))
         {
-          struct frame *tip_f = XFRAME (tip_frame);
-
           /* Only DX and DY have changed.  */
+          tip_f = XFRAME (tip_frame);
           if (!NILP (tip_timer))
             {
               Lisp_Object timer = tip_timer;
+
               tip_timer = Qnil;
               call1 (Qcancel_timer, timer);
             }
@@ -5888,41 +5948,103 @@ Text larger than the specified size is clipped.  */)
           XMoveWindow (FRAME_X_DISPLAY (tip_f), FRAME_X_WINDOW (tip_f),
                        root_x, root_y);
           unblock_input ();
+
           goto start_timer;
         }
-    }
+      else if (tooltip_reuse_hidden_frame && EQ (frame, last_frame))
+        {
+          bool delete = false;
+          Lisp_Object tail, elt, parm, last;
+
+          /* Check if every parameter in PARMS has the same value in
+             last_parms unless it should be ignored by means of
+             Vtooltip_reuse_hidden_frame_parameters.  This may destruct
+             last_parms which, however, will be recreated below.  */
+          for (tail = parms; CONSP (tail); tail = XCDR (tail))
+            {
+              elt = XCAR (tail);
+              parm = Fcar (elt);
+              /* The left, top, right and bottom parameters are handled
+                 by compute_tip_xy so they can be ignored here.  */
+              if (!EQ (parm, Qleft) && !EQ (parm, Qtop)
+                  && !EQ (parm, Qright) && !EQ (parm, Qbottom))
+                {
+                  last = Fassq (parm, last_parms);
+                  if (NILP (Fequal (Fcdr (elt), Fcdr (last))))
+                    {
+                      /* We lost, delete the old tooltip.  */
+                      delete = true;
+                      break;
+                    }
+                  else
+                    last_parms = call2 (Qassq_delete_all, parm, last_parms);
+                }
+              else
+                last_parms = call2 (Qassq_delete_all, parm, last_parms);
+            }
 
-  /* Hide a previous tip, if any.  */
-  Fx_hide_tip ();
+          /* Now check if every parameter in what is left of last_parms
+             with a non-nil value has an association in PARMS unless it
+             should be ignored by means of
+             Vtooltip_reuse_hidden_frame_parameters.  */
+          for (tail = last_parms; CONSP (tail); tail = XCDR (tail))
+            {
+              elt = XCAR (tail);
+              parm = Fcar (elt);
+              if (!EQ (parm, Qleft) && !EQ (parm, Qtop) && !EQ (parm, Qright)
+                  && !EQ (parm, Qbottom) && !NILP (Fcdr (elt)))
+                {
+                  /* We lost, delete the old tooltip.  */
+                  delete = true;
+                  break;
+                }
+            }
+
+          x_hide_tip (delete);
+        }
+      else
+        x_hide_tip (true);
+    }
+  else
+    x_hide_tip (true);
 
   ASET (last_show_tip_args, 0, string);
   ASET (last_show_tip_args, 1, frame);
   ASET (last_show_tip_args, 2, parms);
 
-  /* Add default values to frame parameters.  */
-  if (NILP (Fassq (Qname, parms)))
-    parms = Fcons (Fcons (Qname, build_string ("tooltip")), parms);
-  if (NILP (Fassq (Qinternal_border_width, parms)))
-    parms = Fcons (Fcons (Qinternal_border_width, make_number (3)), parms);
-  if (NILP (Fassq (Qborder_width, parms)))
-    parms = Fcons (Fcons (Qborder_width, make_number (1)), parms);
-  if (NILP (Fassq (Qbottom_divider_width, parms)))
-    parms = Fcons (Fcons (Qbottom_divider_width, make_number (0)), parms);
-  if (NILP (Fassq (Qright_divider_width, parms)))
-    parms = Fcons (Fcons (Qright_divider_width, make_number (0)), parms);
-  if (NILP (Fassq (Qborder_color, parms)))
-    parms = Fcons (Fcons (Qborder_color, build_string ("lightyellow")), parms);
-  if (NILP (Fassq (Qbackground_color, parms)))
-    parms = Fcons (Fcons (Qbackground_color, build_string ("lightyellow")),
-                   parms);
-
-  /* Create a frame for the tooltip, and record it in the global
-     variable tip_frame.  */
-  frame = x_create_tip_frame (FRAME_DISPLAY_INFO (f), parms, string);
-  f = XFRAME (frame);
-
-  /* Set up the frame's root window.  */
-  w = XWINDOW (FRAME_ROOT_WINDOW (f));
+  if (!FRAMEP (tip_frame) || !FRAME_LIVE_P (XFRAME (tip_frame)))
+    {
+      /* Add default values to frame parameters.  */
+      if (NILP (Fassq (Qname, parms)))
+        parms = Fcons (Fcons (Qname, build_string ("tooltip")), parms);
+      if (NILP (Fassq (Qinternal_border_width, parms)))
+        parms = Fcons (Fcons (Qinternal_border_width, make_number (3)), parms);
+      if (NILP (Fassq (Qborder_width, parms)))
+        parms = Fcons (Fcons (Qborder_width, make_number (1)), parms);
+      if (NILP (Fassq (Qborder_color, parms)))
+        parms = Fcons (Fcons (Qborder_color, build_string ("lightyellow")), parms);
+      if (NILP (Fassq (Qbackground_color, parms)))
+        parms = Fcons (Fcons (Qbackground_color, build_string ("lightyellow")),
+                       parms);
+
+      /* Create a frame for the tooltip, and record it in the global
+         variable tip_frame.  */
+      if (NILP (tip_frame = x_create_tip_frame (FRAME_DISPLAY_INFO (f), parms)))
+        /* Creating the tip frame failed.  */
+        return unbind_to (count, Qnil);
+    }
+
+  tip_f = XFRAME (tip_frame);
+  window = FRAME_ROOT_WINDOW (tip_f);
+  AUTO_STRING (tip, " *tip*");
+  set_window_buffer (window, Fget_buffer_create (tip), false, false);
+  w = XWINDOW (window);
+  w->pseudo_window_p = true;
+
+  /* Set up the frame's root window.  Note: The following code does not
+     try to size the window or its frame correctly.  Its only purpose is
+     to make the subsequent text size calculations work.  The right
+     sizes should get installed when the toolkit gets back to us.  */
   w->left_col = 0;
   w->top_line = 0;
   w->pixel_left = 0;
@@ -5941,130 +6063,47 @@ Text larger than the specified size is clipped.  */)
       w->total_lines = 40;
     }
 
-  w->pixel_width = w->total_cols * FRAME_COLUMN_WIDTH (f);
-  w->pixel_height = w->total_lines * FRAME_LINE_HEIGHT (f);
-
-  FRAME_TOTAL_COLS (f) = w->total_cols;
-  adjust_frame_glyphs (f);
-  w->pseudo_window_p = true;
+  w->pixel_width = w->total_cols * FRAME_COLUMN_WIDTH (tip_f);
+  w->pixel_height = w->total_lines * FRAME_LINE_HEIGHT (tip_f);
+  FRAME_TOTAL_COLS (tip_f) = w->total_cols;
+  adjust_frame_glyphs (tip_f);
 
-  /* Display the tooltip text in a temporary buffer.  */
+  /* Insert STRING into root window's buffer and fit the frame to the
+     buffer.  */
+  count_1 = SPECPDL_INDEX ();
   old_buffer = current_buffer;
-  set_buffer_internal_1 (XBUFFER (XWINDOW (FRAME_ROOT_WINDOW (f))->contents));
+  set_buffer_internal_1 (XBUFFER (w->contents));
   bset_truncate_lines (current_buffer, Qnil);
+  specbind (Qinhibit_read_only, Qt);
+  specbind (Qinhibit_modification_hooks, Qt);
+  specbind (Qinhibit_point_motion_hooks, Qt);
+  Ferase_buffer ();
+  Finsert (1, &string);
   clear_glyph_matrix (w->desired_matrix);
   clear_glyph_matrix (w->current_matrix);
   SET_TEXT_POS (pos, BEGV, BEGV_BYTE);
-  try_window (FRAME_ROOT_WINDOW (f), pos, TRY_WINDOW_IGNORE_FONTS_CHANGE);
-
-  /* Compute width and height of the tooltip.  */
-  width = height = 0;
-  seen_reversed_p = false;
-  for (i = 0; i < w->desired_matrix->nrows; ++i)
-    {
-      struct glyph_row *row = &w->desired_matrix->rows[i];
-      struct glyph *last;
-      int row_width;
-
-      /* Stop at the first empty row at the end.  */
-      if (!row->enabled_p || !MATRIX_ROW_DISPLAYS_TEXT_P (row))
-        break;
-
-      /* Let the row go over the full width of the frame.  */
-      row->full_width_p = true;
-
-      row_width = row->pixel_width;
-      if (row->used[TEXT_AREA])
-        {
-          /* There's a glyph at the end of rows that is used to place
-             the cursor there.  Don't include the width of this glyph.  */
-          if (!row->reversed_p)
-            {
-              last = &row->glyphs[TEXT_AREA][row->used[TEXT_AREA] - 1];
-              if (NILP (last->object))
-                row_width -= last->pixel_width;
-            }
-          else
-            {
-              /* There could be a stretch glyph at the beginning of R2L
-                 rows that is produced by extend_face_to_end_of_line.
-                 Don't count that glyph.  */
-              struct glyph *g = row->glyphs[TEXT_AREA];
-
-              if (g->type == STRETCH_GLYPH && NILP (g->object))
-                {
-                  row_width -= g->pixel_width;
-                  seen_reversed_p = true;
-                }
-            }
-        }
-
-      height += row->height;
-      width = max (width, row_width);
-    }
-
-  /* If we've seen partial-length R2L rows, we need to re-adjust the
-     tool-tip frame width and redisplay it again, to avoid over-wide
-     tips due to the stretch glyph that extends R2L lines to full
-     width of the frame.  */
-  if (seen_reversed_p)
-    {
-      /* w->total_cols and FRAME_TOTAL_COLS want the width in columns,
-         not in pixels.  */
-      w->pixel_width = width;
-      width /= WINDOW_FRAME_COLUMN_WIDTH (w);
-      w->total_cols = width;
-      FRAME_TOTAL_COLS (f) = width;
-      SET_FRAME_WIDTH (f, width);
-      adjust_frame_glyphs (f);
-      clear_glyph_matrix (w->desired_matrix);
-      clear_glyph_matrix (w->current_matrix);
-      try_window (FRAME_ROOT_WINDOW (f), pos, 0);
-      width = height = 0;
-      /* Recompute width and height of the tooltip.  */
-      for (i = 0; i < w->desired_matrix->nrows; ++i)
-        {
-          struct glyph_row *row = &w->desired_matrix->rows[i];
-          struct glyph *last;
-          int row_width;
-
-          if (!row->enabled_p || !MATRIX_ROW_DISPLAYS_TEXT_P (row))
-            break;
-          row->full_width_p = true;
-          row_width = row->pixel_width;
-          if (row->used[TEXT_AREA] && !row->reversed_p)
-            {
-              last = &row->glyphs[TEXT_AREA][row->used[TEXT_AREA] - 1];
-              if (NILP (last->object))
-                row_width -= last->pixel_width;
-            }
-
-          height += row->height;
-          width = max (width, row_width);
-        }
-    }
-
-  /* Add the frame's internal border to the width and height the X
-     window should have.  */
-  height += 2 * FRAME_INTERNAL_BORDER_WIDTH (f);
-  width += 2 * FRAME_INTERNAL_BORDER_WIDTH (f);
-
-  /* Move the tooltip window where the mouse pointer is.  Resize and
-     show it.  */
-  compute_tip_xy (f, parms, dx, dy, width, height, &root_x, &root_y);
-
+  try_window (window, pos, TRY_WINDOW_IGNORE_FONTS_CHANGE);
+  /* Calculate size of tooltip window.  */
+  size = Fwindow_text_pixel_size (window, Qnil, Qnil, Qnil,
+                                  make_number (w->pixel_height), Qnil);
+  /* Add the frame's internal border to calculated size.  */
+  width = XINT (Fcar (size)) + 2 * FRAME_INTERNAL_BORDER_WIDTH (tip_f);
+  height = XINT (Fcdr (size)) + 2 * FRAME_INTERNAL_BORDER_WIDTH (tip_f);
+
+  /* Calculate position of tooltip frame.  */
+  compute_tip_xy (tip_f, parms, dx, dy, width, height, &root_x, &root_y);
+
+  /* Show tooltip frame.  */
   block_input ();
-  XMoveResizeWindow (FRAME_X_DISPLAY (f), FRAME_X_WINDOW (f),
+  XMoveResizeWindow (FRAME_X_DISPLAY (tip_f), FRAME_X_WINDOW (tip_f),
                      root_x, root_y, width, height);
-  XMapRaised (FRAME_X_DISPLAY (f), FRAME_X_WINDOW (f));
+  XMapRaised (FRAME_X_DISPLAY (tip_f), FRAME_X_WINDOW (tip_f));
   unblock_input ();
 
-  /* Draw into the window.  */
   w->must_be_updated_p = true;
   update_single_window (w);
-
-  /* Restore original current buffer.  */
   set_buffer_internal_1 (old_buffer);
+  unbind_to (count_1, Qnil);
   windows_or_buffers_changed = old_windows_or_buffers_changed;
 
  start_timer:
@@ -6081,66 +6120,9 @@ DEFUN ("x-hide-tip", Fx_hide_tip, Sx_hide_tip, 0, 0, 0,
 Value is t if tooltip was open, nil otherwise.  */)
   (void)
 {
-  ptrdiff_t count;
-  Lisp_Object deleted, frame, timer;
-
-  /* Return quickly if nothing to do.  */
-  if (NILP (tip_timer) && NILP (tip_frame))
-    return Qnil;
-
-  frame = tip_frame;
-  timer = tip_timer;
-  tip_frame = tip_timer = deleted = Qnil;
-
-  count = SPECPDL_INDEX ();
-  specbind (Qinhibit_redisplay, Qt);
-  specbind (Qinhibit_quit, Qt);
-
-  if (!NILP (timer))
-    call1 (Qcancel_timer, timer);
-
-#ifdef USE_GTK
-  {
-    /* When using system tooltip, tip_frame is the Emacs frame on which
-       the tip is shown.  */
-    struct frame *f = XFRAME (frame);
-    if (FRAME_LIVE_P (f) && xg_hide_tooltip (f))
-      frame = Qnil;
-  }
-#endif
-
-  if (FRAMEP (frame))
-    {
-      delete_frame (frame, Qnil);
-      deleted = Qt;
-
-#ifdef USE_LUCID
-      /* Bloodcurdling hack alert: The Lucid menu bar widget's
-         redisplay procedure is not called when a tip frame over menu
-         items is unmapped.  Redisplay the menu manually...  */
-      {
-        Widget w;
-        struct frame *f = SELECTED_FRAME ();
-        if (FRAME_X_P (f) && FRAME_LIVE_P (f))
-          {
-          w = f->output_data.x->menubar_widget;
-
-          if (!DoesSaveUnders (FRAME_DISPLAY_INFO (f)->screen)
-              && w != NULL)
-            {
-              block_input ();
-              xlwmenu_redisplay (w);
-              unblock_input ();
-            }
-        }
-      }
-#endif /* USE_LUCID */
-    }
-
-  return unbind_to (count, deleted);
+  return x_hide_tip (!tooltip_reuse_hidden_frame);
 }
 
-
 
 /***********************************************************************
                         File selection dialog
@@ -6802,6 +6784,7 @@ syms_of_xfns (void)
   DEFSYM (Qcancel_timer, "cancel-timer");
   DEFSYM (Qfont_param, "font-parameter");
   DEFSYM (Qmono, "mono");
+  DEFSYM (Qassq_delete_all, "assq-delete-all");
 
 #ifdef USE_CAIRO
   DEFSYM (Qpdf, "pdf");