Add pre-redisplay-function and rectangular region

* lisp/rect.el: Use lexical-binding.  Add new rectangular region support.
(rectangle-mark): New command.
(rectangle--region): New var.
(deactivate-mark-hook): Reset rectangle--region.
(rectangle--extract-region, rectangle--insert-for-yank)
(rectangle--highlight-for-redisplay)
(rectangle--unhighlight-for-redisplay): New functions.
(region-extract-function, redisplay-unhighlight-region-function)
(redisplay-highlight-region-function): Use them to handle
rectangular region.
* lisp/simple.el (region-extract-function): New var.
(delete-backward-char, delete-forward-char, deactivate-mark): Use it.
(kill-new, kill-append): Remove obsolete `yank-handler' argument.
(kill-region): Replace obsolete `yank-handler' arg with `region'.
(copy-region-as-kill, kill-ring-save): Add `region' argument.
(redisplay-unhighlight-region-function)
(redisplay-highlight-region-function): New vars.
(redisplay--update-region-highlight): New function.
(pre-redisplay-function): Use it.
(exchange-point-and-mark): Don't deactivate the mark before
reactivate-it anyway.
* lisp/comint.el (comint-kill-region): Remove yank-handler argument.
* lisp/delsel.el (delete-backward-char, backward-delete-char-untabify)
(delete-char): Remove property, since it's now part of their
default behavior.
(self-insert-iso): Remove property since this command doesn't exist.

* src/xdisp.c (prepare_menu_bars): Call Vpre_redisplay_function.
(syms_of_xdisp): Declare pre-redisplay-function.
(markpos_of_region): Remove function.
(init_iterator, compute_stop_pos, handle_face_prop)
(face_before_or_after_it_pos, reseat_to_string)
(get_next_display_element, window_buffer_changed)
(redisplay_internal, try_cursor_movement, redisplay_window)
(try_window_reusing_current_matrix, try_window_id, display_line)
(note_mode_line_or_margin_highlight, note_mouse_highlight)
(display_string, mouse_face_from_buffer_pos): Remove region handling.
* src/window.h (struct window): Remove field `region_showing'.
* src/dispextern.h (struct it): Remove region_beg/end_charpos.
(face_at_buffer_position, face_for_overlay_string)
(face_at_string_position): Update prototypes.
* src/xfaces.c (face_at_buffer_position, face_for_overlay_string)
(face_at_string_position): Remove `region_beg' and `region_end' args.
* src/fontset.c (Finternal_char_font):
* src/font.c (font_at, font_range): Adjust calls accordingly.
* src/insdel.c (Qregion_extract_function): New var.
(syms_of_insdel): Initialize it.
(prepare_to_modify_buffer_1): Use it.

8 files changed, 70 insertions, 187 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 287215392db..06e71e33fde 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,27 @@
+2013-10-29  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * xdisp.c (prepare_menu_bars): Call Vpre_redisplay_function.
+        (syms_of_xdisp): Declare pre-redisplay-function.
+        (markpos_of_region): Remove function.
+        (init_iterator, compute_stop_pos, handle_face_prop)
+        (face_before_or_after_it_pos, reseat_to_string)
+        (get_next_display_element, window_buffer_changed)
+        (redisplay_internal, try_cursor_movement, redisplay_window)
+        (try_window_reusing_current_matrix, try_window_id, display_line)
+        (note_mode_line_or_margin_highlight, note_mouse_highlight)
+        (display_string, mouse_face_from_buffer_pos): Remove region handling.
+        * window.h (struct window): Remove field `region_showing'.
+        * dispextern.h (struct it): Remove region_beg/end_charpos.
+        (face_at_buffer_position, face_for_overlay_string)
+        (face_at_string_position): Update prototypes.
+        * xfaces.c (face_at_buffer_position, face_for_overlay_string)
+        (face_at_string_position): Remove `region_beg' and `region_end' args.
+        * fontset.c (Finternal_char_font):
+        * font.c (font_at, font_range): Adjust calls accordingly.
+        * insdel.c (Qregion_extract_function): New var.
+        (syms_of_insdel): Initialize it.
+        (prepare_to_modify_buffer_1): Use it.
+
 2013-10-29  Dmitry Antipov  <dmantipov@yandex.ru>
 
         Prefer 'unsigned long' to 'long unsigned int' and 'unsigned long int'.
diff --git a/src/dispextern.h b/src/dispextern.h
index 0d225e9616f..dd64ae1921f 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -2214,10 +2214,6 @@ struct it
      used for overlay strings and strings from display properties.  */
   ptrdiff_t string_nchars;
 
-  /* Start and end of a visible region; -1 if the region is not
-     visible in the window.  */
-  ptrdiff_t region_beg_charpos, region_end_charpos;
-
   /* Position at which redisplay end trigger functions should be run.  */
   ptrdiff_t redisplay_end_trigger_charpos;
 
@@ -3325,7 +3321,7 @@ void init_baud_rate (int);
 void init_sigio (int);
 void ignore_sigio (void);
 
-/* Defined in xfaces.c */
+/* Defined in xfaces.c.  */
 
 #ifdef HAVE_X_WINDOWS
 void unload_color (struct frame *, unsigned long);
@@ -3352,16 +3348,13 @@ void init_frame_faces (struct frame *);
 void free_frame_faces (struct frame *);
 void recompute_basic_faces (struct frame *);
 int face_at_buffer_position (struct window *w, ptrdiff_t pos,
-                             ptrdiff_t region_beg, ptrdiff_t region_end,
                              ptrdiff_t *endptr, ptrdiff_t limit,
                              int mouse, int base_face_id);
 int face_for_overlay_string (struct window *w, ptrdiff_t pos,
-                             ptrdiff_t region_beg, ptrdiff_t region_end,
                              ptrdiff_t *endptr, ptrdiff_t limit,
                              int mouse, Lisp_Object overlay);
 int face_at_string_position (struct window *w, Lisp_Object string,
                              ptrdiff_t pos, ptrdiff_t bufpos,
-                             ptrdiff_t region_beg, ptrdiff_t region_end,
                              ptrdiff_t *endptr, enum face_id, int mouse);
 int merge_faces (struct frame *, Lisp_Object, int, int);
 int compute_char_face (struct frame *, int, Lisp_Object);
@@ -3369,7 +3362,7 @@ void free_all_realized_faces (Lisp_Object);
 extern Lisp_Object Qforeground_color, Qbackground_color;
 extern char unspecified_fg[], unspecified_bg[];
 
-/* Defined in xfns.c  */
+/* Defined in xfns.c.  */
 
 #ifdef HAVE_X_WINDOWS
 void gamma_correct (struct frame *, XColor *);
diff --git a/src/font.c b/src/font.c
index aaa02c20e48..1e1670b21af 100644
--- a/src/font.c
+++ b/src/font.c
@@ -3669,10 +3669,10 @@ font_at (int c, ptrdiff_t pos, struct face *face, struct window *w,
       ptrdiff_t endptr;
 
       if (STRINGP (string))
-        face_id = face_at_string_position (w, string, pos, 0, -1, -1, &endptr,
+        face_id = face_at_string_position (w, string, pos, 0, &endptr,
                                            DEFAULT_FACE_ID, 0);
       else
-        face_id = face_at_buffer_position (w, pos, -1, -1, &endptr,
+        face_id = face_at_buffer_position (w, pos, &endptr,
                                            pos + 100, 0, -1);
       face = FACE_FROM_ID (f, face_id);
     }
@@ -3716,7 +3716,7 @@ font_range (ptrdiff_t pos, ptrdiff_t pos_byte, ptrdiff_t *limit,
         {
           int face_id;
 
-          face_id = face_at_buffer_position (w, pos, 0, 0, &ignore,
+          face_id = face_at_buffer_position (w, pos, &ignore,
                                              *limit, 0, -1);
           face = FACE_FROM_ID (XFRAME (w->frame), face_id);
         }
diff --git a/src/fontset.c b/src/fontset.c
index 15fdf9f41a0..090c097c929 100644
--- a/src/fontset.c
+++ b/src/fontset.c
@@ -1875,7 +1875,7 @@ DEFUN ("internal-char-font", Finternal_char_font, Sinternal_char_font, 1, 2, 0,
         return Qnil;
       w = XWINDOW (window);
       f = XFRAME (w->frame);
-      face_id = face_at_buffer_position (w, pos, -1, -1, &dummy,
+      face_id = face_at_buffer_position (w, pos, &dummy,
                                          pos + 100, 0, -1);
     }
   if (! CHAR_VALID_P (c))
diff --git a/src/insdel.c b/src/insdel.c
index 0eb80c04d99..7e6182deb91 100644
--- a/src/insdel.c
+++ b/src/insdel.c
@@ -1778,6 +1778,8 @@ modify_text (ptrdiff_t start, ptrdiff_t end)
   bset_point_before_scroll (current_buffer, Qnil);
 }
 
+Lisp_Object Qregion_extract_function;
+
 /* Check that it is okay to modify the buffer between START and END,
    which are char positions.
 
@@ -1843,6 +1845,7 @@ prepare_to_modify_buffer_1 (ptrdiff_t start, ptrdiff_t end,
 #endif /* not CLASH_DETECTION */
 
   /* If `select-active-regions' is non-nil, save the region text.  */
+  /* FIXME: Move this to Elisp (via before-change-functions).  */
   if (!NILP (BVAR (current_buffer, mark_active))
       && !inhibit_modification_hooks
       && XMARKER (BVAR (current_buffer, mark))->buffer
@@ -1854,10 +1857,8 @@ prepare_to_modify_buffer_1 (ptrdiff_t start, ptrdiff_t end,
     {
       ptrdiff_t b = marker_position (BVAR (current_buffer, mark));
       ptrdiff_t e = PT;
-      if (b < e)
-        Vsaved_region_selection = make_buffer_string (b, e, 0);
-      else if (b > e)
-        Vsaved_region_selection = make_buffer_string (e, b, 0);
+      Vsaved_region_selection
+        = call1 (Fsymbol_value (Qregion_extract_function), Qnil);
     }
 
   signal_before_change (start, end, preserve_ptr);
@@ -2202,5 +2203,7 @@ as well as hooks attached to text properties and overlays.  */);
   inhibit_modification_hooks = 0;
   DEFSYM (Qinhibit_modification_hooks, "inhibit-modification-hooks");
 
+  DEFSYM (Qregion_extract_function, "region-extract-function");
+
   defsubr (&Scombine_after_change_execute);
 }
diff --git a/src/window.h b/src/window.h
index cc4332ccf7f..f619b82e8a3 100644
--- a/src/window.h
+++ b/src/window.h
@@ -341,10 +341,6 @@ struct window
        y-direction (smooth scrolling).  */
     int vscroll;
 
-    /* If we have highlighted the region (or any part of it), the mark
-       (region start) position; otherwise zero.  */
-    ptrdiff_t region_showing;
-
     /* Z_BYTE - buffer position of the last glyph in the current matrix of W.
        Should be nonnegative, and only valid if window_end_valid is nonzero.  */
     ptrdiff_t window_end_bytepos;
diff --git a/src/xdisp.c b/src/xdisp.c
index d62bc6ba96c..5cd2c2badcc 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -2601,24 +2601,6 @@ check_window_end (struct window *w)
 
 #endif /* GLYPH_DEBUG and ENABLE_CHECKING */
 
-/* Return mark position if current buffer has the region of non-zero length,
-   or -1 otherwise.  */
-
-static ptrdiff_t
-markpos_of_region (void)
-{
-  if (!NILP (Vtransient_mark_mode)
-      && !NILP (BVAR (current_buffer, mark_active))
-      && XMARKER (BVAR (current_buffer, mark))->buffer != NULL)
-    {
-      ptrdiff_t markpos = XMARKER (BVAR (current_buffer, mark))->charpos;
-
-      if (markpos != PT)
-        return markpos;
-    }
-  return -1;
-}
-
 /***********************************************************************
                        Iterator initialization
  ***********************************************************************/
@@ -2647,7 +2629,6 @@ init_iterator (struct it *it, struct window *w,
                ptrdiff_t charpos, ptrdiff_t bytepos,
                struct glyph_row *row, enum face_id base_face_id)
 {
-  ptrdiff_t markpos;
   enum face_id remapped_base_face_id = base_face_id;
 
   /* Some precondition checks.  */
@@ -2751,28 +2732,6 @@ init_iterator (struct it *it, struct window *w,
   /* Are multibyte characters enabled in current_buffer?  */
   it->multibyte_p = !NILP (BVAR (current_buffer, enable_multibyte_characters));
 
-  /* If visible region is of non-zero length, set IT->region_beg_charpos
-     and IT->region_end_charpos to the start and end of a visible region
-     in window IT->w.  Set both to -1 to indicate no region.  */
-  markpos = markpos_of_region ();
-  if (markpos >= 0
-      /* Maybe highlight only in selected window.  */
-      && (/* Either show region everywhere.  */
-          highlight_nonselected_windows
-          /* Or show region in the selected window.  */
-          || w == XWINDOW (selected_window)
-          /* Or show the region if we are in the mini-buffer and W is
-             the window the mini-buffer refers to.  */
-          || (MINI_WINDOW_P (XWINDOW (selected_window))
-              && WINDOWP (minibuf_selected_window)
-              && w == XWINDOW (minibuf_selected_window))))
-    {
-      it->region_beg_charpos = min (PT, markpos);
-      it->region_end_charpos = max (PT, markpos);
-    }
-  else
-    it->region_beg_charpos = it->region_end_charpos = -1;
-
   /* Get the position at which the redisplay_end_trigger hook should
      be run, if it is to be run at all.  */
   if (MARKERP (w->redisplay_end_trigger)
@@ -3406,16 +3365,6 @@ compute_stop_pos (struct it *it)
       if (pos < it->stop_charpos)
         it->stop_charpos = pos;
 
-      /* If showing the region, we have to stop at the region
-         start or end because the face might change there.  */
-      if (it->region_beg_charpos > 0)
-        {
-          if (IT_CHARPOS (*it) < it->region_beg_charpos)
-            it->stop_charpos = min (it->stop_charpos, it->region_beg_charpos);
-          else if (IT_CHARPOS (*it) < it->region_end_charpos)
-            it->stop_charpos = min (it->stop_charpos, it->region_end_charpos);
-        }
-
       /* Set up variables for computing the stop position from text
          property changes.  */
       XSETBUFFER (object, current_buffer);
@@ -3799,8 +3748,6 @@ handle_face_prop (struct it *it)
       new_face_id
         = face_at_buffer_position (it->w,
                                    IT_CHARPOS (*it),
-                                   it->region_beg_charpos,
-                                   it->region_end_charpos,
                                    &next_stop,
                                    (IT_CHARPOS (*it)
                                     + TEXT_PROP_DISTANCE_LIMIT),
@@ -3877,8 +3824,6 @@ handle_face_prop (struct it *it)
           base_face_id
             = face_for_overlay_string (it->w,
                                        IT_CHARPOS (*it),
-                                       it->region_beg_charpos,
-                                       it->region_end_charpos,
                                        &next_stop,
                                        (IT_CHARPOS (*it)
                                         + TEXT_PROP_DISTANCE_LIMIT),
@@ -3907,8 +3852,6 @@ handle_face_prop (struct it *it)
                                              it->string,
                                              IT_STRING_CHARPOS (*it),
                                              bufpos,
-                                             it->region_beg_charpos,
-                                             it->region_end_charpos,
                                              &next_stop,
                                              base_face_id, 0);
 
@@ -4051,8 +3994,6 @@ face_before_or_after_it_pos (struct it *it, int before_p)
                                          it->string,
                                          charpos,
                                          bufpos,
-                                         it->region_beg_charpos,
-                                         it->region_end_charpos,
                                          &next_check_charpos,
                                          base_face_id, 0);
 
@@ -4142,8 +4083,6 @@ face_before_or_after_it_pos (struct it *it, int before_p)
       /* Determine face for CHARSET_ASCII, or unibyte.  */
       face_id = face_at_buffer_position (it->w,
                                          CHARPOS (pos),
-                                         it->region_beg_charpos,
-                                         it->region_end_charpos,
                                          &next_check_charpos,
                                          limit, 0, -1);
 
@@ -6441,9 +6380,6 @@ reseat_to_string (struct it *it, const char *s, Lisp_Object string,
                   ptrdiff_t charpos, ptrdiff_t precision, int field_width,
                   int multibyte)
 {
-  /* No region in strings.  */
-  it->region_beg_charpos = it->region_end_charpos = -1;
-
   /* No text property checks performed by default, but see below.  */
   it->stop_charpos = -1;
 
@@ -7033,8 +6969,7 @@ get_next_display_element (struct it *it)
                   INC_TEXT_POS (pos, it->multibyte_p);
 
                   next_face_id = face_at_buffer_position
-                    (it->w, CHARPOS (pos), it->region_beg_charpos,
-                     it->region_end_charpos, &ignore,
+                    (it->w, CHARPOS (pos), &ignore,
                      (IT_CHARPOS (*it) + TEXT_PROP_DISTANCE_LIMIT), 0,
                      -1);
                   it->end_of_box_run_p
@@ -10906,8 +10841,7 @@ buffer_shared_and_changed (void)
           && UNCHANGED_MODIFIED < MODIFF);
 }
 
-/* Nonzero if W's buffer was changed but not saved or Transient Mark mode
-   is enabled and mark of W's buffer was changed since last W's update.  */
+/* Nonzero if W's buffer was changed but not saved.  */
 
 static int
 window_buffer_changed (struct window *w)
@@ -10916,9 +10850,7 @@ window_buffer_changed (struct window *w)
 
   eassert (BUFFER_LIVE_P (b));
 
-  return (((BUF_SAVE_MODIFF (b) < BUF_MODIFF (b)) != w->last_had_star)
-          || ((!NILP (Vtransient_mark_mode) && !NILP (BVAR (b, mark_active)))
-              != (w->region_showing != 0)));
+  return (((BUF_SAVE_MODIFF (b) < BUF_MODIFF (b)) != w->last_had_star));
 }
 
 /* Nonzero if W has %c in its mode line and mode line should be updated.  */
@@ -11273,6 +11205,10 @@ prepare_menu_bars (void)
   all_windows = (update_mode_lines
                  || buffer_shared_and_changed ()
                  || windows_or_buffers_changed);
+
+  if (FUNCTIONP (Vpre_redisplay_function))
+    safe_call1 (Vpre_redisplay_function, all_windows ? Qt : Qnil);
+
   if (all_windows)
     {
       Lisp_Object tail, frame;
@@ -13147,17 +13083,6 @@ redisplay_internal (void)
       clear_garbaged_frames ();
     }
 
-  /* If showing the region, and mark has changed, we must redisplay
-     the whole window.  The assignment to this_line_start_pos prevents
-     the optimization directly below this if-statement.  */
-  if (((!NILP (Vtransient_mark_mode)
-        && !NILP (BVAR (XBUFFER (w->contents), mark_active)))
-       != (w->region_showing > 0))
-      || (w->region_showing
-          && w->region_showing
-          != XINT (Fmarker_position (BVAR (XBUFFER (w->contents), mark)))))
-    CHARPOS (this_line_start_pos) = 0;
-
   /* Optimize the case that only the line containing the cursor in the
      selected window has changed.  Variables starting with this_ are
      set in display_line and record information about the line
@@ -13317,13 +13242,7 @@ redisplay_internal (void)
         }
       /* If highlighting the region, or if the cursor is in the echo area,
          then we can't just move the cursor.  */
-      else if (! (!NILP (Vtransient_mark_mode)
-                  && !NILP (BVAR (current_buffer, mark_active)))
-               && (EQ (selected_window,
-                       BVAR (current_buffer, last_selected_window))
-                   || highlight_nonselected_windows)
-               && !w->region_showing
-               && NILP (Vshow_trailing_whitespace)
+      else if (NILP (Vshow_trailing_whitespace)
                && !cursor_in_echo_area)
         {
           struct it it;
@@ -15003,11 +14922,6 @@ try_cursor_movement (Lisp_Object window, struct text_pos startp, int *scroll_ste
       && !update_mode_lines
       && !windows_or_buffers_changed
       && !f->cursor_type_changed
-      /* Can't use this case if highlighting a region.  When a
-         region exists, cursor movement has to do more than just
-         set the cursor.  */
-      && markpos_of_region () < 0
-      && !w->region_showing
       && NILP (Vshow_trailing_whitespace)
       /* This code is not used for mini-buffer for the sake of the case
          of redisplaying to replace an echo area message; since in
@@ -15622,7 +15536,7 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
              Move it back to a fully-visible line.  */
           new_vpos = window_box_height (w);
         }
-      else if (w->cursor.vpos >=0)
+      else if (w->cursor.vpos >= 0)
         {
           /* Some people insist on not letting point enter the scroll
              margin, even though this part handles windows that didn't
@@ -15680,12 +15594,14 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
 
           /* If we are highlighting the region, then we just changed
              the region, so redisplay to show it.  */
-          if (markpos_of_region () >= 0)
+          /* FIXME: We need to (re)run pre-redisplay-function!  */
+          /* if (markpos_of_region () >= 0)
             {
               clear_glyph_matrix (w->desired_matrix);
               if (!try_window (window, startp, 0))
                 goto need_larger_matrices;
             }
+          */
         }
 
 #ifdef GLYPH_DEBUG
@@ -16380,10 +16296,8 @@ try_window_reusing_current_matrix (struct window *w)
       || f->cursor_type_changed)
     return 0;
 
-  /* Can't do this if region may have changed.  */
-  if (markpos_of_region () >= 0
-      || w->region_showing
-      || !NILP (Vshow_trailing_whitespace))
+  /* Can't do this if showing trailing whitespace.  */
+  if (!NILP (Vshow_trailing_whitespace))
     return 0;
 
   /* If top-line visibility has changed, give up.  */
@@ -17181,19 +17095,10 @@ try_window_id (struct window *w)
   if (!w->window_end_valid)
     GIVE_UP (8);
 
-  /* Can't use this if highlighting a region because a cursor movement
-     will do more than just set the cursor.  */
-  if (markpos_of_region () >= 0)
-    GIVE_UP (9);
-
   /* Likewise if highlighting trailing whitespace.  */
   if (!NILP (Vshow_trailing_whitespace))
     GIVE_UP (11);
 
-  /* Likewise if showing a region.  */
-  if (w->region_showing)
-    GIVE_UP (10);
-
   /* Can't use this if overlay arrow position and/or string have
      changed.  */
   if (overlay_arrows_changed_p ())
@@ -19277,9 +19182,6 @@ display_line (struct it *it)
       return 0;
     }
 
-  /* Is IT->w showing the region?  */
-  it->w->region_showing = it->region_beg_charpos > 0 ? it->region_beg_charpos : 0;
-
   /* Clear the result glyph row and enable it.  */
   prepare_desired_row (row);
 
@@ -22413,9 +22315,7 @@ display_string (const char *string, Lisp_Object lisp_string, Lisp_Object face_st
 
       it->face_id
         = face_at_string_position (it->w, face_string, face_string_pos,
-                                   0, it->region_beg_charpos,
-                                   it->region_end_charpos,
-                                   &endptr, it->base_face_id, 0);
+                                   0, &endptr, it->base_face_id, 0);
       face = FACE_FROM_ID (it->f, it->face_id);
       it->face_box_p = face->box != FACE_NO_BOX;
     }
@@ -27419,7 +27319,7 @@ mouse_face_from_buffer_pos (Lisp_Object window,
 
   hlinfo->mouse_face_window = window;
   hlinfo->mouse_face_face_id
-    = face_at_buffer_position (w, mouse_charpos, 0, 0, &ignore,
+    = face_at_buffer_position (w, mouse_charpos, &ignore,
                                mouse_charpos + 1,
                                !hlinfo->mouse_face_hidden, -1);
   show_mouse_face (hlinfo, DRAW_MOUSE_FACE);
@@ -28100,8 +28000,7 @@ note_mode_line_or_margin_highlight (Lisp_Object window, int x, int y,
 
           hlinfo->mouse_face_face_id = face_at_string_position (w, string,
                                                                 charpos,
-                                                                0, 0, 0,
-                                                                &ignore,
+                                                                0, &ignore,
                                                                 glyph->face_id,
                                                                 1);
           show_mouse_face (hlinfo, DRAW_MOUSE_FACE);
@@ -28402,7 +28301,7 @@ note_mouse_highlight (struct frame *f, int x, int y)
               hlinfo->mouse_face_past_end = 0;
               hlinfo->mouse_face_window = window;
               hlinfo->mouse_face_face_id
-                = face_at_string_position (w, object, pos, 0, 0, 0, &ignore,
+                = face_at_string_position (w, object, pos, 0, &ignore,
                                            glyph->face_id, 1);
               show_mouse_face (hlinfo, DRAW_MOUSE_FACE);
               cursor = No_Cursor;
@@ -28449,13 +28348,14 @@ note_mouse_highlight (struct frame *f, int x, int y)
                      the first row visible in a window does not
                      necessarily display the character whose position
                      is the smallest.  */
-                  Lisp_Object lim1 =
-                    NILP (BVAR (XBUFFER (buffer), bidi_display_reordering))
+                  Lisp_Object lim1
+                    = NILP (BVAR (XBUFFER (buffer), bidi_display_reordering))
                     ? Fmarker_position (w->start)
                     : Qnil;
-                  Lisp_Object lim2 =
-                    NILP (BVAR (XBUFFER (buffer), bidi_display_reordering))
-                    ? make_number (BUF_Z (XBUFFER (buffer)) - w->window_end_pos)
+                  Lisp_Object lim2
+                    = NILP (BVAR (XBUFFER (buffer), bidi_display_reordering))
+                    ? make_number (BUF_Z (XBUFFER (buffer))
+                                   - w->window_end_pos)
                     : Qnil;
 
                   if (NILP (overlay))
@@ -29788,6 +29688,13 @@ cursor shapes.  */);
   DEFSYM (Qthin_space, "thin-space");
   DEFSYM (Qzero_width, "zero-width");
 
+  DEFVAR_LISP ("pre-redisplay-function", Vpre_redisplay_function,
+               doc: /* Function run just before redisplay.
+It is called with one argument, which is the set of windows that are to
+be redisplayed.  This set can be nil (meaning, only the selected window),
+or t (meaning all windows).  */);
+  Vpre_redisplay_function = intern ("ignore");
+
   DEFSYM (Qglyphless_char_display, "glyphless-char-display");
   Fput (Qglyphless_char_display, Qchar_table_extra_slots, make_number (1));
 
diff --git a/src/xfaces.c b/src/xfaces.c
index 2145d7ff59d..f50fffc6419 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -5916,7 +5916,6 @@ compute_char_face (struct frame *f, int ch, Lisp_Object prop)
 
 int
 face_at_buffer_position (struct window *w, ptrdiff_t pos,
-                         ptrdiff_t region_beg, ptrdiff_t region_end,
                          ptrdiff_t *endptr, ptrdiff_t limit,
                          int mouse, int base_face_id)
 {
@@ -5937,8 +5936,6 @@ face_at_buffer_position (struct window *w, ptrdiff_t pos,
   XSETFASTINT (position, pos);
 
   endpos = ZV;
-  if (pos < region_beg && region_beg < endpos)
-    endpos = region_beg;
 
   /* Get the `face' or `mouse_face' text property at POS, and
      determine the next position at which the property changes.  */
@@ -5974,8 +5971,7 @@ face_at_buffer_position (struct window *w, ptrdiff_t pos,
 
   /* Optimize common cases where we can use the default face.  */
   if (noverlays == 0
-      && NILP (prop)
-      && !(pos >= region_beg && pos < region_end))
+      && NILP (prop))
     return default_face->id;
 
   /* Begin with attributes from the default face.  */
@@ -6002,15 +5998,6 @@ face_at_buffer_position (struct window *w, ptrdiff_t pos,
         endpos = oendpos;
     }
 
-  /* If in the region, merge in the region face.  */
-  if (pos >= region_beg && pos < region_end)
-    {
-      merge_named_face (f, Qregion, attrs, 0);
-
-      if (region_end < endpos)
-        endpos = region_end;
-    }
-
   *endptr = endpos;
 
   /* Look up a realized face with the given face attributes,
@@ -6026,7 +6013,6 @@ face_at_buffer_position (struct window *w, ptrdiff_t pos,
 
 int
 face_for_overlay_string (struct window *w, ptrdiff_t pos,
-                         ptrdiff_t region_beg, ptrdiff_t region_end,
                          ptrdiff_t *endptr, ptrdiff_t limit,
                          int mouse, Lisp_Object overlay)
 {
@@ -6045,8 +6031,6 @@ face_for_overlay_string (struct window *w, ptrdiff_t pos,
   XSETFASTINT (position, pos);
 
   endpos = ZV;
-  if (pos < region_beg && region_beg < endpos)
-    endpos = region_beg;
 
   /* Get the `face' or `mouse_face' text property at POS, and
      determine the next position at which the property changes.  */
@@ -6060,7 +6044,6 @@ face_for_overlay_string (struct window *w, ptrdiff_t pos,
 
   /* Optimize common case where we can use the default face.  */
   if (NILP (prop)
-      && !(pos >= region_beg && pos < region_end)
       && NILP (Vface_remapping_alist))
     return DEFAULT_FACE_ID;
 
@@ -6072,15 +6055,6 @@ face_for_overlay_string (struct window *w, ptrdiff_t pos,
   if (!NILP (prop))
     merge_face_ref (f, prop, attrs, 1, 0);
 
-  /* If in the region, merge in the region face.  */
-  if (pos >= region_beg && pos < region_end)
-    {
-      merge_named_face (f, Qregion, attrs, 0);
-
-      if (region_end < endpos)
-        endpos = region_end;
-    }
-
   *endptr = endpos;
 
   /* Look up a realized face with the given face attributes,
@@ -6113,7 +6087,6 @@ face_for_overlay_string (struct window *w, ptrdiff_t pos,
 int
 face_at_string_position (struct window *w, Lisp_Object string,
                          ptrdiff_t pos, ptrdiff_t bufpos,
-                         ptrdiff_t region_beg, ptrdiff_t region_end,
                          ptrdiff_t *endptr, enum face_id base_face_id,
                          int mouse_p)
 {
@@ -6145,15 +6118,8 @@ face_at_string_position (struct window *w, Lisp_Object string,
   base_face = FACE_FROM_ID (f, base_face_id);
   eassert (base_face);
 
-  /* Optimize the default case that there is no face property and we
-     are not in the region.  */
+  /* Optimize the default case that there is no face property.  */
   if (NILP (prop)
-      && (base_face_id != DEFAULT_FACE_ID
-          /* BUFPOS <= 0 means STRING is not an overlay string, so
-             that the region doesn't have to be taken into account.  */
-          || bufpos <= 0
-          || bufpos < region_beg
-          || bufpos >= region_end)
       && (multibyte_p
           /* We can't realize faces for different charsets differently
              if we don't have fonts, so we can stop here if not working
@@ -6169,12 +6135,6 @@ face_at_string_position (struct window *w, Lisp_Object string,
   if (!NILP (prop))
     merge_face_ref (f, prop, attrs, 1, 0);
 
-  /* If in the region, merge in the region face.  */
-  if (bufpos
-      && bufpos >= region_beg
-      && bufpos < region_end)
-    merge_named_face (f, Qregion, attrs, 0);
-
   /* Look up a realized face with the given face attributes,
      or realize a new one for ASCII characters.  */
   return lookup_face (f, attrs);