Re: address@hidden: Overlay string not displayed on text with `display' property]

[Kim F. Storm]

address@hidden (Kim F. Storm) writes:

> YAMAMOTO Mitsuharu <address@hidden> writes:
>
>> I agree with you about not making nontrivial changes before the
>> release.  But I don't think that it is not worth the trouble in the
>> long term.  First, images are usually displayed using the `display'
>> property, and overlay strings are not shown before them.  Second, the
>> `composition' property shows the similar behavior as I mentioned in
>> http://lists.gnu.org/archive/html/emacs-devel/2006-06/msg00119.html.
>
> So it may be a question of specifically handling before-string and
> after-string properties at the boundaries of display and composition
> properties.  That _may_ be doable...

Look at this small example:

; emacs -Q -D
(setq overlay (make-overlay 1 3))
(overlay-put overlay 'before-string (propertize "BE" 'face 'bold))
(overlay-put overlay 'after-string (propertize "AF" 'display 
                         (propertize "XY" 'face 'underline)))
(put-text-property 1 3 'display "DISP")


It seems to work fine With the following patch (not trivial, but
not extremely complex either):

*** dispextern.h        28 May 2006 21:09:42 +0200      1.218
--- dispextern.h        12 Jun 2006 11:15:49 +0200      
***************
*** 1819,1824 ****
--- 1819,1826 ----
    NUM_IT_METHODS
  };
  
+ #define IT_STACK_SIZE 4
+ 
  struct it
  {
    /* The window in which we iterate over current_buffer (or a string).  */
***************
*** 1942,1948 ****
      short voffset;
      Lisp_Object font_height;
    }
!   stack[2];
  
    /* Stack pointer.  */
    int sp;
--- 1944,1950 ----
      short voffset;
      Lisp_Object font_height;
    }
!   stack[IT_STACK_SIZE];
  
    /* Stack pointer.  */
    int sp;

*** xdisp.c     03 Jun 2006 23:54:30 +0200      1.1102
--- xdisp.c     12 Jun 2006 11:23:18 +0200      
***************
*** 916,921 ****
--- 916,922 ----
  static void compute_line_metrics P_ ((struct it *));
  static void run_redisplay_end_trigger_hook P_ ((struct it *));
  static int get_overlay_strings P_ ((struct it *, int));
+ static int get_overlay_strings_1 P_ ((struct it *, int, int));
  static void next_overlay_string P_ ((struct it *));
  static void reseat P_ ((struct it *, struct text_pos, int));
  static void reseat_1 P_ ((struct it *, struct text_pos, int));
***************
*** 3021,3027 ****
          if (handled == HANDLED_RECOMPUTE_PROPS)
            break;
          else if (handled == HANDLED_RETURN)
!           return;
          else if (handled == HANDLED_OVERLAY_STRING_CONSUMED)
            handle_overlay_change_p = 0;
        }
--- 3022,3038 ----
          if (handled == HANDLED_RECOMPUTE_PROPS)
            break;
          else if (handled == HANDLED_RETURN)
!           {
!             /* We still want to show before and after strings from
!                overlays even if the actual buffer text is replaced.  */
!             if (!handle_overlay_change_p || it->sp > 1)
!               return;
!             if (!get_overlay_strings_1 (it, 0, 0))
!               return;
!             handle_overlay_change_p = 0;
!             handled = HANDLED_RECOMPUTE_PROPS;
!             break;
!           }
          else if (handled == HANDLED_OVERLAY_STRING_CONSUMED)
            handle_overlay_change_p = 0;
        }
***************
*** 4545,4555 ****
        pop_it (it);
        xassert (it->stop_charpos >= BEGV
               && it->stop_charpos <= it->end_charpos);
!       it->string = Qnil;
        it->current.overlay_string_index = -1;
-       SET_TEXT_POS (it->current.string_pos, -1, -1);
        it->n_overlay_strings = 0;
-       it->method = GET_FROM_BUFFER;
  
        /* If we're at the end of the buffer, record that we have
         processed the overlay strings there already, so that
--- 4556,4569 ----
        pop_it (it);
        xassert (it->stop_charpos >= BEGV
               && it->stop_charpos <= it->end_charpos);
!       if (it->sp == 0)
!       {
!         it->string = Qnil;
!         SET_TEXT_POS (it->current.string_pos, -1, -1);
!         it->method = GET_FROM_BUFFER;
!       }
        it->current.overlay_string_index = -1;
        it->n_overlay_strings = 0;
  
        /* If we're at the end of the buffer, record that we have
         processed the overlay strings there already, so that
***************
*** 4805,4811 ****
     least one overlay string was found.  */
  
  static int
! get_overlay_strings (it, charpos)
       struct it *it;
       int charpos;
  {
--- 4819,4825 ----
     least one overlay string was found.  */
  
  static int
! get_overlay_strings_1 (it, charpos, compute_stop_p)
       struct it *it;
       int charpos;
  {
***************
*** 4827,4838 ****
        /* Make sure we know settings in current_buffer, so that we can
         restore meaningful values when we're done with the overlay
         strings.  */
!       compute_stop_pos (it);
        xassert (it->face_id >= 0);
  
        /* Save IT's settings.  They are restored after all overlay
         strings have been processed.  */
!       xassert (it->sp == 0);
        push_it (it);
  
        /* Set up IT to deliver display elements from the first overlay
--- 4841,4853 ----
        /* Make sure we know settings in current_buffer, so that we can
         restore meaningful values when we're done with the overlay
         strings.  */
!       if (compute_stop_p)
!       compute_stop_pos (it);
        xassert (it->face_id >= 0);
  
        /* Save IT's settings.  They are restored after all overlay
         strings have been processed.  */
!       xassert (!compute_stop_pos || it->sp == 0);
        push_it (it);
  
        /* Set up IT to deliver display elements from the first overlay
***************
*** 4844,4851 ****
        it->end_charpos = SCHARS (it->string);
        it->multibyte_p = STRING_MULTIBYTE (it->string);
        it->method = GET_FROM_STRING;
      }
!   else
      {
        it->string = Qnil;
        it->current.overlay_string_index = -1;
--- 4859,4876 ----
        it->end_charpos = SCHARS (it->string);
        it->multibyte_p = STRING_MULTIBYTE (it->string);
        it->method = GET_FROM_STRING;
+       return 1;
      }
! 
!   return 0;
! }
! 
! static int
! get_overlay_strings (it, charpos)
!      struct it *it;
!      int charpos;
! {
!   if (!get_overlay_strings_1 (it, charpos, 1))
      {
        it->string = Qnil;
        it->current.overlay_string_index = -1;
***************
*** 4875,4881 ****
  {
    struct iterator_stack_entry *p;
  
!   xassert (it->sp < 2);
    p = it->stack + it->sp;
  
    p->stop_charpos = it->stop_charpos;
--- 4900,4906 ----
  {
    struct iterator_stack_entry *p;
  
!   xassert (it->sp < IT_STACK_SIZE);
    p = it->stack + it->sp;
  
    p->stop_charpos = it->stop_charpos;


-- 
Kim F. Storm <address@hidden> http://www.cua.dk