Start working on invisible text. For now, just untested source changes.

 xdisp.c (handle_invisible_prop): Under bidi iteration, skip
 invisible text using bidi_get_next_char_visually.
 (handle_stop_backwards): Restore it->bidi_p, it->current and
 it->position before calling handle_stop.
 (next_element_from_buffer): Fix formatting.

2 files changed, 51 insertions, 20 deletions

diff --git a/src/ChangeLog.bidi b/src/ChangeLog.bidi
index 08c51d2ee98..40a858b0320 100644
--- a/src/ChangeLog.bidi
+++ b/src/ChangeLog.bidi
@@ -1,3 +1,11 @@
+2010-01-16  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (handle_invisible_prop): Under bidi iteration, skip
+        invisible text using bidi_get_next_char_visually.
+        (handle_stop_backwards): Restore it->bidi_p, it->current and
+        it->position before calling handle_stop.
+        (next_element_from_buffer): Fix formatting.
+
 2010-01-09  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c (handle_stop_backwards): Add a prototype.
diff --git a/src/xdisp.c b/src/xdisp.c
index de3d29d8633..2513c17c8b1 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -3784,18 +3784,18 @@ handle_invisible_prop (it)
   else
     {
       int invis_p;
-      EMACS_INT newpos, next_stop, start_charpos;
+      EMACS_INT newpos, next_stop, start_charpos, tem;
       Lisp_Object pos, prop, overlay;
 
       /* First of all, is there invisible text at this position?  */
-      start_charpos = IT_CHARPOS (*it);
+      tem = start_charpos = IT_CHARPOS (*it);
       pos = make_number (IT_CHARPOS (*it));
       prop = get_char_property_and_overlay (pos, Qinvisible, it->window,
                                             &overlay);
       invis_p = TEXT_PROP_MEANS_INVISIBLE (prop);
 
       /* If we are on invisible text, skip over it.  */
-      if (invis_p && IT_CHARPOS (*it) < it->end_charpos)
+      if (invis_p && start_charpos < it->end_charpos)
         {
           /* Record whether we have to display an ellipsis for the
              invisible text.  */
@@ -3808,17 +3808,16 @@ handle_invisible_prop (it)
           do
             {
               /* Try to skip some invisible text.  Return value is the
-                 position reached which can be equal to IT's position
-                 if there is nothing invisible here.  This skips both
+                 position reached which can be equal to where we start
+                 if there is nothing invisible there.  This skips both
                  over invisible text properties and overlays with
                  invisible property.  */
-              newpos = skip_invisible (IT_CHARPOS (*it),
-                                       &next_stop, ZV, it->window);
+              newpos = skip_invisible (tem, &next_stop, ZV, it->window);
 
               /* If we skipped nothing at all we weren't at invisible
                  text in the first place.  If everything to the end of
                  the buffer was skipped, end the loop.  */
-              if (newpos == IT_CHARPOS (*it) || newpos >= ZV)
+              if (newpos == tem || newpos >= ZV)
                 invis_p = 0;
               else
                 {
@@ -3836,7 +3835,7 @@ handle_invisible_prop (it)
               /* If we ended up on invisible text, proceed to
                  skip starting with next_stop.  */
               if (invis_p)
-                IT_CHARPOS (*it) = next_stop;
+                tem = next_stop;
 
               /* If there are adjacent invisible texts, don't lose the
                  second one's ellipsis. */
@@ -3846,8 +3845,30 @@ handle_invisible_prop (it)
           while (invis_p);
 
           /* The position newpos is now either ZV or on visible text.  */
-          IT_CHARPOS (*it) = newpos;
-          IT_BYTEPOS (*it) = CHAR_TO_BYTE (newpos);
+          if (it->bidi_p && newpos < ZV)
+            {
+              /* With bidi iteration, the region of invisible text
+                 could start and/or end in the middle of a non-base
+                 embedding level.  Therefore, we need to skip
+                 invisible text using the bidi iterator, starting at
+                 IT's current position, until we find ourselves
+                 outside the invisible text.  This avoids affecting
+                 the visual order of the displayed text when invisible
+                 properties are added or removed.  */
+              do
+                {
+                  bidi_get_next_char_visually (&it->bidi_it);
+                }
+              while (start_charpos <= it->bidi_it.charpos
+                     && it->bidi_it.charpos < newpos);
+              IT_CHARPOS (*it) = it->bidi_it.charpos;
+              IT_BYTEPOS (*it) = CHAR_TO_BYTE (newpos);
+            }
+          else
+            {
+              IT_CHARPOS (*it) = newpos;
+              IT_BYTEPOS (*it) = CHAR_TO_BYTE (newpos);
+            }
 
           /* If there are before-strings at the start of invisible
              text, and the text is invisible because of a text
@@ -3877,7 +3898,7 @@ handle_invisible_prop (it)
                  first invisible character.  */
               if (!STRINGP (it->object))
                 {
-                  it->position.charpos = IT_CHARPOS (*it) - 1;
+                  it->position.charpos = newpos - 1;
                   it->position.bytepos = CHAR_TO_BYTE (it->position.charpos);
                 }
               it->ellipsis_p = 1;
@@ -6604,11 +6625,11 @@ handle_stop_backwards (it, charpos)
 
   next_stop = it->stop_charpos;
   it->stop_charpos = it->prev_stop;
-  handle_stop (it);
-  it->stop_charpos = next_stop;
   it->bidi_p = 1;
   it->current = save_current;
   it->position = save_position;
+  handle_stop (it);
+  it->stop_charpos = next_stop;
 }
 
 /* Load IT with the next display element from current_buffer.  Value
@@ -6660,12 +6681,14 @@ next_element_from_buffer (it)
           bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
           if (it->glyph_row && (it->bidi_it.level_stack[0].level & 1) != 0)
             it->glyph_row->reversed_p = 1;
-          do {
-            /* Now return to buffer position where we were asked to
-               get the next display element, and produce that.  */
-            bidi_get_next_char_visually (&it->bidi_it);
-          } while (it->bidi_it.bytepos != orig_bytepos
-                   && it->bidi_it.bytepos < ZV_BYTE);
+          do
+            {
+              /* Now return to buffer position where we were asked to
+                 get the next display element, and produce that.  */
+              bidi_get_next_char_visually (&it->bidi_it);
+            }
+          while (it->bidi_it.bytepos != orig_bytepos
+                 && it->bidi_it.bytepos < ZV_BYTE);
         }
 
       it->bidi_it.first_elt = 0; /* paranoia: bidi.c does this */