Fix glyph_row reversed_p flag in empty lines between paragraphs.

 bidi.c (bidi_get_next_char_visually): Improve commentary.
 dispextern.h (PRODUCE_GLYPHS): Set the reversed_p flag in the
 iterator's glyph_row here.
 xdisp.c (handle_invisible_prop, set_iterator_to_next)
 (next_element_from_buffer): Don't set the reversed_p flag in the
 iterator's glyph_row here.

4 files changed, 23 insertions, 37 deletions

diff --git a/src/ChangeLog.bidi b/src/ChangeLog.bidi
index 9e0236fcefb..d27f747466b 100644
--- a/src/ChangeLog.bidi
+++ b/src/ChangeLog.bidi
@@ -1,3 +1,14 @@
+2010-03-28  Eli Zaretskii  <eliz@gnu.org>
+
+        * bidi.c (bidi_get_next_char_visually): Improve commentary.
+
+        * dispextern.h (PRODUCE_GLYPHS): Set the reversed_p flag in the
+        iterator's glyph_row here.
+
+        * xdisp.c (handle_invisible_prop, set_iterator_to_next)
+        (next_element_from_buffer): Don't set the reversed_p flag in the
+        iterator's glyph_row here.
+
 2010-03-20  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c (set_cursor_from_row): Don't miss a candidate row whose
diff --git a/src/bidi.c b/src/bidi.c
index 5c0169071ff..8089bf811a6 100644
--- a/src/bidi.c
+++ b/src/bidi.c
@@ -1901,7 +1901,7 @@ bidi_get_next_char_visually (struct bidi_it *bidi_it)
 
   /* Reordering of resolved levels (clause L2) is implemented by
      jumping to the other edge of the level and flipping direction of
-     scanning the buffer whenever we find a level change.  */
+     scanning the text whenever we find a level change.  */
   if (new_level != old_level)
     {
       int ascending = new_level > old_level;
@@ -1959,7 +1959,9 @@ bidi_get_next_char_visually (struct bidi_it *bidi_it)
      paragraph direction, if needed.  We do this at the newline before
      the paragraph separator, because the next character might not be
      the first character of the next paragraph, due to the bidi
-     reordering.  */
+     reordering, whereas we _must_ know the paragraph base direction
+     _before_ we process the paragraph's text, since the base
+     direction affects the reordering.  */
   if (bidi_it->scan_dir == 1
       && bidi_it->orig_type == NEUTRAL_B
       && bidi_it->bytepos < ZV_BYTE)
diff --git a/src/dispextern.h b/src/dispextern.h
index 03b35df397c..5083199c529 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -2399,6 +2399,13 @@ struct it
 #define PRODUCE_GLYPHS(IT)                              \
   do {                                                  \
     extern int inhibit_free_realized_faces;             \
+    if ((IT)->glyph_row != NULL && (IT)->bidi_p)        \
+      {                                                 \
+        if ((IT)->bidi_it.paragraph_dir == R2L)         \
+          (IT)->glyph_row->reversed_p = 1;              \
+        else                                            \
+          (IT)->glyph_row->reversed_p = 0;              \
+      }                                                 \
     if (FRAME_RIF ((IT)->f) != NULL)                    \
       FRAME_RIF ((IT)->f)->produce_glyphs ((IT));       \
     else                                                \
diff --git a/src/xdisp.c b/src/xdisp.c
index f2e06c0a2e7..867018180aa 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -3869,15 +3869,6 @@ handle_invisible_prop (it)
                      skip any text at the beginning, which resets the
                      FIRST_ELT flag.  */
                   bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
-                  /* If the paragraph base direction is R2L, its
-                     glyphs should be reversed.  */
-                  if (it->glyph_row)
-                    {
-                      if (it->bidi_it.paragraph_dir == R2L)
-                        it->glyph_row->reversed_p = 1;
-                      else
-                        it->glyph_row->reversed_p = 0;
-                    }
                 }
               do
                 {
@@ -6235,16 +6226,7 @@ set_iterator_to_next (it, reseat_p)
               /* If this is a new paragraph, determine its base
                  direction (a.k.a. its base embedding level).  */
               if (it->bidi_it.new_paragraph)
-                {
-                  bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
-                  if (it->glyph_row)
-                    {
-                      if (it->bidi_it.paragraph_dir == R2L)
-                        it->glyph_row->reversed_p = 1;
-                      else
-                        it->glyph_row->reversed_p = 0;
-                    }
-                }
+                bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
               bidi_get_next_char_visually (&it->bidi_it);
               IT_BYTEPOS (*it) = it->bidi_it.bytepos;
               IT_CHARPOS (*it) = it->bidi_it.charpos;
@@ -6705,15 +6687,6 @@ next_element_from_buffer (it)
           || FETCH_CHAR (it->bidi_it.bytepos) == '\n')
         {
           bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
-          /* If the paragraph base direction is R2L, its glyphs should
-             be reversed.  */
-          if (it->glyph_row)
-            {
-              if (it->bidi_it.paragraph_dir == R2L)
-                it->glyph_row->reversed_p = 1;
-              else
-                it->glyph_row->reversed_p = 0;
-            }
           bidi_get_next_char_visually (&it->bidi_it);
         }
       else
@@ -6728,13 +6701,6 @@ next_element_from_buffer (it)
           it->bidi_it.charpos = IT_CHARPOS (*it);
           it->bidi_it.bytepos = IT_BYTEPOS (*it);
           bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
-          if (it->glyph_row)
-            {
-              if (it->bidi_it.paragraph_dir == R2L)
-                it->glyph_row->reversed_p = 1;
-              else
-                it->glyph_row->reversed_p = 0;
-            }
           do
             {
               /* Now return to buffer position where we were asked to