Fix display of characters adjacent to ZWJ and ZWNJ

* src/bidi.c (bidi_resolve_neutral): Treat all Bn (a.k.a. "control")
characters the same as directional formatting controls.
(bidi_level_of_next_char): Include all Bn characters in rule L1,
as mandated by the UBA.

1 files changed, 12 insertions, 6 deletions

diff --git a/src/bidi.c b/src/bidi.c
index 9427b81298f..e3b1f549685 100644
--- a/src/bidi.c
+++ b/src/bidi.c
@@ -2948,7 +2948,7 @@ bidi_resolve_neutral (struct bidi_it *bidi_it)
                             we are already at paragraph end.  */
        && (is_neutral || bidi_isolate_fmt_char (type)))
       /* N1-N2/Retaining */
-      || (type == WEAK_BN && bidi_explicit_dir_char (bidi_it->ch)))
+      || type == WEAK_BN)
     {
       if (bidi_it->next_for_neutral.type != UNKNOWN_BT)
         {
@@ -2978,6 +2978,7 @@ bidi_resolve_neutral (struct bidi_it *bidi_it)
          entering the expensive loop in the "else" clause.  */
       else if (current_level == 0
                && bidi_it->prev_for_neutral.type == STRONG_L
+               && type != WEAK_BN
                && !bidi_explicit_dir_char (bidi_it->ch)
                && !bidi_isolate_fmt_char (type))
         type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type,
@@ -2991,6 +2992,7 @@ bidi_resolve_neutral (struct bidi_it *bidi_it)
                && (bidi_it->prev_for_neutral.type == STRONG_R
                    || bidi_it->prev_for_neutral.type == WEAK_EN
                    || bidi_it->prev_for_neutral.type == WEAK_AN)
+               && type != WEAK_BN
                && !bidi_explicit_dir_char (bidi_it->ch)
                && !bidi_isolate_fmt_char (type))
         type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type,
@@ -3216,6 +3218,7 @@ bidi_level_of_next_char (struct bidi_it *bidi_it)
      it belongs to a sequence of WS characters preceding a newline
      or a TAB or a paragraph separator.  */
   if ((bidi_it->orig_type == NEUTRAL_WS
+       || bidi_it->orig_type == WEAK_BN
        || bidi_isolate_fmt_char (bidi_it->orig_type))
       && bidi_it->next_for_ws.charpos < bidi_it->charpos)
     {
@@ -3249,11 +3252,14 @@ bidi_level_of_next_char (struct bidi_it *bidi_it)
 
   /* Resolve implicit levels.  */
   if (bidi_it->orig_type == NEUTRAL_B /* L1 */
-           || bidi_it->orig_type == NEUTRAL_S
-           || bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB
-           || (bidi_it->orig_type == NEUTRAL_WS
-               && (bidi_it->next_for_ws.type == NEUTRAL_B
-                   || bidi_it->next_for_ws.type == NEUTRAL_S)))
+      || bidi_it->orig_type == NEUTRAL_S
+      || bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB
+      || ((bidi_it->orig_type == NEUTRAL_WS
+           || bidi_it->orig_type == WEAK_BN
+           || bidi_isolate_fmt_char (bidi_it->orig_type)
+           || bidi_explicit_dir_char (bidi_it->ch))
+          && (bidi_it->next_for_ws.type == NEUTRAL_B
+              || bidi_it->next_for_ws.type == NEUTRAL_S)))
     level = bidi_it->level_stack[0].level;
   else if ((level & 1) == 0) /* I1 */
     {