[Emacs-diffs] /srv/bzr/emacs/trunk r100105: Fix display of R2L lines and cursor motion in bidi buffers.

[Eli Zaretskii]

------------------------------------------------------------
revno: 100105 [merge]
committer: Eli Zaretskii <address@hidden>
branch nick: trunk
timestamp: Sat 2010-05-01 21:11:20 +0300
message:
  Fix display of R2L lines and cursor motion in bidi buffers.
  
   xdisp.c (find_row_end): New function, refactored from display_line.
   (display_line): Use it.
   (extend_face_to_end_of_line): In almost-filled rows, extend only
   if the row is R2L and not continued.
   (display_line): Fix prepending of truncation glyphs to R2L rows.
   Preserve overlay and string info in row->end.
   (insert_left_trunc_glyphs): Support addition of left truncation
   glyphs to R2L rows.
   (set_cursor_from_row): Don't place cursor on the vertical border
   glyph between adjacent windows.  Fix a crash when a display string
   is continued to the next line.  Don't return zero if cursor was
   found by `cursor' property of a display string.
   (try_cursor_movement): Don't assume that row->end == (row+1)->start,
   test for that explicitly.
modified:
  src/ChangeLog
  src/xdisp.c

=== modified file 'src/ChangeLog'
--- a/src/ChangeLog     2010-05-01 03:04:51 +0000
+++ b/src/ChangeLog     2010-05-01 18:11:20 +0000
@@ -1,3 +1,23 @@
+2010-05-01  Eli Zaretskii  <address@hidden>
+
+       Miscellaneous fixes of bidi display.
+
+       * xdisp.c (find_row_end): New function, refactored from
+       display_line.
+       (display_line): Use it.
+       (extend_face_to_end_of_line): In almost-filled rows, extend only
+       if the row is R2L and not continued.
+       (display_line): Fix prepending of truncation glyphs to R2L rows.
+       Preserve overlay and string info in row->end.
+       (insert_left_trunc_glyphs): Support addition of left truncation
+       glyphs to R2L rows.
+       (set_cursor_from_row): Don't place cursor on the vertical border
+       glyph between adjacent windows.  Fix a crash when a display string
+       is continued to the next line.  Don't return zero if cursor was
+       found by `cursor' property of a display string.
+       (try_cursor_movement): Don't assume that row->end == (row+1)->start,
+       test for that explicitly.
+
 2010-05-01  Glenn Morris  <address@hidden>
 
        * Makefile.in (gmallocobj, rallocobj, vmlimitobj): Initialize to null,

=== modified file 'src/xdisp.c'
--- a/src/xdisp.c       2010-04-25 17:06:41 +0000
+++ b/src/xdisp.c       2010-05-01 18:11:20 +0000
@@ -12776,6 +12776,13 @@
         rightmost glyph.  Case in point: an empty last line that is
         part of an R2L paragraph.  */
       cursor = end - 1;
+      /* Avoid placing the cursor on the last glyph of the row, where
+        on terminal frames we hold the vertical border between
+        adjacent windows.  */
+      if (!FRAME_WINDOW_P (WINDOW_XFRAME (w))
+         && !WINDOW_RIGHTMOST_P (w)
+         && cursor == row->glyphs[LAST_AREA] - 1)
+       cursor--;
       x = -1;  /* will be computed below, at label compute_x */
     }
 
@@ -13015,7 +13022,8 @@
 
                          cursor = glyph;
                          for (glyph += incr;
-                              EQ (glyph->object, str);
+                              (row->reversed_p ? glyph > stop : glyph < stop)
+                                && EQ (glyph->object, str);
                               glyph += incr)
                            {
                              Lisp_Object cprop;
@@ -13055,8 +13063,9 @@
 
          /* If we reached the end of the line, and END was from a string,
             the cursor is not on this line.  */
-         if (glyph == end
-             && STRINGP ((glyph - incr)->object)
+         if (cursor == NULL
+             && (row->reversed_p ? glyph <= end : glyph >= end)
+             && STRINGP (end->object)
              && row->continued_p)
            return 0;
        }
@@ -13714,11 +13723,14 @@
                  ++row;
                }
 
-             /* The end position of a row equals the start position
-                of the next row.  If PT is there, we would rather
-                display it in the next line.  */
+             /* If the end position of a row equals the start
+                position of the next row, and PT is at that position,
+                we would rather display cursor in the next line.  */
              while (MATRIX_ROW_BOTTOM_Y (row) < last_y
                     && MATRIX_ROW_END_CHARPOS (row) == PT
+                    && row < w->current_matrix->rows
+                               + w->current_matrix->nrows - 1
+                    && MATRIX_ROW_START_CHARPOS (row+1) == PT
                     && !cursor_row_p (w, row))
                ++row;
 
@@ -16737,24 +16749,61 @@
   produce_special_glyphs (&truncate_it, IT_TRUNCATION);
 
   /* Overwrite glyphs from IT with truncation glyphs.  */
-  from = truncate_it.glyph_row->glyphs[TEXT_AREA];
-  end = from + truncate_it.glyph_row->used[TEXT_AREA];
-  to = it->glyph_row->glyphs[TEXT_AREA];
-  toend = to + it->glyph_row->used[TEXT_AREA];
-
-  while (from < end)
-    *to++ = *from++;
-
-  /* There may be padding glyphs left over.  Overwrite them too.  */
-  while (to < toend && CHAR_GLYPH_PADDING_P (*to))
+  if (!it->glyph_row->reversed_p)
     {
       from = truncate_it.glyph_row->glyphs[TEXT_AREA];
+      end = from + truncate_it.glyph_row->used[TEXT_AREA];
+      to = it->glyph_row->glyphs[TEXT_AREA];
+      toend = to + it->glyph_row->used[TEXT_AREA];
+
       while (from < end)
        *to++ = *from++;
-    }
-
-  if (to > toend)
-    it->glyph_row->used[TEXT_AREA] = to - it->glyph_row->glyphs[TEXT_AREA];
+
+      /* There may be padding glyphs left over.  Overwrite them too.  */
+      while (to < toend && CHAR_GLYPH_PADDING_P (*to))
+       {
+         from = truncate_it.glyph_row->glyphs[TEXT_AREA];
+         while (from < end)
+           *to++ = *from++;
+       }
+
+      if (to > toend)
+       it->glyph_row->used[TEXT_AREA] = to - it->glyph_row->glyphs[TEXT_AREA];
+    }
+  else
+    {
+      /* In R2L rows, overwrite the last (rightmost) glyphs, and do
+        that back to front.  */
+      end = truncate_it.glyph_row->glyphs[TEXT_AREA];
+      from = end + truncate_it.glyph_row->used[TEXT_AREA] - 1;
+      toend = it->glyph_row->glyphs[TEXT_AREA];
+      to = toend + it->glyph_row->used[TEXT_AREA] - 1;
+
+      while (from >= end && to >= toend)
+       *to-- = *from--;
+      while (to >= toend && CHAR_GLYPH_PADDING_P (*to))
+       {
+         from =
+           truncate_it.glyph_row->glyphs[TEXT_AREA]
+           + truncate_it.glyph_row->used[TEXT_AREA] - 1;
+         while (from >= end && to >= toend)
+           *to-- = *from--;
+       }
+      if (from >= end)
+       {
+         /* Need to free some room before prepending additional
+            glyphs.  */
+         int move_by = from - end + 1;
+         struct glyph *g0 = it->glyph_row->glyphs[TEXT_AREA];
+         struct glyph *g = g0 + it->glyph_row->used[TEXT_AREA] - 1;
+
+         for ( ; g >= g0; g--)
+           g[move_by] = *g;
+         while (from >= end)
+           *to-- = *from--;
+         it->glyph_row->used[TEXT_AREA] += move_by;
+       }
+    }
 }
 
 
@@ -16946,8 +16995,13 @@
 
   /* If line is already filled, do nothing.  Non window-system frames
      get a grace of one more ``pixel'' because their characters are
-     1-``pixel'' wide, so they hit the equality too early.  */
-  if (it->current_x >= it->last_visible_x + !FRAME_WINDOW_P (f))
+     1-``pixel'' wide, so they hit the equality too early.  This grace
+     is needed only for R2L rows that are not continued, to produce
+     one extra blank where we could display the cursor.  */
+  if (it->current_x >= it->last_visible_x
+      + (!FRAME_WINDOW_P (f)
+        && it->glyph_row->reversed_p
+        && !it->glyph_row->continued_p))
     return;
 
   /* Face extension extends the background and box of IT->face_id
@@ -17368,6 +17422,123 @@
     glyph[-n] = *glyph;
 }
 
+/* Find the positions in a bidi-reordered ROW to serve as ROW->start
+   and ROW->end.  */
+static struct display_pos
+find_row_end (it, row)
+     struct it *it;
+     struct glyph_row *row;
+{
+  /* FIXME: Revisit this when glyph ``spilling'' in continuation
+     lines' rows is implemented for bidi-reordered rows.  */
+  EMACS_INT min_pos = ZV + 1, max_pos = 0;
+  struct glyph *g;
+  struct it save_it;
+  struct text_pos tpos;
+  struct display_pos row_end = it->current;
+
+  for (g = row->glyphs[TEXT_AREA];
+       g < row->glyphs[TEXT_AREA] + row->used[TEXT_AREA];
+       g++)
+    {
+      if (BUFFERP (g->object))
+       {
+         if (g->charpos > 0 && g->charpos < min_pos)
+           min_pos = g->charpos;
+         if (g->charpos > max_pos)
+           max_pos = g->charpos;
+       }
+    }
+  /* Empty lines have a valid buffer position at their first
+     glyph, but that glyph's OBJECT is zero, as if it didn't come
+     from a buffer.  If we didn't find any valid buffer positions
+     in this row, maybe we have such an empty line.  */
+  if (max_pos == 0 && row->used[TEXT_AREA])
+    {
+      for (g = row->glyphs[TEXT_AREA];
+          g < row->glyphs[TEXT_AREA] + row->used[TEXT_AREA];
+          g++)
+       {
+         if (INTEGERP (g->object))
+           {
+             if (g->charpos > 0 && g->charpos < min_pos)
+               min_pos = g->charpos;
+             if (g->charpos > max_pos)
+               max_pos = g->charpos;
+           }
+       }
+    }
+
+  /* ROW->start is the value of min_pos, the minimal buffer position
+     we have in ROW.  */
+  if (min_pos <= ZV)
+    {
+      /* Avoid calling the costly CHAR_TO_BYTE if possible.  */
+      if (min_pos != row->start.pos.charpos)
+       SET_TEXT_POS (row->start.pos, min_pos, CHAR_TO_BYTE (min_pos));
+      if (max_pos == 0)
+       max_pos = min_pos;
+    }
+
+  /* For ROW->end, we need the position that is _after_ max_pos, in
+     the logical order, unless we are at ZV.  */
+  if (row->ends_at_zv_p)
+    {
+      if (!row->used[TEXT_AREA])
+       row->start.pos = row_end.pos;
+    }
+  else if (row->used[TEXT_AREA] && max_pos)
+    {
+      int at_eol_p;
+
+      SET_TEXT_POS (tpos, max_pos, CHAR_TO_BYTE (max_pos));
+      save_it = *it;
+      it->bidi_p = 0;
+      reseat (it, tpos, 0);
+      if (!get_next_display_element (it))
+       abort ();       /* this row cannot be at ZV, see above */
+      at_eol_p = ITERATOR_AT_END_OF_LINE_P (it);
+      set_iterator_to_next (it, 1);
+      row_end = it->current;
+      /* If the character at max_pos is not a newline and the
+        characters at max_pos+1 is a newline, skip that newline as
+        well.  Note that this may skip some invisible text.  */
+      if (!at_eol_p
+         && get_next_display_element (it)
+         && ITERATOR_AT_END_OF_LINE_P (it))
+       {
+         set_iterator_to_next (it, 1);
+         /* Record the position after the newline of a continued row.
+            We will need that to set ROW->end of the last row
+            produced for a continued line.  */
+         if (row->continued_p)
+           save_it.eol_pos = it->current.pos;
+         else
+           {
+             row_end = it->current;
+             save_it.eol_pos.charpos = save_it.eol_pos.bytepos = 0;
+           }
+       }
+      else if (!row->continued_p
+              && MATRIX_ROW_CONTINUATION_LINE_P (row)
+              && it->eol_pos.charpos > 0)
+       {
+         /* Last row of a continued line.  Use the position recorded
+            in IT->eol_pos, to the effect that the newline belongs to
+            this row, not to the row which displays the character
+            with the largest buffer position before the newline.  */
+         row_end.pos = it->eol_pos;
+         it->eol_pos.charpos = it->eol_pos.bytepos = 0;
+       }
+      *it = save_it;
+      /* The members of ROW->end that are not taken from buffer
+        positions are copied from IT->current.  */
+      row_end.string_pos = it->current.string_pos;
+      row_end.overlay_string_index = it->current.overlay_string_index;
+      row_end.dpvec_index = it->current.dpvec_index;
+    }
+  return row_end;
+}
 
 /* Construct the glyph row IT->glyph_row in the desired matrix of
    IT->w from text at the current position of IT.  See dispextern.h
@@ -17386,7 +17557,6 @@
   int wrap_row_used = -1, wrap_row_ascent, wrap_row_height;
   int wrap_row_phys_ascent, wrap_row_phys_height;
   int wrap_row_extra_line_spacing;
-  struct display_pos row_end;
   int cvpos;
 
   /* We always start displaying at hpos zero even if hscrolled.  */
@@ -17815,10 +17985,14 @@
                  for (i = 0; i < row->used[TEXT_AREA]; i++)
                    if (!CHAR_GLYPH_PADDING_P (row->glyphs[TEXT_AREA][i]))
                      break;
-                 /* Remove padding glyphs at the front of ROW, to
+                 /* Remove any padding glyphs at the front of ROW, to
                     make room for the truncation glyphs we will be
-                    adding below.  */
-                 unproduce_glyphs (it, i);
+                    adding below.  The loop below always inserts at
+                    least one truncation glyph, so also remove the
+                    last glyph added to ROW.  */
+                 unproduce_glyphs (it, i + 1);
+                 /* Adjust i for the loop below.  */
+                 i = row->used[TEXT_AREA] - (i + 1);
                }
 
              for (n = row->used[TEXT_AREA]; i < n; ++i)
@@ -17910,118 +18084,13 @@
   compute_line_metrics (it);
 
   /* Remember the position at which this line ends.  */
-  row->end = row_end = it->current;
+  row->end = it->current;
+  /* ROW->start and ROW->end must be the smallest and the largest
+     buffer positions in ROW.  But if ROW was bidi-reordered, these
+     two positions can be anywhere in the row, so we must rescan all
+     of the ROW's glyphs to find them.  */
   if (it->bidi_p)
-    {
-      /* ROW->start and ROW->end must be the smallest and largest
-        buffer positions in ROW.  But if ROW was bidi-reordered,
-        these two positions can be anywhere in the row, so we must
-        rescan all of the ROW's glyphs to find them.  */
-      /* FIXME: Revisit this when glyph ``spilling'' in continuation
-        lines' rows is implemented for bidi-reordered rows.  */
-      EMACS_INT min_pos = ZV + 1, max_pos = 0;
-      struct glyph *g;
-      struct it save_it;
-      struct text_pos tpos;
-
-      for (g = row->glyphs[TEXT_AREA];
-          g < row->glyphs[TEXT_AREA] + row->used[TEXT_AREA];
-          g++)
-       {
-         if (BUFFERP (g->object))
-           {
-             if (g->charpos > 0 && g->charpos < min_pos)
-               min_pos = g->charpos;
-             if (g->charpos > max_pos)
-               max_pos = g->charpos;
-           }
-       }
-      /* Empty lines have a valid buffer position at their first
-        glyph, but that glyph's OBJECT is zero, as if it didn't come
-        from a buffer.  If we didn't find any valid buffer positions
-        in this row, maybe we have such an empty line.  */
-      if (min_pos == ZV + 1 && row->used[TEXT_AREA])
-       {
-         for (g = row->glyphs[TEXT_AREA];
-              g < row->glyphs[TEXT_AREA] + row->used[TEXT_AREA];
-              g++)
-           {
-             if (INTEGERP (g->object))
-               {
-                 if (g->charpos > 0 && g->charpos < min_pos)
-                   min_pos = g->charpos;
-                 if (g->charpos > max_pos)
-                   max_pos = g->charpos;
-               }
-           }
-       }
-      if (min_pos <= ZV)
-       {
-         if (min_pos != row->start.pos.charpos)
-           {
-             row->start.pos.charpos = min_pos;
-             row->start.pos.bytepos = CHAR_TO_BYTE (min_pos);
-           }
-         if (max_pos == 0)
-           max_pos = min_pos;
-       }
-      /* For ROW->end, we need the position that is _after_ max_pos,
-        in the logical order, unless we are at ZV.  */
-      if (row->ends_at_zv_p)
-       {
-         row_end = row->end = it->current;
-         if (!row->used[TEXT_AREA])
-           {
-             row->start.pos.charpos = row_end.pos.charpos;
-             row->start.pos.bytepos = row_end.pos.bytepos;
-           }
-       }
-      else if (row->used[TEXT_AREA] && max_pos)
-       {
-         SET_TEXT_POS (tpos, max_pos, CHAR_TO_BYTE (max_pos));
-         save_it = *it;
-         it->bidi_p = 0;
-         reseat (it, tpos, 0);
-         if (!get_next_display_element (it))
-           abort ();   /* row at ZV was already handled above */
-         set_iterator_to_next (it, 1);
-         row_end = it->current;
-         /* If the character at max_pos+1 is a newline, skip that as
-            well.  Note that this may skip some invisible text.  */
-         if (get_next_display_element (it)
-             && ITERATOR_AT_END_OF_LINE_P (it))
-           {
-             set_iterator_to_next (it, 1);
-             /* Record the position after the newline of a continued
-                row.  We will need that to set ROW->end of the last
-                row produced for a continued line.  */
-             if (row->continued_p)
-               {
-                 save_it.eol_pos.charpos = IT_CHARPOS (*it);
-                 save_it.eol_pos.bytepos = IT_BYTEPOS (*it);
-               }
-             else
-               {
-                 row_end = it->current;
-                 save_it.eol_pos.charpos = save_it.eol_pos.bytepos = 0;
-               }
-           }
-         else if (!row->continued_p
-                  && MATRIX_ROW_CONTINUATION_LINE_P (row)
-                  && it->eol_pos.charpos > 0)
-           {
-             /* Last row of a continued line.  Use the position
-                recorded in ROW->eol_pos, to the effect that the
-                newline belongs to this row, not to the row which
-                displays the character with the largest buffer
-                position.  */
-             row_end.pos = it->eol_pos;
-             it->eol_pos.charpos = it->eol_pos.bytepos = 0;
-           }
-         *it = save_it;
-         row->end = row_end;
-       }
-    }
+    row->end = find_row_end (it, row);
 
   /* Record whether this row ends inside an ellipsis.  */
   row->ends_in_ellipsis_p
@@ -18075,7 +18144,7 @@
      the flag accordingly.  */
   if (it->glyph_row < MATRIX_BOTTOM_TEXT_ROW (it->w->desired_matrix, it->w))
     it->glyph_row->reversed_p = row->reversed_p;
-  it->start = row_end;
+  it->start = row->end;
   return row->displays_text_p;
 }