Fix bug #6349 with cursor positioning in truncated lines.

 xdisp.c (set_cursor_from_row): When the row is truncated and
 point is outside the range of displayed characters, position the
 cursor inside the scroll margin.

2 files changed, 21 insertions, 3 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 5e7ac0cc4b2..c7bdb0b2d84 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2010-10-01  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (set_cursor_from_row): When the row is truncated and
+        point is outside the range of displayed characters, position the
+        cursor inside the scroll margin.  (Bug#6349)
+
 2010-10-01  Dan Nicolaescu  <dann@ics.uci.edu>
 
         Do not include stdlib.h and string.h, config.h does it.
diff --git a/src/xdisp.c b/src/xdisp.c
index 9b0f94ef657..4c007e572ce 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -12494,8 +12494,10 @@ set_cursor_from_row (struct window *w, struct glyph_row *row,
   /* Non-zero means we've seen at least one glyph that came from a
      display string.  */
   int string_seen = 0;
-  /* Largest buffer position seen so far during scan of glyph row.  */
-  EMACS_INT bpos_max = last_pos;
+  /* Largest and smalles buffer positions seen so far during scan of
+     glyph row.  */
+  EMACS_INT bpos_max = pos_before;
+  EMACS_INT bpos_min = pos_after;
   /* Last buffer position covered by an overlay string with an integer
      `cursor' property.  */
   EMACS_INT bpos_covered = 0;
@@ -12585,6 +12587,8 @@ set_cursor_from_row (struct window *w, struct glyph_row *row,
 
             if (glyph->charpos > bpos_max)
               bpos_max = glyph->charpos;
+            if (glyph->charpos < bpos_min)
+              bpos_min = glyph->charpos;
             if (!glyph->avoid_cursor_p)
               {
                 /* If we hit point, we've found the glyph on which to
@@ -12659,6 +12663,8 @@ set_cursor_from_row (struct window *w, struct glyph_row *row,
 
             if (glyph->charpos > bpos_max)
               bpos_max = glyph->charpos;
+            if (glyph->charpos < bpos_min)
+              bpos_min = glyph->charpos;
             if (!glyph->avoid_cursor_p)
               {
                 if (dpos == 0)
@@ -12745,7 +12751,13 @@ set_cursor_from_row (struct window *w, struct glyph_row *row,
             }
         }
       else if (match_with_avoid_cursor
-               /* zero-width characters produce no glyphs */
+               /* A truncated row may not include PT among its
+                  character positions.  Setting the cursor inside the
+                  scroll margin will trigger recalculation of hscroll
+                  in hscroll_window_tree.  */
+               || (row->truncated_on_left_p && pt_old < bpos_min)
+               || (row->truncated_on_right_p && pt_old > bpos_max)
+               /* Zero-width characters produce no glyphs.  */
                || ((row->reversed_p
                     ? glyph_after > glyphs_end
                     : glyph_after < glyphs_end)