[Emacs-diffs] emacs-24 r117363: Fix bug #17969 with vertical-motion through continuation lines with TABs.

[Eli Zaretskii]

------------------------------------------------------------
revno: 117363
revision-id: address@hidden
parent: address@hidden
fixes bug: http://debbugs.gnu.org/17969
committer: Eli Zaretskii <address@hidden>
branch nick: emacs-24
timestamp: Tue 2014-07-08 18:12:39 +0300
message:
  Fix bug #17969 with vertical-motion through continuation lines with TABs.
  
   src/xdisp.c (move_it_to): Adjust calculation of line_start_x to what
   x_produce_glyphs does when it generates a stretch glyph that
   represents a TAB.
modified:
  src/ChangeLog                  changelog-20091113204419-o5vbwnq5f7feedwu-1438
  src/xdisp.c                    xdisp.c-20091113204419-o5vbwnq5f7feedwu-240

=== modified file 'src/ChangeLog'
--- a/src/ChangeLog     2014-07-05 09:53:50 +0000
+++ b/src/ChangeLog     2014-07-08 15:12:39 +0000
@@ -1,3 +1,9 @@
+2014-07-08  Eli Zaretskii  <address@hidden>
+
+       * xdisp.c (move_it_to): Adjust calculation of line_start_x to what
+       x_produce_glyphs does when it generates a stretch glyph that
+       represents a TAB.  (Bug#17969)
+
 2014-07-05  Eli Zaretskii  <address@hidden>
 
        * xdisp.c (pos_visible_p): If CHARPOS is at beginning of window,

=== modified file 'src/xdisp.c'
--- a/src/xdisp.c       2014-07-05 10:24:11 +0000
+++ b/src/xdisp.c       2014-07-08 15:12:39 +0000
@@ -9250,6 +9250,25 @@
                {
                  line_start_x = it->current_x + it->pixel_width
                    - it->last_visible_x;
+                 if (FRAME_WINDOW_P (it->f))
+                   {
+                     struct face *face = FACE_FROM_ID (it->f, it->face_id);
+                     struct font *face_font = face->font;
+
+                     /* When display_line produces a continued line
+                        that ends in a TAB, it skips a tab stop that
+                        is closer than the font's space character
+                        width (see x_produce_glyphs where it produces
+                        the stretch glyph which represents a TAB).
+                        We need to reproduce the same logic here.  */
+                     eassert (face_font);
+                     if (face_font)
+                       {
+                         if (line_start_x < face_font->space_width)
+                           line_start_x
+                             += it->tab_width * face_font->space_width;
+                       }
+                   }
                  set_iterator_to_next (it, 0);
                }
            }