Fix fill-column-indicator on TTY frames

* src/xdisp.c (extend_face_to_end_of_line): Fix calculation of
fill-column-indicator on TTY frames.  Suggested by Jimmy Aguilar
Mena <spacibba@aol.com>.

1 files changed, 11 insertions, 3 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 0e8672961ae..e761ef8b37c 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -22386,15 +22386,23 @@ extend_face_to_end_of_line (struct it *it)
       it->face_id = (it->glyph_row->ends_at_zv_p ?
                      default_face->id : face->id);
 
-      /* Display fill-column indicator if needed.  */
-      const int indicator_column = fill_column_indicator_column (it, 1);
-
       /* Make sure our idea of current_x is in sync with the glyphs
          actually in the glyph row.  They might differ because
          append_space_for_newline can insert one glyph without
          updating current_x.  */
       it->current_x = it->glyph_row->used[TEXT_AREA];
 
+      /* The above assignment causes the code below to use a
+         non-standard semantics of it->current_x: it is measured
+         relative to the beginning of the text-area, thus disregarding
+         the window's hscroll.  That is why we need to correct the
+         indicator column for the hscroll, otherwise the indicator
+         will not move together with the text as result of horizontal
+         scrolling.  */
+      const int indicator_column =
+        fill_column_indicator_column (it, 1) - it->first_visible_x;
+
+      /* Display fill-column indicator if needed.  */
       while (it->current_x <= it->last_visible_x)
         {
           if (it->current_x != indicator_column)