(update_window): Detect pending input every nth line

updated, i.e. do it depending on real work done, and not on the
vpos of the line.

2 files changed, 10 insertions, 3 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 989ff4b9400..0cd551b3512 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,12 @@
 2000-12-15  Gerd Moellmann  <gerd@gnu.org>
 
+        * dispnew.c (update_window): Detect pending input every nth line
+        updated, i.e. do it depending on real work done, and not on the
+        vpos of the line.
+
+        * xterm.c (expose_window): Don't redraw the window that's
+        currently being updated.
+
         * window.c (Fset_window_point): Remove test for
         cursor_in_non_selected_windows.
 
diff --git a/src/dispnew.c b/src/dispnew.c
index 7694233e36f..dcff59d5698 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -3789,7 +3789,7 @@ update_window (w, force_p)
       struct glyph_row *row, *end;
       struct glyph_row *mode_line_row;
       struct glyph_row *header_line_row = NULL;
-      int yb, changed_p = 0, mouse_face_overwritten_p = 0;
+      int yb, changed_p = 0, mouse_face_overwritten_p = 0, n_updated;
 
       rif->update_window_begin_hook (w);
       yb = window_text_bottom_y (w);
@@ -3844,7 +3844,7 @@ update_window (w, force_p)
         }
 
       /* Update the rest of the lines.  */
-      for (; row < end && (force_p || !input_pending); ++row)
+      for (n_updated = 0; row < end && (force_p || !input_pending); ++row)
         if (row->enabled_p)
           {
             int vpos = MATRIX_ROW_VPOS (row, desired_matrix);
@@ -3854,7 +3854,7 @@ update_window (w, force_p)
                detect_input_pending.  If it's done too often,
                scrolling large windows with repeated scroll-up
                commands will too quickly pause redisplay.  */
-            if (!force_p && vpos % preempt_count == 0)
+            if (!force_p && ++n_updated % preempt_count == 0)
               detect_input_pending ();
 
             changed_p |= update_window_line (w, vpos,