Prevent flickering in curses

Reading from curs_refresh(3X) from curses, calling doupdate() repeatedly
will cause 'several bursts of output to the screen'. wnoutrefresh() has
the smarts to only copy the changed lines to the copied virtual screen,
but doupdate() does not.

There have been several bug reports related to flickering but all seems
to be inconsistenly reproducible due to different terminal buffering
behavior. See #1032, #327

Unfortunately, when I am using a slow display, I still notice
flickering, so this commit changes the routines for opening new windows
and splitting windows to wait until the last change is finished before
calling doupdate().

1 files changed, 7 insertions, 0 deletions

diff --git a/vis.h b/vis.h
index f8c5680..ae059b4 100644
--- a/vis.h
+++ b/vis.h
@@ -144,6 +144,13 @@ void vis_suspend(Vis*);
  */
 void vis_resume(Vis*);
 /**
+ * Set doupdate flag.
+ * @rst
+ * .. note:: Prevent flickering in curses by delaying window updates.
+ * @endrst
+ */
+void vis_doupdates(Vis*, bool);
+/**
  * Inform the editor core that a signal occurred.
  * @return Whether the signal was handled.
  * @rst