basta.fullscreen_alt: assume worst case if no realows

* basta.sh (basta.fullscreen_alt): If not able to obtain
the current line and number of terminal lines from
the terminal, then assume that the worst case number
of scrolls are needed: size of the status area.

1 files changed, 9 insertions, 3 deletions

diff --git a/basta.sh b/basta.sh
index 9acaa89..2d55598 100644
--- a/basta.sh
+++ b/basta.sh
@@ -356,15 +356,21 @@ basta.fullscreen_alt() {
   basta_deferred_intr=WINCH
   LINES=$realrows command "$@" || exit=$?
 
+  local scrolls_needed=$basta_prev_reserved_rows
+
   if basta.query_terminal_lines realrows >&$ttyfd <&$ttyfd &&
-     basta.get_cur_line curline >&$ttyfd <&$ttyfd &&
-     [ $curline -ge $(( realrows - basta_prev_reserved_rows )) ]
+     basta.get_cur_line curline >&$ttyfd <&$ttyfd
   then
-    local scrolls_needed=$(( curline - realrows + basta_prev_reserved_rows ))
+    : $(( scrolls_needed -= realrows - curline ))
+  fi
+
+  if [ $scrolls_needed -gt 0 ] ; then
     printf $'\e[%s;1H' $realrows >&$ttyfd
+
     for (( i = 0 ; i < scrolls_needed; i++ )) ; do
       printf $'\n' >&$ttyfd
     done
+
     printf $'\n\e[%sA' $(( basta_prev_reserved_rows + 1 )) >&$ttyfd
   fi