void
kscrolldown(const Arg* a)
{
int n = a->i;
if (n < 0)
n = term.row + n;
if (n > term.scr)
n = term.scr;
if (term.scr > 0) {
term.scr -= n;
selscroll(0, -n);
tfulldirt();
}
scroll_images(-1*n);
kscrollup(const Arg* a)
if (term.scr + n > term.histi)
n = term.histi - term.scr;
if (!n)
return;
if (term.scr <= HISTSIZE-n) {
term.scr += n;
selscroll(0, n);
scroll_images(n);