func (t *tbfe) clip(v *backend.View, s, e int) Region {
p := util.Prof.Enter("clip")
defer p.Exit()
t.lock.Lock()
h := t.layout[v].height
t.lock.Unlock()
if e-s > h {
e = s + h
} else if e-s < h {
s = e - h
}
if e2, _ := v.RowCol(v.TextPoint(e, 0)); e2 < e {
e = e2
}
if s < 0 {
s = 0
}
e = s + h
r := Region{v.TextPoint(s, 0), v.TextPoint(e, 0)}
return v.LineR(r)
}
