clarify Rect.Intersect doc
@@ -268,6 +268,8 @@ func (r Rect) Union(s Rect) Rect {
}
// Intersect returns the maximal Rect which is covered by both r and s. Rects r and s must be normalized.
+//
+// If r and s don't overlap, this function returns R(0, 0, 0, 0).
func (r Rect) Intersect(s Rect) Rect {
t := R(
math.Min(r.Max.X, s.Max.X),
