# File lib/rubygame/rect.rb, line 611
        def union_all!(array_rects)
                left, top, right, bottom = self.normalize
                array_rects.each do |r|
                        r = Rect.new_from_object(r).normalize
                        left = min(left,r.left)
                        top = min(top,r.top)
                        right = max(right,r.right)
                        bottom = max(bottom,r.bottom)
                end
                self[0..3] = left, top, right - left, bottom-top
                return self
        end