# File lib/rubygame/rect.rb, line 563
        def normalize!
                if self.at(2) < 0
                        self[0], self[2] = self.at(0)+self.at(2), -self.at(2)
                end
                if self.at(3) < 0
                        self[1], self[3] = self.at(1)+self.at(3), -self.at(3)
                end
                self
        end