# File lib/rvg/stretchable.rb, line 16
        def preserve_aspect_ratio(align, meet_or_slice='meet')
            @align = align.to_s
            if @align != 'none'
                m = /\A(xMin|xMid|xMax)(YMin|YMid|YMax)\z/.match(@align)
                raise(ArgumentError, "unknown alignment specifier: #{@align}") unless m
            end

            if meet_or_slice
                meet_or_slice = meet_or_slice.to_s.downcase
                if meet_or_slice == 'meet' || meet_or_slice == 'slice'
                    @meet_or_slice = meet_or_slice
                else
                    raise(ArgumentError, "specifier must be `meet' or `slice' (got #{meet_or_slice})")
                end
            end
            yield(self) if block_given?
            self
        end