# File lib/rvg/text.rb, line 157 def tref(obj, x=nil, y=nil) if ! obj.kind_of?(Tspan) raise ArgumentError, "wrong argument type #{obj.class} (expected Tspan)" end obj = obj.deep_copy obj.parent = self tref = Tref.new(obj, x, y, self) @tspans << tref return tref end