In this section:
%ts (Text Size) takes one DOUBLE PRECISION argument that is used to scale the size of any text that follows until the next %ts or %sf format code. The default value of this argument is 1.0. Values of the argument in the range from 0 to 1.0 are used to scale down, whilst values greater than 1.0 are used to scale up. Note that the system font cannot be scaled, so %fn (Font) must always be used before %ts (also see Font name - %fn[font_name]).
For example:
i=winio@('%fn[Courier New]%tsThis is larger',1.5D0)