Set the character size attribute. The size affects all text and graph
markers drawn later in the program. The default character size is
1.0, corresponding to a character height about 1/40 the height of
the view surface. Changing the character size also scales the length
of tick marks drawn by PGBOX and terminals drawn by PGERRX and PGERRY.
Arguments
SIZE (input) : new character size (dimensionless multiple of
the default size).