text_style classThe text_style class is a structure which represents a text
style. It contains a font name, a size in tenths of a point and a
colour. It also defines an enumerated type which may be used to
describe text alignment.
struct text_style {
string font;
int size;
colour col;
enum alignment { left, right, centre };
};
Font names are dependent on the output device; as the only output device currently supported is a PostScript device, the font name should be a PostScript font name such as Helvetica-Oblique or Times-Roman.