figure(fn, w, h) opens a new QPLOT figure with given filename and size in inches. If h is omitted, h defaults to 3/4 w. If w is also omitted, w defaults to 5 inches.
fn = figure('', w, h) opens a new QPlot figure of given size (in inches) with a temporary filename.
Optional argument unit specifies alternative units. figure understands inch, mm, cm, and pt.