Initialise a graphical using the area components graphical<-x, graphical<-y, graphical<-width
and
graphical<-height.
It sets the following defaults:
<-displayed @off (will be set by ->display)
<-device @nil
<-area new area from the arguments
<-pen 1 1
<-texture none
<-colour @default
<-selected @off
<-name Classname (box, ellipse, ...)
<-handles @nil
<-inverted @off
<-cursor @nil
<-request_compute @nil
Class graphical
is a super-class of all graphical classes. Instances of this class can
be created, but are probably of little use.
