artist-draw-circle is a compiled Lisp function in `
(artist-draw-circle X1 Y1 X2 Y2)
Draw a circle with center at X1, Y1 and point X2,Y2.
Output is an ellipse, which is a list (END-POINT-1 END-POINT-2 SHAPE-INFO).
END-POINT-1 and END-POINT-2 are two-element vectors on the form [X Y].
SHAPE-INFO is a two-element vector on the form [POINT-LIST FILL-INFO].
POINT-LIST is a list of vectors on the form [X Y SAVED-CHAR NEW-CHAR].
FILL-INFO is a list of vectors on the form [X Y ELLIPSE-WIDTH-ON-THIS-LINE].