[comp.windows.x] repeated points in FillPoly request allowed?

jensen@granite.dec.com (Paul Jensen) (02/15/89)

Is it allowable for a FillPoly request specifying a shape of
Convex or Nonconvex to include repeated points (other than possibly the
first and last)?  The protocol document does not say one way or the other.
Since the rationale for the shape parameter is to improve performance,
it seems undesirable to force the DDX code to make an extra pass
over the data to weed out repeated points (necessary because efficient
tessellation algorithms assume a well-behaved polygon specification).

This is not a hypothetical question: the Athena clock widget
draws hands by passing a segment list defining the border
(i.e. P0, P1, P1, P2, P2, P0) to both XDrawSegments() and
XFillPolygon(), specifying shape Convex for the latter.


					/Paul Jensen
					 Digital Equipment Corp.
					 Palo Alto, CA

-- 
					/Paul Jensen
					 Digital Equipment Corp.
					 Palo Alto, CA