hpux man page for xsetfillrule

XSetFillRule()															    XSetFillRule()

Name
  XSetFillRule - set the fill rule in a graphics context.

Synopsis
  XSetFillRule(display, gc, fill_rule)
	Display *display;
	GC gc;
	int fill_rule;

Arguments
  display   Specifies a connection to an X server; returned from XOpenDisplay().

  gc	    Specifies the graphics context.

  fill_rule Specifies the fill rule you want to set for the specified graphics context.  Possible values are EvenOddRule or WindingRule.

Description
  XSetFillRule()  sets	the  fill_rule	component of a GC.  The fill_rule member of the GC determines what pixels are drawn in XFillPolygon()
  requests.  Simply put, WindingRule fills overlapping areas of the polygon, while EvenOddRule does not fill areas that overlap an odd number
  of  times.  Technically, EvenOddRule means that the point is drawn if an arbitrary ray drawn from the point would cross the path determined
  by the request an odd number of times.  WindingRule indicates that a point is drawn if a point crosses an unequal number of  clockwise  and
  counterclockwise path segments, as seen from the point.

  A  clockwise-directed  path segment is one which crosses the ray from left to right as observed from the point.  A counterclockwise segment
  is one which crosses the ray from right to left as observed from the point.  The case where a directed line segment is coincident with  the
  ray is uninteresting because you can simply choose a different ray that is not coincident with a segment.

  All  calculations  are  performed on infinitely small points, so that if any point within a pixel is considered inside, the entire pixel is
  drawn. Pixels with centers exactly on boundaries are considered inside only if the filled area is to the right, except that  on  horizontal
  boundaries, the pixel is considered inside only if the filled area is below the pixel.

  See Volume One, Chapter 5, The Graphics Context, for more information.

Errors
  BadAlloc
  BadGC
  BadValue

See Also
  XDefaultGC(),  XChangeGC(), XCopyGC(), XCreateGC(), XFreeGC(), XGContextFromGC(), XSetArcMode(), XSetBackground(), XSetClipMask(), XSetCli-
  pOrigin(), XSetClipRectangles(), XSetDashes(),  XSetFillStyle(),  XSetForeground(),  XSetFunction(),	XSetGraphicsExposures(),  XSetLineAt-
  tributes(), XSetPlaneMask(), XSetState(), XSetStipple(), XSetSubwindowMode(), XSetTSOrigin().

Xlib - Graphics Context 													    XSetFillRule()