[GRASS5] [bug #242] (grass) R_polygon_abs() seems to ignore islands

[Eric G. Miller]

On Wed, May 02, 2001 at 01:23:53PM +0100, Glynn Clements wrote:
> XDRIVER24 uses XFillPolygon's "Complex" mode, which should handle
> self-intersecting polygons. However, there is a choice of two filling
> rules: EvenOdd and WindingRule. From the XChangeGC manpage:

Yes, I played with them, they aren't the problem.

Problem is, there's no protocol for drawing polygons with holes.  That
is, the inner "holes" of the polygon should mask out the drawing of the
outer polygon.  I fooled around with d.area to create something of a
work around, but it isn't a very good implementation.  This capability
needs to exist in the drivers so they can implement it however is best
for their "device".  Built vector areas have the holes identified, so
it's at least partially a matter of passing this data to the driver for
appropriate behavior.

-- 
Eric G. Miller <egm2 at jps.net>

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