On 2011-03-03 12:41-0800 Alan W. Irwin wrote:

> Please test -eofill (and not) for example 27 for both the Apple
> platform and the Microsoft Windows platform and report back results.
> Such tests will show whether there exists any platform that does
> correct filling in either the even-odd or nonzero winding number fill
> rule cases for self-intersecting boundaries.  The results may also
> support the hypothesis that every platform has consistently copied bad
> fill code from a common (X?) source, and that would be an interesting
> result as well.

As of revision 11594 I have sorted out all the Linux fill issues (with
and without -eofill) for example 27 for both python and C.  The
results with -eofill are not only correct but also beautiful.  The
results without -eofill are also correct (symmetrical).

The issue was an incorrect windings number that so complicated the
boundary (with many duplicate boundaries) that correct fills were
being generated that looked incorrect for the -eofill case.  The
incorrect windings also caused a large last boundary segment that
introduced asymmetries into the case without -eofill.  My thanks to M
Joonas Pihlaja of the cairo team who gave me a strong hint that helped
me solve this windings issue.

Now that the issue has been fixed, a nice side benefit is NPTS can be
reduced by a factor of 10 without compromising the smooth-looking
results.

Please propagate these example 27 changes to all other languages.

Also, please try out example 27 with and without -eofill for both Mac
and Windows platforms to make sure fills on non-Linux platforms are
also working correctly for self-intersecting boundaries.  Assuming
that is verified the urgency of figuring out the Master's thesis on
partitioning polygons with self-intersecting boundaries is not nearly
as urgent.  However, at some date in the distant future I think we may
need to implement that logic for the case where we are dealing with
filling a _clipped_ polygon with self-intersecting boundaries.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
__________________________

Linux-powered Science
__________________________

------------------------------------------------------------------------------
What You Don't Know About Data Connectivity CAN Hurt You
This paper provides an overview of data connectivity, details
its effect on application quality, and explores various alternative
solutions. http://p.sf.net/sfu/progress-d2d
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