I don't know if this simplifies things (you're much deeper in the middle of doing what you need to do), but PolyCollection really is a path collection these days. (The name is really for historical reasons). And since paths can be compound, you could draw a hollow circle using an inner and an outer circle. See Path.unit_circle for a direct way to get a series of bezier curves to approximate a circle.
Of course, if you've found a simpler way in the mean time, go for it! Cheers, Mike Eric Firing wrote: > Ryan May wrote: > >> Hi, >> >> In trying to add a symbol for an empty wind barb, I ran into problem. >> Traditionally, a smaller, non-filled circle is used for low wind speeds >> when doing a barb plot. I can draw the circle easily as a polygon, >> using CirclePolygon from patches, but unfortunately, the fill color for >> this polygon ends up being the same as the color of the flags on the >> barbs. Therefore, as currently implemented, the only way to have >> unfilled circles is to have unfilled flags. >> >> The only technical solution I can think of here is to have separate >> collections for the circles and the polygons. Unfortunately, I have no >> idea how to begin to do that within a class that inherits from >> collections. Another option would be to somehow manually set the fill >> colors on the circles after the collection is initialized. Anyone have >> suggestions on how to make this work, or maybe a better technical solution. >> > > Ryan, > > Yes, this would require some bigger changes. Instead of inheriting from > PolyCollection, it would have to contain two collections, or a > collection and a Line2D with markers. > > An alternative would be to override the PolyCollection.draw() method > with a near-copy, but with logic added right before the renderer call to > set the alpha (column 3) of the rgba array to zero for the circles. > > A better way might be to modify the original draw method to use > self.get_facecolors() instead of self._facecolors; then one could > override the get_facecolors method, which would require much less code. > > Eric > > >> Jeff, how aesthetically displeasing do you think it would be to have >> small (possibly colored) circles to represent the low winds instead of >> the traditional (somewhat larger) hollow circle? It would make it >> impossible to do sky cover in a traditional surface map, but maybe >> Z-ordering could be used to hack around it. >> >> Thoughts, >> >> Ryan >> >> > > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > Build the coolest Linux based applications with Moblin SDK & win great prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Matplotlib-devel mailing list > Matplotlib-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-devel > ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
