Charlie Moad wrote: > I did some more digging and it looks like this changed with the > transforms. curve4 is now being called instead of arc_to, which uses > beziers.
curve4 is the way to specify a cubic bezier curve, so it is functionally equivalent to the old arc_to approach (but easier to be consistent across backends, which is why the change was made). I'm attempting to implement the 8-spline approximation and I'll let you know how that goes. In any case, I think we should add James' example to our unit tests, since it illustrates a case where my assumptions about how ellipses would be used breaks down. Cheers, Mike > On Dec 9, 2007 10:11 AM, Charlie Moad <[EMAIL PROTECTED]> wrote: >> I found a great doc I am linking. The 4 spline method we are using >> has an error tolerance of 2.7*10^-4, which I am pretty sure is coming >> into play here. If we move to an 8 spline approach, it would reduce >> the error a few orders of magnitude. >> >> http://www.tinaja.com/glib/ellipse4.pdf >> >> - Charlie >> >> >> >> On Dec 8, 2007 9:09 AM, John Hunter <[EMAIL PROTECTED]> wrote: >>> On Dec 7, 2007 6:02 PM, James Evans <[EMAIL PROTECTED]> wrote: >>> >>>> There appears to be an issue with the agg backend with how it is drawing >>>> ellipses (or maybe it is how matplotlib uses agg), but the attached script >>>> shows how a point, which should be coincident with the center circle, but >>>> it >>>> is not. The second plot shows the same data, but using a custom (and much >>>> slower) algorithm for drawing the ellipses, where the point is properly >>>> coincident. >>> Thanks for the test case James -- I will try and sort this out ASAP. >>> Michael, do you see the same on the transforms branch? The branch is >>> on a newer version of agg so if not, perhaps it is a simple matter of >>> upgrading agg on the trunk. I'm travelling currently bt will be back >>> omorrow and ill look at this ASAP. >>> >>> JDH >>> >>> ------------------------------------------------------------------------- >>> SF.Net email is sponsored by: >>> Check out the new SourceForge.net Marketplace. >>> It's the best place to buy or sell services for >>> just about anything Open Source. >>> http://sourceforge.net/services/buy/index.php >>> _______________________________________________ >>> Matplotlib-devel mailing list >>> Matplotlib-devel@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/matplotlib-devel >>> > > ------------------------------------------------------------------------- > SF.Net email is sponsored by: > Check out the new SourceForge.net Marketplace. > It's the best place to buy or sell services for > just about anything Open Source. > http://sourceforge.net/services/buy/index.php > _______________________________________________ > Matplotlib-devel mailing list > Matplotlib-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-devel -- Michael Droettboom Science Software Branch Operations and Engineering Division Space Telescope Science Institute Operated by AURA for NASA ------------------------------------------------------------------------- SF.Net email is sponsored by: Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
