CC to matplotlib-devel & matplotlib-users 2010/9/3 Tony S Yu <tsy...@gmail.com>: > On Sep 3, 2010, at 4:33 AM, Sébastien Barthélemy wrote: > >> Hello, >> >> While using sage [1], I got problems drawing a line: for some reason, >> the points with negative coordinates are not plotted (or are plotted >> on top of others due to an offset problem and thus I cannot see them). >> I can only reproduce the bug with specific data sets. >> >> [1] www.sagemath.org >> >> I think I could track down the bug to matplotlib, which sage uses to >> render 2d plots. >> >> I included a sage script which generates the data set (in a pickle >> file), and a python script which draws the faulty line. >> >> Usage is : >> >> $ sage generate_data.sage >> $ python test_mpl.py >> >> I also included the pickled data, thus you don't need sage at all. >> I use matplotlib 1.0.0 for python 2.6 on mac os (as provided by macport). >> >> Could somebody here confirm the problem, and give me a hint about what >> is going on? > > I can confirm the issue.
Great, thank you. I filed a bug: https://sourceforge.net/tracker/?func=detail&aid=3058804&group_id=80706&atid=560720 > This appears to be a drawing bug: when I pan the drawing so that the negative > data touches the edge of the axes frame, the rest of the line is drawn. So > the line object is being created, but for some reason it's not being drawn > correctly. > > The bug is really finicky: if I plot starting from the 3rd value of your data > (i.e. slice xdata, ydata with [2:]), the line is drawn completely. The > strange thing is that the first 100 or so data points defines the exact same > point, so there's noting special about those first two points. (but this > overlaying of data may be related to the bug) > > I've reproduced the issue on TkAgg, Qt4Agg, and MacOSX backends, so maybe the > bug is in backend_bases. (Note: unlike Agg backends, MacOSX backend doesn't > show line even after panning the plot) > > I don't really know how to debug drawing errors like this; so this is as far > as can get. ------------------------------------------------------------------------------ This SF.net Dev2Dev email is sponsored by: Show off your parallel programming skills. Enter the Intel(R) Threading Challenge 2010. http://p.sf.net/sfu/intel-thread-sfd _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
