On 13/11/2011 23:20, Christoph Schröder wrote:
> we are two computer science students currently enrolled in a lecture
> about "software processes" and selected this project to get first
> experiences in participating in open source projects. We selected the
> Issue (ID: *3425881*)"*XYDifferenceRenderer does not handle two
> identical x-values"* from the bug-tracker as our first attempt to fix
> a bug in an OSS project.
> The user did report that the XYDifferenceRenderer produces incorrect
> graphic displays of the space between the two xy-graphs. As far as we
> could see, this space should be displayed as one single-coloured
> plane, but some special input values (identical x-values) cause that
> the plane only covers a triangular part of the respective space.
> We already checked the Pictures and Code the user attached to his bug
> report and where able to reconstruct the reported Bug. We also got
> ourselves a basic understanding about the structure of the project and
> where the bug could be located. The bug seems to be located in the
> drawItemPass0 method, but it still needs a deeper analysis.
> We hope to be able to make a valuable contribution to the
> "JFreeChart"-Community, even though our experience whith participating
> in open source projects is limited. Please notify us if this bug is
> already on the way to be fixed by other developers. If not, we would
> like to try solving this problem. We would also be glad about any
> help/suggestions we could get from the community.
> Best regards,
> Patrick Schlott & Christoph Schroeder
Thanks for your interest in the JFreeChart project. To my knowledge,
nobody is working on this issue right now so your assistance is
welcome. It's not completely clear to me what the "correct" behaviour
should be for this renderer when there are multiple y-values for the
same x-value...the ordering of the x-values is important, for sure. I
suppose at least the Javadocs for the renderer should note the
limitations. But if you can come up with a sensible way to handle the
data in general, then even better.
Please feel free to post comments on the bug entry at SourceForge and
also to post your progress or questions here on the developers list.