#1055 XYDifferenceRenderer does not handle two identical x-values


A dataset of two series with values like [[0, 1], [1, 2], [1, 3], [2, 4]] and [[0, -1], [1, -2], [1, -3], [2, -4]] will cause a weird rendering of the difference between the two series. This is caused by the the two tuple pairs ([1, 2], [1, 3]) and ([1, -2], [1, -3]).

This could be a situation where someone could withdraw a sum of money from a saving account on one day. This would show as a step-effect. Simply removing the lowest value would give a different image and would not display the jump.

To work around the error I had to check for similar x-values in the input and add a small delta. The code attached in the zip file will show how to reproduce and work around this.

Three pics included.
Bug: http://img32.imageshack.us/img32/659/xydifferencerendererbug.png
Introduce delta works around bug: http://img171.imageshack.us/img171/258/xydifferencerendererint.png
Remove value: http://img710.imageshack.us/img710/8521/xydifferencerendererrem.png


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    Anonymous - 2011-10-19

    Source code to display the bug

  • Martin Höller

    Martin Höller - 2012-02-13
    • assigned_to: nobody --> matinh
    • status: open --> closed-fixed
  • Martin Höller

    Martin Höller - 2012-02-13

    The bug has been fixed in the upcoming 1.0.15 release.


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