[Libreoffice] Incompatible changes for B-spline smoothing in ODF1.2
rb.henschel at t-online.de
Mon Apr 25 09:30:31 PDT 2011
Currently smoothing with B-Splines uses the inner data points as control
points. Therefore the smoothed line does not go through the data points
and it is no interpolation.
In ODF 1.2 the definition of smoothing with B-Splines does it in a way,
that you get a real interpolation, that means, the smoothed line goes
through all data points.
The current behavior is so inscrutable, that I endorse the definition in
The current way exist at least since StarOffice 5.1. But I do not know,
whether anyone really uses it, because it is not suitable for
interpolation. On the other hand, there might be users, who know to use
control points and have calculated them in a way to get a special,
It is possible to add another method in class SplineCalculater. That it
not the problem. But I see no way, to directly store a distinction
between the two ways in file format. So a chart in an actual version
using the new kind of smoothing looks different in an older version and
existing documents will change their appearance when opened in a new
So, how to handle the change? I like to hear your opinions and ideas.
I have put libreoffice at lists.freedesktop.org in CC, because I think it
is important for them too and they might not read this mailing list.
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