Hi,
I have written some code to implement error bars in libgoffice, but I
would like to discuss some options before going further.
First of all, error bars concern several plot types, so I suppose the
best place to implement them is in GogSeries. I think we can have a
field in GogSeriesDesc which can take one of the following values:
GOG_ERROR_BARS_NONE,
GOG_ERROR_BARS_VERT,
GOG_ERROR_BARS_HORIZ,
GOG_ERROR_BARS_BOTH
and in GogSeries pointers to the appropriate number of GogErrorBar
structures (or should every thing be directly in GogSeries?).
Concerning the options for error bars, I studied what Excel and OpenCalc
do. They behave quite differently and I do not understand all options
(in Excel, I could not understand what "standard error" is and how to
calculate the length of the bars). At first, I'll implement constant
absolute and relative (%) errors which do not need statistical
functions. Comments?
Some plots need two styles, one for positive values and the other for
negative ones (bubble plots and some financial plots). I do not know how
to implement that since GogStyledObject contains only one style.
Regards,
Jean
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