Chart with 14 lines and 3 scales
lazarus / 39-Graphics

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Nera · 2020-02-18 16:31

Good afternoon people.

I need to make a chart with 14 lines and 3 scales. Which component do
you indicate for this function?
I would like it to be a native component, but if not, indicate an
opensource component.

Thanks

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Handoko · 2020-02-18 16:41

Have you tried TAChart?

https://wiki.lazarus.freepascal.org/TAChart

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wp · 2020-02-18 17:17

If you never worked with TAChart before you should look at the Getting
started tutorial:
https://wiki.lazarus.freepascal.org/TAChart_Tutorial:_Getting_started
"14 lines": A "series" in TAChart is a presentation of a variety of
(x,y) pairs. A TLineSeries connects the data points by straight line
segments. So you need to add 14 series to the chart. But there are
also cubic spline and b-splite series which can draw smooth curves
between the data points.

Alternatively, if data points on all series share the same x values,
you can use a single series and adjust it such that it allows for 14 y
values for each x value.

"3 scales": You can add two more y axes so that there are 3 y axes, in
total. You also need so-called chart transformations which are
responsible to accomplish the mapping of the 3 y data scales onto a
common graph scale. The procedure how to set this up is explained in
two tutorials:
https://wiki.lazarus.freepascal.org/TAChart_Tutorial:_Dual_y_axis,_Leg
endhttps://wiki.lazarus.freepascal.org/TAChart_Tutorial:_Multiple_Pane
s_in_one_Chart