New feature in Calc: Stepped Lines graphs

[Regina Henschel]

Hi Eric,

Eric Seynaeve schrieb:
> Hello everyone,
>
> in order to scratch my own itch, I started working on a stepped lines
> feature for XY graphs (and Line graphs) in Calc. See bugzilla 61135
> <https://bugs.freedesktop.org/show_bug.cgi?id=61135>. This is my first
> coding in LO :-)

you are welcome.

>
> Next steps would be to expose this functionality in the UI and check
> that it would be saved and read in the file format.
>
> However, before spending more time, I would like to know about the
> following:
>
> - can we just add a new type of graph ? Don't we have to follow the ODF
> 1.2 specification ?

The specification is not written in a way, that some people image cool 
new features, but they look, what existing programs do. And those things 
which are common are standardized. Therefore LO has "ODF1.2 extended" 
and Gnumeric "with foreign elements".

In Gnumeric I see an interpolation with stepped lines. Is it that, what 
you want to get? If yes, then I would not implement them as new chart 
type in LO, but use the same way as in Gnumeric and make it a new kind 
of interpolation.

There exists already a request for ODF1.3 to specify such interpolation. 
If LO will implement them too, it will become more likely, that they 
will be specified in ODF1.3.

>
> - if I add this, what about compatibility with older LO/OOo versions and
> other spreadsheets using ODF (Gnumeric, KOffice, ...) ?
>
> - how to handle UI changes ? Can I create a patch/proposal independently ?

Applications, which support ODF but do not know special elements or 
attributes, ignore such elements or attributes. If you will make the 
stepped lines an interpolation in an XY-chart, those applications would 
only show the points of the chart but not the interpolating lines.

Kind regards
Regina