You are right. I assumed that the first selected column in the table is the x axis and the others are different Y axes (and for each one I allocate a PlotDataNode).

It is possible to change the X and Y columns of a PlotDataNode. However, I am not sure how to implement a change of the X-axis for all the PlotDataNodes in a PlotChartNode through the PlotViewController GUI after the plots have been already instantiated.

I think the best is to modify the widget in the table Module giving more options. Something like in which the user can choose which is the X-axis between the selected or if all the selected columns are all Y-axes and the Plot should use simple ordinal numbers as X-axis. Let me know if you like this solution.

I would use the same (or very similar GUI) as in Paraview - see the attached image. You have the option to just use the index or select a column for X array.

PlottingOptionsParaview.png (31,749 bytes)

OK, but where shall I put this: in the PlotViewController GUI? or in the table Module GUI?

The problem is that the current implementation of the button to create the plot from the Table Module GUI assume that the first column is the X-Axis.
So I think the best is to change that behavior and add something similar to Paraview in the GUI of the Table Module, do you agree?

In Tables module GUI you only set table properties, so it's not a good place to specify if a column should act as X axis in a certain plot. What we have in the table module GUI is a convenience function that may assume that the first column is the X axis (or it may use index as X axis and interpret all columns as arrays) but the X axis selection should be later editable in PlotViewController.

I don't understand what makes some columns show up in the series list. How PlotData nodes can be created and edited?

I've noticed that in vtkMRMLPlotChartNode you store both column index and name. Column index should not be used for referring to a column in a table, as it can be changed too easily (e.g., you add or delete a column before). Store the column name only.

ok, I'll modify and store only the name. Sorry, but I didn't understand your previous question

P.S.:
I am preparing another pull request with all the new modifications:
https://github.com/Punzo/Slicer/tree/AdditionalFeaturesForVTKPLotting

I don't understand what makes some columns show up in the series list. How PlotData nodes can be created and edited?
Sorry, but I didn't understand your previous question

If I create a table node and add a column, then the new column does not show up in the plot view controls. How do I make it show up?
I know that I can do it using the plot button in tables module, but how can I edit the resulting PlotData node?

We should have a way of viewing list of all PlotData nodes, create new ones, and editing existing ones - all at one place. It could be in the Plot view controller, but if there is not enough space or the GUI would become too complex then it may be better to create a module GUI where we could view/edit/create/delete all PlotChart and PlotData nodes.

OK, now I got what you mean. The answer is that it is not possible to edit the properties of PlotData from the GUI. The properties of PlotChart instead are all exposed in the GUI of the PlotViewController. Each PlotData will need some GUI, definitively it cannot be inserted in the ViewController, both for reason of complexity and space. We may think to add a PlotViewController more extended in the module ViewControllers

So at the moment, if you want to show a column added after the first plot, you need to select the new column (+ the x-Axis column) and push again the button plot in the Table Module GUI

sorry neither the PlotChart proprieties are all exposed in the GUI: here is the full list of them

/// \li "Type" - "Line", "Line and Scatter", "Scatter", "Bar"
/// \li "TitleName" - title ploted on the PlotChart
/// \li "ShowTitle" - show title "on" or "off"
/// \li "XAxisLabelName" - label ploted on the x-axis
/// \li "ShowXAxisLabel" - show x-axis label "on" or "off"
/// \li "ClickAndDragAlongX" - set the action along x-axis "on" or "off"
/// \li "ClickAndDragAlongY" - set the action along y-axis "on" or "off"
/// \li "YAxisLabelName" - label ploted on the y-axis
/// \li "ShowYAxisLabel" - show y-axis label "on" or "off"
/// \li "ShowGrid" - show grid "on" or "off"
/// \li "ShowLegend" - show legend "on" or "off"
/// \li "FontType" - global Font for the PlotChart: "Arial", "Times", "Courier"
/// \li "TitleFontSize" - default: "20"
/// \li "AxisTitleFontSize" - default: "16"
/// \li "AxisLabelFontSize" - default: "12"
/// \li "LookupTable" colorNodeID default: NULL

as you can see the Font Size, Font Type, the ClickAndDrag and the LookupTable (for the colors) options are not accessible from the GUI of the current PlotViewController.

done in https://github.com/Slicer/Slicer/pull/795

i.e.:
Change x-Axis, store only Name and not indexes in PlotDataNodes

NEXT TO DO:

1) Adding in the Table Module some GUI to cast the Column Type (current default is string, not working with Plots);

2) Adding a more extended GUI of the PlotViewController in the Module ViewControllers.

Andras, will you take care of the first point or do you want I do it?
For the second point, sorry but now I don't have the time.

fixed in https://github.com/Slicer/Slicer/commit/57e0ad748af7f97592bbb2c34da0a050ba07c179
https://github.com/Slicer/Slicer/commit/6a57e1861dd8c4c17e8c065e28f417d684f7ecc1