[vtkusers] How to select a VtkPlot object in a vtkChart?

[Marcus D. Hanwell]

On Mon, Dec 22, 2014 at 1:05 PM, Marcus D. Hanwell
<marcus.hanwell at kitware.com> wrote:
> Hi Maarten,
>
> On Mon, Dec 22, 2014 at 12:49 PM, Maarten Beek via vtkusers
> <vtkusers at vtk.org> wrote:
>> Hi all,
>>
>> I would like to know how I would select a vtkPlot (better: vtkPlotLine)
>> object in a vtkChart (better: vtkChartXY)?
>>
>> I get the impression that only points can be selected in a vtkContextScene.
>> However, I have two vertical lines each with two (bottom and top) points, to
>> indicate a (threshold) range, and that I would like to move left and right
>> with my mouse.
>> Would this be possible (or should I go back to something like QCustomPlot)?
>>
> I worked on a somewhat similar type of chart in the tomviz project,
> see vtkChartHistogram in the CentralWidget.cxx file (that needs to be
> split out/refactored, but should illustrate). It has a vertical line
> marking the selected isosurface value the user clicked on
> (vtkHistogramMarker).
>
> I think we should make this simpler, when you add a plot you get its
> index, you can create a vtkPlotLine, add it to the chart, maintain a
> pointer to it, and update that object in your own code too.
>
Not enough coffee today...the link to the file I mentioned,

https://github.com/OpenChemistry/tomviz/blob/master/CentralWidget.cxx

Marcus