[vtkusers] How to make vtkChartXY non-interactive?

Elvis Stansvik elvis.stansvik at orexplore.com
Wed Jun 14 03:08:12 EDT 2017

2017-06-14 8:37 GMT+02:00 Elvis Stansvik <elvis.stansvik at orexplore.com>:

> Den 13 juni 2017 5:53 em skrev "Marcus D. Hanwell" <
> marcus.hanwell at kitware.com>:
> >
> > On Tue, Jun 13, 2017 at 9:16 AM, Elvis Stansvik <
> elvis.stansvik at orexplore.com> wrote:
> >>
> >> 2017-06-13 15:10 GMT+02:00 Elvis Stansvik <elvis.stansvik at orexplore.com
> >:
> >>>
> >>> I'm using a
> >>>
> >>>    vtkChartXY
> >>>    vtkColorTransferControlPointsItem
> >>>    vtkColorTransferFunctionItem
> >>>
> >>> trio for editing a vtkColorTransferFunction.
> >>>
> >>> I'm now trying to make it non-editable (I want this for system
> "built-in" color functions). I've tried calling SetInteractive(false) on
> all three of them. I even tried hiding the control points item, but still I
> can interact with the points using the mouse.
> >>>
> >>> How can I make it non-interactive?
> >>>
> >>> I'm using VTK 8.0.0.rc1.
> >>
> >>
> >> I know I could always override and swallow mouse events, but that seems
> like the wrong approach?
> >>
> >> I'm only interested in disabling interaction with the control points
> item. Even hiding it as well would be OK.
> >>
> > So I would use the SetActionToButton method in vtkChart, and set each
> action to -1 (no button).
> Ah thanks, I'll take a look at that.
> > Looking at the vtkControlPointsItem the press event is not configurable,
> and so you would really have to derive from it, and override it that way as
> far as I can see. It could be modified, but that ability doesn't appear to
> be present. I am trying to remember how we propagate mouse events from the
> containing chart, but am a little rusty on that logic.
> >
> > We don't have the equivalent of an event filter as far as I am aware,
> but in the Qt world I would use that to intercept events before they get to
> the chart.
> Alright, thanks a lot for the info.
> What surprised me most was that neither SetInteractive(false) on the
> control points item, nor hiding it with SetVisible(false) would prevent
> interaction with the points. Should either of those be considered bugs?
> The heavy-handed approach I came up with yesterday was to simply remove
> the  control points item from the chart temporarily when I want to disable
> interaction. This was OK for me since having the points also disappear was
> actually my ultimate goal. Just thought SetVisible(false) would be enough.
Sorry, it's a little early. This was not the approach I ended up with (I
tried that though, but had problems adding the control points item back).
What I did do was to simply disable (in the Qt sense) the entire
QVTKOpenGLWidget that holds the chart (in addition to hiding the control
points items with SetVisible(false)). This works, but is less than optimal
of course, since now it's impossible to interact with the widget in any
way. This is OK for now, but I may need to reconsider, since I might want
to e.g. support zoom/panning in the chart (and only disallow interaction
with the control points item).


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