[vtk-developers] Comments on vtkBalloonWidget

[John Platt]

Hi All,

 

I have recently used this widget to display info about different curves
on an XY plot. Here are some of the issues I encountered.

 

1. The virtual overrides void StartWidgetInteraction(double e[2]) and
void EndWidgetInteraction(double e[2]) in vtkBalloonRepresentation are
not called because the argument specifications are slightly different (
double* ) v ( double* const ). I have reported this as bug for
vtkBorderRepresentation under VC6.

 

2. If you move the actors using the keyboard the balloon is shown
pointing to an actor which is now in a different position. In my
particular case 'r' redraws the graphs to the original scale after
zooming. Therefore mapping key press 'r' to vtkHoverWidget::MoveAction
should solve the problem. Of course, it would be very nice if the
interactor could 'tell' the widget that props have moved.

 

3. Actors are still picked when the mouse is servicing another widget.
The particular case here is a vtkBorderWidget used to move a legend
actor. When the mouse is hovering over the border widget, which in turn
is placed over the curves, the cursor shape is changed to match the
border widget but the balloon also appears. I don't know what the
intended behaviour is.

 

John.

 

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