[vtkusers] Inconvenient color balance with vtkInteractorStyleRubberBandZoom

[Denis Shamonin]

Hi Amy,

Here is example of inconvenient color balance with "Rubber Band" in case 
setting background to (0.5, 0.5, 0.5)
Also сlose values to this RBG value will do the same.

I think OnMouseMove() should be a little different.
Probably a feature, I do not know... :-\
Anyway here is it :
==============================================================
vtkInteractorStyleRubberBandZoom *style = 
vtkInteractorStyleRubberBandZoom::New();

vtkConeSource *cone = vtkConeSource::New();
cone->SetHeight( 3.0 );
cone->SetRadius( 1.0 );
cone->SetResolution( 10 );

vtkPolyDataMapper *coneMapper = vtkPolyDataMapper::New();
coneMapper->SetInput( cone->GetOutput() );

vtkActor *coneActor = vtkActor::New();
coneActor->SetMapper( coneMapper );

ren->AddActor( coneActor );
ren->SetBackground( 0.5, 0.5, 0.5 );

vtkRenderWindow *renWin = vtkRenderWindow::New();
renWin->AddRenderer( ren );
renWin->SetSize( 300, 300 );

vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
iren->SetRenderWindow(renWin);

iren->SetInteractorStyle(style);
==============================================================
-- 
Denis Shamonin
Section Computational Science
University of Amsterdam
Kruislaan 403, 1098 SJ Amsterdam
the Netherlands
http://carol.wins.uva.nl/~dshamoni/