[vtkusers] Transparent vtkRenderer with Qt

[Francois Bertel]

I don't think you can do that with Qt. The OpenGL area is not on top
of the Qt window, it is owning this part of the window. I don't think
you can blend an OpenGL area.

Maybe somebody else can help. It is becoming more a Qt/OpenGL question
than a vtk question.


PS: please keep the discussion on the mailing list.


On Wed, Apr 28, 2010 at 10:21 AM, Guillaume DARDENNE
<guillaume.dardenne at telecom-bretagne.eu> wrote:
>
> Thank you very much for your answer.
>
>
>
> I integrated your code :
>
> renWin->SetAlphaBitPlanes(1);
>
>
>
> but the background is still black. Do you have any ideas ?
>
>
>
>
>
> Thank you.
>
>
>
> Guillaume
>
>
>
> -----Message d'origine-----
> De : vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] De la part de Francois Bertel
> Envoyé : mercredi 28 avril 2010 15:43
> À : vtkusers at vtk.org
> Objet : Re: [vtkusers] Transparent vtkRenderer with Qt
>
>
>
> Hello Guillaume,
>
>
>
> First you need a renderwindow with some alpha (this is false by default):
>
>
>
> vtkRenderWindow *renWin = vtkRenderWindow::New();
>
> renWin->SetAlphaBitPlanes(1);
>
>
>
> There is no API to set a specific opacity on the background color,
>
> however, the hardcoded alpha value is 0 (this actual code is in
>
> VTK/Rendering/vtkOpenGLRenderer::Clear() ), if your use case is to
>
> have a fully transparent background.
>
>
>
> Still in the case of a fully transparent background, the other way to
>
> set it, is to assign the layer of the renderer to be a value greater
>
> than 1. By default it is 0, a value greater than 1 will set the
>
> renderer on an overlay. (see vtkRenderer::SetLayer() )
>
>
>
>
>
>
>
> On Wed, Apr 28, 2010 at 8:21 AM, Guillaume DARDENNE
>
> <guillaume.dardenne at telecom-bretagne.eu> wrote:
>
> > Dear Vtk users,
>
> >
>
> >
>
> >
>
> > I insert a vtk widget in a Qt widget with the QVtkWidget class.
>
> >
>
> > I would like to make the vtkWidget transparent.
>
> >
>
> > I know that it’s possible to set the backward color with the
>
> > setRendererBackground(double, double, double) function but is it possible to
>
> > set also the opacity of this renderer window ?
>
> >
>
> >
>
> >
>
> > Thank you very much for your answers.
>
> >
>
> >
>
> >
>
> > Guillaume
>
> >
>
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>
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> >
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>
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>
>
>
>
> --
>
> François Bertel, PhD  | Kitware Inc. Suite 204
>
> 1 (518) 371 3971 x113 | 28 Corporate Drive
>
>                       | Clifton Park NY 12065, USA
>
> _______________________________________________
>
> Powered by www.kitware.com
>
>
>
> Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html
>
>
>
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>
>
>
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--
François Bertel, PhD  | Kitware Inc. Suite 204
1 (518) 371 3971 x113 | 28 Corporate Drive
                     | Clifton Park NY 12065, USA