Re: [wxVTK] screen coordinates to world coordinates

[Andres M. <mun...@gm...>]

Hi Nigel,

Thank you so very much for your help.

Regards,
Andres

On 09/08/2006, at 5:19PM, Nigel Nunn wrote:

> Hi Andres,
> Thanks for the details.  I'll try setting up such a pipeline
> myself this weekend, then let you know what I find!
> Nigel
>
> -----Original Message-----
> From: Andres Munarriz [mun...@gm...]
> Sent: Thursday, 10 August 2006 8:02 AM
> To: Nigel Nunn
> Subject: Re: [wxVTK] screen coordinates to world coordinates
>
>
> Hi Nigel,
>
> Thank you for your reply.  I've loaded a single 2d DICOM image to a
> vtkImageViewer2.  I wish to allow a user to double click a point on
> this image (slice) and draw a "marker" in this case a sphere on the
> point the user double clicked.  Later down the pipeline I will be
> using this point as a seed for a connectivity filter.
>
> I've created my own wxVTKInteractor derived class (ie.
> MyVTKRenderWindowInteractor) where I've defined my own EVT_LEFT_DCLICK
> handler (ie. void
> MyVTKRenderWindowInteractor::OnButtonDouble(wxMouseEvent& p_Event) ).
>
> I can obtain two sets of "display" coordinates (wx coordinates); one
> by calling the p_Event.m_x, p_Event.m_y property or by calling the
> wxVTKInteractor GetEventPosition method.
>
> I'll pass whichever coordinate set to a vtkWorldPointPicker through
> the Pick method
> (ie.
>  vtk_pointPicker->Pick(double(eventPosition[0]), double
> (eventPosition[1]), 0.0, vtk_windowRenderer);
> )
>
> however when I retrieve the picked coordinates using the
> vtk_pointPicker->GetPickPosition(pointCoordSet); call the coordinates
> returned are not the coordinates I expect.  The x values are OK but
> the Y coord is wrong.
>
> Could you please help me?
>
>
> Regards,
> Andres
>
>
> On 8/9/06, Nigel Nunn <nN...@au...> wrote:
> >
> >
> > Andres Munarriz <mun...@gm...> wrote:
> >
> > > > Has someone come across the need of converting screen "display"
> > > > corrdinates (ie. wxEvent ._x, ._y) to VTK world coordinates?
> > > > I've read about a get event method in the  
> VTKRenderWindowInteractor
> > > > but wxVTKRenderWindowInteractor doesn't seem to support this  
> method.
> > > > If someone can help it'll be greatly appreciated.
> >
> > ...
> >
> >
> > > I'm using the interactor->GetLastEventPosition(&event_x,  
> &event_y);
> > > method. event_x and event_y are both integers.
> > >
> > > Am I using the wrong method?
> >
> >
> > Hi Andres,
> >
> > From file <vtkCoordinate.h>:
> >
> > The coordinate systems in vtk are as follows:
> >
> >   DISPLAY -             x-y pixel values in window
> >   NORMALIZED DISPLAY -  x-y (0,1) normalized values
> >   VIEWPORT -            x-y pixel values in viewport
> >   NORMALIZED VIEWPORT - x-y (0,1) normalized value in viewport
> >   VIEW -                x-y-z (-1,1) values in camera  
> coordinates. (z is depth)
> >   WORLD -               x-y-z global coordinate values
> >   USERDEFINED -         x-y-z in User defined space
> >
> >
> > First question is what would you like to do?  Are you trying to  
> convert a
> > wxWindow "pick" position to vtk "world" or "viewport"?  Or are  
> you trying to
> > go the other way, i.e. from Vtk to Wx?  Can you describe when and  
> how you
> > get the source coordinates, and what you would like to do with  
> the target
> > coordinates?
> >
> > A test for most possible conversions can be found here:
> >
> >   /VTK/Rendering/Testing/Cxx/otherCoordinate.cxx
> >
> >
> > Nigel
> --
>
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