Re: [wxVTK] screen coordinates to world coordinates

[Nigel N. <nN...@au...>]

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 dep=
th)
  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 wx=
Window "pick" position to vtk "world" or "viewport"?  Or are you trying to g=
o 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 coord=
inates?

A test for most possible conversions can be found here:

  /VTK/Rendering/Testing/Cxx/otherCoordinate.cxx


Nigel


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