[vtkusers] Zoom Question

[Paulo Henrique Junqueira Amorim]

Thank you David!

Regards,
Paulo Amorim




2008/11/13 David Gobbi <david.gobbi at gmail.com>

> Hi Paulo,
>
> The documentation for SetZSlice() is pretty bad.  When it says "not
> the same as on the hard drive" what it really means is this:
>
> - The "Z" direction in VTK does not always correspond to the Slice
> direction in the original files
> - Even when the VTK Z direction and the slice direction are the same,
> when you read an image into VTK, it resets the Z indexing so that it
> starts at zero.  So if you read slices 3-12 from disk, you end up with
> Z indexes 0-9 in VTK.
>
> I'm not sure which one of the items above is causing the SetZSlice()
> method to do something unexpected for you.  Usually I use
> vtkImageReslice to extract the slice that I want, as in the
> Examples/ImageProcessing/Cxx/ImageSlicing.cxx, by calling
> reslice->SetOutputDimensionality(2) to make reslice extract just a
> single slice, and by using reslice->SetResliceAxes() to choose the
> slice position and orientation.
>
> The trick with ImageReslice is that it expects you to select slice
> positions using physical data coordinates (i.e. millimetre positions)
> instead of using (I,J,K) pixel indices.
>
>  David
>
>
>
> On Thu, Nov 13, 2008 at 4:50 AM, Paulo Henrique Junqueira Amorim
> <paulojamorim at gmail.com> wrote:
> > Hi,
> >
> > How can I change the slice in vtkImageActor ?
> >
> > I am trying to use the image_actor.SetZSlice (10), but does not change
> the
> > piece, it seems that the manual says it is not on the slices that are in
> HD.
> >
> >
> > Regards,
> > Paulo Amorim
> >
> >
> >
> > 2008/11/11 David Gobbi <david.gobbi at gmail.com>
> >>
> >> Hi Paulo,
> >>
> >> It is impossible to zoom a 2D actor.  Instead, you have to magnify the
> >> image before it goes to the vtkImageMapper.  To zoom by an integer
> >> factor, you can use something like vtkImageMagnify to enlarge the
> >> image and then vtkImageClip to crop the image to the desired size.
> >>
> >> You might find it easier to use vtkImageActor, though, since
> >> vtkImageActor is a 3D actor and you can just zoom the camera.
> >>
> >>    David
> >>
> >>
> >> On Tue, Nov 11, 2008 at 1:28 PM, Paulo Henrique Junqueira Amorim
> >> <paulojamorim at gmail.com> wrote:
> >> > Hi,
> >> >
> >> > How do I zoom into a vtkActor2D with vtkImageMapper?
> >> >
> >> > The vtkCamera only works with 3D.
> >> >
> >> >
> >> > Regards,
> >> > Paulo Amorim
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> >
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