[vtk-developers] Problem when creating vtkImageData by hand

[Prabhu Ramachandran]

Hi,

Sorry for the barrage of emails this week.  I just ran into a peculiar
problem with VTK from CVS.  If I use the vtkImagePlaneWidget along
with image data read from a file, everything seems to work.  However,
when I create a vtkImageData object by hand and use that as input, I
get wierd problems.  Stranger still, this works fine with VTK-4.4.

I've attached a slightly modified version of
Examples/GUI/Python/ImagePlaneWidget.py that demonstrates this
problem.

When run without modifications everything runs fine.  I recreate the
same image data like so:

    img_data = v16.GetOutput()
    # Now lets create this data without the reader.
    my_img_data = vtk.vtkImageData()
    my_img_data.SetDimensions(img_data.GetDimensions())
    my_img_data.SetSpacing(img_data.GetSpacing())
    my_img_data.SetOrigin(img_data.GetOrigin())
    my_img_data.SetScalarType(img_data.GetScalarType())
    my_img_data.GetPointData().SetScalars(img_data.GetPointData().GetScalars())
    my_img_data.Update()

I then use 'my_img_data' instead of img_data as the input to the image
plane widgets.  The example breaks and I get black planes which can't
be moved.  The outline disappears (or maybe reduces to a point).
Something seems very wrong.  If I don't use the vtkImagePlaneWidgets
and only use the outline then it is visible and looks OK.

The same exact code works with VTK-4.4.  I wonder if I am doing
something wrong or is there a bug somewhere?

Any clarifications would be appreciated.

cheers,
prabhu

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