[vtkusers] Rendering and saving unstructured grid mesh to image file

[Amine Aboufirass]

Dear all,

I have an unstructured grid cell data file which I would like to render and
then save to a png image. I made use of available examples to generate a
python code which I have attached below. The file I am using this with is
also attached. The rendering seems to work but I am not sure why it cannot
send the render window content to an image. It keeps giving me the
following error:

 �!: libpng warning: Image width is zero in IHDR
 �!: libpng warning: Image height is zero in IHDR

I'm not sure what is causing this, I followed the documentation to the best
of my ability but still can't figure it out. Could anyone please help?
Thanks

Amine
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from vtk import *

# The source file
file_name = 'MeshData.vtk'#"MeshData.vtk"

# Read the source file.
reader = vtkUnstructuredGridReader()
reader.SetFileName(file_name)
reader.Update()  # Needed because of GetScalarRange
output = reader.GetOutput()
#scalar_range = output.GetScalarRange()

# Create the mapper that corresponds the objects of the vtk file
# into graphics elements
mapper = vtkDataSetMapper()
mapper.SetInputData(output)
#mapper.SetScalarRange(scalar_range)

# Create the Actor
actor = vtkActor()
actor.GetProperty().SetRepresentationToWireframe()
actor.SetMapper(mapper)

# Create the Renderer
renderer = vtkRenderer()
renderer.AddActor(actor)
renderer.SetBackground(1, 1, 1)  # Set background to white

# Create the RendererWindow
renderer_window = vtkRenderWindow()
renderer_window.AddRenderer(renderer)

#Image https://www.vtk.org/Wiki/VTK/Examples/Python/Screenshot
w2if = vtk.vtkWindowToImageFilter()
w2if.SetInput(renderer_window)
w2if.Update()
writer = vtk.vtkPNGWriter()
writer.SetFileName("screenshot.png")
writer.SetInputData(w2if.GetOutput())
writer.Write()


# Create the RendererWindowInteractor and display the vtk_file
#interactor = vtkRenderWindowInteractor()
#interactor.SetRenderWindow(renderer_window)
#interactor.Initialize()
#interactor.Start()
#



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