How to create a mask from some ordered points?

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1

I want to create a binary mask from some ordered points.

For example, for the points:

ps = [
    [64, 64, 0],
    [128, 64, 0],
    [128, 128, 0],
    [64, 128, 0],
]

I hope it can create a binary mask which is agree with:

import numpy as np
img = np.zeros(shape=[256, 256])
img[64:128, 64:128] = 1

I find vtkPolyDataToImageStencil&vtkImageStencilToImage may be the solution. And my code is:

import vtkmodules.all as vtk
from vtk.util.numpy_support import vtk_to_numpy, numpy_to_vtk


ps = [
    [64, 64, 0],
    [128, 64, 0],
    [128, 128, 0],
    [64, 128, 0],
]

polydata = vtk.vtkPolyData()
points = vtk.vtkPoints()
polygon = vtk.vtkPolygon()
polygon.GetPointIds().SetNumberOfIds(len(ps))

for idx, p in enumerate(ps):
    points.InsertNextPoint(p[0], p[1], p[2])
    polygon.GetPointIds().SetId(idx, idx)

polygons = vtk.vtkCellArray()
polygons.InsertNextCell(polygon)
polydata.SetPoints(points)
polydata.SetPolys(polygons)

polyDataToImageStencil = vtk.vtkPolyDataToImageStencil()
polyDataToImageStencil.SetInputData(polydata)
polyDataToImageStencil.SetOutputOrigin(0, 0, 0)
polyDataToImageStencil.SetOutputSpacing([1, 1, 1])
polyDataToImageStencil.SetOutputWholeExtent([0, 255, 0, 255, 0, 0])
polyDataToImageStencil.Update()

imgStencilToImage = vtk.vtkImageStencilToImage()
imgStencilToImage.SetInputConnection(polyDataToImageStencil.GetOutputPort())
imgStencilToImage.SetInsideValue(1)
imgStencilToImage.SetOutsideValue(0)
imgStencilToImage.Update()

vtkMask = imgStencilToImage.GetOutput()
mask = vtk_to_numpy(vtkMask.GetPointData().GetScalars())
print(mask.sum())

However, the final mask is all 0.

What’s wrong with my code? Any suggestion is appreciated~~~