Hi all,
I’m struggling with getting a vtkImageMapper + vtkActor2D to show up correctly. It’s showing up in black when I expect it to be all red.
Test Case
#!/usr/bin/env python
from vtk import (
vtkImageData,
vtkImageMapper,
vtkActor2D,
vtkRenderer,
vtkRenderWindow,
vtkRenderWindowInteractor,
VTK_FLOAT,
)
def main():
# Create a 100x100 red image
width = 100
height = 100
imageData = vtkImageData()
imageData.SetSpacing(1.0, 1.0, 1.0)
imageData.SetOrigin(0.0, 0.0, 0.0)
imageData.SetDimensions(width, height, 1)
imageData.AllocateScalars(VTK_FLOAT, 3)
for x in range(width):
for y in range(height):
imageData.SetScalarComponentFromFloat(x, y, 0, 0, 255) # R
imageData.SetScalarComponentFromFloat(x, y, 0, 1, 0) # G
imageData.SetScalarComponentFromFloat(x, y, 0, 2, 0) # B
# Create mapper and actor
mapper = vtkImageMapper()
mapper.SetInputData(imageData)
actor = vtkActor2D()
actor.SetMapper(mapper)
# Create renderer/window/interactor
renderer = vtkRenderer()
renderer.SetBackground(1.0, 1.0, 1.0)
renderer.AddActor(actor)
window = vtkRenderWindow()
window.AddRenderer(renderer)
interactor = vtkRenderWindowInteractor()
interactor.SetRenderWindow(window)
interactor.Start()
if __name__ == '__main__':
main()
Result
What’s puzzling is that I’m doing something very similar in a C++ application and it works well. But I’m constructing the image a little differently there (using vtkQImageToImageData).
Am I doing something wrong when I manually create a red vtkImageData like this, by setting the first component of its scalars to 255 using SetScalarComponentFromFloat? I’ve tried changing the type of the scalars to VTK_UNSIGNED_CHAR but it didn’t change anything. I have a feeling I’m doing something basic wrong.
I’m using VTK 8.1.2 from PyPI.