ExtractSelection
vtk-examples/Python/PolyData/ExtractSelection
Description¶
This example creates 50 random points and extracts 10 of them (the points with ids 10-19).
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Code¶
ExtractSelection.py
'''
converted from:
- http://www.vtk.org/Wiki/VTK/Examples/Python/PolyData/ExtractSelectionCells
'''
import vtk
def main():
colors = vtk.vtkNamedColors()
# colors.SetColor('leftBkg', [0.6, 0.5, 0.4, 1.0])
# colors.SetColor('centreBkg', [0.3, 0.1, 0.4, 1.0])
# colors.SetColor('rightBkg', [0.4, 0.5, 0.6, 1.0])
pointSource = vtk.vtkPointSource()
pointSource.SetNumberOfPoints(50)
pointSource.Update()
print('There are %s input points\n' % pointSource.GetOutput().GetNumberOfPoints())
ids = vtk.vtkIdTypeArray()
ids.SetNumberOfComponents(1)
# Set values
i = 10
while i < 20:
ids.InsertNextValue(i)
i += 1
selectionNode = vtk.vtkSelectionNode()
selectionNode.SetFieldType(1) # POINT
# CELL_DATA = 0
# POINT_DATA = 1
# FIELD_DATA = 2
# VERTEX_DATA = 3
# EDGE_DATA = 4
selectionNode.SetContentType(4) # INDICES
# SELECTIONS = 0
# GLOBALIDS = 1
# PEDIGREEIDS = 2
# VALUES = 3
# INDICES = 4
# FRUSTUM = 5
# LOCATIONS = 6
# THRESHOLDS = 7
# BLOCKS = 8
selectionNode.SetSelectionList(ids)
selection = vtk.vtkSelection()
selection.AddNode(selectionNode)
extractSelection = vtk.vtkExtractSelection()
extractSelection.SetInputConnection(0, pointSource.GetOutputPort())
extractSelection.SetInputData(1, selection)
extractSelection.Update()
# In selection
selected = vtk.vtkUnstructuredGrid()
selected.ShallowCopy(extractSelection.GetOutput())
print('There are %s points in the selection' % selected.GetNumberOfPoints())
print('There are %s cells in the selection' % selected.GetNumberOfCells())
# Get points that are NOT in the selection
# invert the selection
selectionNode.GetProperties().Set(vtk.vtkSelectionNode.INVERSE(), 1)
extractSelection.Update()
notSelected = vtk.vtkUnstructuredGrid()
notSelected.ShallowCopy(extractSelection.GetOutput())
print('There are %s points NOT in the selection' % notSelected.GetNumberOfPoints())
print('There are %s cells NOT in the selection' % notSelected.GetNumberOfCells())
inputMapper = vtk.vtkDataSetMapper()
inputMapper.SetInputConnection(pointSource.GetOutputPort())
inputActor = vtk.vtkActor()
inputActor.SetMapper(inputMapper)
inputActor.GetProperty().SetColor(colors.GetColor3d('MidnightBlue'))
inputActor.GetProperty().SetPointSize(5)
selectedMapper = vtk.vtkDataSetMapper()
selectedMapper.SetInputData(selected)
selectedActor = vtk.vtkActor()
selectedActor.SetMapper(selectedMapper)
selectedActor.GetProperty().SetColor(colors.GetColor3d('MidnightBlue'))
selectedActor.GetProperty().SetPointSize(5)
notSelectedMapper = vtk.vtkDataSetMapper()
notSelectedMapper.SetInputData(notSelected)
notSelectedActor = vtk.vtkActor()
notSelectedActor.SetMapper(notSelectedMapper)
notSelectedActor.GetProperty().SetColor(colors.GetColor3d('MidnightBlue'))
notSelectedActor.GetProperty().SetPointSize(5)
# There will be one render window
renderWindow = vtk.vtkRenderWindow()
renderWindow.SetSize(900, 300)
renderWindow.SetWindowName('ExtractSelection')
# And one interactor
interactor = vtk.vtkRenderWindowInteractor()
interactor.SetRenderWindow(renderWindow)
# Define viewport ranges
# (xmin, ymin, xmax, ymax)
leftViewport = [0.0, 0.0, 0.33, 1.0]
centerViewport = [0.33, 0.0, 0.66, 1.0]
rightViewport = [0.66, 0.0, 1.0, 1.0]
# Create a camera for all renderers
camera = vtk.vtkCamera()
# Setup the renderers
leftRenderer = vtk.vtkRenderer()
renderWindow.AddRenderer(leftRenderer)
leftRenderer.SetViewport(leftViewport)
leftRenderer.SetBackground(colors.GetColor3d('BurlyWood'))
leftRenderer.SetActiveCamera(camera)
centerRenderer = vtk.vtkRenderer()
renderWindow.AddRenderer(centerRenderer)
centerRenderer.SetViewport(centerViewport)
centerRenderer.SetBackground(colors.GetColor3d('orchid_dark'))
centerRenderer.SetActiveCamera(camera)
rightRenderer = vtk.vtkRenderer()
renderWindow.AddRenderer(rightRenderer)
rightRenderer.SetViewport(rightViewport)
rightRenderer.SetBackground(colors.GetColor3d('CornflowerBlue'))
rightRenderer.SetActiveCamera(camera)
leftRenderer.AddActor(inputActor)
centerRenderer.AddActor(selectedActor)
rightRenderer.AddActor(notSelectedActor)
leftRenderer.ResetCamera()
renderWindow.Render()
interactor.Start()
if __name__ == '__main__':
main()