HighlightWithSilhouette
vtk-examples/Python/Picking/HighlightWithSilhouette
Description¶
Click on a sphere to highlight it. vtkPolyDataSilhoutte creates a silhouette of the picked vtkActor. The example subclasses vtkInteractorStyleTrackballCamera with a local class called MouseInteractorHighLightActor. The new interactor overrides the OnLeftButtonDown of vtkInteractorStyleTrackballCamera.
Watch this video showing the picking of several spheres.
Seealso
HighlightPickedActor C++ or Python where the color and edge visibility of the picked actor is changed.
Other languages
See (Cxx)
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
HighlightWithSilhouette.py
# !/usr/bin/env python
# noinspection PyUnresolvedReferences
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkCommonCore import vtkMinimalStandardRandomSequence
from vtkmodules.vtkFiltersHybrid import vtkPolyDataSilhouette
from vtkmodules.vtkFiltersSources import vtkSphereSource
from vtkmodules.vtkInteractionStyle import vtkInteractorStyleTrackballCamera
from vtkmodules.vtkRenderingCore import (
vtkActor,
vtkPolyDataMapper,
vtkPropPicker,
vtkRenderWindow,
vtkRenderWindowInteractor,
vtkRenderer
)
def get_program_parameters():
import argparse
description = 'Highlighting a selected object with a silhouette.'
epilogue = '''
Click on the object to highlight it.
The selected object is highlighted with a silhouette.
'''
parser = argparse.ArgumentParser(description=description, epilog=epilogue,
formatter_class=argparse.RawTextHelpFormatter)
parser.add_argument('numberOfSpheres', nargs='?', type=int, default=10,
help='The number of spheres, default is 10.')
args = parser.parse_args()
return args.numberOfSpheres
class MouseInteractorHighLightActor(vtkInteractorStyleTrackballCamera):
def __init__(self, silhouette=None, silhouetteActor=None):
self.AddObserver("LeftButtonPressEvent", self.onLeftButtonDown)
self.LastPickedActor = None
self.Silhouette = silhouette
self.SilhouetteActor = silhouetteActor
def onLeftButtonDown(self, obj, event):
clickPos = self.GetInteractor().GetEventPosition()
# Pick from this location.
picker = vtkPropPicker()
picker.Pick(clickPos[0], clickPos[1], 0, self.GetDefaultRenderer())
self.LastPickedActor = picker.GetActor()
# If we picked something before, remove the silhouette actor and
# generate a new one.
if self.LastPickedActor:
self.GetDefaultRenderer().RemoveActor(self.SilhouetteActor)
# Highlight the picked actor by generating a silhouette
self.Silhouette.SetInputData(self.LastPickedActor.GetMapper().GetInput())
self.GetDefaultRenderer().AddActor(self.SilhouetteActor)
# Forward events
self.OnLeftButtonDown()
return
def SetSilhouette(self, silhouette):
self.Silhouette = silhouette
def SetSilhouetteActor(self, silhouetteActor):
self.SilhouetteActor = silhouetteActor
def main():
numberOfSpheres = get_program_parameters()
colors = vtkNamedColors()
# A renderer and render window
renderer = vtkRenderer()
renderer.SetBackground(colors.GetColor3d('SteelBlue'))
renderWindow = vtkRenderWindow()
renderWindow.SetSize(640, 480)
renderWindow.AddRenderer(renderer)
# An interactor
interactor = vtkRenderWindowInteractor()
interactor.SetRenderWindow(renderWindow)
randomSequence = vtkMinimalStandardRandomSequence()
# randomSequence.SetSeed(1043618065)
# randomSequence.SetSeed(5170)
randomSequence.SetSeed(8775070)
# Add spheres to play with
for i in range(numberOfSpheres):
source = vtkSphereSource()
# random position and radius
x = randomSequence.GetRangeValue(-5.0, 5.0)
randomSequence.Next()
y = randomSequence.GetRangeValue(-5.0, 5.0)
randomSequence.Next()
z = randomSequence.GetRangeValue(-5.0, 5.0)
randomSequence.Next()
radius = randomSequence.GetRangeValue(0.5, 1.0)
randomSequence.Next()
source.SetRadius(radius)
source.SetCenter(x, y, z)
source.SetPhiResolution(11)
source.SetThetaResolution(21)
mapper = vtkPolyDataMapper()
mapper.SetInputConnection(source.GetOutputPort())
actor = vtkActor()
actor.SetMapper(mapper)
r = randomSequence.GetRangeValue(0.4, 1.0)
randomSequence.Next()
g = randomSequence.GetRangeValue(0.4, 1.0)
randomSequence.Next()
b = randomSequence.GetRangeValue(0.4, 1.0)
randomSequence.Next()
actor.GetProperty().SetDiffuseColor(r, g, b)
actor.GetProperty().SetDiffuse(0.8)
actor.GetProperty().SetSpecular(0.5)
actor.GetProperty().SetSpecularColor(colors.GetColor3d('White'))
actor.GetProperty().SetSpecularPower(30.0)
renderer.AddActor(actor)
# Render and interact
renderWindow.Render()
# Create the silhouette pipeline, the input data will be set in the
# interactor
silhouette = vtkPolyDataSilhouette()
silhouette.SetCamera(renderer.GetActiveCamera())
# Create mapper and actor for silhouette
silhouetteMapper = vtkPolyDataMapper()
silhouetteMapper.SetInputConnection(silhouette.GetOutputPort())
silhouetteActor = vtkActor()
silhouetteActor.SetMapper(silhouetteMapper)
silhouetteActor.GetProperty().SetColor(colors.GetColor3d("Tomato"))
silhouetteActor.GetProperty().SetLineWidth(5)
# Set the custom type to use for interaction.
style = MouseInteractorHighLightActor(silhouette, silhouetteActor)
style.SetDefaultRenderer(renderer)
# Start
interactor.Initialize()
interactor.SetInteractorStyle(style)
renderWindow.SetWindowName('HighlightWithSilhouette')
renderWindow.Render()
interactor.Start()
if __name__ == "__main__":
main()