BoxWidget

Description¶

This example uses a vtkBoxWidget to manipulate an actor. The class includes geometry to draw a box around the object, which is bound to it via SetProp3D. The box is dimensioned using the SetPlaceFactor method, and positioned with the PlaceWidget method. After the initial setup, synchronizing the box with the object is done through a custom callback class, which is passed to the box widget through the AddObserver method.

For a widget that isn't tied to a specific vtkProp3D and has its geometric representation separate from the interaction logic, see the example BoxWidget2 - to be written.

Other languages

See (Cxx)

Question

If you have a question about this example, please use the VTK Discourse Forum

Code¶

BoxWidget.py

#!/usr/bin/env python3

# noinspection PyUnresolvedReferences
import vtkmodules.vtkInteractionStyle
# noinspection PyUnresolvedReferences
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkCommonTransforms import vtkTransform
from vtkmodules.vtkFiltersSources import vtkConeSource
from vtkmodules.vtkInteractionWidgets import vtkBoxWidget
from vtkmodules.vtkRenderingCore import (
    vtkActor,
    vtkPolyDataMapper,
    vtkRenderWindow,
    vtkRenderWindowInteractor,
    vtkRenderer
)


# Call back function to resize the cone


def boxCallback(obj, event):
    t = vtkTransform()
    obj.GetTransform(t)
    obj.GetProp3D().SetUserTransform(t)


def main():
    colors = vtkNamedColors()

    # Create a Cone
    cone = vtkConeSource()
    cone.SetResolution(20)
    coneMapper = vtkPolyDataMapper()
    coneMapper.SetInputConnection(cone.GetOutputPort())
    coneActor = vtkActor()
    coneActor.SetMapper(coneMapper)
    coneActor.GetProperty().SetColor(colors.GetColor3d('BurlyWood'))

    # A renderer and render window
    renderer = vtkRenderer()
    renderer.SetBackground(colors.GetColor3d('Blue'))
    renderer.AddActor(coneActor)

    renwin = vtkRenderWindow()
    renwin.AddRenderer(renderer)
    renwin.SetWindowName('BoxWidget')

    # An interactor
    interactor = vtkRenderWindowInteractor()
    interactor.SetRenderWindow(renwin)

    # A Box widget
    boxWidget = vtkBoxWidget()
    boxWidget.SetInteractor(interactor)
    boxWidget.SetProp3D(coneActor)
    boxWidget.SetPlaceFactor(1.25)  # Make the box 1.25x larger than the actor
    boxWidget.PlaceWidget()
    boxWidget.On()

    # Connect the event to a function
    boxWidget.AddObserver('InteractionEvent', boxCallback)

    # Start
    interactor.Initialize()
    renwin.Render()
    interactor.Start()


if __name__ == '__main__':
    main()