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Tutorial Step5

vtk-examples/Python/Tutorial/Tutorial_Step5


Description

This example introduces the concepts of interaction into the Python environment. A different interaction style (than the default) is defined.

Other languages

See (Cxx)

Question

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Code

Tutorial_Step5.py

#!/usr/bin/env python

"""
=========================================================================

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/

"""

# First access the VTK module (and any other needed modules) by importing them.
import vtk


def main(argv):
    colors = vtk.vtkNamedColors()

    #
    # Next we create an instance of vtkConeSource and set some of its
    # properties. The instance of vtkConeSource 'cone' is part of a
    # visualization pipeline (it is a source process object) it produces data
    # (output type is vtkPolyData) which other filters may process.
    #
    cone = vtk.vtkConeSource()
    cone.SetHeight(3.0)
    cone.SetRadius(1.0)
    cone.SetResolution(10)

    #
    # In this example we terminate the pipeline with a mapper process object.
    # (Intermediate filters such as vtkShrinkPolyData could be inserted in
    # between the source and the mapper.)  We create an instance of
    # vtkPolyDataMapper to map the polygonal data into graphics primitives. We
    # connect the output of the cone source to the input of this mapper.
    #
    coneMapper = vtk.vtkPolyDataMapper()
    coneMapper.SetInputConnection(cone.GetOutputPort())

    #
    # Create an actor to represent the cone. The actor orchestrates rendering
    # of the mapper's graphics primitives. An actor also refers to properties
    # via a vtkProperty instance, and includes an internal transformation
    # matrix. We set this actor's mapper to be coneMapper which we created
    # above.
    #
    coneActor = vtk.vtkActor()
    coneActor.SetMapper(coneMapper)
    coneActor.GetProperty().SetColor(colors.GetColor3d('Bisque'))

    #
    # Create the Renderer and assign actors to it. A renderer is like a
    # viewport. It is part or all of a window on the screen and it is
    # responsible for drawing the actors it has.  We also set the background
    # color here.
    #
    ren1 = vtk.vtkRenderer()
    ren1.AddActor(coneActor)
    ren1.SetBackground(colors.GetColor3d('MidnightBlue'))

    #
    # Finally we create the render window which will show up on the screen.
    # We put our renderer into the render window using AddRenderer. We also
    # set the size to be 300 pixels by 300.
    #
    renWin = vtk.vtkRenderWindow()
    renWin.AddRenderer(ren1)
    renWin.SetSize(300, 300)
    renWin.SetWindowName('Tutorial_Step5')

    #
    # The vtkRenderWindowInteractor class watches for events (e.g., keypress,
    # mouse) in the vtkRenderWindow. These events are translated into
    # event invocations that VTK understands (see VTK/Common/vtkCommand.h
    # for all events that VTK processes). Then observers of these VTK
    # events can process them as appropriate.
    iren = vtk.vtkRenderWindowInteractor()
    iren.SetRenderWindow(renWin)

    #
    # By default the vtkRenderWindowInteractor instantiates an instance
    # of vtkInteractorStyle. vtkInteractorStyle translates a set of events
    # it observes into operations on the camera, actors, and/or properties
    # in the vtkRenderWindow associated with the vtkRenderWinodwInteractor.
    # Here we specify a particular interactor style.
    style = vtk.vtkInteractorStyleTrackballCamera()
    iren.SetInteractorStyle(style)

    #
    # Unlike the previous scripts where we performed some operations and then
    # exited, here we leave an event loop running. The user can use the mouse
    # and keyboard to perform the operations on the scene according to the
    # current interaction style. When the user presses the 'e' key, by default
    # an ExitEvent is invoked by the vtkRenderWindowInteractor which is caught
    # and drops out of the event loop (triggered by the Start() method that
    # follows.
    #
    iren.Initialize()
    iren.Start()

    #
    # Final note: recall that observers can watch for particular events and
    # take appropriate action. Pressing 'u' in the render window causes the
    # vtkRenderWindowInteractor to invoke a UserEvent. This can be caught to
    # popup a GUI, etc. See the Tcl Cone5.tcl example for an idea of how this
    # works.


if __name__ == '__main__':
    import sys

    main(sys.argv)