vtkPointPlacer

Section: Visualization Toolkit Widget Classes

Usage

Most widgets in VTK have a need to translate of 2D display coordinates (as reported by the RenderWindowInteractor) to 3D world coordinates. This class is an abstraction of this functionality. A few subclasses are listed below: <p>1) vtkFocalPlanePointPlacer: This class converts 2D display positions to world positions such that they lie on the focal plane. <p>2) vtkPolygonalSurfacePointPlacer: Converts 2D display positions to world positions such that they lie on the surface of one or more specified polydatas. <p>3) vtkImageActorPointPlacer: Converts 2D display positions to world positions such that they lie on an ImageActor <p>4) vtkBoundedPlanePointPlacer: Converts 2D display positions to world positions such that they lie within a set of specified bounding planes. <p>5) vtkTerrainDataPointPlacer: Converts 2D display positions to world positions such that they lie on a height field. <p> Point placers provide an extensible framework to specify constraints on points. The methods ComputeWorldPosition, ValidateDisplayPosition and ValidateWorldPosition may be overridden to dictate whether a world or display position is allowed. These classes are currently used by the HandleWidget and the ContourWidget to allow various constraints to be enforced on the placement of their handles.

To create an instance of class vtkPointPlacer, simply invoke its constructor as follows

  obj = vtkPointPlacer

Methods

The class vtkPointPlacer has several methods that can be used. They are listed below. Note that the documentation is translated automatically from the VTK sources, and may not be completely intelligible. When in doubt, consult the VTK website. In the methods listed below, obj is an instance of the vtkPointPlacer class.