Section: Visualization Toolkit Rendering Classes
vtkPicker may return more than one vtkProp3D, since more than one bounding box may be intersected. vtkPicker returns an unsorted list of props that were hit, and a list of the corresponding world points of the hits. For the vtkProp3D that is closest to the camera, vtkPicker returns the pick coordinates in world and untransformed mapper space, the prop itself, the data set, and the mapper. For vtkPicker the closest prop is the one whose center point (i.e., center of bounding box) projected on the view ray is closest to the camera. Subclasses of vtkPicker use other methods for computing the pick point.
To create an instance of class vtkPicker, simply invoke its constructor as follows
obj = vtkPicker
obj
is an instance of the vtkPicker class.
string = obj.GetClassName ()
int = obj.IsA (string name)
vtkPicker = obj.NewInstance ()
vtkPicker = obj.SafeDownCast (vtkObject o)
obj.SetTolerance (double )
- Specify tolerance for performing pick operation. Tolerance is specified
as fraction of rendering window size. (Rendering window size is measured
across diagonal.)
double = obj.GetTolerance ()
- Specify tolerance for performing pick operation. Tolerance is specified
as fraction of rendering window size. (Rendering window size is measured
across diagonal.)
double = obj. GetMapperPosition ()
- Return position in mapper (i.e., non-transformed) coordinates of
pick point.
vtkAbstractMapper3D = obj.GetMapper ()
- Return mapper that was picked (if any).
vtkDataSet = obj.GetDataSet ()
- Get a pointer to the dataset that was picked (if any). If nothing
was picked then NULL is returned.
vtkProp3DCollection = obj.GetProp3Ds ()
- Return a collection of all the prop 3D's that were intersected
by the pick ray. This collection is not sorted.
vtkActorCollection = obj.GetActors ()
- Return a collection of all the actors that were intersected.
This collection is not sorted. (This is a convenience method
to maintain backward compatibility.)
vtkPoints = obj.GetPickedPositions ()
- Return a list of the points the the actors returned by GetProp3Ds
were intersected at. The order of this list will match the order of
GetProp3Ds.
int = obj.Pick (double selectionX, double selectionY, double selectionZ, vtkRenderer renderer)
- Perform pick operation with selection point provided. Normally the
first two values for the selection point are x-y pixel coordinate, and
the third value is =0. Return non-zero if something was successfully
picked.
int = obj.Pick (double selectionPt[3], vtkRenderer ren)
- Perform pick operation with selection point provided. Normally the first
two values for the selection point are x-y pixel coordinate, and the
third value is =0. Return non-zero if something was successfully picked.