Section: Visualization Toolkit Rendering Classes
To create an instance of class vtkCellPicker, simply invoke its constructor as follows
obj = vtkCellPicker
obj
is an instance of the vtkCellPicker class.
string = obj.GetClassName ()
int = obj.IsA (string name)
vtkCellPicker = obj.NewInstance ()
vtkCellPicker = obj.SafeDownCast (vtkObject o)
int = obj.Pick (double selectionX, double selectionY, double selectionZ, vtkRenderer renderer)
- Perform pick operation with selection point provided. Normally the
first two values are the (x,y) pixel coordinates for the pick, and
the third value is z=0. The return value will be non-zero if
something was successfully picked.
obj.AddLocator (vtkAbstractCellLocator locator)
- Add a locator for one of the data sets that will be included in the
scene. You must set up the locator with exactly the same data set
that was input to the mapper of one or more of the actors in the
scene. As well, you must either build the locator before doing the
pick, or you must turn on LazyEvaluation in the locator to make it
build itself on the first pick. Note that if you try to add the
same locator to the picker twice, the second addition will be ignored.
obj.RemoveLocator (vtkAbstractCellLocator locator)
- Remove a locator that was previously added. If you try to remove a
nonexistent locator, then nothing will happen and no errors will be
raised.
obj.RemoveAllLocators ()
- Remove all locators associated with this picker.
obj.SetVolumeOpacityIsovalue (double )
- Set the opacity isovalue to use for defining volume surfaces. The
pick will occur at the location along the pick ray where the
opacity of the volume is equal to this isovalue. If you want to do
the pick based on an actual data isovalue rather than the opacity,
then pass the data value through the scalar opacity function before
using this method.
double = obj.GetVolumeOpacityIsovalue ()
- Set the opacity isovalue to use for defining volume surfaces. The
pick will occur at the location along the pick ray where the
opacity of the volume is equal to this isovalue. If you want to do
the pick based on an actual data isovalue rather than the opacity,
then pass the data value through the scalar opacity function before
using this method.
obj.SetUseVolumeGradientOpacity (int )
- Use the product of the scalar and gradient opacity functions when
computing the opacity isovalue, instead of just using the scalar
opacity. This parameter is only relevant to volume picking and
is off by default.
obj.UseVolumeGradientOpacityOn ()
- Use the product of the scalar and gradient opacity functions when
computing the opacity isovalue, instead of just using the scalar
opacity. This parameter is only relevant to volume picking and
is off by default.
obj.UseVolumeGradientOpacityOff ()
- Use the product of the scalar and gradient opacity functions when
computing the opacity isovalue, instead of just using the scalar
opacity. This parameter is only relevant to volume picking and
is off by default.
int = obj.GetUseVolumeGradientOpacity ()
- Use the product of the scalar and gradient opacity functions when
computing the opacity isovalue, instead of just using the scalar
opacity. This parameter is only relevant to volume picking and
is off by default.
obj.SetPickClippingPlanes (int )
- The PickClippingPlanes setting controls how clipping planes are
handled by the pick. If it is On, then the clipping planes become
pickable objects, even though they are usually invisible. This
means that if the pick ray intersects a clipping plane before it
hits anything else, the pick will stop at that clipping plane.
The GetProp3D() and GetMapper() methods will return the Prop3D
and Mapper that the clipping plane belongs to. The
GetClippingPlaneId() method will return the index of the clipping
plane so that you can retrieve it from the mapper, or -1 if no
clipping plane was picked. The picking of vtkImageActors is not
influenced by this setting, since they have no clipping planes.
obj.PickClippingPlanesOn ()
- The PickClippingPlanes setting controls how clipping planes are
handled by the pick. If it is On, then the clipping planes become
pickable objects, even though they are usually invisible. This
means that if the pick ray intersects a clipping plane before it
hits anything else, the pick will stop at that clipping plane.
The GetProp3D() and GetMapper() methods will return the Prop3D
and Mapper that the clipping plane belongs to. The
GetClippingPlaneId() method will return the index of the clipping
plane so that you can retrieve it from the mapper, or -1 if no
clipping plane was picked. The picking of vtkImageActors is not
influenced by this setting, since they have no clipping planes.
obj.PickClippingPlanesOff ()
- The PickClippingPlanes setting controls how clipping planes are
handled by the pick. If it is On, then the clipping planes become
pickable objects, even though they are usually invisible. This
means that if the pick ray intersects a clipping plane before it
hits anything else, the pick will stop at that clipping plane.
The GetProp3D() and GetMapper() methods will return the Prop3D
and Mapper that the clipping plane belongs to. The
GetClippingPlaneId() method will return the index of the clipping
plane so that you can retrieve it from the mapper, or -1 if no
clipping plane was picked. The picking of vtkImageActors is not
influenced by this setting, since they have no clipping planes.
int = obj.GetPickClippingPlanes ()
- The PickClippingPlanes setting controls how clipping planes are
handled by the pick. If it is On, then the clipping planes become
pickable objects, even though they are usually invisible. This
means that if the pick ray intersects a clipping plane before it
hits anything else, the pick will stop at that clipping plane.
The GetProp3D() and GetMapper() methods will return the Prop3D
and Mapper that the clipping plane belongs to. The
GetClippingPlaneId() method will return the index of the clipping
plane so that you can retrieve it from the mapper, or -1 if no
clipping plane was picked. The picking of vtkImageActors is not
influenced by this setting, since they have no clipping planes.
int = obj.GetClippingPlaneId ()
- Get the index of the clipping plane that was intersected during
the pick. This will be set regardless of whether PickClippingPlanes
is On, all that is required is that the pick intersected a clipping
plane of the Prop3D that was picked. The result will be -1 if the
Prop3D that was picked has no clipping planes, or if the ray didn't
intersect the planes.
double = obj. GetPickNormal ()
- Return the normal of the picked surface at the PickPosition. If no
surface was picked, then a vector pointing back at the camera is
returned.
double = obj. GetMapperNormal ()
- Return the normal of the surface at the PickPosition in mapper
coordinates. The result is undefined if no prop was picked.
int = obj. GetPointIJK ()
- Get the structured coordinates of the point at the PickPosition.
Only valid for image actors and volumes with vtkImageData.
int = obj. GetCellIJK ()
- Get the structured coordinates of the cell at the PickPosition.
Only valid for image actors and volumes with vtkImageData.
Combine this with the PCoords to get the position within the cell.
vtkIdType = obj.GetPointId ()
- Get the id of the picked point. If PointId = -1, nothing was picked.
This point will be a member of any cell that is picked.
vtkIdType = obj.GetCellId ()
- Get the id of the picked cell. If CellId = -1, nothing was picked.
int = obj.GetSubId ()
- Get the subId of the picked cell. This is useful, for example, if
the data is made of triangle strips. If SubId = -1, nothing was picked.
double = obj. GetPCoords ()
- Get the parametric coordinates of the picked cell. Only valid if
a prop was picked. The PCoords can be used to compute the weights
that are needed to interpolate data values within the cell.
vtkTexture = obj.GetTexture ()
- Get the texture that was picked. This will always be set if the
picked prop has a texture, and will always be null otherwise.
obj.SetPickTextureData (int )
- If this is "On" and if the picked prop has a texture, then the data
returned by GetDataSet() will be the texture's data instead of the
mapper's data. The GetPointId(), GetCellId(), GetPCoords() etc. will
all return information for use with the texture's data. If the picked
prop does not have any texture, then GetDataSet() will return the
mapper's data instead and GetPointId() etc. will return information
related to the mapper's data. The default value of PickTextureData
is "Off".
obj.PickTextureDataOn ()
- If this is "On" and if the picked prop has a texture, then the data
returned by GetDataSet() will be the texture's data instead of the
mapper's data. The GetPointId(), GetCellId(), GetPCoords() etc. will
all return information for use with the texture's data. If the picked
prop does not have any texture, then GetDataSet() will return the
mapper's data instead and GetPointId() etc. will return information
related to the mapper's data. The default value of PickTextureData
is "Off".
obj.PickTextureDataOff ()
- If this is "On" and if the picked prop has a texture, then the data
returned by GetDataSet() will be the texture's data instead of the
mapper's data. The GetPointId(), GetCellId(), GetPCoords() etc. will
all return information for use with the texture's data. If the picked
prop does not have any texture, then GetDataSet() will return the
mapper's data instead and GetPointId() etc. will return information
related to the mapper's data. The default value of PickTextureData
is "Off".
int = obj.GetPickTextureData ()
- If this is "On" and if the picked prop has a texture, then the data
returned by GetDataSet() will be the texture's data instead of the
mapper's data. The GetPointId(), GetCellId(), GetPCoords() etc. will
all return information for use with the texture's data. If the picked
prop does not have any texture, then GetDataSet() will return the
mapper's data instead and GetPointId() etc. will return information
related to the mapper's data. The default value of PickTextureData
is "Off".