202 Chapter 8: Creating a Manipulator
Manipulators and the Undo/Redo System iTool Developer’s Guide
Manipulators and the Undo/Redo System
A manipulator can be configured to support undo/redo functionality when it invokes
an associated operation that records the actions performed by the manipulator in the
undo/redo buffer. This operation can be a custom operation or an existing operation.
(See Chapter 7, “Creating an Operation” for details on operation creation.) In the
manipulator class Init method, specify a string value for the
OPERATION_IDENTIFIER keyword to indicate the name of the operation
associated with the manipulator.
Note
If the manipulator modifies a property exposed on the target object, you can specify
the built-in SET_PROPERTY operation to manage undo-redo information. Set
OPERATION_IDENTIFIER='SET_PROPERTY' as shown in “Creating a
Manipulator Init Method” on page 208. This built-in operation automates undo/redo
transactions.
When using the SET_PROPERTY operation, you must also set the
PARAMETER_IDENTIFIER keyword during initialization. Set this keyword to the
property identifier of the property being manipulated. To determine the identifiers of
a visualization’s properties, you can retrieve the object’s identifier and retrieve the
names of all registered properties as described in “Retrieving Property Information”
in Appendix A. The following example uses the itPropertyReport procedure to print
all the registered property names and identifiers supported by the object to the Output
Log window. The following sample code shows how to retrieve the properties
associated with an image.
; Get the tool reference.
idtool=ITGETCURRENT(TOOL = oTool)
; Retrieve the parameter identifier for the the image.
; Print the identifier, name and type of each associated
; registered property using the ItPropertyReport procedure.
vImage = oTool->FindIdentifiers('*image*', /VISUALIZATION)
itPropertyReport, otool, vImage
Note
See “Retrieving Property Information” in Appendix A for more information about
property identifiers and names.
