ITT Rule IDL Version 7.0 User Manual download pdf (Page 165)

Chapter 7: Creating an Operation 165

iTool Developer’s Guide Creating a New Generalized Operation

Creating a New Generalized Operation

Generalized operations are iTool operations that are not limited to acting on data that

underlies a visualization. Generalized operations are based on the IDLitOperation

class. The class definition file for an IDLitOperation object must (at the least) provide

methods to initialize the operation class, get and set property values, execute the

operation, undo and redo the operation, and define the operation class structure.

Complex operations will likely provide additional methods.

How an IDLitOperation Works

When an IDLitOperation is requested by a user, the operation’s DoAction method

(which must be provided by the operation class’ developer) is called. The DoAction

method is responsible for doing the following:

1. Retrieving the currently selected items and determining which items the

operation should be applied to.

2. Creating an IDLitCommandSet object to contain undo/redo information.

3. Recording the initial values of the selected objects in the IDLitCommandSet

object, if necessary.

4. Performing the actions associated with the operation.

5. Recording the final values of the selected objects in the IDLitCommandSet

object, if necessary.

6. Returning the IDLitCommandSet object.

Creating an IDLitOperation

The process of creating an IDLitDataOperation is outlined in the following sections:

• “Creating the Class Structure Definition” on page 166

• “Creating an Init Method” on page 167

• “Creating a Cleanup Method” on page 171

• “Creating a DoAction Method” on page 172

• “Creating a RecordInitialValues Method” on page 174

• “Creating a RecordFinalValues Method” on page 175

• “Creating a GetProperty Method” on page 176

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ITT Rule IDL Version 7.0 User Manual Page 165