ITT Rule IDL Version 7.0 User Manual download pdf (Page 210)

210 Chapter 8: Creating a Manipulator

Creating a New Manipulator iTool Developer’s Guide

RETURN, 0

This convention is used in all manipulator classes included with IDL. We strongly

suggest that you include similar checks in your own class definition files.

Keywords to the Init Method

Properties of the manipulator class can be set in the Init method by specifying the

property names and values as IDL keyword-value pairs. In addition to any keywords

implemented directly in the Init method of the superclass on which you base your

class, the properties of the IDLitManipulator class, the IDLitIMessaging class, and

the IDLitComponent class are available to any manipulator class. See

“IDLitManipulator Properties”, “IDLitIMessaging Properties”, and

“IDLitComponent Properties” (IDL Reference Guide).

Note

Always use keyword inheritance (the _EXTRA keyword) to pass keyword

parameters through to the superclass. (See “Keyword Inheritance” (Chapter 5,

Application Programming) for details on IDL’s keyword inheritance mechanism.)

Standard Base Class

While you can create your new manipulator class from any existing manipulator

class, the manipulator classes you create will usually be subclassed directly from the

base class, IDLitManipulator:

IF (self->IDLitManipulator::Init(_EXTRA = _extra) EQ 0) $

THEN RETURN, 0

The IDLitManipulator class provides the base iTool functionality used in the

manipulator classes created by ITT Visual Information Solutions. See “Subclassing

From the IDLitManipulator Class” on page 207 for details.

Return Value

If all of the routines and methods used in the Init method execute successfully, it

should indicate successful initialization by returning 1. Other manipulator classes that

subclass from your manipulator class may check this return value, as your routine

should check the value returned by any superclass Init methods called.

Example Init Method

The following example code shows a very simple Init method for a manipulator

named

ExampleManip. This function would be included (along with the class

structure definition routine and any other methods defined by the class) in a file

named

examplemanip__define.pro.

1 2 ... 205 206 207 208 209 210 211 212 213 214 215 ... 429 430

No comments

ITT Rule IDL Version 7.0 User Manual Page 210