ITT Rule IDL Version 7.0 用户手册

99

Creating a New iTool Class

specifies the file 

writer.bmp

 located in the 

home/mydir

 directory as the icon to 

use on the toolbar.

self->RegisterFileReader, 'myWriter', 'myFileWriter', $

ICON = '/home/mydir/writer.bmp'

See 

 on page 269 for additional details. See 

 on page 255 for a list of file writers included in the iTool system 

as installed with IDL.

The following example code shows a very simple Init method for an iTool named 

FirstExampleTool

. This function should be included in a file named 

FirstExampleTool__define.pro

.

FUNCTION FirstExampleTool::Init, _REF_EXTRA = _extra

; Call the Init method of the super class.

IF (self->IDLitToolbase::Init(NAME='FirstExampleTool', $

DESCRIPTION = 'Example Tool Class', _EXTRA = _extra) EQ 0) THEN 

$

RETURN, 0

; Register a visualization

self->RegisterVisualization, 'Image', 'IDLitVisImage', $

ICON = 'image'

; Register an operation

self->RegisterOperation, 'Byte Scale', 'IDLitOpBytScl', $

IDENTIFIER = 'Operations/Byte Scale'

RETURN, 1

END

The 

FirstExampleTool

 is based on the IDLitToolbase class (discussed in 

 on page 91). As a result, all of the 

standard iTool operations, manipulators, file readers and writers are already present. 
The 

FirstExampleTool

 Init method needs to do only three things:

1. Call the Init method of the superclass, IDLitToolbase, using the _EXTRA 

keyword inheritance mechanism to pass through any keywords provided when 
the 

FirstExampleTool

 Init method is called.