ITT Rule IDL Version 7.0 Uživatelský manuál stáhnout pdf (Strana 129)

Chapter 6: Creating a Visualization 129

iTool Developer’s Guide Creating a New Visualization Type

/INPUT, TYPES='IDLVECTOR', /OPTARGET

; Add a plotting symbol object and aggregate its properties

; into the visualization.

self._oSymbol = OBJ_NEW('IDLitSymbol', PARENT = self)

self->Aggregate, self._oSymbol

; Create an IDLitVisPlot object, setting its SYMBOL property to

; the symbol object we just created. Add the plot object to the

; visualization, and aggregate its properties.

self._oPlot = OBJ_NEW('IDLitVisPlot', /REGISTER_PROPERTIES, $

SYMBOL = self._oSymbol->GetSymbol())

self->Add, self._oPlot, /AGGREGATE

; Register an example property that holds a string value.

self->RegisterProperty, 'ExampleProperty', $

/STRING, DESCRIPTION='An example property', $

NAME='Example Property', SENSITIVE = 1

; Pass any extra keyword parameters through to the SetProperty

; method.

IF (N_ELEMENTS(_extra) GT 0) THEN $

self->ExampleVis::SetProperty, _EXTRA = _extra

; Return success

RETURN, 1

END

Discussion

The

ExampleVis class is based on the IDLitVisualization class (discussed in

“Subclassing from the IDLitVisualization Class” on page 121). As a result, all of the

standard features of an iTool visualization class are already present. We don’t define

any keyword values to be handled explicitly in the Init method, but we do use the

keyword inheritance mechanism to pass keyword values through to methods called

within the Init method. The

ExampleVis Init method does the following things:

1. Calls the Init method of the superclass, IDLitVisualization. We use the

REGISTER_PROPERTIES keyword to ensure that all registrable properties of

the superclass are exposed in the ExampleVis object’s property sheet. We also

set the visualization type to be an “ExampleVis,” provide a Name for the object

instance, and provide an icon. Finally, we use the _EXTRA keyword

inheritance mechanism to pass through any keywords provided when the

ExampleVis Init method is called.

2. Registers an input parameter called Y that must be a vector. The OPTARGET

keyword specifies that the Y parameter can be the target for iTool operations.

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ITT Rule IDL Version 7.0 Uživatelský manuál Strana 129