user manual

114 Chapter 6: Creating a Visualization
Overview of iTool Visualization Types iTool Developer’s Guide
Overview of iTool Visualization Types
A visualization type is an iTool component object class that contains core IDL
graphic objects (IDLgrPlot objects, for example), other iTool visualization
components, or both. Visualization type components can also contain data. A number
of visualization types are predefined and included in the IDL iTools package. If none
of the predefined types suits your needs, you can create your own visualization type
by subclassing either from one of the predefined types or from the base
IDLitVisualization class on which all of the predefined types are based.
The Visualization Type Creation Process
To create a new iTool visualization type, you will do the following:
• Choose an iTool visualization class on which your new visualization type will
be based. In almost all cases, you will base new visualization types either on
the IDLitVisualization class or on a visualization class that is itself based on
IDLitVisualization. The IDLitVisualization class automatically handles
selection, selection visuals, data ranges, and notification of data changes.
• Define the data parameters necessary to create a visualization of the new type.
• Define the properties of the visualization, and set default property values.
• Override methods used to get or set properties, react to changes in the
underlying data, and clean up, as necessary.
This chapter describes the process of creating a new visualization type based on the
IDLitVisualization class.