IDL and External Widgets

This section describes an IDL widget type not documented in the IDL Reference Guide, called the stub widget. It also describes a small set of internal functions to manipulate stub widgets. Stub widgets allow CALL_EXTERNAL, LINKIMAGE, DLM, and Callable IDL users to add their own widgets to IDL widget hierarchies.

This feature depends on your system providing the window system libraries used by IDL (particularly the Motif libraries under UNIX) as sharable libraries. It will not work with versions of IDL that statically link against the window system libraries.

The next two sections describe IDL's WIDGET_STUB function and changes to WIDGET_CONTROL when used with WIDGET_STUB. Functions for Use with Stub Widgets describes support functions that can be called from your external code to manipulate stub widgets. Internal Callback Functions describes how to make stub widgets generate IDL widget events. Finally, UNIX WIDGET_STUB Example: WIDGET_ARROWB illustrates the use of stub widgets with an external program.

Note
Although WIDGET_STUB can be used under Microsoft Windows, this feature is primarily of interest with UNIX IDL. Under Windows, we recommend the use of the WIDGET_ACTIVEX functionality, which allows you to use ActiveX controls with IDL without requiring external programming.