ECLPSListener Class

ECLPSListener is an abstract base class. An application cannot create an instance of this class directly. To use this class, the application must define its own class which is derived from ECLPSListener. The application must implement all the methods in this class.

The ECLPSListener class is used to allow an application to be notified of updates to the presentation space. Events are generated whenever the host screen is updated (any data in the presentation space is changed in any plane).

This class is similar to the ECLPSNotify class in that it is used to receive notifications of PS updates. It differs however in that it receives much more information about the cause and scope of the update than the ECLPSNotify class. In general using this class will be more expensive in terms of processing time and memory since more information has to be generated with each event. For applications which need to efficiently update a visual representation of the host screen this class may be more efficient than redrawing the representation each time an update occurs. Using this class the application can update only the portion of the visual representation that has changed.

This class also differs from ECLPSNotify in that all the methods are pure virtual and therefor must be implemented by the application (there is no default implementation of any methods).