Taxonomy Categories:
Member Functions:
Interface Category:
API.
Inherits From:
TVideoDeviceDriver
Inherited By:
None.
Purpose:
TFrameBufferVideoDeviceDriver provides access to a FrameBuffer based video device. The TFrameBufferVideoDeviceDriver handles requests from the TFrameBufferVideoDeviceHandle and also communicates with the Interrupt Handler for the video device.
TFrameBufferVideoDeviceDriver derives from the base class TVideoDeviceDriver. This class is instantiated directly by the configuration manager that has located the video device handle/driver pair. For example, the NuBus configuration access manager may find a frame buffer video card, and then start the FrameBufferVideoDeviceDriver, which instantiates the FrameBufferVideoDeviceHandle object for clients.
Instantiation:
Allocate on the heap or the stack.
Deriving Classes:
Derive a class from TFrameBufferVideoDeviceDriver to add more specific functionality that a different video device's frame buffer may need. For example, TVideoDeviceDriverLiveVideo may be a derived class that inherits all of the FrameBufferVideoDeviceDriver request handlers, but also adds a set of request handler member functions for Video overlay support, alpha channel video codes, and live video register support.
In general, derived classes can override any of the virtual functions and add request handlers, but they are not forced to override any particular members.
Concurrency:
Not multithread safe. Calling tasks will use the client/server style architecture.
Resource Use:
No special requirements. In general, objects of this class are only deleted at system shutdown time. If live install and uninstall devices come online, then the Video Device server may delete the uninstalled video device's TFrameBufferVideoDeviceDriver object, which will do a standard shutdown for request handling tasks.
Click the icon to mail questions or corrections about this material to Taligent personnel.
Copyright©1995 Taligent,Inc. All rights reserved.