Class: TVideoDeviceHandle

Declaration: VideoDeviceHandle.h

Taxonomy Categories:

Member Functions:

Interface Category:

API.

Inherits From:

TDisplayDeviceHandle

Inherited By:

TFrameBufferVideoDeviceHandle

Purpose:

TVideoDeviceHandle is a base class that defines the behavior of video device derived classes. Instantiations of TVideoDeviceHandle derived classes are meant to act as implicit surrogates of the the TVideoDeviceDrivers that act directly on the Video hardware.

Instantiation:

Allocate on the heap or the stack.

Deriving Classes:

Derive a class from TVideoDeviceHandle to add more specific functionality needed by a different video device. For example, TFrameBufferVideoDeviceHandle is a derived class that inherits all of the TVideoDeviceHandle member function calls, but also adds a set of member functions for frame buffer Video devices. In this example, the derived class overrides the CreateScreen function in order to create a special frame buffer screen for the device.

Concurrency:

Not multithread safe.

Resource Use:

No special requirements.

Member Function: TVideoDeviceHandle::CreateScreen

virtual MScreen * CreateScreen ()

Interface Category:

API.

Purpose:

Returns a pointer to a copy of the MScreen, which is actually a TScreenDevice derived class, that the TFrameBufferVideoDeviceHandle constructs from its knowledge of the actual physical Video device handle being represented. The Window server or Video Device server calls this function to get the screen device that has the characteristics of this VideoDeviceHandle type. The screen device is created using the configuration of the VideoDeviceHandle as well as the current world bounds setting for the screen device layout.

Calling Context:

Called by the Window server or Video Device server to start the Graphics system.

Parameters:

Takes no parameters.

Return Value:

Returns the appropriate MScreen subtype.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TVideoDeviceHandle::GetScreenHeight

virtual GCoordinate GetScreenHeight () const

Interface Category:

API.

Purpose:

Returns the height of the screen polymorphically.

Calling Context:

Called internally to obtain information used to create the screen device.

Parameters:

Takes no parameters.

Return Value:

Returns the GCoordinate value for the height of the screen in pixels.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TVideoDeviceHandle::GetScreenWidth

virtual GCoordinate GetScreenWidth () const

Interface Category:

API.

Purpose:

Returns the width of the screen polymorphically.

Calling Context:

Called internally to obtain information used to create the screen device.

Parameters:

Takes no parameters.

Return Value:

Returns the GCoordinate value for the width of the screen in pixels.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TVideoDeviceHandle::TVideoDeviceHandle

TVideoDeviceHandle ()
TVideoDeviceHandle (const TVideoDeviceHandle &)

Interface Category:

API.

Purpose:

Default constructor.
Copy constructor.

Calling Context:

Called by the stream-in operators
Called to copy an object.

Parameters:

Takes no parameters.
const TVideoDeviceHandle & -A reference to the object to be copied.

Return Value:

None.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TVideoDeviceHandle::operator=

TVideoDeviceHandle & operator =(const TVideoDeviceHandle &)

Interface Category:

API.

Purpose:

Assignment operator.

Calling Context:

Called when an object is assigned to another compatible object.

Parameters:

const TVideoDeviceHandle & -The object to be assigned to another compatible object.

Return Value:

A non-const reference to the left-hand side object.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TVideoDeviceHandle::GetWorldBoundsOffset

virtual TGPoint GetWorldBoundsOffset () const

Interface Category:

API.

Purpose:

Gets the position in world coordinates.

Calling Context:

Called during system configuration.

Parameters:

Takes no parameters.

Return Value:

Returns a TGPoint with x,y offset position.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TVideoDeviceHandle::~TVideoDeviceHandle

virtual ~ TVideoDeviceHandle ()

Interface Category:

API.

Purpose:

Destructor.

Calling Context:

Called to destroy an object.

Parameters:

Takes no parameters.

Return Value:

None.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

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