Default C++ constructor which creates a sessionless backed-up window handle.

Handles to server-side objects must be created in a session in order to be operational; this constructor is merely a convenience to allow the handle to be stored as a data member. See RWindowTreeNode::RWindowTreeNode() for details of how the complete setup of a handle field may be deferred until the window server session is known.

Constructor which creates an uninitialised backed-up window handle within a session.

Gets a handle to the backup bitmap.

This handle can then be passed to CFbsBitmap::Duplicate() to gain access to the bitmap. Once the bitmap has been obtained, it can be drawn to or read from by the application.

Notes: in most circumstances this function should be used only after MaintainBackup() has been called. Otherwise, the content of the backup bitmap will be unpredictable.

This function always causes a flush of the window server buffer.

Completes the construction of a backed up window.

This method should be called after the RBackedUpWindow(RWsSession&) constructor, and before any other functions are performed on the window. It creates a window in the window server corresponding to the RBackedUpWindow object, and allocates a bitmap with which to perform the window backup.

Unlike non backed up windows, the size of a backed up window is not inherited from its parent. The window will be created with an initial size of zero, but this can be altered. The display mode must be specified because it determines the amount of memory required to store the backup bitmap.

This function always causes a flush of the window server buffer.

RWindowBase::SetSizeErr() RWindowBase::SetExtentErr() RWindow::Construct()

Tells the window server to start maintaining a backup bitmap with the entire window contents.

By default, the window only backs up the non-visible and shadowed part of the window. Calling this function makes drawing to the window much faster.

Once this function has been called, it cannot be reversed.

Copies to the backup bitmap any areas of the window which are not currently stored in the bitmap.

This method does not need to be called if the server has not been instructed to maintain the backup buffer constantly

MaintainBackup()

Copies the backup bitmap's image to the on-screen bitmap.

This function should be used if the application draws directly to the backup bitmap. Any changes made to the backup bitmap will not be reflected on the screen until this function is called.

Copies a part of the backup bitmap to the on-screen bitmap.

This function behaves in the same way as UpdateScreen(), but copies only the specified region of the backup bitmap to the window on screen.

This function always causes a flush of the window server buffer.