Logical Screen

The LogicalScreen is the memory area where the VDI draws. LogicalScreen and PhysicalScreen are normally the same (which explains why you usually sees VDI graphics being displayed while they are being drawn) but they are addressed individually to enable screen flipping.

The address of this buffer can be obtained with a call to the XBIOS function Logbase(). In a VirtualScreen situation, the LogicalScreen address is the upper-left corner of the whole virtual field (the one on which the VDI draws). Then the graphics that are drawn have to wait for the next screen flip to get a chance to be actually displayed on the monitor.

See PhysicalScreen for a discussion about determining the screen buffer size.

See Also

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