EnableHAVG 
 Enables horizontal averaging.
Synopsis
Err EnableHAVG (Item screenItem)
Description
This call enables horizontal averaging of the specified screen. Vertical 
averaging is left undisturbed. 
Arguments
- screenItem
- Item number of the screen whose display is to be modified. 
Return Value
The call returns 0 if successful or an error code (a negative value) if an 
error occurs. 
Implementation
Folio call implemented in Graphics folio V20. 
Associated Files
graphics.h, graphics.lib
See Also
DisableHAVG(), DisableVAVG, EnableVAVG()