print #handle, "rule rulename"
or
print #handle, "rule "; _R2_NOTXORPEN

This command specifies whether drawing overwrites (rulename OVER) graphics already on the screen or uses the exclusive-OR technique (rulename XOR).  It is also possible to use Windows constants to select a drawing rule.  Here are the constants that Windows defines:

  _R2_BLACK		_R2_WHITE
  _R2_NOP		_R2_NOT
  _R2_COPYPEN           <- the default LB drawing rule
  _R2_NOTCOPYPEN
  _R2_MERGEPENNOT	_R2_MASKPENNOT
  _R2_MERGENOTPEN	_R2_MASKNOTPEN
  _R2_MERGEPEN	_R2_NOTMERGEPEN
  _R2_MASKPEN	_R2_NOTMASKPEN
  _R2_XORPEN		
  _R2_NOTXORPEN         <- the xor LB drawing rule


