writemask(3G)							 writemask(3G)

NAME    [Toc]    [Back]

     writemask - grants	write permission to bitplanes

C SPECIFICATION    [Toc]    [Back]

     void writemask(wtm)
     Colorindex	wtm;

PARAMETERS    [Toc]    [Back]

     wtm   expects a mask whose	bits control which bitplanes are available for
	   drawing and which are read only.

	   The mask contains one bit per available bitplane. If	a bit is set
	   in the writemask, the system	writes the current color index into
	   the corresponding bitplane. If a bit	is set to zero in the
	   writemask, the corresponding	bitplane is read-only.

DESCRIPTION    [Toc]    [Back]

     Use writemask to reserve bitplanes	for special purposes.  When the
     writemask marks a bitplane	as read-only, that bitplane is write protected
     from ordinary drawing routines.

     Use RGBwritemask in RGB mode.

SEE ALSO    [Toc]    [Back]

     color, drawmode, RGBwritemask

BUGS    [Toc]    [Back]

     writemask does not	work properly on the IRIS-4D VGX, VGXT and SKYWRITER
     models when the current drawmode is not NORMALDRAW.


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