NAME

writemask - grants write permission to available bitplanes

SPECIFICATION

C
writemask(wtm)
Colorindex wtm;

FORTRAN
subroutine writem(wtm)
integer*4 wtm

Pascal
procedure writemask(wtm: Colorindex);

DESCRIPTION

writemask shields selected bitplanes reserved for special uses from ordinary drawing commands.  Its argument is a mask with one bit per available bitplane.  Wherever there are ones in the writemask, the corresponding bits in the color will be written into the bitplanes.  Zeros in the writemask mark bitplanes as read-only.  These planes will not be changed, regardless of the bits in the color.  RGBwritemask should be used in RGB mode. 

SEE ALSO

RGBwritemask, color

Version 2.4  —  May 08, 1986