NAME

writemask - grant write permission to available bitplanes

SYNOPSIS

C
writemask(wtm)
Colorindex wtm;

FORTRAN
subroutine writem(wtm)
integer*2 wtm

Pascal
procedure writemask(wtm: Colorindex);

DESCRIPTION

Writemask shields bitplanes reserved for special uses from ordinary drawing commands.  Its argument is a mask with one bit per available bitplane.  Wherever there are one’s 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. 

If an invalid writemask is specified, it is replaced with the maximum color map index. 

SEE ALSO

RGBwritemask

Version 2.3  —  July 04, 1985