WRITE_ENABLE(3G)

NAME

write_enable − select which planes of a frame buffer device are modifiable.

SYNOPSIS

C SYNTAX

void write_enable(fildes,plane_mask);
int fildes;
int plane_mask;

FORTRAN77 SYNTAX

subroutine write_enable(fildes,plane_mask)
integer*4 fildes,plane_mask

PASCAL SYNTAX

procedure write_enable(fildes,plane_mask:integer);

HP-UX COMPATIBILITY

Level: HP-UX/STANDARD

Origin: HP

DESCRIPTION

INPUT PARAMETERS

fildes
is an integer file descriptor returned by gopen when an I/O path to a graphics device is opened.
plane_mask
is a mask that is used to determine which planes are enabled to be modified. Each bit is interpreted as the plane enable of that respective plane; i.e., If least significant bit is 0 then plane 1 is disabled. If the 2nd bit is 1, then plane 2 is enabled, etc.

DISCUSSION

If a plane is disabled writing into the frame buffer will not affect that plane. For example if the plane_mask is 15 (hex 0F) and 170 (hex AA) is written into a location containing 85 (hex 55), then that location will change to 90 (hex 5A).

All the raster operations and output primitives are affected by write_enable.

Write_enable is useful if some bit planes are to be written into while leaving others unchanged in conjunction with display_enable (double buffering).

DEFAULTS

All planes are enabled.

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