DISPLAY_ENABLE(3G)

NAME

display_enable − select which planes of a raster device are to be displayed.

SYNOPSIS

C SYNTAX

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

FORTRAN77 SYNTAX

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

PASCAL SYNTAX

procedure display_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 drive the visual output. 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 2nd bit is 1, then plane 2 is enabled, etc.

DISCUSSION

The planes of the frame buffer device that are disabled will drive the visual output as if they were zeros. For example, if the background_color_index was set to 170 (hex AA) and the display is cleared then: for plane_mask = 255 (hex FF) the color seen would be the color at color table index 170, for plane_mask = 15 (hex 0F) then the color seen would be the color at color table index 10 (hex 0A), etc. This procedure, along with write_enable are very useful if undisplayed bit planes are to be written into while leaving the displayed ones unchanged (double-buffering).

Some devices may not support this operation.

DEFAULTS

Plane_index=255. All planes enabled

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