ECHO_UPDATE(3G)

NAME

echo_update − change the position of the output device’s echo.

SYNOPSIS

C SYNTAX

void echo_update(fildes,echo_number,x,y,z);
int fildes,echo_number;
float x,y,z;

void dcecho_update(fildes,echo_number,dcx,dcy);
int fildes,echo_number,dcx,dcy;

FORTRAN77 SYNTAX

        subroutine echo_update(fildes,echo_number,x,y,z)
        integer*4 fildes,echo_number
        real x,y,z

        subroutine dcecho_update(fildes,echo_number,dcx,dcy)
        integer*4 fildes,echo_number,dcx,dcy

PASCAL SYNTAX

procedure echo_update(fildes,echo_number:integer;
x,y,z:real);
procedure dcecho_update(fildes,echo_number,dcx,dcy:integer);

HP-UX COMPATIBILITY

Level: HP-UX/STANDARD

Origin: ANSI Computer Graphics Interface

DESCRIPTION

INPUT PARAMETERS

fildes
is an integer file descriptor returned by gopen when an I/O path to a graphic device is opened.
echo_number
selects the particular echo to be moved if the graphics device supports more than one simultaneous echo. For single echo devices, use 0 (zero).
x,y,z
define the updated position of the echo in Virtual Device Coordinates.
dcx,dcy
define the updated position of the echo in Device Coordinates.

DISCUSSION

echo_update defines an updated echo position for the echo number specified. For echo types that use one stationary point and one moving point determined by the input device’s location, such as rubber band line echo, this updated position is used as the moving point. The initial position set with the echo_type command is then used as the base point of the echo.

If tracking is on, echo_update will have little effect on the position of the echo as the tracking process will very soon move it to the current locator position.

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