ECHO_TYPE(3G)

NAME

echo_type − change the type of echo being used on an output device.

SYNOPSIS

C SYNTAX

void echo_type(fildes,echo_number,echo_value,x,y,z);
int fildes,echo_number,echo_value;
float x,y,z; void dcecho_type(fildes,echo_number,echo_value,dcx,dcy);
int fildes,echo_number,echo_value,dcx,dcy;

FORTRAN77 SYNTAX

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

        subroutine dcecho_type(fildes,echo_number,echo_value,dcx,dcy)
        integer*4 fildes,echo_number,echo_value,dcx,dcy

PASCAL SYNTAX

procedure echo_type(fildes,echo_number,echo_value:integer;
x,y,z:real);
procedure dcecho_type(fildes,echo_number,echo_value,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 a particular echo to be modified if the graphic device supports more than one simultaneous echo. For devices with single echo outputs, use 0 (zero).
echo_value
indicates the type of the echo to be used by the device. Predefined types are listed below.

        0 - no echo
        1 - device’s best echo
        2 - full screen cross hair
        3 - small tracking cross
        4 - rubber band line
        5 - rubber band rectangle
        6 - alpha digital representation
        7 - user defined raster cursor
        >= 8 - device dependent representation

There is no maximum value for echo_value so if a device does not support any of the above echos, #1 is used.
x,y,z
define the position for the echo in Virtual Device Coordinates.
dcx,dcy
define the position for the echo in device coordinates.

DISCUSSION

Echo_type defines what type of echo is to be used for the echo number specified and the echo’s initial location. For echo types that use one stationary point and one moving point, such as rubber band line echo, this initial position is also used as a stationary (base) point.

Having an echo on will reduce the performance of output primitives for most devices. Therefore, turning the echo off when it is not needed is recommended.

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