DISPLAY_ELEMENT(3G)

NAME

display_element − display current element on specified graphics display device

SYNOPSIS

C Syntax:

void display_element(fildes,devdes)
int fildes,devdes;

FORTRAN77 Syntax:

subroutine display_element(fildes,devdes)
integer*4 fildes,devdes

Pascal Syntax:

procedure display_element(fildes,devdes:integer);

DESCRIPTION

Input Parameters

fildes Integer file descriptor returned by gopen when an I/O path to a graphics device is opened. This file descriptor identifies the display list device.

devdes Integer file descriptor returned by gopen when an I/O path to a graphics output device is opened. This file descriptor identifies the graphics display device on which the current elment will be displayed.

Discussion

Display_element displays the current element from the open segment of the specified graphics display device.

Display_element generates errors if:

• Fildes does not identify a display list device.

• The current element of the open segment is element 0 (element 0 cannot be displayed).

• There is no currently open segment in the display list identified by fildes.

If the current element is a call_segment element, the segment network is traversed, beginning with the called segment. Set_traversal_depth(3G) can be used to limit the traversal depth. The default maximum traversal depth limits traversal processing to 42 call_segment elements. If a call_segment element would exceed the maximum traversal depth, a warning is generated and the call_segment element is not traversed.

Segment network traversal can also be limited by display traversal control elements (see set_disp_traversal_control(3G)).

Output from the display traversal process is subject to buffering (see buffer_mode(3G)). If buffering is enabled, output from the display traversal process may not be displayed until the buffer is flushed. Calling make_picture_current(3G) will make sure that the buffers have been flushed.

ERRORS

1 Graphics device is not initialized for this operation.

24 Segment not open.

36 At element 0 - element 0 cannot be displayed.

40 Fildes not a display list device.

1042 Warning: Traversal attempted beyond specified maximum traversal depth.

Museum

Related Articles