refresh_element(3G)

NAME

refresh_element − display the current element on the associated graphics display device

SYNOPSIS

C Syntax:

void refresh_element(fildes)
int fildes;

FORTRAN77 Syntax:

subroutine refresh_element(fildes)
integer*4 fildes

Pascal Syntax:

procedure refresh_element(fildes:integer);

DESCRIPTION

Input Parameters

fildes Integer file descriptor returned by gopen when an I/O path to a graphics output device is opened.

Discussion

Refresh_element displays the current element of the open segment on its associated graphics display device.

If a segment is open on graphics display device fildes, the segment is, in effect, closed during traversal, then reopened when display traversal is complete. This prevents new elements from being entered into an open segment as a result of refresh operations.

The current element of an open segment must not be element zero because element 0 cannot be displayed. Violating this rule generates an error.

If there is no open segment in the display list fildes, an error is generated.

If the current element is a call_segment or execute_segment element, the segment network is traversed, beginning with the referenced segment. If the current element is a cond_call_segment or cond_execute_segment element, the segment referenced by that element is traversed if the conditions specified with that element are met.

Set_traversal_depth(3G) can be used to limit the traversal depth. The default maximum traversal depth limits traversal processing to 42 segment-referencing elements (i.e., call_segment, execute_segment, cond_call_segment or cond_execute_segment). If traversal of one of these elements would exceed the maximum traversal depth, a warning is generated and the 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 will not be displayed until the buffer is flushed. Calling make_picture_current(3G) will ensure that the buffers have been flushed.

When refresh_element(3G) is called using the HP 98736, the VDMA interface will be used automatically.

ERRORS

1 Graphics device is not initialized for this operation.

24 Segment not open.

36 At element 0 - element 0 cannot be refreshed.

1042 Warning: Traversal attempted beyond specified maximum traversal depth.

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