lan_spect_stream::set_background

Source: stream/spect/Lan/lan_spect_stream__set_background.pro

 lan_spect_stream::set_background
        Set the backgrounds for a lan rates stream.

 Usage:
        strid->set_background, bglevel

 Argument:
        bglevel The background level (or levels) for the stream.

 Keywords:
        before  If set, then bglevel is a scalar with the level before
                the shift.
        after   If set, then bglevel is a scalar with the level after
                the shift
        index   int     The channel index to change. Note that this is
                        a zero-based channel index from the list of
                        channels in the current group.
        default If set, then restore the default background levels
                from IDF.DAT

 History:
        Original: 20/3/00; SJT
        Clear ready flag in parent if needed: 11/7/00; SJT
        Add default key: 17/4/02; SJT