Spectra::display()
Display the active GQEs.
Spectra::display( cls => 'yes');
The graphical screen is cleared before the display.
Spectra::display( over => 'yes');
No clear-screen, no axes, no TEXTs. An example can be
found in 10.13.
Spectra::display( update => 'yes');
This parameter
is an Online feature: The whole plot is re-displayed only, if one
SCAN changes its window limits. Otherwise the new data points are
just filled in. See also section 7.4.6.
Spectra::display( vp => 'yes');
This flag tells Spectra to display all active GQEs in separate viewports.