Class globals screen display

screen.display
------------------------------------------------------------------------------
Class that manages a dialog, which displays an arbitrary number of properties
periodically updating the values. Property names are abbreviated to the
shortest possible unique part.

Example:

var dpy = screen.display.new(20, 10);    # x/y coordinate
dpy.setcolor(1, 0, 1);                   # magenta (default: white)
dpy.setfont("SANS_12B",12);              # see $FG_ROOT/gui/styles/*.xml

dpy.add("/position/latitude-deg", "/position/longitude-deg");
dpy.add(props.globals.getNode("/orientation").getChildren());


The add() method takes one or more property paths or props.Nodes, or a vector
containing those, or a hash with properties, or vectors with properties, etc.
Internal "public" parameters may be set directly:

dpy.interval = 0;                        # update every frame
dpy.format = "%.3g";                     # max. 3 digits fractional part
dpy.tagformat = "%-12s";                 # align prop names to 12 spaces
dpy.redraw();                            # pick up new settings


The open() method should only be used to undo a close() call. In all other
cases this is done implicitly. redraw() is automatically called by an add(),
but can be used to let the dialog pick up new settings of internal variables.


Methods add(), setfont() and setcolor() can be appended to the new()
constructor (-> show big yellow frame rate counter in upper right corner):

screen.display.new(-15, -5, 0).setfont("TIMES_24").setcolor(1, 0.9, 0).add("/sim/frame-rate");