QUIC/inet/examples/visualization/instruments

This is an example for instrument figures. Here is some background and
usage info on instrument figures.

The following instrument figure types exist: gauge, linearGauge,
progressMeter, thermometer, counter, indicatorLabel, and indicatorText.
They are implemented with the C++ types GaugeFigure, LinearGaugeFigure,
ProgressMeterFigure, ThermometerFigure, CounterFigure,
IndicatorLabelFigurea and IndicatorTextFigure. These C++ types all
implement IIndicatorFigure.

In practice, instrument figures are driven by signals, using a @statistic
for converting emitted signals into calls to IIndicatorFigure's setValue()
method. An example:

@figure[thruputMeter](type=gauge; pos=50,100; size=150,150);
@statistic[dummy](source=throughput; record=figure; targetFigure=thruputMeter);

The first line adds a figure of the type GaugeFigure to the canvas, with
the name thruputMeter. The second line adds a special "figure" result
recorder for the throughput signal. The result recorder (see the
FigureRecorder C++ class) sends every emitted value to the figure denoted
by the targetFigure attribute of the @statistic, in this case thruputMeter.

One issue is that @statistic can only add signal listeners to the current
module (on which the @statistic is declared), but not to a submodule or
sub-submodule. The workaround for this issue is to use a @delegatesignal
property to "teleport" the signal from its emitted module to the module of
the @statistic, under a new name. An example:

@delegatesignal[rcvdPk](source=hostB.udpApp[0].rcvdPk; target=hostB_rcvdPk);
@signal[hostB_rcvdPk];

The first line adds a listener to the hostB.udpApp[0] submodule for the
rcvdPk signal, and emits it on the current module as hostB_rcvdPk. A
@statistic can then use hostB_rcvdPk as its source signal. The second,
@signal line is necessary because OMNeT++ only allows declared signals to
be emitted.

IMPORTANT: When using @delegatesignal, the network must contain a
DelegateSignalConfigurator module somewhere, because it is what processes
those properties and makes them work.

See the Wireless Tutorial (tutorials/wireless) for an example.