# QwtSamplingThread Class Reference

A thread collecting samples at regular intervals. More...

`#include <qwt_sampling_thread.h>`

List of all members.

## Public Slots

void | setInterval (double interval)
void | stop ()

## Public Member Functions

double | elapsed () const
double | interval () const
virtual | ~QwtSamplingThread ()

## Protected Member Functions

| QwtSamplingThread (QObject *parent=NULL)
virtual void | run ()
virtual void | sample (double elapsed)=0

## Detailed Description

A thread collecting samples at regular intervals.

Contiounous signals are converted into a discrete signal by collecting samples at regular intervals. A discrete signal can be displayed by a QwtPlotSeriesItem on a QwtPlot widget.

QwtSamplingThread starts a thread calling perodically sample(), to collect and store ( or emit ) a single sample.

See also:
  QwtPlotCurve, QwtPlotSeriesItem

## Constructor & Destructor Documentation

QwtSamplingThread::~QwtSamplingThread | ( |  | ) | `[virtual]`

Destructor.

QwtSamplingThread::QwtSamplingThread | ( | QObject * | parent = `NULL` | ) | `[explicit, protected]`

Constructor.

## Member Function Documentation

double QwtSamplingThread::elapsed | ( |  | ) | const

Returns:
  Time (in ms) since the thread was started

See also:
  QThread::start(), run()

double QwtSamplingThread::interval | ( |  | ) | const

Returns:
  Interval (in ms), between 2 calls of sample()

See also:
  setInterval()

void QwtSamplingThread::run | ( |  | ) | `[protected, virtual]`

Loop collecting samples started from QThread::start()

See also:
  stop()

virtual void QwtSamplingThread::sample | ( | double | elapsed | ) | `[protected, pure virtual]`

Collect a sample

Parameters:

  elapsed | Time since the thread was started in miliseconds

void QwtSamplingThread::setInterval | ( | double | interval | ) | `[slot]`

Change the interval (in ms), when sample() is called. The default interval is 1000.0 ( = 1s )

Parameters:

  interval | Interval

See also:
  interval()

void QwtSamplingThread::stop | ( |  | ) | `[slot]`

Terminate the collecting thread

See also:
  QThread::start(), run()