Qwt User's Guide: QwtSamplingThread Class Reference

Qwt User's Guide 6.1.3

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QwtSamplingThread Class Referenceabstract

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

`#include <qwt_sampling_thread.h>`

Inheritance diagram for QwtSamplingThread:
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## Public Slots
void | setInterval (double interval)
void | stop ()

## Public Member Functions
virtual | ~QwtSamplingThread ()
| Destructor.
double | interval () const
double | elapsed () const

## Protected Member Functions
| QwtSamplingThread (QObject *parent=NULL)
| Constructor.
virtual void | run ()
virtual void | sample (double elapsed)=0

## Detailed Description

A thread collecting samples at regular intervals.

Continuous 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 periodically sample(), to collect and store ( or emit ) a single sample.

See also
  QwtPlotCurve, QwtPlotSeriesItem

## 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 | ( |  | ) |
| protectedvirtual

Loop collecting samples started from QThread::start()

See also
  stop()

virtual void QwtSamplingThread::sample | ( | double | elapsed | ) |
| protectedpure virtual

Collect a sample

Parameters

  elapsed | Time since the thread was started in milliseconds

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()