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QwtSamplingThread(3) Qwt User's Guide QwtSamplingThread(3)

NAME

QwtSamplingThread -
A thread collecting samples at regular intervals.

SYNOPSIS

#include <qwt_sampling_thread.h>

Public Slots


void setInterval (double interval)
 
void stop ()
 

Public Member Functions


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

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 (doubleelapsed) [protected, pure virtual] Collect a sample

Parameters:
elapsed Time since the thread was started in miliseconds

void QwtSamplingThread::setInterval (doubleinterval) [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()

Author

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Fri Apr 15 2011 Version 6.0.0