qt_demoe/qwtdemo/qwt/qwt_sampling_thread.cpp

107 lines
2.2 KiB
C++

/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
* Qwt Widget Library
* Copyright (C) 1997 Josef Wilgen
* Copyright (C) 2002 Uwe Rathmann
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the Qwt License, Version 1.0
*****************************************************************************/
#include "qwt_sampling_thread.h"
#include "qwt_system_clock.h"
class QwtSamplingThread::PrivateData
{
public:
QwtSystemClock clock;
double interval;
bool isStopped;
};
//! Constructor
QwtSamplingThread::QwtSamplingThread( QObject *parent ):
QThread( parent )
{
d_data = new PrivateData;
d_data->interval = 1000; // 1 second
d_data->isStopped = true;
}
//! Destructor
QwtSamplingThread::~QwtSamplingThread()
{
delete d_data;
}
/*!
Change the interval (in ms), when sample() is called.
The default interval is 1000.0 ( = 1s )
\param interval Interval
\sa interval()
*/
void QwtSamplingThread::setInterval( double interval )
{
if ( interval < 0.0 )
interval = 0.0;
d_data->interval = interval;
}
/*!
\return Interval (in ms), between 2 calls of sample()
\sa setInterval()
*/
double QwtSamplingThread::interval() const
{
return d_data->interval;
}
/*!
\return Time (in ms) since the thread was started
\sa QThread::start(), run()
*/
double QwtSamplingThread::elapsed() const
{
if ( d_data->isStopped )
return 0.0;
return d_data->clock.elapsed();
}
/*!
Terminate the collecting thread
\sa QThread::start(), run()
*/
void QwtSamplingThread::stop()
{
d_data->isStopped = true;
}
/*!
Loop collecting samples started from QThread::start()
\sa stop()
*/
void QwtSamplingThread::run()
{
d_data->clock.start();
d_data->isStopped = false;
while ( !d_data->isStopped )
{
const double elapsed = d_data->clock.elapsed();
sample( elapsed / 1000.0 );
if ( d_data->interval > 0.0 )
{
const double msecs =
d_data->interval - ( d_data->clock.elapsed() - elapsed );
if ( msecs > 0.0 )
usleep( qRound( 1000.0 * msecs ) );
}
}
}