彻底改版2.0

third/3rd_qwt/qwt_sampling_thread.cpp

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+/* -*- 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 ) );
+        }
+    }
+}