彻底改版2.0

third/qwtdemo/examples/oscilloscope/samplingthread.cpp

@@ -0,0 +1,54 @@
+#include "samplingthread.h"
+#include "signaldata.h"
+#include <qwt_math.h>
+#include <math.h>
+
+#if QT_VERSION < 0x040600
+#define qFastSin(x) ::sin(x)
+#endif
+
+SamplingThread::SamplingThread( QObject *parent ):
+    QwtSamplingThread( parent ),
+    d_frequency( 5.0 ),
+    d_amplitude( 20.0 )
+{
+}
+
+void SamplingThread::setFrequency( double frequency )
+{
+    d_frequency = frequency;
+}
+
+double SamplingThread::frequency() const
+{
+    return d_frequency;
+}
+
+void SamplingThread::setAmplitude( double amplitude )
+{
+    d_amplitude = amplitude;
+}
+
+double SamplingThread::amplitude() const
+{
+    return d_amplitude;
+}
+
+void SamplingThread::sample( double elapsed )
+{
+    if ( d_frequency > 0.0 )
+    {
+        const QPointF s( elapsed, value( elapsed ) );
+        SignalData::instance().append( s );
+    }
+}
+
+double SamplingThread::value( double timeStamp ) const
+{
+    const double period = 1.0 / d_frequency;
+
+    const double x = ::fmod( timeStamp, period );
+    const double v = d_amplitude * qFastSin( x / period * 2 * M_PI );
+
+    return v;
+}