Add files from zip

examples/refreshtest/CircularBuffer.cpp

@@ -0,0 +1,78 @@
+/*****************************************************************************
+ * Qwt Examples - Copyright (C) 2002 Uwe Rathmann
+ * This file may be used under the terms of the 3-clause BSD License
+ *****************************************************************************/
+
+#include "CircularBuffer.h"
+#include <QwtMath>
+
+CircularBuffer::CircularBuffer( double interval, size_t numPoints )
+    : m_y( NULL )
+    , m_referenceTime( 0.0 )
+    , m_startIndex( 0 )
+    , m_offset( 0.0 )
+{
+    fill( interval, numPoints );
+}
+
+void CircularBuffer::fill( double interval, size_t numPoints )
+{
+    if ( interval <= 0.0 || numPoints < 2 )
+        return;
+
+    m_values.resize( numPoints );
+    m_values.fill( 0.0 );
+
+    if ( m_y )
+    {
+        m_step = interval / ( numPoints - 2 );
+        for ( size_t i = 0; i < numPoints; i++ )
+            m_values[i] = m_y( i * m_step );
+    }
+
+    m_interval = interval;
+}
+
+void CircularBuffer::setFunction( double ( * y )( double ) )
+{
+    m_y = y;
+}
+
+void CircularBuffer::setReferenceTime( double timeStamp )
+{
+    m_referenceTime = timeStamp;
+
+    const double startTime = std::fmod( m_referenceTime, m_values.size() * m_step );
+
+    m_startIndex = int( startTime / m_step ); // floor
+    m_offset = std::fmod( startTime, m_step );
+}
+
+double CircularBuffer::referenceTime() const
+{
+    return m_referenceTime;
+}
+
+size_t CircularBuffer::size() const
+{
+    return m_values.size();
+}
+
+QPointF CircularBuffer::sample( size_t i ) const
+{
+    const int size = m_values.size();
+
+    int index = m_startIndex + i;
+    if ( index >= size )
+        index -= size;
+
+    const double x = i * m_step - m_offset - m_interval;
+    const double y = m_values.data()[index];
+
+    return QPointF( x, y );
+}
+
+QRectF CircularBuffer::boundingRect() const
+{
+    return QRectF( -1.0, -m_interval, 2.0, m_interval );
+}