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examples/splineeditor/CanvasPicker.cpp

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+/*****************************************************************************
+ * Qwt Examples - Copyright (C) 2002 Uwe Rathmann
+ * This file may be used under the terms of the 3-clause BSD License
+ *****************************************************************************/
+
+#include "CanvasPicker.h"
+
+#include <QwtPlot>
+#include <QwtPlotCurve>
+
+#include <QMouseEvent>
+
+CanvasPicker::CanvasPicker( bool sortedX, QwtPlot* plot )
+    : QObject( plot )
+    , m_selectedPoint( -1 )
+    , m_sortedX( sortedX )
+{
+    plot->canvas()->installEventFilter( this );
+}
+
+QwtPlot* CanvasPicker::plot()
+{
+    return qobject_cast< QwtPlot* >( parent() );
+}
+
+const QwtPlot* CanvasPicker::plot() const
+{
+    return qobject_cast< const QwtPlot* >( parent() );
+}
+
+bool CanvasPicker::eventFilter( QObject* object, QEvent* event )
+{
+    if ( plot() == NULL || object != plot()->canvas() )
+        return false;
+
+    switch( event->type() )
+    {
+        case QEvent::MouseButtonPress:
+        {
+            const QMouseEvent* mouseEvent = static_cast< QMouseEvent* >( event );
+            select( mouseEvent->pos() );
+            return true;
+        }
+        case QEvent::MouseMove:
+        {
+            const QMouseEvent* mouseEvent = static_cast< QMouseEvent* >( event );
+            move( mouseEvent->pos() );
+            return true;
+        }
+        default:
+            break;
+    }
+
+    return QObject::eventFilter( object, event );
+}
+
+// Select the point at a position. If there is no point
+// deselect the selected point
+
+void CanvasPicker::select( const QPointF& pos )
+{
+    QwtPlotCurve* curve = NULL;
+    double dist = 10e10;
+    int index = -1;
+
+    const QwtPlotItemList& itmList = plot()->itemList();
+    for ( QwtPlotItemIterator it = itmList.begin();
+        it != itmList.end(); ++it )
+    {
+        if ( ( *it )->rtti() == QwtPlotItem::Rtti_PlotCurve )
+        {
+            QwtPlotCurve* c = static_cast< QwtPlotCurve* >( *it );
+            if ( c->isVisible() )
+            {
+                double d;
+                int idx = c->closestPoint( pos, &d );
+                if ( d < dist )
+                {
+                    curve = c;
+                    index = idx;
+                    dist = d;
+                }
+            }
+        }
+    }
+
+    m_selectedCurve = NULL;
+    m_selectedPoint = -1;
+
+    if ( curve && dist < 10 ) // 10 pixels tolerance
+    {
+        m_selectedCurve = curve;
+        m_selectedPoint = index;
+    }
+}
+
+// Move the selected point
+void CanvasPicker::move( const QPointF& pos )
+{
+    if ( m_selectedCurve == 0 || m_selectedPoint < 0  )
+        return;
+
+    QVector< double > xData( m_selectedCurve->dataSize() );
+    QVector< double > yData( m_selectedCurve->dataSize() );
+
+    double dx = 0.0;
+    double dy = 0.0;
+
+    int numPoints = static_cast< int >( m_selectedCurve->dataSize() );
+    for ( int i = 0; i < numPoints; i++ )
+    {
+        const QPointF sample = m_selectedCurve->sample( i );
+
+        if ( i == m_selectedPoint )
+        {
+            double x = plot()->invTransform(
+                m_selectedCurve->xAxis(), pos.x() );
+            double y = plot()->invTransform(
+                m_selectedCurve->yAxis(), pos.y() );
+
+            if ( m_sortedX )
+            {
+                if ( i > 0 )
+                {
+                    const double xMin = m_selectedCurve->sample( i - 1 ).x();
+                    if ( x <= xMin )
+                        x = xMin + 1;
+                }
+
+                if ( i < numPoints - 1 )
+                {
+                    const double xMax = m_selectedCurve->sample( i + 1 ).x();
+                    if ( x >= xMax )
+                        x = xMax - 1;
+                }
+            }
+
+            xData[i] = x;
+            yData[i] = y;
+
+            dx = x - sample.x();
+            dy = y - sample.y();
+        }
+        else
+        {
+            xData[i] = sample.x();
+            yData[i] = sample.y();
+        }
+    }
+    m_selectedCurve->setSamples( xData, yData );
+
+    const QwtPlotItemList curves = plot()->itemList( QwtPlotItem::Rtti_PlotCurve );
+    for ( int i = 0; i < curves.size(); i++ )
+    {
+        QwtPlotCurve* curve = static_cast< QwtPlotCurve* >( curves[i] );
+        if ( curve == m_selectedCurve )
+            continue;
+
+        xData.resize( curve->dataSize() );
+        yData.resize( curve->dataSize() );
+
+        numPoints = static_cast< int >( curve->dataSize() );
+        for ( int j = 0; j < numPoints; j++ )
+        {
+            const QPointF sample = curve->sample( j );
+
+            xData[j] = sample.x();
+            yData[j] = sample.y();
+
+            if ( j == m_selectedPoint )
+            {
+                xData[j] += dx;
+                yData[j] += dy;
+            }
+        }
+        curve->setSamples( xData, yData );
+    }
+
+    plot()->replot();
+}