138 lines
3.4 KiB
C++
138 lines
3.4 KiB
C++
/*****************************************************************************
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* Qwt Examples - Copyright (C) 2002 Uwe Rathmann
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* This file may be used under the terms of the 3-clause BSD License
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*****************************************************************************/
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#include "CurveTracker.h"
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#include <QwtPickerMachine>
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#include <QwtPlot>
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#include <QwtPlotCurve>
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#include <QwtText>
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#include <QPen>
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struct compareX
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{
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inline bool operator()( const double x, const QPointF& pos ) const
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{
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return ( x < pos.x() );
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}
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};
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CurveTracker::CurveTracker( QWidget* canvas )
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: QwtPlotPicker( canvas )
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{
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setTrackerMode( QwtPlotPicker::ActiveOnly );
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setRubberBand( VLineRubberBand );
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setStateMachine( new QwtPickerDragPointMachine() );
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}
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QRect CurveTracker::trackerRect( const QFont& font ) const
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{
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QRect r = QwtPlotPicker::trackerRect( font );
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// align r to the first curve
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const QwtPlotItemList curves = plot()->itemList( QwtPlotItem::Rtti_PlotCurve );
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if ( curves.size() > 0 )
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{
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QPointF pos = invTransform( trackerPosition() );
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const QLineF line = curveLineAt(
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static_cast< const QwtPlotCurve* >( curves[0] ), pos.x() );
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if ( !line.isNull() )
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{
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const double curveY = line.pointAt(
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( pos.x() - line.p1().x() ) / line.dx() ).y();
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pos.setY( curveY );
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pos = transform( pos );
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r.moveBottom( pos.y() );
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}
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}
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return r;
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}
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QwtText CurveTracker::trackerTextF( const QPointF& pos ) const
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{
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QwtText trackerText;
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trackerText.setColor( Qt::black );
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QColor c( "#333333" );
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trackerText.setBorderPen( QPen( c, 2 ) );
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c.setAlpha( 200 );
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trackerText.setBackgroundBrush( c );
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QString info;
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const QwtPlotItemList curves =
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plot()->itemList( QwtPlotItem::Rtti_PlotCurve );
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for ( int i = 0; i < curves.size(); i++ )
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{
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const QString curveInfo = curveInfoAt(
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static_cast< const QwtPlotCurve* >( curves[i] ), pos );
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if ( !curveInfo.isEmpty() )
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{
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if ( !info.isEmpty() )
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info += "<br>";
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info += curveInfo;
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}
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}
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trackerText.setText( info );
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return trackerText;
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}
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QString CurveTracker::curveInfoAt(
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const QwtPlotCurve* curve, const QPointF& pos ) const
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{
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const QLineF line = curveLineAt( curve, pos.x() );
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if ( line.isNull() )
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return QString();
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const double y = line.pointAt(
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( pos.x() - line.p1().x() ) / line.dx() ).y();
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QString info( "<font color=" "%1" ">%2</font>" );
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return info.arg( curve->pen().color().name() ).arg( y );
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}
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QLineF CurveTracker::curveLineAt(
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const QwtPlotCurve* curve, double x ) const
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{
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QLineF line;
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if ( curve->dataSize() >= 2 )
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{
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const QRectF br = curve->boundingRect();
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if ( ( br.width() > 0 ) && ( x >= br.left() ) && ( x <= br.right() ) )
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{
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int index = qwtUpperSampleIndex< QPointF >(
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*curve->data(), x, compareX() );
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if ( index == -1 &&
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x == curve->sample( curve->dataSize() - 1 ).x() )
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{
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// the last sample is excluded from qwtUpperSampleIndex
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index = curve->dataSize() - 1;
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}
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if ( index > 0 )
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{
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line.setP1( curve->sample( index - 1 ) );
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line.setP2( curve->sample( index ) );
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}
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}
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}
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return line;
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}
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