making a RubberBand for selecting an area

**Uwe** · 13th July 2016, 06:37

QwtPlotZoomer - zooming = QwtPlotPicker;

The keys or mouse actions being used for starting,moving and terminating the selection is customizable.

Uwe

**Alex22** · 13th July 2016, 16:01

Thanks Uwe, I used this and nothing happens and no RubberBand has been appeared:

Qt Code:

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QwtPlotPicker* picker= new QwtPlotPicker( canvas );
 
    picker->setRubberBandPen( QColor( Qt::red ) );
    picker->setTrackerPen( QColor( Qt::green ) );
    picker->setMousePattern( QwtEventPattern::MouseSelect2,
        Qt::RightButton, Qt::ControlModifier );

QwtPlotPicker* picker= new QwtPlotPicker( canvas );

    picker->setRubberBandPen( QColor( Qt::red ) );
    picker->setTrackerPen( QColor( Qt::green ) );
    picker->setMousePattern( QwtEventPattern::MouseSelect2,
        Qt::RightButton, Qt::ControlModifier );

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**Uwe** · 13th July 2016, 19:43

This is your initial sequence to get something started:

Qt Code:

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QwtPlotPicker* picker= new QwtPlotPicker( plot->canvas() );
picker->setStateMachine( new QwtPickerDragRectMachine() );
picker->setRubberBand( QwtPlotPicker::RectRubberBand );
picker->setRubberBandPen( QColor( Qt::red ) );
picker->setTrackerPen( QColor( Qt::green ) );
picker->setTrackerMode( QwtPlotPicker::ActiveOnly );
 
connect( picker, SIGNAL( selected( const QRectF &rect ) ), ... );

QwtPlotPicker* picker= new QwtPlotPicker( plot->canvas() );
picker->setStateMachine( new QwtPickerDragRectMachine() );
picker->setRubberBand( QwtPlotPicker::RectRubberBand );
picker->setRubberBandPen( QColor( Qt::red ) );
picker->setTrackerPen( QColor( Qt::green ) );
picker->setTrackerMode( QwtPlotPicker::ActiveOnly );

connect( picker, SIGNAL( selected( const QRectF &rect ) ), ... );

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Choose the type of state machine you like and check its docs, what type of event patterns are used by it. In case of the rectangle machines it is using QwtEventPattern::MouseSelect1 and QwtEventPattern::KeySelect1 - what means changing QwtEventPattern::MouseSelect2 ( like in your code snippet ) will have no effect.

Uwe