qwt_picker.cpp

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/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#include "qwt_picker.h"
#include "qwt_picker_machine.h"
#include "qwt_painter.h"
#include "qwt_math.h"
#include "qwt_widget_overlay.h"
#include <qapplication.h>
#include <qevent.h>
#include <qpainter.h>
#include <qframe.h>
#include <qcursor.h>
#include <qbitmap.h>
#include <qpointer.h>
#include <qpaintengine.h>
#include <qmath.h>

static inline QRegion qwtMaskRegion( const QRect &r, int penWidth )
{
    const int pw = qMax( penWidth, 1 );
    const int pw2 = penWidth / 2;

    int x1 = r.left() - pw2;
    int x2 = r.right() + 1 + pw2 + ( pw % 2 );

    int y1 = r.top() - pw2;
    int y2 = r.bottom() + 1 + pw2 + ( pw % 2 );

    QRegion region;

    region += QRect( x1, y1, x2 - x1, pw );
    region += QRect( x1, y1, pw, y2 - y1 );
    region += QRect( x1, y2 - pw, x2 - x1, pw );
    region += QRect( x2 - pw, y1, pw, y2 - y1 );

    return region;
}

static inline QRegion qwtMaskRegion( const QLine &l, int penWidth )
{
    const int pw = qMax( penWidth, 1 );
    const int pw2 = penWidth / 2;

    QRegion region;

    if ( l.x1() == l.x2() )
    {
        region += QRect( l.x1() - pw2, l.y1(), 
            pw, l.y2() ).normalized();
    }
    else if ( l.y1() == l.y2() )
    {
        region += QRect( l.x1(), l.y1() - pw2, 
            l.x2(), pw ).normalized();
    }

    return region;
}

class QwtPickerRubberband: public QwtWidgetOverlay
{
public:
    QwtPickerRubberband( QwtPicker *, QWidget * );

protected:
    virtual void drawOverlay( QPainter * ) const;
    virtual QRegion maskHint() const;

    QwtPicker *d_picker;
};

class QwtPickerTracker: public QwtWidgetOverlay
{                                  
public:
    QwtPickerTracker( QwtPicker *, QWidget * );
    
protected:
    virtual void drawOverlay( QPainter * ) const;
    virtual QRegion maskHint() const;
    
    QwtPicker *d_picker;
};  


class QwtPicker::PrivateData
{
public:
    PrivateData():
        enabled( false ),
        stateMachine( NULL ),
        resizeMode( QwtPicker::Stretch ),
        rubberBand( QwtPicker::NoRubberBand ),
        trackerMode( QwtPicker::AlwaysOff ),
        isActive( false ),
        trackerPosition( -1, -1 ),
        mouseTracking( false ),
        openGL( false )
    {
    }
        
    bool enabled;

    QwtPickerMachine *stateMachine;

    QwtPicker::ResizeMode resizeMode;

    QwtPicker::RubberBand rubberBand;
    QPen rubberBandPen;

    QwtPicker::DisplayMode trackerMode;
    QPen trackerPen;
    QFont trackerFont;

    QPolygon pickedPoints;
    bool isActive;
    QPoint trackerPosition;

    bool mouseTracking; // used to save previous value

    QPointer< QwtPickerRubberband > rubberBandOverlay;
    QPointer< QwtPickerTracker> trackerOverlay;

    bool openGL;
};

QwtPickerRubberband::QwtPickerRubberband(
        QwtPicker *picker, QWidget *parent ):
    QwtWidgetOverlay( parent ),
    d_picker( picker )
{
    setMaskMode( QwtWidgetOverlay::MaskHint );
}

QRegion QwtPickerRubberband::maskHint() const
{
    return d_picker->rubberBandMask();
}

void QwtPickerRubberband::drawOverlay( QPainter *painter ) const
{
    painter->setPen( d_picker->rubberBandPen() );
    d_picker->drawRubberBand( painter );
}

QwtPickerTracker::QwtPickerTracker(
        QwtPicker *picker, QWidget *parent ):
    QwtWidgetOverlay( parent ),
    d_picker( picker )
{
    setMaskMode( QwtWidgetOverlay::MaskHint );
}

QRegion QwtPickerTracker::maskHint() const
{
    return d_picker->trackerMask();
}

void QwtPickerTracker::drawOverlay( QPainter *painter ) const
{
    painter->setPen( d_picker->trackerPen() );
    d_picker->drawTracker( painter );
}

QwtPicker::QwtPicker( QWidget *parent ):
    QObject( parent )
{
    init( parent, NoRubberBand, AlwaysOff );
}

QwtPicker::QwtPicker( RubberBand rubberBand,
        DisplayMode trackerMode, QWidget *parent ):
    QObject( parent )
{
    init( parent, rubberBand, trackerMode );
}

QwtPicker::~QwtPicker()
{
    setMouseTracking( false );

    delete d_data->stateMachine;
    delete d_data->rubberBandOverlay;
    delete d_data->trackerOverlay;

    delete d_data;
}

void QwtPicker::init( QWidget *parent,
    RubberBand rubberBand, DisplayMode trackerMode )
{
    d_data = new PrivateData;

    d_data->rubberBand = rubberBand;

    if ( parent )
    {
        if ( parent->focusPolicy() == Qt::NoFocus )
            parent->setFocusPolicy( Qt::WheelFocus );

        d_data->openGL = parent->inherits( "QGLWidget" );
        d_data->trackerFont = parent->font();
        d_data->mouseTracking = parent->hasMouseTracking();

        setEnabled( true );
    }

    setTrackerMode( trackerMode );
}

void QwtPicker::setStateMachine( QwtPickerMachine *stateMachine )
{
    if ( d_data->stateMachine != stateMachine )
    {
        reset();

        delete d_data->stateMachine;
        d_data->stateMachine = stateMachine;

        if ( d_data->stateMachine )
            d_data->stateMachine->reset();
    }
}

QwtPickerMachine *QwtPicker::stateMachine()
{
    return d_data->stateMachine;
}

const QwtPickerMachine *QwtPicker::stateMachine() const
{
    return d_data->stateMachine;
}

QWidget *QwtPicker::parentWidget()
{
    QObject *obj = parent();
    if ( obj && obj->isWidgetType() )
        return static_cast<QWidget *>( obj );

    return NULL;
}

const QWidget *QwtPicker::parentWidget() const
{
    QObject *obj = parent();
    if ( obj && obj->isWidgetType() )
        return static_cast< const QWidget *>( obj );

    return NULL;
}

void QwtPicker::setRubberBand( RubberBand rubberBand )
{
    d_data->rubberBand = rubberBand;
}

QwtPicker::RubberBand QwtPicker::rubberBand() const
{
    return d_data->rubberBand;
}

void QwtPicker::setTrackerMode( DisplayMode mode )
{
    if ( d_data->trackerMode != mode )
    {
        d_data->trackerMode = mode;
        setMouseTracking( d_data->trackerMode == AlwaysOn );
    }
}

QwtPicker::DisplayMode QwtPicker::trackerMode() const
{
    return d_data->trackerMode;
}

void QwtPicker::setResizeMode( ResizeMode mode )
{
    d_data->resizeMode = mode;
}

QwtPicker::ResizeMode QwtPicker::resizeMode() const
{
    return d_data->resizeMode;
}

void QwtPicker::setEnabled( bool enabled )
{
    if ( d_data->enabled != enabled )
    {
        d_data->enabled = enabled;

        QWidget *w = parentWidget();
        if ( w )
        {
            if ( enabled )
                w->installEventFilter( this );
            else
                w->removeEventFilter( this );
        }

        updateDisplay();
    }
}

bool QwtPicker::isEnabled() const
{
    return d_data->enabled;
}

void QwtPicker::setTrackerFont( const QFont &font )
{
    if ( font != d_data->trackerFont )
    {
        d_data->trackerFont = font;
        updateDisplay();
    }
}

QFont QwtPicker::trackerFont() const
{
    return d_data->trackerFont;
}

void QwtPicker::setTrackerPen( const QPen &pen )
{
    if ( pen != d_data->trackerPen )
    {
        d_data->trackerPen = pen;
        updateDisplay();
    }
}

QPen QwtPicker::trackerPen() const
{
    return d_data->trackerPen;
}

void QwtPicker::setRubberBandPen( const QPen &pen )
{
    if ( pen != d_data->rubberBandPen )
    {
        d_data->rubberBandPen = pen;
        updateDisplay();
    }
}

QPen QwtPicker::rubberBandPen() const
{
    return d_data->rubberBandPen;
}

QwtText QwtPicker::trackerText( const QPoint &pos ) const
{
    QString label;

    switch ( rubberBand() )
    {
        case HLineRubberBand:
            label.sprintf( "%d", pos.y() );
            break;
        case VLineRubberBand:
            label.sprintf( "%d", pos.x() );
            break;
        default:
            label.sprintf( "%d, %d", pos.x(), pos.y() );
    }
    return label;
}

QRegion QwtPicker::trackerMask() const
{
    return trackerRect( d_data->trackerFont );
}

QRegion QwtPicker::rubberBandMask() const
{
    QRegion mask;

    if ( !isActive() || rubberBand() == NoRubberBand ||
        rubberBandPen().style() == Qt::NoPen )
    {
        return mask;
    }

    const QPolygon pa = adjustedPoints( d_data->pickedPoints );

    QwtPickerMachine::SelectionType selectionType =
        QwtPickerMachine::NoSelection;

    if ( d_data->stateMachine )
        selectionType = d_data->stateMachine->selectionType();

    switch ( selectionType )
    {
        case QwtPickerMachine::NoSelection:
        case QwtPickerMachine::PointSelection:
        {
            if ( pa.count() < 1 )
                return mask;

            const QPoint pos = pa[0];
            const int pw = rubberBandPen().width();

            const QRect pRect = pickArea().boundingRect().toRect();
            switch ( rubberBand() )
            {
                case VLineRubberBand:
                {
                    mask += qwtMaskRegion( QLine( pos.x(), pRect.top(), 
                        pos.x(), pRect.bottom() ), pw );
                    break;
                }
                case HLineRubberBand:
                {
                    mask += qwtMaskRegion( QLine( pRect.left(), pos.y(), 
                        pRect.right(), pos.y() ), pw );
                    break;
                }
                case CrossRubberBand:
                {
                    mask += qwtMaskRegion( QLine( pos.x(), pRect.top(), 
                        pos.x(), pRect.bottom() ), pw );
                    mask += qwtMaskRegion( QLine( pRect.left(), pos.y(), 
                        pRect.right(), pos.y() ), pw );
                    break;
                }
                default:
                    break;
            }
            break;
        }
        case QwtPickerMachine::RectSelection:
        {
            if ( pa.count() < 2 )
                return mask;

            const int pw = rubberBandPen().width();

            switch ( rubberBand() )
            {
                case RectRubberBand:
                {
                    const QRect r = QRect( pa.first(), pa.last() );
                    mask = qwtMaskRegion( r.normalized(), pw );
                    break;
                }
                case EllipseRubberBand:
                {
                    const QRect r = QRect( pa.first(), pa.last() );
                    mask += r.adjusted( -pw, -pw, pw, pw );
                    break;
                }
                default:
                    break;
            }
            break;
        }
        case QwtPickerMachine::PolygonSelection:
        {
            const int pw = rubberBandPen().width();
            if ( pw <= 1 )
            {
                // because of the join style we better
                // return a mask for a pen width <= 1 only

                const int off = 2 * pw;
                const QRect r = pa.boundingRect();
                mask += r.adjusted( -off, -off, off, off );
            }
            break;
        }
        default:
            break;
    }

    return mask;
}

void QwtPicker::drawRubberBand( QPainter *painter ) const
{
    if ( !isActive() || rubberBand() == NoRubberBand ||
        rubberBandPen().style() == Qt::NoPen )
    {
        return;
    }

    const QPolygon pa = adjustedPoints( d_data->pickedPoints );

    QwtPickerMachine::SelectionType selectionType =
        QwtPickerMachine::NoSelection;

    if ( d_data->stateMachine )
        selectionType = d_data->stateMachine->selectionType();

    switch ( selectionType )
    {
        case QwtPickerMachine::NoSelection:
        case QwtPickerMachine::PointSelection:
        {
            if ( pa.count() < 1 )
                return;

            const QPoint pos = pa[0];

            const QRect pRect = pickArea().boundingRect().toRect();
            switch ( rubberBand() )
            {
                case VLineRubberBand:
                {
                    QwtPainter::drawLine( painter, pos.x(),
                        pRect.top(), pos.x(), pRect.bottom() );
                    break;
                }
                case HLineRubberBand:
                {
                    QwtPainter::drawLine( painter, pRect.left(),
                        pos.y(), pRect.right(), pos.y() );
                    break;
                }
                case CrossRubberBand:
                {
                    QwtPainter::drawLine( painter, pos.x(),
                        pRect.top(), pos.x(), pRect.bottom() );
                    QwtPainter::drawLine( painter, pRect.left(),
                        pos.y(), pRect.right(), pos.y() );
                    break;
                }
                default:
                    break;
            }
            break;
        }
        case QwtPickerMachine::RectSelection:
        {
            if ( pa.count() < 2 )
                return;

            const QRect rect = QRect( pa.first(), pa.last() ).normalized();
            switch ( rubberBand() )
            {
                case EllipseRubberBand:
                {
                    QwtPainter::drawEllipse( painter, rect );
                    break;
                }
                case RectRubberBand:
                {
                    QwtPainter::drawRect( painter, rect );
                    break;
                }
                default:
                    break;
            }
            break;
        }
        case QwtPickerMachine::PolygonSelection:
        {
            if ( rubberBand() == PolygonRubberBand )
                painter->drawPolyline( pa );
            break;
        }
        default:
            break;
    }
}

void QwtPicker::drawTracker( QPainter *painter ) const
{
    const QRect textRect = trackerRect( painter->font() );
    if ( !textRect.isEmpty() )
    {
        const QwtText label = trackerText( d_data->trackerPosition );
        if ( !label.isEmpty() )
            label.draw( painter, textRect );
    }
}

QPolygon QwtPicker::adjustedPoints( const QPolygon &points ) const
{
    return points;
}

QPolygon QwtPicker::selection() const
{
    return adjustedPoints( d_data->pickedPoints );
}

QPoint QwtPicker::trackerPosition() const
{
    return d_data->trackerPosition;
}

QRect QwtPicker::trackerRect( const QFont &font ) const
{
    if ( trackerMode() == AlwaysOff ||
        ( trackerMode() == ActiveOnly && !isActive() ) )
    {
        return QRect();
    }

    if ( d_data->trackerPosition.x() < 0 || d_data->trackerPosition.y() < 0 )
        return QRect();

    QwtText text = trackerText( d_data->trackerPosition );
    if ( text.isEmpty() )
        return QRect();

    const QSizeF textSize = text.textSize( font );
    QRect textRect( 0, 0, qCeil( textSize.width() ), qCeil( textSize.height() ) );

    const QPoint &pos = d_data->trackerPosition;

    int alignment = 0;
    if ( isActive() && d_data->pickedPoints.count() > 1
        && rubberBand() != NoRubberBand )
    {
        const QPoint last =
            d_data->pickedPoints[int( d_data->pickedPoints.count() ) - 2];

        alignment |= ( pos.x() >= last.x() ) ? Qt::AlignRight : Qt::AlignLeft;
        alignment |= ( pos.y() > last.y() ) ? Qt::AlignBottom : Qt::AlignTop;
    }
    else
        alignment = Qt::AlignTop | Qt::AlignRight;

    const int margin = 5;

    int x = pos.x();
    if ( alignment & Qt::AlignLeft )
        x -= textRect.width() + margin;
    else if ( alignment & Qt::AlignRight )
        x += margin;

    int y = pos.y();
    if ( alignment & Qt::AlignBottom )
        y += margin;
    else if ( alignment & Qt::AlignTop )
        y -= textRect.height() + margin;

    textRect.moveTopLeft( QPoint( x, y ) );

    const QRect pickRect = pickArea().boundingRect().toRect();

    int right = qMin( textRect.right(), pickRect.right() - margin );
    int bottom = qMin( textRect.bottom(), pickRect.bottom() - margin );
    textRect.moveBottomRight( QPoint( right, bottom ) );

    int left = qMax( textRect.left(), pickRect.left() + margin );
    int top = qMax( textRect.top(), pickRect.top() + margin );
    textRect.moveTopLeft( QPoint( left, top ) );

    return textRect;
}

bool QwtPicker::eventFilter( QObject *object, QEvent *event )
{
    if ( object && object == parentWidget() )
    {
        switch ( event->type() )
        {
            case QEvent::Resize:
            {
                const QResizeEvent *re = static_cast<QResizeEvent *>( event );

                /*
                   Adding/deleting additional event filters inside of an event filter
                   is not safe dues to the implementation in Qt ( changing alist while iterating ).
                   So we create the overlays in a way, that they don't install en event filter
                   ( parent set to NULL ) and do the resizing here.
                 */
                if ( d_data->trackerOverlay )
                    d_data->trackerOverlay->resize( re->size() );

                if ( d_data->rubberBandOverlay )
                    d_data->rubberBandOverlay->resize( re->size() );

                if ( d_data->resizeMode == Stretch )
                    stretchSelection( re->oldSize(), re->size() );

                updateDisplay();
                break;
            }
            case QEvent::Enter:
            {
                widgetEnterEvent( event );
                break;
            }
            case QEvent::Leave:
            {
                widgetLeaveEvent( event );
                break;
            }
            case QEvent::MouseButtonPress:
            {
                widgetMousePressEvent( static_cast<QMouseEvent *>( event ) );
                break;
            }
            case QEvent::MouseButtonRelease:
            {
                widgetMouseReleaseEvent( static_cast<QMouseEvent *>( event ) );
                break;
            }
            case QEvent::MouseButtonDblClick:
            {
                widgetMouseDoubleClickEvent( static_cast<QMouseEvent *>( event ) );
                break;
            }
            case QEvent::MouseMove:
            {
                widgetMouseMoveEvent( static_cast<QMouseEvent *>( event ) );
                break;
            }
            case QEvent::KeyPress:
            {
                widgetKeyPressEvent( static_cast<QKeyEvent *>( event ) );
                break;
            }
            case QEvent::KeyRelease:
            {
                widgetKeyReleaseEvent( static_cast<QKeyEvent *>( event ) );
                break;
            }
            case QEvent::Wheel:
            {
                widgetWheelEvent( static_cast<QWheelEvent *>( event ) );
                break;
            }
            default:
                break;
        }
    }
    return false;
}

void QwtPicker::widgetMousePressEvent( QMouseEvent *mouseEvent )
{
    transition( mouseEvent );
}

void QwtPicker::widgetMouseMoveEvent( QMouseEvent *mouseEvent )
{
    if ( pickArea().contains( mouseEvent->pos() ) )
        d_data->trackerPosition = mouseEvent->pos();
    else
        d_data->trackerPosition = QPoint( -1, -1 );

    if ( !isActive() )
        updateDisplay();

    transition( mouseEvent );
}

void QwtPicker::widgetEnterEvent( QEvent *event )
{
    transition( event );
}

void QwtPicker::widgetLeaveEvent( QEvent *event )
{
    transition( event );

    d_data->trackerPosition = QPoint( -1, -1 );
    if ( !isActive() )
        updateDisplay();
}

void QwtPicker::widgetMouseReleaseEvent( QMouseEvent *mouseEvent )
{
    transition( mouseEvent );
}

void QwtPicker::widgetMouseDoubleClickEvent( QMouseEvent *mouseEvent )
{
    transition( mouseEvent );
}


void QwtPicker::widgetWheelEvent( QWheelEvent *wheelEvent )
{
    if ( pickArea().contains( wheelEvent->pos() ) )
        d_data->trackerPosition = wheelEvent->pos();
    else
        d_data->trackerPosition = QPoint( -1, -1 );

    updateDisplay();

    transition( wheelEvent );
}

void QwtPicker::widgetKeyPressEvent( QKeyEvent *keyEvent )
{
    int dx = 0;
    int dy = 0;

    int offset = 1;
    if ( keyEvent->isAutoRepeat() )
        offset = 5;

    if ( keyMatch( KeyLeft, keyEvent ) )
        dx = -offset;
    else if ( keyMatch( KeyRight, keyEvent ) )
        dx = offset;
    else if ( keyMatch( KeyUp, keyEvent ) )
        dy = -offset;
    else if ( keyMatch( KeyDown, keyEvent ) )
        dy = offset;
    else if ( keyMatch( KeyAbort, keyEvent ) )
    {
        reset();
    }
    else
        transition( keyEvent );

    if ( dx != 0 || dy != 0 )
    {
        const QRect rect = pickArea().boundingRect().toRect();
        const QPoint pos = parentWidget()->mapFromGlobal( QCursor::pos() );

        int x = pos.x() + dx;
        x = qMax( rect.left(), x );
        x = qMin( rect.right(), x );

        int y = pos.y() + dy;
        y = qMax( rect.top(), y );
        y = qMin( rect.bottom(), y );

        QCursor::setPos( parentWidget()->mapToGlobal( QPoint( x, y ) ) );
    }
}

void QwtPicker::widgetKeyReleaseEvent( QKeyEvent *keyEvent )
{
    transition( keyEvent );
}

void QwtPicker::transition( const QEvent *event )
{
    if ( !d_data->stateMachine )
        return;

    const QList<QwtPickerMachine::Command> commandList =
        d_data->stateMachine->transition( *this, event );

    QPoint pos;
    switch ( event->type() )
    {
        case QEvent::MouseButtonDblClick:
        case QEvent::MouseButtonPress:
        case QEvent::MouseButtonRelease:
        case QEvent::MouseMove:
        {
            const QMouseEvent *me = 
                static_cast< const QMouseEvent * >( event );
            pos = me->pos();
            break;
        }
        default:
            pos = parentWidget()->mapFromGlobal( QCursor::pos() );
    }

    for ( int i = 0; i < commandList.count(); i++ )
    {
        switch ( commandList[i] )
        {
            case QwtPickerMachine::Begin:
            {
                begin();
                break;
            }
            case QwtPickerMachine::Append:
            {
                append( pos );
                break;
            }
            case QwtPickerMachine::Move:
            {
                move( pos );
                break;
            }
            case QwtPickerMachine::Remove:
            {
                remove();
                break;
            }
            case QwtPickerMachine::End:
            {
                end();
                break;
            }
        }
    }
}

void QwtPicker::begin()
{
    if ( d_data->isActive )
        return;

    d_data->pickedPoints.resize( 0 );
    d_data->isActive = true;
    Q_EMIT activated( true );

    if ( trackerMode() != AlwaysOff )
    {
        if ( d_data->trackerPosition.x() < 0 || d_data->trackerPosition.y() < 0 )
        {
            QWidget *w = parentWidget();
            if ( w )
                d_data->trackerPosition = w->mapFromGlobal( QCursor::pos() );
        }
    }

    updateDisplay();
    setMouseTracking( true );
}

bool QwtPicker::end( bool ok )
{
    if ( d_data->isActive )
    {
        setMouseTracking( false );

        d_data->isActive = false;
        Q_EMIT activated( false );

        if ( trackerMode() == ActiveOnly )
            d_data->trackerPosition = QPoint( -1, -1 );

        if ( ok )
            ok = accept( d_data->pickedPoints );

        if ( ok )
            Q_EMIT selected( d_data->pickedPoints );
        else
            d_data->pickedPoints.resize( 0 );

        updateDisplay();
    }
    else
        ok = false;

    return ok;
}

void QwtPicker::reset()
{
    if ( d_data->stateMachine )
        d_data->stateMachine->reset();

    if ( isActive() )
        end( false );
}

void QwtPicker::append( const QPoint &pos )
{
    if ( d_data->isActive )
    {
        const int idx = d_data->pickedPoints.count();
        d_data->pickedPoints.resize( idx + 1 );
        d_data->pickedPoints[idx] = pos;

        updateDisplay();
        Q_EMIT appended( pos );
    }
}

void QwtPicker::move( const QPoint &pos )
{
    if ( d_data->isActive )
    {
        const int idx = d_data->pickedPoints.count() - 1;
        if ( idx >= 0 )
        {
            if ( d_data->pickedPoints[idx] != pos )
            {
                d_data->pickedPoints[idx] = pos;

                updateDisplay();
                Q_EMIT moved( pos );
            }
        }
    }
}

void QwtPicker::remove()
{
    if ( d_data->isActive )
    {
        const int idx = d_data->pickedPoints.count() - 1;
        if ( idx > 0 )
        {
            const int idx = d_data->pickedPoints.count();

            const QPoint pos = d_data->pickedPoints[idx - 1];
            d_data->pickedPoints.resize( idx - 1 );

            updateDisplay();
            Q_EMIT removed( pos );
        }
    }
}

bool QwtPicker::accept( QPolygon &selection ) const
{
    Q_UNUSED( selection );
    return true;
}

bool QwtPicker::isActive() const
{
    return d_data->isActive;
}

const QPolygon &QwtPicker::pickedPoints() const
{
    return d_data->pickedPoints;
}

void QwtPicker::stretchSelection( const QSize &oldSize, const QSize &newSize )
{
    if ( oldSize.isEmpty() )
    {
        // avoid division by zero. But scaling for small sizes also
        // doesn't make much sense, because of rounding losses. TODO ...
        return;
    }

    const double xRatio =
        double( newSize.width() ) / double( oldSize.width() );
    const double yRatio =
        double( newSize.height() ) / double( oldSize.height() );

    for ( int i = 0; i < int( d_data->pickedPoints.count() ); i++ )
    {
        QPoint &p = d_data->pickedPoints[i];
        p.setX( qRound( p.x() * xRatio ) );
        p.setY( qRound( p.y() * yRatio ) );

        Q_EMIT changed( d_data->pickedPoints );
    }
}

void QwtPicker::setMouseTracking( bool enable )
{
    QWidget *widget = parentWidget();
    if ( !widget )
        return;

    if ( enable )
    {
        d_data->mouseTracking = widget->hasMouseTracking();
        widget->setMouseTracking( true );
    }
    else
    {
        widget->setMouseTracking( d_data->mouseTracking );
    }
}

QPainterPath QwtPicker::pickArea() const
{
    QPainterPath path;

    const QWidget *widget = parentWidget();
    if ( widget )
        path.addRect( widget->contentsRect() );

    return path;
}

void QwtPicker::updateDisplay()
{
    QWidget *w = parentWidget();

    bool showRubberband = false;
    bool showTracker = false;

    if ( w && w->isVisible() && d_data->enabled )
    {
        if ( rubberBand() != NoRubberBand && isActive() &&
            rubberBandPen().style() != Qt::NoPen )
        {
            showRubberband = true;
        }

        if ( trackerMode() == AlwaysOn ||
            ( trackerMode() == ActiveOnly && isActive() ) )
        {
            if ( trackerPen() != Qt::NoPen 
                && !trackerRect( QFont() ).isEmpty() )
            {
                showTracker = true;
            }
        }
    }

    QPointer< QwtPickerRubberband > &rw = d_data->rubberBandOverlay;
    if ( showRubberband )
    {
        if ( rw.isNull() )
        {
            rw = new QwtPickerRubberband( this, NULL ); // NULL -> no extra event filter
            rw->setObjectName( "PickerRubberBand" );
            rw->setParent( w );
            rw->resize( w->size() );
        }

        if ( d_data->rubberBand <= RectRubberBand )
            rw->setMaskMode( QwtWidgetOverlay::MaskHint );
        else
            rw->setMaskMode( QwtWidgetOverlay::AlphaMask );

        rw->updateOverlay();
    }
    else
    {
        if ( d_data->openGL )
        {
            // Qt 4.8 crashes for a delete
            if ( !rw.isNull() )
            {
                rw->hide();
                rw->deleteLater();
                rw = NULL;
            }
        }
        else
        {
            delete rw;
        }
    }

    QPointer< QwtPickerTracker > &tw = d_data->trackerOverlay;
    if ( showTracker )
    {
        if ( tw.isNull() )
        {
            tw = new QwtPickerTracker( this, NULL ); // NULL -> no extra event filter
            tw->setObjectName( "PickerTracker" );
            tw->setParent( w );
            tw->resize( w->size() );
        }
        tw->setFont( d_data->trackerFont );
        tw->updateOverlay();
    }
    else
    {
        if ( d_data->openGL )
        {
            // Qt 4.8 crashes for a delete
            if ( !tw.isNull() )
            {
                tw->hide();
                tw->deleteLater();
                tw = NULL;
            }
        }
        else
        {
            delete tw;
        }
    }
}

const QwtWidgetOverlay *QwtPicker::rubberBandOverlay() const
{
    return d_data->rubberBandOverlay;
}

const QwtWidgetOverlay *QwtPicker::trackerOverlay() const
{
    return d_data->trackerOverlay;
}