qwt_picker.cpp

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

/*!
  Handle a leave event for the observed widget.

  \param event Qt event

  \sa eventFilter(), widgetMousePressEvent(), widgetMouseReleaseEvent(),
      widgetMouseDoubleClickEvent(),
      widgetWheelEvent(), widgetKeyPressEvent(), widgetKeyReleaseEvent()
*/
void QwtPicker::widgetLeaveEvent( QEvent *event )
{
    transition( event );

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

/*!
  Handle a mouse release event for the observed widget.

  \param mouseEvent Mouse event

  \sa eventFilter(), widgetMousePressEvent(),
      widgetMouseDoubleClickEvent(), widgetMouseMoveEvent(),
      widgetWheelEvent(), widgetKeyPressEvent(), widgetKeyReleaseEvent()
*/
void QwtPicker::widgetMouseReleaseEvent( QMouseEvent *mouseEvent )
{
    transition( mouseEvent );
}

/*!
  Handle mouse double click event for the observed widget.

  \param mouseEvent Mouse event

  \sa eventFilter(), widgetMousePressEvent(), widgetMouseReleaseEvent(),
      widgetMouseMoveEvent(),
      widgetWheelEvent(), widgetKeyPressEvent(), widgetKeyReleaseEvent()
*/
void QwtPicker::widgetMouseDoubleClickEvent( QMouseEvent *mouseEvent )
{
    transition( mouseEvent );
}


/*!
  Handle a wheel event for the observed widget.

  Move the last point of the selection in case of isActive() == true

  \param wheelEvent Wheel event

  \sa eventFilter(), widgetMousePressEvent(), widgetMouseReleaseEvent(),
      widgetMouseDoubleClickEvent(), widgetMouseMoveEvent(),
      widgetKeyPressEvent(), widgetKeyReleaseEvent()
*/
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 );
}

/*!
  Handle a key press event for the observed widget.

  Selections can be completely done by the keyboard. The arrow keys
  move the cursor, the abort key aborts a selection. All other keys
  are handled by the current state machine.

  \param keyEvent Key event

  \sa eventFilter(), widgetMousePressEvent(), widgetMouseReleaseEvent(),
      widgetMouseDoubleClickEvent(), widgetMouseMoveEvent(),
      widgetWheelEvent(), widgetKeyReleaseEvent(), stateMachine(),
      QwtEventPattern::KeyPatternCode
*/
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 ) ) );
    }
}

/*!
  Handle a key release event for the observed widget.

  Passes the event to the state machine.

  \param keyEvent Key event

  \sa eventFilter(), widgetMousePressEvent(), widgetMouseReleaseEvent(),
      widgetMouseDoubleClickEvent(), widgetMouseMoveEvent(),
      widgetWheelEvent(), widgetKeyPressEvent(), stateMachine()
*/
void QwtPicker::widgetKeyReleaseEvent( QKeyEvent *keyEvent )
{
    transition( keyEvent );
}

/*!
  Passes an event to the state machine and executes the resulting
  commands. Append and Move commands use the current position
  of the cursor ( QCursor::pos() ).

  \param event Event
*/
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;
            }
        }
    }
}

/*!
  Open a selection setting the state to active

  \sa isActive(), end(), append(), move()
*/
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 );
}

/*!
  \brief Close a selection setting the state to inactive.

  The selection is validated and maybe fixed by accept().

  \param ok If true, complete the selection and emit a selected signal
            otherwise discard the selection.
  \return true if the selection is accepted, false otherwise
  \sa isActive(), begin(), append(), move(), selected(), accept()
*/
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;
}

/*!
   Reset the state machine and terminate ( end(false) ) the selection
*/
void QwtPicker::reset()
{
    if ( d_data->stateMachine )
        d_data->stateMachine->reset();

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

/*!
  Append a point to the selection and update rubber band and tracker.
  The appended() signal is emitted.

  \param pos Additional point

  \sa isActive(), begin(), end(), move(), appended()
*/
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 );
    }
}

/*!
  Move the last point of the selection
  The moved() signal is emitted.

  \param pos New position
  \sa isActive(), begin(), end(), append()
*/
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 );
            }
        }
    }
}

/*!
  Remove the last point of the selection
  The removed() signal is emitted.

  \sa isActive(), begin(), end(), append(), move()
*/
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 );
        }
    }
}

/*!
  \brief Validate and fix up the selection

  Accepts all selections unmodified

  \param selection Selection to validate and fix up
  \return true, when accepted, false otherwise
*/
bool QwtPicker::accept( QPolygon &selection ) const
{
    Q_UNUSED( selection );
    return true;
}

/*!
  A picker is active between begin() and end().
  \return true if the selection is active.
*/
bool QwtPicker::isActive() const
{
    return d_data->isActive;
}

/*!
  Return the points, that have been collected so far. The selection()
  is calculated from the pickedPoints() in adjustedPoints().
  \return Picked points
*/
const QPolygon &QwtPicker::pickedPoints() const
{
    return d_data->pickedPoints;
}

/*!
  Scale the selection by the ratios of oldSize and newSize
  The changed() signal is emitted.

  \param oldSize Previous size
  \param newSize Current size

  \sa ResizeMode, setResizeMode(), resizeMode()
*/
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 );
    }
}

/*!
  Set mouse tracking for the observed widget.

  In case of enable is true, the previous value
  is saved, that is restored when enable is false.

  \warning Even when enable is false, mouse tracking might be restored
           to true. When mouseTracking for the observed widget
           has been changed directly by QWidget::setMouseTracking
           while mouse tracking has been set to true, this value can't
           be restored.
*/

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 );
    }
}

/*!
  Find the area of the observed widget, where selection might happen.

  \return parentWidget()->contentsRect() 
*/
QPainterPath QwtPicker::pickArea() const
{
    QPainterPath path;

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

    return path;
}

//! Update the state of rubber band and tracker label
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, w );
            rw->setObjectName( "PickerRubberBand" );
            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, w );
            tw->setObjectName( "PickerTracker" );
            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;
        }
    }
}

//! \return Overlay displaying the rubber band
const QwtWidgetOverlay *QwtPicker::rubberBandOverlay() const
{
    return d_data->rubberBandOverlay;
}

//! \return Overlay displaying the tracker text
const QwtWidgetOverlay *QwtPicker::trackerOverlay() const
{
    return d_data->trackerOverlay;
}