C++ QwtPlotCanvas::installEventFilter方法代码示例

    CanvasPicker::CanvasPicker(Plot *plot):
        QObject(plot),
        d_selectedCurve(NULL),
        d_selectedPoint(-1)
    {
        qDebug() << __FILE__ << __FUNCTION__;

        QwtPlotCanvas *canvas = (QwtPlotCanvas*) plot->canvas();

        canvas->installEventFilter(this);

        // We want the focus, but no focus rect. The
        // selected point will be highlighted instead.

        canvas->setFocusPolicy(Qt::StrongFocus);
    #ifndef QT_NO_CURSOR
        canvas->setCursor(Qt::PointingHandCursor);
    #endif
        canvas->setFocusIndicator(QwtPlotCanvas::ItemFocusIndicator);
        canvas->setFocus();

        mousePressed = false;

        accelerate = 0;

    }

CanvasPicker::CanvasPicker( QwtPlot *plot ):
    QObject( plot ),
    d_selectedCurve( NULL ),
    d_selectedPoint( -1 )
{
    QwtPlotCanvas *canvas = qobject_cast<QwtPlotCanvas *>( plot->canvas() );
    canvas->installEventFilter( this );

    // We want the focus, but no focus rect. The
    // selected point will be highlighted instead.

    canvas->setFocusPolicy( Qt::StrongFocus );
#ifndef QT_NO_CURSOR
    canvas->setCursor( Qt::PointingHandCursor );
#endif
    canvas->setFocusIndicator( QwtPlotCanvas::ItemFocusIndicator );
    canvas->setFocus();

    const char *text =
        "All points can be moved using the left mouse button "
        "or with these keys:\n\n"
        "- Up:\t\tSelect next curve\n"
        "- Down:\t\tSelect previous curve\n"
        "- Left, ´-´:\tSelect next point\n"
        "- Right, ´+´:\tSelect previous point\n"
        "- 7, 8, 9, 4, 6, 1, 2, 3:\tMove selected point";
    canvas->setWhatsThis( text );

    shiftCurveCursor( true );
}

CanvasPicker::CanvasPicker(Graph *graph):
	QObject(graph)
{
	pointSelected = false;
	d_editing_marker = 0;

	QwtPlotCanvas *canvas = graph->canvas();
	canvas->installEventFilter(this);
}

CanvasPicker::CanvasPicker( QwtPlot* plot ): QObject( plot ), m_isEnabled( false ), m_dragAndDropInProgress( false ),
	m_typeOfItemsToDrag( -1 ), m_itemToPick( 0 )
{
    QwtPlotCanvas* canvas = qobject_cast<QwtPlotCanvas*>( plot->canvas() );
    canvas->installEventFilter( this );
	m_isEnabled = true;

    canvas->setFocusPolicy( Qt::StrongFocus );
    canvas->setFocusIndicator( QwtPlotCanvas::ItemFocusIndicator );
    canvas->setFocus();
}

void CanvasPicker::setEnabled( bool enabled )
{
	if( m_isEnabled != enabled )
	{
		QwtPlotCanvas* canvas = qobject_cast<QwtPlotCanvas*>( plot()->canvas() );
		m_isEnabled = enabled;
		if( enabled )
			canvas->installEventFilter( this );
		else
			canvas->removeEventFilter( this );
	}
}

LineChartPicker::LineChartPicker(QwtPlot *plot) :
    QwtPlotPicker(plot->canvas()),
    p(plot)
{
  QwtPlotCanvas *canvas = plot->canvas();

  canvas->installEventFilter(this);

  canvas->setFocusPolicy(Qt::StrongFocus);
  canvas->setMouseTracking(true);
  canvas->setFocusIndicator(QwtPlotCanvas::ItemFocusIndicator);
  canvas->setFocus();
}

DialogFunction::DialogFunction( const LinearFunction::Description::Ptr& pDescription,
								const QPolygonF& curveSamples,
								QWidget* pParent)
	: QDialog(pParent)
	, _pDescription(pDescription)
	, _indexSelectedPoint(-1)
	, _relativeIndex(0)
{
	setupUi(this);

	widgetPlot->setMinimumSize(1,1);
	widgetPlot->setAxisScale(QwtPlot::xBottom, _pDescription->xMin, _pDescription->xMax);
	widgetPlot->setAxisScale(QwtPlot::yLeft, _pDescription->yMin, _pDescription->yMax);
	widgetPlot->setAxisMaxMinor(QwtPlot::yLeft, 2);
	widgetPlot->setAxisMaxMinor(QwtPlot::xBottom, 2);
	widgetPlot->setCanvasBackground(QColor(Qt::black));
	widgetPlot->setAxisTitle(QwtPlot::xBottom, _pDescription->szLabelX);
	widgetPlot->setAxisTitle(QwtPlot::yLeft, _pDescription->szLabelY);

	_pCurve.reset(new QwtPlotCurve());
	_pCurve->setStyle(QwtPlotCurve::Lines);
	_pCurve->setPen(Qt::white);
	_pCurve->setSymbol(new QwtSymbol(QwtSymbol::Diamond, Qt::lightGray, _pCurve->pen(), QSize(8,8)));
	QwtArraySeriesData<QPointF>* pSeries = static_cast<QwtArraySeriesData<QPointF>*>(_pCurve->data());
	if (pSeries)
	{
		_pCurve->setSamples(curveSamples);
	}
	_pCurve->attach(widgetPlot);

	QwtPlotGrid* pGrid = new QwtPlotGrid;
	pGrid->setMajorPen(QPen(Qt::gray, 0, Qt::DotLine));
	pGrid->attach(widgetPlot);

	QwtPlotCanvas* pPlotCanvas = static_cast<QwtPlotCanvas*>(widgetPlot->canvas());
	pPlotCanvas->installEventFilter(this);
	pPlotCanvas->setMouseTracking(true);
}

/*!
  \brief Draw a set of points of a curve.

  When observing an measurement while it is running, new points have to be
  added to an existing curve. drawCurve can be used to display them avoiding
  a complete redraw of the canvas.

  Setting plot()->canvas()->setAttribute(Qt::WA_PaintOutsidePaintEvent, true);
  will result in faster painting, if the paint engine of the canvas widget
  supports this feature. 

  \param from Index of the first point to be painted
  \param to Index of the last point to be painted. If to < 0 the
         curve will be painted to its last point.

  \sa drawCurve(), drawSymbols()
*/
void QwtPlotCurve::draw(int from, int to) const
{
    if ( !plot() )
        return;

    QwtPlotCanvas *canvas = plot()->canvas();

#if QT_VERSION >= 0x040000
#if 0
    if ( canvas->paintEngine()->type() == QPaintEngine::OpenGL )
    {
        /*
            OpenGL alway repaint the complete widget.
            So for this operation OpenGL is one of the slowest
            environments.
         */
        canvas->repaint();
        return;
    }
#endif

    if ( !canvas->testAttribute(Qt::WA_WState_InPaintEvent) &&
        !canvas->testAttribute(Qt::WA_PaintOutsidePaintEvent) )
    {
        /*
          We save curve and range in helper and call repaint.
          The helper filters the Paint event, to repeat
          the QwtPlotCurve::draw, but now from inside the paint
          event.
         */

        QwtPlotCurvePaintHelper helper(this, from, to);
        canvas->installEventFilter(&helper);

        const bool noSystemBackground =
            canvas->testAttribute(Qt::WA_NoSystemBackground);
        canvas->setAttribute(Qt::WA_NoSystemBackground, true);
        canvas->repaint();
        canvas->setAttribute(Qt::WA_NoSystemBackground, noSystemBackground);

        return;
    }
#endif

    const QwtScaleMap xMap = plot()->canvasMap(xAxis());
    const QwtScaleMap yMap = plot()->canvasMap(yAxis());

    if ( canvas->testPaintAttribute(QwtPlotCanvas::PaintCached) &&
        canvas->paintCache() && !canvas->paintCache()->isNull() )
    {
        QPainter cachePainter((QPixmap *)canvas->paintCache());
        cachePainter.translate(-canvas->contentsRect().x(),
            -canvas->contentsRect().y());

        draw(&cachePainter, xMap, yMap, from, to);
    }

#if QT_VERSION >= 0x040000
    if ( canvas->testAttribute(Qt::WA_WState_InPaintEvent) )
    {
        QPainter painter(canvas);

        painter.setClipping(true);
        painter.setClipRect(canvas->contentsRect());

        draw(&painter, xMap, yMap, from, to);
    }
    else
#endif
    {
        QPainter *painter = d_data->guardedPainter.begin(canvas);
        draw(painter, xMap, yMap, from, to);
    }
}

/*!
  \brief Draw a set of points of a seriesItem.

  When observing an measurement while it is running, new points have to be
  added to an existing seriesItem. drawSeries can be used to display them avoiding
  a complete redraw of the canvas.

  Setting plot()->canvas()->setAttribute(Qt::WA_PaintOutsidePaintEvent, true);
  will result in faster painting, if the paint engine of the canvas widget
  supports this feature.

  \param seriesItem Item to be painted
  \param from Index of the first point to be painted
  \param to Index of the last point to be painted. If to < 0 the
         series will be painted to its last point.
*/
void QwtPlotDirectPainter::drawSeries(
    QwtPlotAbstractSeriesItem *seriesItem, int from, int to )
{
    if ( seriesItem == NULL || seriesItem->plot() == NULL )
        return;

    QwtPlotCanvas *canvas = seriesItem->plot()->canvas();
    const QRect canvasRect = canvas->contentsRect();

    const bool hasBackingStore = 
        canvas->testPaintAttribute( QwtPlotCanvas::BackingStore ) 
        && canvas->backingStore() && !canvas->backingStore()->isNull();

    if ( hasBackingStore )
    {
        QPainter painter( const_cast<QPixmap *>( canvas->backingStore() ) );

        if ( d_data->hasClipping )
            painter.setClipRegion( d_data->clipRegion );

        renderItem( &painter, canvasRect, seriesItem, from, to );

        if ( testAttribute( QwtPlotDirectPainter::FullRepaint ) )
        {
            canvas->repaint();
            return;
        }
    }

    bool immediatePaint = true;
    if ( !canvas->testAttribute( Qt::WA_WState_InPaintEvent ) )
    {
        immediatePaint = false;
    }

    if ( immediatePaint )
    {
        if ( !d_data->painter.isActive() )
        {
            reset();

            d_data->painter.begin( canvas );
            canvas->installEventFilter( this );
        }

        if ( d_data->hasClipping )
        {
            d_data->painter.setClipRegion( 
                QRegion( canvasRect ) & d_data->clipRegion );
        }
        else
        {
            if ( !d_data->painter.hasClipping() )
                d_data->painter.setClipRect( canvasRect );
        }

        renderItem( &d_data->painter, canvasRect, seriesItem, from, to );

        if ( d_data->attributes & QwtPlotDirectPainter::AtomicPainter )
        {
            reset();
        }
        else
        {
            if ( d_data->hasClipping )
                d_data->painter.setClipping( false );
        }
    }
    else
    {
        reset();

        d_data->seriesItem = seriesItem;
        d_data->from = from;
        d_data->to = to;

        QRegion clipRegion = canvasRect;
        if ( d_data->hasClipping )
            clipRegion &= d_data->clipRegion;

        canvas->installEventFilter( this );
        canvas->repaint(clipRegion);
        canvas->removeEventFilter( this );

//.........这里部分代码省略.........

/*!
  \brief Draw a set of points of a seriesItem.

  When observing an measurement while it is running, new points have to be
  added to an existing seriesItem. drawSeries can be used to display them avoiding
  a complete redraw of the canvas.

  Setting plot()->canvas()->setAttribute(Qt::WA_PaintOutsidePaintEvent, true);
  will result in faster painting, if the paint engine of the canvas widget
  supports this feature.

  \param seriesItem Item to be painted
  \param from Index of the first point to be painted
  \param to Index of the last point to be painted. If to < 0 the
         series will be painted to its last point.
*/
void QwtPlotDirectPainter::drawSeries(
    QwtPlotAbstractSeriesItem *seriesItem, int from, int to )
{
    if ( seriesItem == NULL || seriesItem->plot() == NULL )
        return;

    QwtPlotCanvas *canvas = seriesItem->plot()->canvas();

    if ( canvas->testPaintAttribute( QwtPlotCanvas::PaintCached ) &&
        canvas->paintCache() && !canvas->paintCache()->isNull() )
    {
        QPainter painter( ( QPixmap * )canvas->paintCache() );
        painter.translate( -canvas->contentsRect().x(),
            -canvas->contentsRect().y() );

        renderItem( &painter, seriesItem, from, to );

        if ( d_data->attributes & FullRepaint )
        {
            canvas->repaint();
            return;
        }
    }

    bool immediatePaint = true;
    if ( !canvas->testAttribute( Qt::WA_WState_InPaintEvent ) &&
        !canvas->testAttribute( Qt::WA_PaintOutsidePaintEvent ) )
    {
        immediatePaint = false;
    }

    if ( immediatePaint )
    {
        QwtPlotCanvas *canvas = seriesItem->plot()->canvas();
        if ( !( d_data->painter.isActive() &&
            d_data->painter.device() == canvas ) )
        {
            reset();

            d_data->painter.begin( canvas );
            d_data->painter.setClipping( true );
            d_data->painter.setClipRect( canvas->contentsRect() );

            canvas->installEventFilter( this );
        }

        renderItem( &d_data->painter, seriesItem, from, to );

        if ( d_data->attributes & AtomicPainter )
            reset();
    }
    else
    {
        reset();

        d_data->seriesItem = seriesItem;
        d_data->from = from;
        d_data->to = to;

        canvas->installEventFilter( this );
        canvas->repaint();
        canvas->removeEventFilter( this );

        d_data->seriesItem = NULL;
    }
}