qwt_legend.cpp

QWT5.01用于Qt开发的二维图形库程序

    d_data->itemMode = mode;
}

QwtLegend::LegendItemMode QwtLegend::itemMode() const
{
    return d_data->itemMode;
}

/*!
  \return the IdentifierMode to be used in combination with
  LegendDisplayPolicy::Fixed.

  Default is ShowLine | ShowSymbol | ShowText.
*/

int QwtLegend::identifierMode() const
{
    return d_data->identifierMode;
}

/*! 
  The contents widget is the only child of the viewport() and
  the parent widget of all legend items.
*/
QWidget *QwtLegend::contentsWidget() 
{ 
    return d_data->view->contentsWidget; 
}

QScrollBar *QwtLegend::horizontalScrollBar() const
{
    return d_data->view->horizontalScrollBar();
}

QScrollBar *QwtLegend::verticalScrollBar() const
{
    return d_data->view->horizontalScrollBar();
}

/*!  
  The contents widget is the only child of the viewport() and
  the parent widget of all legend items.
*/

const QWidget *QwtLegend::contentsWidget() const 
{ 
    return d_data->view->contentsWidget; 
}

/*!
  Insert a new item for a plot item
  \param plotItem Plot item
  \param legendItem New legend item
  \note The parent of item will be changed to QwtLegend::contentsWidget()
*/
void QwtLegend::insert(const QwtPlotItem *plotItem, QWidget *legendItem)
{
    if ( legendItem == NULL || plotItem == NULL )
        return;

    QWidget *contentsWidget = d_data->view->contentsWidget;

    if ( legendItem->parent() != contentsWidget )
    {
#if QT_VERSION >= 0x040000
        legendItem->setParent(contentsWidget);
#else
        legendItem->reparent(contentsWidget, QPoint(0, 0));
#endif
    }

    legendItem->show();

    d_data->map.insert(plotItem, legendItem);

    layoutContents();

    if ( contentsWidget->layout() )
    {
#if QT_VERSION >= 0x040000
        contentsWidget->layout()->addWidget(legendItem);
#endif

        // set tab focus chain

        QWidget *w = NULL;

#if QT_VERSION < 0x040000
        QLayoutIterator layoutIterator = 
            contentsWidget->layout()->iterator();
        for ( QLayoutItem *item = layoutIterator.current();
            item != 0; item = ++layoutIterator)
        {
#else
        for (int i = 0; i < contentsWidget->layout()->count(); i++)
        {
            QLayoutItem *item = contentsWidget->layout()->itemAt(i);
#endif
            if ( w && item->widget() )
            {
                QWidget::setTabOrder(w, item->widget());
                w = item->widget();
            }
        }
    }
    if ( parentWidget() && parentWidget()->layout() == NULL )
    {
       /*
          updateGeometry() doesn't post LayoutRequest in certain
          situations, like when we are hidden. But we want the
          parent widget notified, so it can show/hide the legend
          depending on its items.
        */
#if QT_VERSION < 0x040000
        QApplication::postEvent(parentWidget(),
            new QEvent(QEvent::LayoutHint));
#else
        QApplication::postEvent(parentWidget(),
            new QEvent(QEvent::LayoutRequest));
#endif
    }
}

/*!
  Find the widget that represents a plot item

  \param plotItem Plot item
  \return Widget on the legend, or NULL
*/
QWidget *QwtLegend::find(const QwtPlotItem *plotItem) const
{
    return d_data->map.find(plotItem);
}

/*!
  Find the widget that represents a plot item

  \param plotItem Plot item
  \return Widget on the legend, or NULL
*/
QwtPlotItem *QwtLegend::find(const QWidget *legendItem) const
{
    return d_data->map.find(legendItem);
}

/*! 
   Find the corresponding item for a plotItem and remove it 
   from the item list.

   \param plotItem Plot item
*/
void QwtLegend::remove(const QwtPlotItem *plotItem)
{ 
    QWidget *legendItem = d_data->map.find(plotItem);
    d_data->map.remove(legendItem); 
    delete legendItem;
}

//! Remove all items.
void QwtLegend::clear()
{
#if QT_VERSION < 0x040000
    bool doUpdate = isUpdatesEnabled();
#else
    bool doUpdate = updatesEnabled();
#endif
    setUpdatesEnabled(false);

    d_data->map.clear();

    setUpdatesEnabled(doUpdate);
    update();
}

//! Return a size hint.
QSize QwtLegend::sizeHint() const
{
    QSize hint = d_data->view->contentsWidget->sizeHint();
    hint += QSize(2 * frameWidth(), 2 * frameWidth());

    return hint;
}

/*!
  \return The preferred height, for the width w.
  \param width Width
*/
int QwtLegend::heightForWidth(int width) const
{
    width -= 2 * frameWidth();

    int h = d_data->view->contentsWidget->heightForWidth(width);
#if QT_VERSION < 0x040000

    // Asking the layout is the default implementation in Qt4 

    if ( h <= 0 ) 
    {
        QLayout *l = d_data->view->contentsWidget->layout();
        if ( l && l->hasHeightForWidth() )
            h = l->heightForWidth(width);
    }
#endif
    if ( h >= 0 )
        h += 2 * frameWidth();

    return h;
}

/*!
  Adjust contents widget and item layout to the size of the viewport().
*/
void QwtLegend::layoutContents()
{
    const QSize visibleSize = d_data->view->viewport()->size();

    const QLayout *l = d_data->view->contentsWidget->layout();
    if ( l && l->inherits("QwtDynGridLayout") )
    {
        const QwtDynGridLayout *tl = (const QwtDynGridLayout *)l;

        const int minW = int(tl->maxItemWidth()) + 2 * tl->margin();

        int w = qwtMax(visibleSize.width(), minW);
        int h = qwtMax(tl->heightForWidth(w), visibleSize.height());

        const int vpWidth = d_data->view->viewportSize(w, h).width();
        if ( w > vpWidth )
        {
            w = qwtMax(vpWidth, minW);
            h = qwtMax(tl->heightForWidth(w), visibleSize.height());
        }

        d_data->view->contentsWidget->resize(w, h);
#if QT_VERSION < 0x040000
        d_data->view->resizeContents(w, h);
#endif
    }
}

/*
  Filter layout related events of QwtLegend::contentsWidget().

  \param o Object to be filtered
  \param e Event
*/

bool QwtLegend::eventFilter(QObject *o, QEvent *e)
{
    if ( o == d_data->view->contentsWidget )
    {
        switch(e->type())
        {
            case QEvent::ChildRemoved:
            {   
                const QChildEvent *ce = (const QChildEvent *)e;
                if ( ce->child()->isWidgetType() )
                    d_data->map.remove((QWidget *)ce->child());
                break;
            }
#if QT_VERSION < 0x040000
            case QEvent::LayoutHint:
#else
            case QEvent::LayoutRequest:
#endif
            {
                layoutContents();
                break;
            }
#if QT_VERSION < 0x040000
            case QEvent::Resize:
            {
                updateGeometry();
                break;
            }
#endif
            default:
                break;
        }
    }
    
    return QFrame::eventFilter(o, e);
}


//! Return true, if there are no legend items.
bool QwtLegend::isEmpty() const
{
    return d_data->map.count() == 0;
}

//! Return the number of legend items.
uint QwtLegend::itemCount() const
{
    return d_data->map.count();
}

#if QT_VERSION < 0x040000
QValueList<QWidget *> QwtLegend::legendItems() const
#else
QList<QWidget *> QwtLegend::legendItems() const
#endif
{
    const QMap<QWidget *, const QwtPlotItem *> &map = 
        d_data->map.widgetMap();

#if QT_VERSION < 0x040000
    QValueList<QWidget *> list;
#else
    QList<QWidget *> list;
#endif

    QMap<QWidget *, const QwtPlotItem *>::const_iterator it;
    for ( it = map.begin(); it != map.end(); ++it ) 
        list += it.key();

    return list;
}

/*!
   Resize event
   \param e Event
*/
void QwtLegend::resizeEvent(QResizeEvent *e)
{
    QFrame::resizeEvent(e);
    d_data->view->setGeometry(contentsRect());
}