The legend widget. More...

#include <qwt_legend.h>

Inheritance diagram for QwtLegend:

Classes
class	PrivateData

Public Slots
virtual void	updateLegend (const QVariant &, const QList< QwtLegendData > &) override
	Update the entries for an item.

Public Slots inherited from QwtAbstractLegend
virtual void	updateLegend (const QVariant &itemInfo, const QList< QwtLegendData > &data)=0

Signals
void	clicked (const QVariant &itemInfo, int index)
	Signal emitted when the user clicks on a legend label in Clickable mode.

void	checked (const QVariant &itemInfo, bool on, int index)
	Signal emitted when the user clicks on a legend label in Checkable mode.

Public Member Functions
	QwtLegend (QWidget *parent=nullptr)
	Constructor for QwtLegend.

void	setMaxColumns (uint numColums)
	Set the maximum number of entries in a row.

uint	maxColumns () const
	Return the maximum number of entries in a row.

void	setDefaultItemMode (QwtLegendData::Mode)
	Set the default mode for legend labels.

QwtLegendData::Mode	defaultItemMode () const
	Return the default item mode.

QWidget *	contentsWidget ()
	Return the contents widget.

const QWidget *	contentsWidget () const
	Return the contents widget (const version)

QWidget *	legendWidget (const QVariant &) const
	Return first widget in the list of widgets associated to an item.

QList< QWidget * >	legendWidgets (const QVariant &) const
	Return list of widgets associated to an item.

QVariant	itemInfo (const QWidget *) const
	Find the item that is associated to a widget.

virtual bool	eventFilter (QObject , QEvent ) override
	Handle QEvent::ChildRemoved and QEvent::LayoutRequest events.

virtual QSize	sizeHint () const override
	Return a size hint.

virtual int	heightForWidth (int w) const override
	Return the preferred height for a given width.

QScrollBar *	horizontalScrollBar () const
	Return the horizontal scrollbar.

QScrollBar *	verticalScrollBar () const
	Return the vertical scrollbar.

virtual void	renderLegend (QPainter *, const QRectF &, bool fillBackground) const override
	Render the legend into a given rectangle.

virtual void	renderItem (QPainter , const QWidget , const QRectF &, bool fillBackground) const
	Render a legend entry into a given rectangle.

virtual bool	isEmpty () const override
	Check if the legend is empty.

virtual int	scrollExtent (Qt::Orientation) const override
	Return the extent that is needed for the scrollbars.

Public Member Functions inherited from QwtAbstractLegend
	QwtAbstractLegend (QWidget *parent=nullptr)
	Constructor for QwtAbstractLegend.

	~QwtAbstractLegend () override
	Destructor for QwtAbstractLegend.

Protected Slots
void	itemClicked ()
	Called internally when the legend has been clicked on.

void	itemChecked (bool)
	Called internally when the legend has been checked.

Protected Member Functions
virtual QWidget *	createWidget (const QwtLegendData &) const
	Create a widget to be inserted into the legend.

virtual void	updateWidget (QWidget *, const QwtLegendData &)
	Update the widget.

Detailed Description

The legend widget.

The QwtLegend widget is a tabular arrangement of legend items. Legend items might be any type of widget, but in general they will be a QwtLegendLabel.

See also: QwtLegendLabel, QwtPlotItem, QwtPlot

Constructor & Destructor Documentation

◆ QwtLegend()

QwtLegend::QwtLegend ( QWidget * parent = nullptr )

explicit

Constructor for QwtLegend.

Parameters

parent Parent widget

Destructor

Member Function Documentation

◆ checked

void QwtLegend::checked	(	const QVariant &	itemInfo,
		bool	on,
		int	index
	)

signal

Signal emitted when the user clicks on a legend label in Checkable mode.

Parameters

itemInfo	Info for the item of the selected legend label
on	True when the legend label is checked
index	Index of the legend label in the list of widgets associated with the plot item

Note: Clicks are disabled as default

See also: setDefaultItemMode(), defaultItemMode(), QwtPlot::itemToInfo()

◆ clicked

void QwtLegend::clicked	(	const QVariant &	itemInfo,
		int	index
	)

signal

Signal emitted when the user clicks on a legend label in Clickable mode.

Parameters

itemInfo	Info for the item of the selected legend item
index	Index of the legend label in the list of widgets associated with the plot item

Note: Clicks are disabled as default

See also: setDefaultItemMode(), defaultItemMode(), QwtPlot::itemToInfo()

◆ contentsWidget() [1/2]

QWidget * QwtLegend::contentsWidget ( )

Return the contents widget.

The contents widget is the only child of the viewport of the internal QScrollArea and the parent widget of all legend items.

Returns: Container widget of the legend items

◆ contentsWidget() [2/2]

const QWidget * QwtLegend::contentsWidget ( ) const

Return the contents widget (const version)

The contents widget is the only child of the viewport of the internal QScrollArea and the parent widget of all legend items.

Returns: Container widget of the legend items

◆ createWidget()

QWidget * QwtLegend::createWidget ( const QwtLegendData & legendData ) const

protectedvirtual

Create a widget to be inserted into the legend.

The default implementation returns a QwtLegendLabel.

Parameters

legendData Attributes of the legend entry

Returns: Widget representing data on the legend

Note: updateWidget() will called soon after createWidget() with the same attributes.

See also: updateWidget()

◆ defaultItemMode()

QwtLegendData::Mode QwtLegend::defaultItemMode ( ) const

Return the default item mode.

Returns: Default item mode

See also: setDefaultItemMode()

◆ eventFilter()

bool QwtLegend::eventFilter	(	QObject *	object,
		QEvent *	event
	)

overridevirtual

Handle QEvent::ChildRemoved and QEvent::LayoutRequest events.

Handle QEvent::ChildRemoved and QEvent::LayoutRequest events for the contentsWidget().

Parameters

object	Object to be filtered
event	Event

Returns: Forwarded to QwtAbstractLegend::eventFilter()

◆ heightForWidth()

int QwtLegend::heightForWidth ( int width ) const

overridevirtual

Return the preferred height for a given width.

Parameters

width Width

Returns: Preferred height

See also: sizeHint()

◆ horizontalScrollBar()

QScrollBar * QwtLegend::horizontalScrollBar ( ) const

Return the horizontal scrollbar.

Returns: Horizontal scrollbar

See also: verticalScrollBar()

◆ isEmpty()

bool QwtLegend::isEmpty ( ) const

overridevirtual

Check if the legend is empty.

Returns: True, when no item is inserted

Implements QwtAbstractLegend.

◆ itemChecked

void QwtLegend::itemChecked ( bool on )

protectedslot

Called internally when the legend has been checked.

Emits a checked() signal.

See also: checked(), itemClicked()

◆ itemClicked

void QwtLegend::itemClicked ( )

protectedslot

Called internally when the legend has been clicked on.

Emits a clicked() signal.

See also: clicked(), itemChecked()

◆ itemInfo()

QVariant QwtLegend::itemInfo ( const QWidget * widget ) const

Find the item that is associated to a widget.

Parameters

widget Widget on the legend

Returns: Associated item info

See also: legendWidget()

◆ legendWidget()

QWidget * QwtLegend::legendWidget ( const QVariant & itemInfo ) const

Return first widget in the list of widgets associated to an item.

Parameters

itemInfo Info about an item

Returns: First widget in the list of widgets associated to an item

See also: itemInfo(), QwtPlot::itemToInfo()

Note: Almost all types of items have only one widget

◆ legendWidgets()

QList< QWidget * > QwtLegend::legendWidgets ( const QVariant & itemInfo ) const

Return list of widgets associated to an item.

Parameters

itemInfo Info about an item

Returns: List of widgets associated to an item

See also: legendWidget(), itemInfo(), QwtPlot::itemToInfo()

◆ maxColumns()

uint QwtLegend::maxColumns ( ) const

Return the maximum number of entries in a row.

Returns: Maximum number of entries in a row

See also: setMaxColumns(), QwtDynGridLayout::maxColumns()

◆ renderItem()

void QwtLegend::renderItem	(	QPainter *	painter,
		const QWidget *	widget,
		const QRectF &	rect,
		bool	fillBackground
	)		const

virtual

Render a legend entry into a given rectangle.

Parameters

painter	Painter
widget	Widget representing a legend entry
rect	Bounding rectangle
fillBackground	When true, fill rect with the widget background

Note: When widget is not derived from QwtLegendLabel renderItem does nothing beside the background

◆ renderLegend()

void QwtLegend::renderLegend	(	QPainter *	painter,
		const QRectF &	rect,
		bool	fillBackground
	)		const

overridevirtual

Render the legend into a given rectangle.

Parameters

painter	Painter
rect	Bounding rectangle
fillBackground	When true, fill rect with the widget background

See also: renderLegend() is used by QwtPlotRenderer - not by QwtLegend itself

Implements QwtAbstractLegend.

◆ scrollExtent()

int QwtLegend::scrollExtent ( Qt::Orientation orientation ) const

overridevirtual

Return the extent that is needed for the scrollbars.

Parameters

orientation Orientation

Returns: The width of the vertical scrollbar for Qt::Horizontal and v.v.

Reimplemented from QwtAbstractLegend.

◆ setDefaultItemMode()

void QwtLegend::setDefaultItemMode ( QwtLegendData::Mode mode )

Set the default mode for legend labels.

Legend labels will be constructed according to the attributes in a QwtLegendData object. When it doesn't contain a value for the QwtLegendData::ModeRole the label will be initialized with the default mode of the legend.

Parameters

mode	Default item mode

See also: itemMode(), QwtLegendData::value(), QwtPlotItem::legendData()

Note: Changing the mode doesn't have any effect on existing labels.

◆ setMaxColumns()

void QwtLegend::setMaxColumns ( uint numColums )

Set the maximum number of entries in a row.

F.e when the maximum is set to 1 all items are aligned vertically. 0 means unlimited

Parameters

numColums Maximum number of entries in a row

See also: maxColumns(), QwtDynGridLayout::setMaxColumns()

◆ sizeHint()

QSize QwtLegend::sizeHint ( ) const

overridevirtual

Return a size hint.

Returns: Size hint

See also: heightForWidth()

◆ updateLegend

void QwtLegend::updateLegend	(	const QVariant &	itemInfo,
		const QList< QwtLegendData > &	legendData
	)

overridevirtualslot

Update the entries for an item.

Parameters

itemInfo	Info for an item
legendData	List of legend entry attributes for the item

See also: updateWidget(), createWidget()

◆ updateWidget()

void QwtLegend::updateWidget	(	QWidget *	widget,
		const QwtLegendData &	legendData
	)

protectedvirtual

Update the widget.

Parameters

widget	Usually a QwtLegendLabel
legendData	Attributes to be displayed

See also: createWidget()

Note: When widget is no QwtLegendLabel updateWidget() does nothing.

◆ verticalScrollBar()

QScrollBar * QwtLegend::verticalScrollBar ( ) const

Return the vertical scrollbar.

Returns: Vertical scrollbar

See also: horizontalScrollBar()

The documentation for this class was generated from the following files:

/home/runner/work/QWT/QWT/src/plot/qwt_legend.h
/home/runner/work/QWT/QWT/src/plot/qwt_legend.cpp

Classes

Public Slots

Signals

Public Member Functions

Protected Slots

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ QwtLegend()

Member Function Documentation

◆ checked

◆ clicked

◆ contentsWidget() [1/2]

◆ contentsWidget() [2/2]

◆ createWidget()

◆ defaultItemMode()

◆ eventFilter()

◆ heightForWidth()

◆ horizontalScrollBar()

◆ isEmpty()

◆ itemChecked

◆ itemClicked

◆ itemInfo()

◆ legendWidget()

◆ legendWidgets()

◆ maxColumns()

◆ renderItem()

◆ renderLegend()

◆ scrollExtent()

◆ setDefaultItemMode()

◆ setMaxColumns()

◆ sizeHint()

◆ updateLegend

◆ updateWidget()

◆ verticalScrollBar()