QLegend Class

The QLegend class displays the legend of a chart. More...

Header:	#include <QLegend>
Instantiated By:	Legend
Inherits:	QGraphicsWidget

• List of all members, including inherited members

Public Types

enum	MarkerShape { MarkerShapeDefault, MarkerShapeRectangle, MarkerShapeCircle, MarkerShapeRotatedRectangle, MarkerShapeTriangle, …, MarkerShapeFromSeries }

Properties

alignment : Qt::Alignment backgroundVisible : bool borderColor : QColor color : QColor font : QFont

labelColor : QColor markerShape : MarkerShape reverseMarkers : bool showToolTips : bool

Public Functions

virtual	~QLegend()
Qt::Alignment	alignment() const
void	attachToChart()
QColor	borderColor()
QBrush	brush() const
QColor	color()
void	detachFromChart()
QFont	font() const
bool	isAttachedToChart()
bool	isBackgroundVisible() const
bool	isInteractive() const
QBrush	labelBrush() const
QColor	labelColor() const
QLegend::MarkerShape	markerShape() const
QList<QLegendMarker *>	markers(QAbstractSeries *series = nullptr) const
QPen	pen() const
bool	reverseMarkers()
void	setAlignment(Qt::Alignment alignment)
void	setBackgroundVisible(bool visible = true)
void	setBorderColor(QColor color)
void	setBrush(const QBrush &brush)
void	setColor(QColor color)
void	setFont(const QFont &font)
void	setInteractive(bool interactive)
void	setLabelBrush(const QBrush &brush)
void	setLabelColor(QColor color)
void	setMarkerShape(QLegend::MarkerShape shape)
void	setPen(const QPen &pen)
void	setReverseMarkers(bool reverseMarkers = true)
void	setShowToolTips(bool show)
bool	showToolTips() const

Signals

void	attachedToChartChanged(bool attached)
void	backgroundVisibleChanged(bool visible)
void	borderColorChanged(QColor color)
void	colorChanged(QColor color)
void	fontChanged(QFont font)
void	labelColorChanged(QColor color)
void	markerShapeChanged(QLegend::MarkerShape shape)
void	reverseMarkersChanged(bool reverseMarkers)
void	showToolTipsChanged(bool showToolTips)

Detailed Description

A legend is a graphical object that displays the legend of a chart. The legend state is updated by QChart when series change. By default, the legend is attached to the chart, but it can be detached to make it independent of chart layout. Legend objects cannot be created or deleted, but they can be referenced via the QChart class.

See also QChart.

Member Type Documentation

enum QLegend::MarkerShape

This enum describes the shape used when rendering legend marker items.

Constant	Value	Description
QLegend::MarkerShapeDefault	0	Default shape determined by QLegend is used for the marker. This value is supported only for individual QLegendMarker items.
QLegend::MarkerShapeRectangle	1	Rectangular markers are used. Marker size is determined by font size.
QLegend::MarkerShapeCircle	2	Circular markers are used. Marker size is determined by font size.
QLegend::MarkerShapeRotatedRectangle	4	Rotated rectangle shaped markers are used. Marker size is determined by font size.
QLegend::MarkerShapeTriangle	5	Triangular markers are used. Marker size is determined by font size.
QLegend::MarkerShapeStar	6	Star shaped markers are used. Marker size is determined by font size.
QLegend::MarkerShapePentagon	7	Pentagon shaped markers are used. Marker size is determined by font size.
QLegend::MarkerShapeFromSeries	3	The marker shape is determined by the series. In case of a scatter series, the legend marker looks like a scatter dot and is the same size as the dot. In case of a line or spline series, the legend marker looks like a small segment of the line. For other series types, rectangular markers are shown. If a lightMarker is specified for a series, the lightMarker will be shown and its size will be determined by the series marker size.

See also markerShape.

Member Function Documentation

[signal, since 6.2] void QLegend::attachedToChartChanged(bool attached)

This signal is emitted when the legend is attached to or detached from the chart.

This function was introduced in Qt 6.2.

[signal] void QLegend::backgroundVisibleChanged(bool visible)

This signal is emitted when the visibility of the legend background changes to visible.

Note: Notifier signal for property backgroundVisible.

[signal] void QLegend::borderColorChanged(QColor color)

This signal is emitted when the border color of the legend background changes to color.

Note: Notifier signal for property borderColor.

[signal] void QLegend::colorChanged(QColor color)

This signal is emitted when the color of the legend background changes to color.

Note: Notifier signal for property color.

[signal] void QLegend::fontChanged(QFont font)

This signal is emitted when the font of the markers of the legend changes to font.

Note: Notifier signal for property font.

[signal] void QLegend::labelColorChanged(QColor color)

This signal is emitted when the color of the brush used to draw the legend labels changes to color.

Note: Notifier signal for property labelColor.

[signal] void QLegend::reverseMarkersChanged(bool reverseMarkers)

This signal is emitted when the use of reverse order for the markers in the legend is changed to reverseMarkers.

Note: Notifier signal for property reverseMarkers.

[signal] void QLegend::showToolTipsChanged(bool showToolTips)

This signal is emitted when the visibility of tooltips is changed to showToolTips.

Note: Notifier signal for property showToolTips.

[virtual] QLegend::~QLegend()

Destroys the legend object. The legend is always owned by a QChart, so an application should never call this function.

void QLegend::attachToChart()

Attaches the legend to a chart. The chart may adjust the layout of the legend.

QBrush QLegend::brush() const

Returns the brush used by the legend.

See also setBrush().

void QLegend::detachFromChart()

Detaches the legend from the chart. The chart will no longer adjust the layout of the legend.

bool QLegend::isAttachedToChart()

Returns true, if the legend is attached to a chart.

bool QLegend::isBackgroundVisible() const

Returns the visibility of the legend background.

Note: Getter function for property backgroundVisible.

[since 6.2] bool QLegend::isInteractive() const

Returns whether the legend can be dragged or resized using a mouse when it is detached.

This function was introduced in Qt 6.2.

See also QLegend::setInteractive().

QBrush QLegend::labelBrush() const

Returns the brush used to draw labels.

See also setLabelBrush().

QList<QLegendMarker *> QLegend::markers(QAbstractSeries *series = nullptr) const

Returns the list of markers in the legend. The list can be filtered by specifying the series for which the markers are returned.

QPen QLegend::pen() const

Returns the pen used by the legend.

See also setPen().

void QLegend::setBackgroundVisible(bool visible = true)

Sets the visibility of the legend background to visible.

Note: Setter function for property backgroundVisible.

See also isBackgroundVisible().

void QLegend::setBrush(const QBrush &brush)

Sets the brush that is used to draw the background of the legend.

See also brush().

[since 6.2] void QLegend::setInteractive(bool interactive)

When interactive is true and the legend is detached, the legend is able to be moved and resized with a mouse in a similar way to a window.

The legend will automatically attach to an edge of the chart by dragging it off of that edge. Double clicking an attached legend will detach it. This is false by default.

This function was introduced in Qt 6.2.

See also QLegend::isInteractive().

void QLegend::setLabelBrush(const QBrush &brush)

Sets the brush used to draw the legend labels to brush.

See also labelBrush().

void QLegend::setPen(const QPen &pen)

Sets the pen that is used to draw the legend borders.

See also pen().

void QLegend::setShowToolTips(bool show)

When show is true, the legend labels will show a tooltip when the mouse hovers over them if the label itself is shown elided. This is false by default.

Note: Setter function for property showToolTips.

See also showToolTips().

bool QLegend::showToolTips() const

Returns whether the tooltips are shown for the legend labels when they are elided.

Note: Getter function for property showToolTips.

See also setShowToolTips().