QLegend Class

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

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

Public Types

enum MarkerShape { MarkerShapeDefault, MarkerShapeRectangle, MarkerShapeCircle, MarkerShapeFromSeries }

Properties

Public Functions

~QLegend()
Qt::Alignment alignment() const
void attachToChart()
QColor borderColor()
QBrush brush() const
QColor color()
void detachFromChart()
QFont font() const
bool isAttachedToChart()
bool isBackgroundVisible() const
QBrush labelBrush() const
QColor labelColor() const
MarkerShape markerShape() const
QList<QLegendMarker *> markers(QAbstractSeries *series = Q_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 setLabelBrush(const QBrush &brush)
void setLabelColor(QColor color)
void setMarkerShape(MarkerShape shape)
void setPen(const QPen &pen)
void setReverseMarkers(bool reverseMarkers = true)
void setShowToolTips(bool show)
bool showToolTips() const

Signals

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

Additional Inherited Members

Detailed Description

The QLegend class displays the legend of a chart.

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.

ConstantValueDescription
QLegend::MarkerShapeDefault0Default shape determined by QLegend is used for the marker. This value is supported only for individual QLegendMarker items.
QLegend::MarkerShapeRectangle1Rectangular markers are used. Marker size is determined by font size.
QLegend::MarkerShapeCircle2Circular markers are used. Marker size is determined by font size.
QLegend::MarkerShapeFromSeries3The 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.

See also markerShape.

Property Documentation

alignment : Qt::Alignment

How the legend is aligned with the chart.

Can be Qt::AlignTop, Qt::AlignBottom, Qt::AlignLeft, Qt::AlignRight. If you set more than one flag, the result is undefined.

Access functions:

Qt::Alignment alignment() const
void setAlignment(Qt::Alignment alignment)

backgroundVisible : bool

This property holds whether the legend background is visible.

Access functions:

bool isBackgroundVisible() const
void setBackgroundVisible(bool visible = true)

Notifier signal:

void backgroundVisibleChanged(bool visible)

borderColor : QColor

This property holds the line color of the legend.

Access functions:

QColor borderColor()
void setBorderColor(QColor color)

Notifier signal:

void borderColorChanged(QColor color)

color : QColor

This property holds the background (brush) color of the legend.

If you change the color of the legend, the style of the legend brush is set to Qt::SolidPattern.

Access functions:

QColor color()
void setColor(QColor color)

Notifier signal:

void colorChanged(QColor color)

font : QFont

This property holds the font of the markers used by the legend.

Access functions:

QFont font() const
QFont font() const
void setFont(const QFont &font)
void setFont(const QFont &font)

Notifier signal:

void fontChanged(QFont font)

labelColor : QColor

This property holds the color of the brush used to draw labels.

Access functions:

QColor labelColor() const
void setLabelColor(QColor color)

Notifier signal:

void labelColorChanged(QColor color)

markerShape : MarkerShape

The default shape of the legend markers. The default value is MarkerShapeRectangle.

This property was introduced in Qt 5.9.

Access functions:

MarkerShape markerShape() const
void setMarkerShape(MarkerShape shape)

Notifier signal:

void markerShapeChanged(MarkerShape shape)

reverseMarkers : bool

This property holds whether reverse order is used for the markers in the legend.

This property is false by default.

Access functions:

bool reverseMarkers()
void setReverseMarkers(bool reverseMarkers = true)

Notifier signal:

void reverseMarkersChanged(bool reverseMarkers)

showToolTips : bool

This property holds whether tooltips are shown when the text is truncated.

This property is false by default.

Access functions:

bool showToolTips() const
void setShowToolTips(bool show)

Notifier signal:

void showToolTipsChanged(bool showToolTips)

Member Function Documentation

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.

[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.

QBrush QLegend::brush() const

Returns the brush used by the legend.

See also setBrush().

[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.

void QLegend::detachFromChart()

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

[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.

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.

QBrush QLegend::labelBrush() const

Returns the brush used to draw labels.

See also setLabelBrush().

[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.

QList<QLegendMarker *> QLegend::markers(QAbstractSeries *series = Q_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().

[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.

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().

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().

[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.

© 2017 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.