QPieSlice Class

The QPieSlice class represents a single slice in a pie series. More...

Header:	`#include <QPieSlice>`
CMake:	`find_package(Qt6 REQUIRED COMPONENTS Graphs)` `target_link_libraries(mytarget PRIVATE Qt6::Graphs)`
qmake:	`QT += graphs`
In QML:	PieSlice
Inherits:	QObject

List of all members, including inherited members
QPieSlice is part of Qt Graphs C++ Classes for 2D.

Public Types

enum class LabelPosition { Outside, InsideHorizontal, InsideTangential, InsideNormal }

Properties

angleSpan : const qreal
borderColor : QColor
borderWidth : qreal
color : QColor
explodeDistanceFactor : qreal
exploded : bool
label : QString
labelArmLengthFactor : qreal
labelColor : QColor

labelFont : QFont
labelPosition : LabelPosition
labelVisible : bool
percentage : const qreal
startAngle : const qreal
subSlicesCount : const qsizetype
subSlicesSum : const qreal
value : qreal

Public Functions

	QPieSlice(QObject *parent = nullptr)
	QPieSlice(const QString &label, qreal value, QObject *parent = nullptr)
virtual	~QPieSlice() override
qreal	angleSpan() const
bool	append(QPieSlice *slice)
bool	append(const QList<QPieSlice > &slices*)
QPieSlice *	append(const QString &label, qreal value)
QPieSlice *	at(qsizetype index)
QColor	borderColor() const
qreal	borderWidth() const
void	clear()
QColor	color() const
qreal	explodeDistanceFactor() const
QPieSlice *	find(const QString &label)
bool	insert(qsizetype index, QPieSlice *slice)
bool	isEmpty() const
bool	isExploded() const
bool	isLabelVisible() const
QString	label() const
qreal	labelArmLengthFactor() const
QColor	labelColor() const
QFont	labelFont() const
QPieSlice::LabelPosition	labelPosition()
qreal	percentage() const
bool	remove(QPieSlice *slice)
bool	remove(qsizetype index)
void	removeMultiple(qsizetype index, int count)
bool	replace(QPieSlice *oldSlice, QPieSlice *newSlice)
bool	replace(qsizetype index, QPieSlice *slice)
bool	replaceAll(const QList<QPieSlice > &slices*)
QPieSeries *	series() const
void	setBorderColor(QColor color)
void	setBorderWidth(qreal borderWidth)
void	setColor(QColor color)
void	setExplodeDistanceFactor(qreal factor)
void	setExploded(bool exploded)
void	setLabel(const QString &label)
void	setLabelArmLengthFactor(qreal factor)
void	setLabelColor(QColor color)
void	setLabelFont(const QFont &font)
void	setLabelPosition(QPieSlice::LabelPosition position)
void	setLabelVisible(bool visible = true)
void	setSubSlicesRatio(qreal subSlicesRatio)
void	setValue(qreal value)
QQmlListProperty<QPieSlice>	sliceChildren()
qreal	startAngle() const
QList<QPieSlice *>	subSlices() const
qsizetype	subSlicesCount() const
qreal	subSlicesRatio() const
qreal	subSlicesSum() const
bool	take(QPieSlice *slice)
qreal	value() const
QPieSlice &	operator<<(QPieSlice *slice)

Signals

void	angleSpanChanged()
void	borderColorChanged()
void	borderWidthChanged()
void	colorChanged()
void	explodeDistanceFactorChanged()
void	explodedChanged()
void	labelArmLengthFactorChanged()
void	labelChanged()
void	labelColorChanged()
void	labelFontChanged()
void	labelPositionChanged()
void	labelVisibleChanged()
void	percentageChanged()
void	startAngleChanged()
void	subSlicesAdded(const QList<QPieSlice > &slices*)
void	subSlicesCountChanged(qsizetype count)
void	subSlicesRatioChanged(qreal subSlicesRatio)
void	subSlicesRemoved(const QList<QPieSlice > &slices*)
void	subSlicesSumChanged(qreal sum)
void	valueChanged()

Detailed Description

A pie slice has a value and a label. When the slice is added to a pie series, the QPieSeries object calculates the percentage of the slice compared with the sum of all slices in the series to determine the actual size of the slice in the graph.

By default, the label is hidden. If it is visible, it can be either located outside the slice and connected to it with an arm or centered inside the slice either horizontally or in parallel with the tangential or normal of the slice's arc.

By default, the visual appearance of the slice is set by a theme, but the theme can be overridden by specifying slice properties. However, if the theme is changed after the slices are customized, all customization will be lost.

To enable user interaction with the pie graph, some basic signals are emitted when users click pie slices or hover the mouse over them.

A pie slice can contain sub slices.

See also QPieSeries.

Member Type Documentation

enum class QPieSlice::LabelPosition

This enum describes the position of the slice label.

Constant	Value	Description
`QPieSlice::LabelPosition::Outside`	`0`	The label is located outside the slice connected to it with an arm. This is the default value.
`QPieSlice::LabelPosition::InsideHorizontal`	`1`	The label is centered within the slice and laid out horizontally.
`QPieSlice::LabelPosition::InsideTangential`	`2`	The label is centered within the slice and rotated to be parallel with the tangential of the slice's arc.
`QPieSlice::LabelPosition::InsideNormal`	`3`	The label is centered within the slice and rotated to be parallel with the normal of the slice's arc.

Property Documentation

`[read-only]` angleSpan : const qreal

This property holds the span of the slice in degrees. A full pie is 360 degrees, where 0 degrees is at 12 a'clock. Updated automatically once the slice is added to the series.

Access functions:

qreal angleSpan() const

Notifier signal:

void	angleSpanChanged()

borderColor : QColor

This property holds the color used to draw the slice border. This is a convenience property for modifying the slice.

Access functions:

QColor	borderColor() const
void	setBorderColor(QColor color)

Notifier signal:

void	borderColorChanged()

See also borderWidth.

borderWidth : qreal

This property holds the width of the slice border. This is a convenience property for modifying the slice border width.

Access functions:

qreal	borderWidth() const
void	setBorderWidth(qreal borderWidth)

Notifier signal:

void	borderWidthChanged()

See also borderColor.

color : QColor

This property holds the fill color of the slice. This is a convenience property for modifying the slice fill color.

Access functions:

QColor	color() const
void	setColor(QColor color)

Notifier signal:

void	colorChanged()

explodeDistanceFactor : qreal

Determines how far away from the pie the slice is exploded.

1.0 means that the distance is the same as the radius.
0.5 means that the distance is half of the radius.

By default, the distance is 0.15

Access functions:

qreal	explodeDistanceFactor() const
void	setExplodeDistanceFactor(qreal factor)

Notifier signal:

void	explodeDistanceFactorChanged()

See also exploded.

exploded : bool

This property holds whether the slice is separated from the pie.

Access functions:

bool	isExploded() const
void	setExploded(bool exploded)

Notifier signal:

void	explodedChanged()

See also explodeDistanceFactor.

label : QString

This property holds the label of the slice.

Note: The string can be HTML formatted.

Access functions:

QString	label() const
void	setLabel(const QString &label)

Notifier signal:

void	labelChanged()

See also labelVisible, labelFont, and labelArmLengthFactor.

labelArmLengthFactor : qreal

This property holds the length of the label arm. The factor is relative to the pie radius. For example:

1.0 means that the length is the same as the radius.
0.5 means that the length is half of the radius.

By default, the arm length is 0.15

Access functions:

qreal	labelArmLengthFactor() const
void	setLabelArmLengthFactor(qreal factor)

Notifier signal:

void	labelArmLengthFactorChanged()

See also label, labelVisible, and labelFont.

labelColor : QColor

This property holds the color used to draw the slice label.

Access functions:

QColor	labelColor() const
void	setLabelColor(QColor color)

Notifier signal:

void	labelColorChanged()

labelFont : QFont

This property holds the font used for drawing the label text.

Access functions:

QFont	labelFont() const
void	setLabelFont(const QFont &font)

Notifier signal:

void	labelFontChanged()

See also label, labelVisible, and labelArmLengthFactor.

labelPosition : LabelPosition

This property holds the position of the slice label.

Access functions:

QPieSlice::LabelPosition	labelPosition()
void	setLabelPosition(QPieSlice::LabelPosition position)

Notifier signal:

void	labelPositionChanged()

See also label and labelVisible.

labelVisible : bool

This property holds the visibility of the slice label. By default, the label is not visible.

Access functions:

bool	isLabelVisible() const
void	setLabelVisible(bool visible = true)

Notifier signal:

void	labelVisibleChanged()

See also label, labelFont, and labelArmLengthFactor.

`[read-only]` percentage : const qreal

This property holds the percentage of the slice compared to the sum of all slices in the series. The actual value ranges from 0.0 to 1.0. Updated automatically once the slice is added to the series.

Access functions:

qreal percentage() const

Notifier signal:

void	percentageChanged()

See also value and QPieSeries::sum.

`[read-only]` startAngle : const qreal

This property holds the starting angle of this slice in the series it belongs to. A full pie is 360 degrees, where 0 degrees is at 12 a'clock. Updated automatically once the slice is added to the series.

Access functions:

qreal startAngle() const

Notifier signal:

void	startAngleChanged()

`[read-only]` subSlicesCount : const qsizetype

This property holds the number of sub slices in the slice.

Access functions:

qsizetype subSlicesCount() const

Notifier signal:

void	subSlicesCountChanged(qsizetype count)

`[read-only]` subSlicesSum : const qreal

This property holds the sum of all sub slices.

The slice keeps track of the sum of all the sub slices it holds.

Access functions:

qreal subSlicesSum() const

Notifier signal:

void	subSlicesSumChanged(qreal sum)

value : qreal

This property holds the value of the slice.

Note: A negative value is converted to a positive value.

Access functions:

qreal	value() const
void	setValue(qreal value)

Notifier signal:

void	valueChanged()

See also percentage() and QPieSeries::sum().

Member Function Documentation

`[explicit]` QPieSlice::QPieSlice(QObject **parent* = nullptr)

Constructs an empty slice with the parent parent.

See also QPieSeries::append() and QPieSeries::insert().

QPieSlice::QPieSlice(const QString &label, qreal value, QObject **parent* = nullptr)

Constructs an empty slice with the specified value, label, and parent.

See also QPieSeries::append() and QPieSeries::insert().

`[override virtual noexcept]` QPieSlice::~QPieSlice()

Removes the slice. The slice should not be removed if it has been added to a series.

`[invokable]` bool QPieSlice::append(QPieSlice **slice*)

Appends the sub slice specified by slice to the slice. Sub slice ownership is passed to the slice.

Returns true if appending succeeds.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` bool QPieSlice::append(const QList<QPieSlice > &slices*)

Appends the array of sub slices specified by slices to the slice. Sub slice ownership is passed to the slice.

Returns true if appending succeeds.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` QPieSlice QPieSlice::append(const QString &label, qreal value*)

Appends a single sub slice with the specified value and label to the slice. Sub slice ownership is passed to the slice. Returns null if value is NaN, Inf, or -Inf and adds nothing to the series.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` QPieSlice QPieSlice::at(qsizetype index*)

Returns the PieSlice at the position index. Returns null if no PieSlice was found.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` void QPieSlice::clear()

Clears all sub slices from the slice.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` QPieSlice QPieSlice::find(const QString &label*)

Searches for a PieSlice which contains the label label. Returns the PieSlice if found, null otherwise.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` bool QPieSlice::insert(qsizetype index, QPieSlice **slice*)

Inserts the sub slice specified by slice to the slice before the sub slice at the position specified by index. Sub slice ownership is passed to the slice.

Returns true if inserting succeeds.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

bool QPieSlice::isEmpty() const

Returns true if the sub slices list is empty.

`[invokable]` bool QPieSlice::remove(QPieSlice **slice*)

Removes a single sub slice, specified by slice, from the slice and deletes it permanently.

The pointer cannot be referenced after this call.

Returns true if the removal succeeds.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` bool QPieSlice::remove(qsizetype index)

Removes the PieSlice at the location index. The PieSlice will be permanently deleted. Returns true if removing is successful.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` void QPieSlice::removeMultiple(qsizetype index, int count)

Removes multiple PieSlices from the slice starting from index to a number of count. The PieSlices will be permanently deleted.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` bool QPieSlice::replace(QPieSlice **oldSlice*, QPieSlice **newSlice*)

Replaces the PieSlice oldSlice with newSlice if found in the slice. oldSlice will be permanently deleted. Returns true if replacing is successful.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` bool QPieSlice::replace(qsizetype index, QPieSlice **slice*)

Replaces the PieSlice at position index with the one specified by slice. The original PieSlice will be permanently deleted. Returns false if replacing any of the PieSlices fails.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

`[invokable]` bool QPieSlice::replaceAll(const QList<QPieSlice > &slices*)

Replaces the entire list of PieSlices in the slice with the list specified by slices. All the original PieSlices will be permanently deleted. Returns true if all PieSlices are replaced successfully.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

QPieSeries *QPieSlice::series() const

Returns the series that this slice belongs to.

See also QPieSeries::append().

QList<QPieSlice *> QPieSlice::subSlices() const

Returns a list of sub slices that belong to this slice.

`[signal]` void QPieSlice::subSlicesAdded(const QList<QPieSlice > &slices*)

This signal is emitted when the sub slices specified by slices are added to the slice.

See also append().

qsizetype QPieSlice::subSlicesCount() const

Returns the number of the sub slices in this slice.

Note: Getter function for property subSlicesCount.

`[signal]` void QPieSlice::subSlicesRemoved(const QList<QPieSlice > &slices*)

This signal is emitted when the sub slices specified by slices are removed from the slice.

See also remove().

qreal QPieSlice::subSlicesSum() const

Returns the sum of all sub slices values in this slice.

Note: Getter function for property subSlicesSum.

See also QPieSlice::value(), QPieSlice::setValue(), and QPieSlice::percentage().

`[invokable]` bool QPieSlice::take(QPieSlice **slice*)

Takes a single sub slice, specified by slice, from the series. Does not delete the slice object.

Note: The slice remains the slice's parent object. You must set the parent object to take full ownership.

Returns true if the take operation was successful.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

QPieSlice &QPieSlice::operator<<(QPieSlice **slice*)

Appends the sub slice specified by slice to the slice and returns a reference to the slice. Sub slice ownership is passed to the slice.

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QPieSlice Class

Public Types

Properties

Public Functions

Signals

Detailed Description

Member Type Documentation

enum class QPieSlice::LabelPosition

Property Documentation

[read-only] angleSpan : const qreal

borderColor : QColor

borderWidth : qreal

color : QColor

explodeDistanceFactor : qreal

exploded : bool

label : QString

labelArmLengthFactor : qreal

labelColor : QColor

labelFont : QFont

labelPosition : LabelPosition

labelVisible : bool

[read-only] percentage : const qreal

[read-only] startAngle : const qreal

[read-only] subSlicesCount : const qsizetype

[read-only] subSlicesSum : const qreal

value : qreal

Member Function Documentation

[explicit] QPieSlice::QPieSlice(QObject *parent = nullptr)

QPieSlice::QPieSlice(const QString &label, qreal value, QObject *parent = nullptr)

[override virtual noexcept] QPieSlice::~QPieSlice()

[invokable] bool QPieSlice::append(QPieSlice *slice)

[invokable] bool QPieSlice::append(const QList<QPieSlice *> &slices)

[invokable] QPieSlice *QPieSlice::append(const QString &label, qreal value)

[invokable] QPieSlice *QPieSlice::at(qsizetype index)

[invokable] void QPieSlice::clear()

[invokable] QPieSlice *QPieSlice::find(const QString &label)

[invokable] bool QPieSlice::insert(qsizetype index, QPieSlice *slice)

bool QPieSlice::isEmpty() const

[invokable] bool QPieSlice::remove(QPieSlice *slice)

[invokable] bool QPieSlice::remove(qsizetype index)

[invokable] void QPieSlice::removeMultiple(qsizetype index, int count)

[invokable] bool QPieSlice::replace(QPieSlice *oldSlice, QPieSlice *newSlice)

[invokable] bool QPieSlice::replace(qsizetype index, QPieSlice *slice)

[invokable] bool QPieSlice::replaceAll(const QList<QPieSlice *> &slices)

QPieSeries *QPieSlice::series() const

QList<QPieSlice *> QPieSlice::subSlices() const

[signal] void QPieSlice::subSlicesAdded(const QList<QPieSlice *> &slices)

qsizetype QPieSlice::subSlicesCount() const

[signal] void QPieSlice::subSlicesRemoved(const QList<QPieSlice *> &slices)

qreal QPieSlice::subSlicesSum() const

[invokable] bool QPieSlice::take(QPieSlice *slice)

QPieSlice &QPieSlice::operator<<(QPieSlice *slice)

`[read-only]` angleSpan : const qreal

`[read-only]` percentage : const qreal

`[read-only]` startAngle : const qreal

`[read-only]` subSlicesCount : const qsizetype

`[read-only]` subSlicesSum : const qreal

`[explicit]` QPieSlice::QPieSlice(QObject **parent* = nullptr)

QPieSlice::QPieSlice(const QString &label, qreal value, QObject **parent* = nullptr)

`[override virtual noexcept]` QPieSlice::~QPieSlice()

`[invokable]` bool QPieSlice::append(QPieSlice **slice*)

`[invokable]` bool QPieSlice::append(const QList<QPieSlice > &slices*)

`[invokable]` QPieSlice QPieSlice::append(const QString &label, qreal value*)

`[invokable]` QPieSlice QPieSlice::at(qsizetype index*)

`[invokable]` void QPieSlice::clear()

`[invokable]` QPieSlice QPieSlice::find(const QString &label*)

`[invokable]` bool QPieSlice::insert(qsizetype index, QPieSlice **slice*)

`[invokable]` bool QPieSlice::remove(QPieSlice **slice*)

`[invokable]` bool QPieSlice::remove(qsizetype index)

`[invokable]` void QPieSlice::removeMultiple(qsizetype index, int count)

`[invokable]` bool QPieSlice::replace(QPieSlice **oldSlice*, QPieSlice **newSlice*)

`[invokable]` bool QPieSlice::replace(qsizetype index, QPieSlice **slice*)

`[invokable]` bool QPieSlice::replaceAll(const QList<QPieSlice > &slices*)

`[signal]` void QPieSlice::subSlicesAdded(const QList<QPieSlice > &slices*)

`[signal]` void QPieSlice::subSlicesRemoved(const QList<QPieSlice > &slices*)

`[invokable]` bool QPieSlice::take(QPieSlice **slice*)

QPieSlice &QPieSlice::operator<<(QPieSlice **slice*)