QValueAxis Class

The QValueAxis class adds values to a chart's axes. More...

Header:	`#include <QValueAxis>`
In QML:	ValueAxis
Inherits:	QAbstractAxis
Inherited By:	QCategoryAxis

List of all members, including inherited members

Public Types

enum	TickType { TicksDynamic, TicksFixed }

Properties

labelFormat : QString
max : qreal
min : qreal
minorTickCount : int

tickAnchor : qreal
tickCount : int
tickInterval : qreal
tickType : TickType

Public Functions

	QValueAxis(QObject *parent = nullptr)
virtual	~QValueAxis()
QString	labelFormat() const
qreal	max() const
qreal	min() const
int	minorTickCount() const
void	setLabelFormat(const QString &format)
void	setMax(qreal max)
void	setMin(qreal min)
void	setMinorTickCount(int count)
void	setRange(qreal min, qreal max)
void	setTickAnchor(qreal anchor)
void	setTickCount(int count)
void	setTickInterval(qreal insterval)
void	setTickType(QValueAxis::TickType type)
qreal	tickAnchor() const
int	tickCount() const
qreal	tickInterval() const
QValueAxis::TickType	tickType() const

Reimplemented Public Functions

virtual QAbstractAxis::AxisType type() const override

Public Slots

void	applyNiceNumbers()

Signals

void	labelFormatChanged(const QString &format)
void	maxChanged(qreal max)
void	minChanged(qreal min)
void	minorTickCountChanged(int minorTickCount)
void	rangeChanged(qreal min, qreal max)
void	tickAnchorChanged(qreal anchor)
void	tickCountChanged(int tickCount)
void	tickIntervalChanged(qreal interval)
void	tickTypeChanged(QValueAxis::TickType type)

Detailed Description

A value axis can be set up to show an axis line with tick marks, grid lines, and shades. The values on the axis are drawn at the positions of tick marks.

The following example code illustrates how to use the QValueAxis class:

 QChartView *chartView = new QChartView;
 QLineSeries *series = new QLineSeries;
 // ...
 chartView->chart()->addSeries(series);

 QValueAxis *axisX = new QValueAxis;
 axisX->setRange(10, 20.5);
 axisX->setTickCount(10);
 axisX->setLabelFormat("%.2f");
 chartView->chart()->setAxisX(axisX, series);

Member Type Documentation

enum QValueAxis::TickType

This enum describes how the ticks and labels are positioned on the axis.

Constant	Value	Description
`QValueAxis::TicksDynamic`	`0`	Ticks are placed according to tickAnchor and tickInterval values.
`QValueAxis::TicksFixed`	`1`	Ticks are placed evenly across the axis range. The tickCount value specifies the number of ticks.

Property Documentation

labelFormat : QString

This property holds the label format of the axis.

The format string supports the following conversion specifiers, length modifiers, and flags provided by printf() in the standard C++ library: d, i, o, x, X, f, F, e, E, g, G, c.

If QChart::localizeNumbers is true, the supported specifiers are limited to: d, e, E, f, g, G, and i. Also, only the precision modifier is supported. The rest of the formatting comes from the default QLocale of the application.

Access functions:

QString	labelFormat() const
void	setLabelFormat(const QString &format)

Notifier signal:

void	labelFormatChanged(const QString &format)

See also QString::asprintf().

max : qreal

This property holds the maximum value on the axis.

When setting this property, the minimum value is adjusted if necessary, to ensure that the range remains valid.

Access functions:

qreal	max() const
void	setMax(qreal max)

Notifier signal:

void	maxChanged(qreal max)

min : qreal

This property holds the minimum value on the axis.

When setting this property, the maximum value is adjusted if necessary, to ensure that the range remains valid.

Access functions:

qreal	min() const
void	setMin(qreal min)

Notifier signal:

void	minChanged(qreal min)

minorTickCount : int

This property holds the number of minor tick marks on the axis. This indicates how many grid lines are drawn between major ticks on the chart. Labels are not drawn for minor ticks. The default value is 0.

Access functions:

int	minorTickCount() const
void	setMinorTickCount(int count)

Notifier signal:

void	minorTickCountChanged(int minorTickCount)

tickAnchor : qreal

This property holds the base value where the dynamically placed tick marks and labels are started from.

Access functions:

qreal	tickAnchor() const
void	setTickAnchor(qreal anchor)

Notifier signal:

void	tickAnchorChanged(qreal anchor)

tickCount : int

This property holds the number of tick marks on the axis. This indicates how many grid lines are drawn on the chart. The default value is 5, and the number cannot be less than 2.

Access functions:

int	tickCount() const
void	setTickCount(int count)

Notifier signal:

void	tickCountChanged(int tickCount)

tickInterval : qreal

This property holds the interval between dynamically placed tick marks and labels.

Access functions:

qreal	tickInterval() const
void	setTickInterval(qreal insterval)

Notifier signal:

void	tickIntervalChanged(qreal interval)

tickType : TickType

This property holds the positioning method of tick and labels.

Access functions:

QValueAxis::TickType	tickType() const
void	setTickType(QValueAxis::TickType type)

Notifier signal:

void	tickTypeChanged(QValueAxis::TickType type)

Member Function Documentation

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

Constructs an axis object that is a child of parent.

`[virtual noexcept]` QValueAxis::~QValueAxis()

Destroys the object.

`[slot]` void QValueAxis::applyNiceNumbers()

Modifies the current range and number of tick marks on the axis to look nice. The algorithm considers numbers that can be expressed as a form of 1*10^n, 2* 10^n, or 5*10^n to be nice numbers. These numbers are used for setting spacing for the tick marks.

See also setRange() and setTickCount().

`[signal]` void QValueAxis::labelFormatChanged(const QString &format)

This signal is emitted when the format of axis labels changes.

Note: Notifier signal for property labelFormat.

`[signal]` void QValueAxis::maxChanged(qreal max)

This signal is emitted when the maximum value of the axis, specified by max, changes.

Note: Notifier signal for property max.

`[signal]` void QValueAxis::minChanged(qreal min)

This signal is emitted when the minimum value of the axis, specified by min, changes.

Note: Notifier signal for property min.

`[signal]` void QValueAxis::minorTickCountChanged(int minorTickCount)

This signal is emitted when the number of minor tick marks on the axis, specified by minorTickCount, changes.

Note: Notifier signal for property minorTickCount.

`[signal]` void QValueAxis::rangeChanged(qreal min, qreal max)

This signal is emitted when the minimum or maximum value of the axis, specified by min and max, changes.

void QValueAxis::setRange(qreal min, qreal max)

Sets the range from min to max on the axis. If min is greater than max, this function returns without making any changes.

`[signal]` void QValueAxis::tickCountChanged(int tickCount)

This signal is emitted when the number of tick marks on the axis, specified by tickCount, changes.

Note: Notifier signal for property tickCount.

`[override virtual]` QAbstractAxis::AxisType QValueAxis::type() const

Reimplements: QAbstractAxis::type() const.

Returns the type of the axis.

Contents

QValueAxis Class

Public Types

Properties

Public Functions

Reimplemented Public Functions

Public Slots

Signals

Detailed Description

Member Type Documentation

enum QValueAxis::TickType

Property Documentation

labelFormat : QString

max : qreal

min : qreal

minorTickCount : int

tickAnchor : qreal

tickCount : int

tickInterval : qreal

tickType : TickType

Member Function Documentation

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

[virtual noexcept] QValueAxis::~QValueAxis()

[slot] void QValueAxis::applyNiceNumbers()

[signal] void QValueAxis::labelFormatChanged(const QString &format)

[signal] void QValueAxis::maxChanged(qreal max)

[signal] void QValueAxis::minChanged(qreal min)

[signal] void QValueAxis::minorTickCountChanged(int minorTickCount)

[signal] void QValueAxis::rangeChanged(qreal min, qreal max)

void QValueAxis::setRange(qreal min, qreal max)

[signal] void QValueAxis::tickCountChanged(int tickCount)

[override virtual] QAbstractAxis::AxisType QValueAxis::type() const

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

`[virtual noexcept]` QValueAxis::~QValueAxis()

`[slot]` void QValueAxis::applyNiceNumbers()

`[signal]` void QValueAxis::labelFormatChanged(const QString &format)

`[signal]` void QValueAxis::maxChanged(qreal max)

`[signal]` void QValueAxis::minChanged(qreal min)

`[signal]` void QValueAxis::minorTickCountChanged(int minorTickCount)

`[signal]` void QValueAxis::rangeChanged(qreal min, qreal max)

`[signal]` void QValueAxis::tickCountChanged(int tickCount)

`[override virtual]` QAbstractAxis::AxisType QValueAxis::type() const