- Qt 6.10
- Qt Data Visualization
- C++ Classes
- QValue3DAxisFormatter
- Qt Data Visualization | Commercial or GPLv3

# QValue3DAxisFormatter Class

The QValue3DAxisFormatter class is a base class for value axis formatters. More...

Header: | `#include <QValue3DAxisFormatter>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS DataVisualization)` `target_link_libraries(mytarget PRIVATE Qt6::DataVisualization)`
qmake: | `QT += datavisualization`
Since: | QtDataVisualization 1.1
In QML: | ValueAxis3DFormatter
Inherits: | QObject
Inherited By: | QLogValue3DAxisFormatter

- List of all members, including inherited members

## Public Functions

| QValue3DAxisFormatter(QObject *parent = nullptr)
virtual | ~QValue3DAxisFormatter()

## Protected Functions

bool | allowNegatives() const
bool | allowZero() const
QValue3DAxis * | axis() const
virtual QValue3DAxisFormatter * | createNewInstance() const
QList<float> & | gridPositions() const
QList<float> & | labelPositions() const
QStringList & | labelStrings() const
QLocale | locale() const
void | markDirty(bool labelsChange = false)
virtual void | populateCopy(QValue3DAxisFormatter &copy) const
virtual float | positionAt(float value) const
virtual void | recalculate()
void | setAllowNegatives(bool allow)
void | setAllowZero(bool allow)
void | setLocale(const QLocale &locale)
virtual QString | stringForValue(qreal value, const QString &format) const
QList<float> & | subGridPositions() const
virtual float | valueAt(float position) const

## Detailed Description

This class provides formatting rules for a linear value 3D axis. Subclass it if you want to implement custom value axes.

The base class has no public API beyond constructors and destructors. It is meant to be only used internally. However, subclasses may implement public properties as needed.

See also QValue3DAxis and QLogValue3DAxisFormatter.

## Member Function Documentation

### `[explicit]` QValue3DAxisFormatter::QValue3DAxisFormatter(QObject *parent = nullptr)

Constructs a new value 3D axis formatter with the optional parent parent.

### `[virtual noexcept]` QValue3DAxisFormatter::~QValue3DAxisFormatter()

Deletes the value 3D axis formatter.

### `[protected]` bool QValue3DAxisFormatter::allowNegatives() const

Returns `true` if negative values are valid values for the parent axis. The default implementation always returns `true`.

See also setAllowNegatives().

### `[protected]` bool QValue3DAxisFormatter::allowZero() const

Returns `true` if zero is a valid value for the parent axis. The default implementation always returns `true`.

See also setAllowZero().

### `[protected]` QValue3DAxis *QValue3DAxisFormatter::axis() const

Returns the parent axis. The parent axis must only be accessed in the recalculate() method to maintain thread safety in environments using a threaded renderer.

See also recalculate().

### `[virtual protected]` QValue3DAxisFormatter *QValue3DAxisFormatter::createNewInstance() const

Creates a new empty value 3D axis formatter. Must be reimplemented in a subclass.

Returns the new formatter. The renderer uses this method to cache a copy of the formatter. The ownership of the new copy is transferred to the caller.

### `[protected]` QList<float> &QValue3DAxisFormatter::gridPositions() const

Returns a reference to the array of normalized grid line positions. The default array size is equal to the segment count of the parent axis plus one, but a subclassed implementation of the recalculate() method may resize the array differently. The values should be between `0.0` (the minimum value) and `1.0` (the maximum value), inclusive.

See also QValue3DAxis::segmentCount and recalculate().

### `[protected]` QList<float> &QValue3DAxisFormatter::labelPositions() const

Returns a reference to the array of normalized label positions. The default array size is equal to the segment count of the parent axis plus one, but a subclassed implementation of the recalculate() method may resize the array differently. The values should be between `0.0` (the minimum value) and `1.0` (the maximum value), inclusive. By default, the label at the index zero corresponds to the minimum value of the axis.

See also QValue3DAxis::segmentCount, QAbstract3DAxis::labels, and recalculate().

### `[protected]` QStringList &QValue3DAxisFormatter::labelStrings() const

Returns a reference to the string list containing formatter label strings. The array size must be equal to the size of the label positions array, which the indexes also correspond to.

See also labelPositions().

### `[protected]` QLocale QValue3DAxisFormatter::locale() const

Returns the current locale this formatter is using.

See also setLocale().

### `[protected]` void QValue3DAxisFormatter::markDirty(bool labelsChange = false)

Marks this formatter dirty, prompting the renderer to make a new copy of its cache on the next renderer synchronization. This method should be called by a subclass whenever the formatter is changed in a way that affects the resolved values. Set labelsChange to `true` if the change requires regenerating the parent axis label strings.

### `[virtual protected]` void QValue3DAxisFormatter::populateCopy(QValue3DAxisFormatter &copy) const

Copies all the values necessary for resolving positions, values, and strings with this formatter to the copy of the formatter. When reimplementing this method in a subclass, call the superclass version at some point. The renderer uses this method to cache a copy of the formatter.

Returns the new copy. The ownership of the new copy transfers to the caller.

### `[virtual protected]` float QValue3DAxisFormatter::positionAt(float value) const

Returns the normalized position along the axis for the given value. The returned value should be between `0.0` (the minimum value) and `1.0` (the maximum value), inclusive, if the value is within the parent axis range.

Reimplement this method if the position cannot be resolved by linear interpolation between the parent axis minimum and maximum values.

See also recalculate() and valueAt().

### `[virtual protected]` void QValue3DAxisFormatter::recalculate()

Resizes and populates the label and grid line position arrays and the label strings array, as well as calculates any values needed to map a value to its position. The parent axis can be accessed from inside this function.

This method must be reimplemented in a subclass if the default array contents are not suitable.

See gridPositions(), subGridPositions(), labelPositions(), and labelStrings() methods for documentation about the arrays that need to be resized and populated.

See also gridPositions(), subGridPositions(), labelPositions(), labelStrings(), and axis().

### `[protected]` void QValue3DAxisFormatter::setAllowNegatives(bool allow)

Allows the parent axis to have negative values if allow is `true`.

See also allowNegatives().

### `[protected]` void QValue3DAxisFormatter::setAllowZero(bool allow)

Allows the parent axis to have a zero value if allow is `true`.

See also allowZero().

### `[protected]` void QValue3DAxisFormatter::setLocale(const QLocale &locale)

Sets the locale that this formatter uses. The graph automatically sets the formatter's locale to a graph's locale whenever the parent axis is set as an active axis of the graph, the axis formatter is set to an axis attached to the graph, or the graph's locale changes.

See also locale() and QAbstract3DGraph::locale.

### `[virtual protected]` QString QValue3DAxisFormatter::stringForValue(qreal value, const QString &format) const

Returns the formatted label string using the specified value and format.

Reimplement this method in a subclass to resolve the formatted string for a given value if the default formatting rules specified for QValue3DAxis::labelFormat property are not sufficient.

See also recalculate(), labelStrings(), and QValue3DAxis::labelFormat.

### `[protected]` QList<float> &QValue3DAxisFormatter::subGridPositions() const

Returns a reference to the array of normalized subgrid line positions. The default array size is equal to the segment count of the parent axis times the sub-segment count of the parent axis minus one, but a subclassed implementation of the recalculate() method may resize the array differently. The values should be between `0.0` (the minimum value) and `1.0` (the maximum value), inclusive.

See also QValue3DAxis::segmentCount, QValue3DAxis::subSegmentCount, and recalculate().

### `[virtual protected]` float QValue3DAxisFormatter::valueAt(float position) const

Returns the value at the normalized position along the axis. The position value should be between `0.0` (the minimum value) and `1.0` (the maximum value), inclusive, to obtain values within the parent axis range.

Reimplement this method if the value cannot be resolved by linear interpolation between the parent axis minimum and maximum values.

See also recalculate() and positionAt().