---
name: "QwtLegendData"
section: "3"
platform: "linux"
package: "libqwt-doc"
version: "6.1.4-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/QwtLegendData"
---

# QwtLegendData(3)

Attributes of an entry on a legend.

## NAME

QwtLegendData - Attributes of an entry on a legend.

## SYNOPSIS

`#include <qwt_legend_data.h>`

### Public Types

enum **Mode** { **ReadOnly**, **Clickable**, **Checkable** }\
 Mode defining how a legend entry interacts.  enum **Role** { **ModeRole**, **TitleRole**, **IconRole**, **UserRole** = 32 }\
 Identifier how to interprete a QVariant.

### Public Member Functions

**QwtLegendData** ()\
 Constructor.  **~QwtLegendData** ()\
 Destructor.  void **setValues** (const QMap\< int, QVariant \> &)\
 const QMap\< int, QVariant \> & **values** () const\
 void **setValue** (int role, const QVariant &)\
 QVariant **value** (int role) const\
 bool **hasRole** (int role) const\
 bool **isValid** () const\
 **QwtGraphic** **icon** () const\
 **QwtText** **title** () const\
 **Mode** **mode** () const\

## Detailed Description

Attributes of an entry on a legend.

**QwtLegendData** is an abstract container ( like QAbstractModel ) to exchange attributes, that are only known between to the plot item and the legend.

By overloading **QwtPlotItem::legendData()** any other set of attributes could be used, that can be handled by a modified ( or completely different ) implementation of a legend.

**See also:**

**QwtLegend**, **QwtPlotLegendItem**

**Note:**

The stockchart example implements a legend as a tree with checkable items

## Member Enumeration Documentation

### enum QwtLegendData::Mode

Mode defining how a legend entry interacts.

**Enumerator**

- *ReadOnly*

  *The legend item is not interactive, like a label.*

- *Clickable*

  *The legend item is clickable, like a push button.*

- *Checkable*

  *The legend item is checkable, like a checkable button.*

## Member Function Documentation

### bool QwtLegendData::hasRole (int role) const

**Parameters:**

*role Attribute role*

**Returns:**

*True, when the internal map has an entry for role*

### QwtGraphic QwtLegendData::icon () const

**Returns:**

*Value of the IconRole attribute*

### bool QwtLegendData::isValid () const

**Returns:**

*True, when the internal map is empty*

### QwtLegendData::Mode QwtLegendData::mode () const

**Returns:**

*Value of the ModeRole attribute*

### void QwtLegendData::setValue (int role, const QVariant & data)

*Set an attribute value*

**Parameters:**

*role Attribute role* \
 *data Attribute value*

**See also:**

**value()**

### void QwtLegendData::setValues (const QMap\< int, QVariant \> & map)

*Set the legend attributes*

**QwtLegendData** *actually is a QMap\<int, QVariant\> with some convenience interfaces*

**Parameters:**

*map Values*

**See also:**

**values()**

### QwtText QwtLegendData::title () const

**Returns:**

*Value of the TitleRole attribute*

### QVariant QwtLegendData::value (int role) const

**Parameters:**

*role Attribute role*

**Returns:**

*Attribute value for a specific role*

### const QMap\< int, QVariant \> & QwtLegendData::values () const

**Returns:**

*Legend attributes*

**See also:**

**setValues()**

## Author

*Generated automatically by Doxygen for Qwt User's Guide from the source code.*