Qwt User's Guide  6.2.0
QwtLegendData Class Reference

Attributes of an entry on a legend. More...

#include <qwt_legend_data.h>

Public Types

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

Definition at line 36 of file qwt_legend_data.h.

Member Enumeration Documentation

◆ 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.

Definition at line 40 of file qwt_legend_data.h.

Member Function Documentation

◆ hasRole()

bool QwtLegendData::hasRole ( int  role) const
Parameters
roleAttribute role
Returns
True, when the internal map has an entry for role

Definition at line 51 of file qwt_legend_data.cpp.

◆ icon()

QwtGraphic QwtLegendData::icon ( ) const
Returns
Value of the IconRole attribute

Definition at line 106 of file qwt_legend_data.cpp.

◆ isValid()

bool QwtLegendData::isValid ( ) const
Returns
True, when the internal map is empty

Definition at line 82 of file qwt_legend_data.cpp.

◆ mode()

QwtLegendData::Mode QwtLegendData::mode ( ) const
Returns
Value of the ModeRole attribute

Definition at line 120 of file qwt_legend_data.cpp.

◆ setValue()

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

Set an attribute value

Parameters
roleAttribute role
dataAttribute value
See also
value()

Definition at line 64 of file qwt_legend_data.cpp.

◆ setValues()

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

Set the legend attributes

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

Parameters
mapValues
See also
values()

Definition at line 33 of file qwt_legend_data.cpp.

◆ title()

QwtText QwtLegendData::title ( ) const
Returns
Value of the TitleRole attribute

Definition at line 88 of file qwt_legend_data.cpp.

◆ value()

QVariant QwtLegendData::value ( int  role) const
Parameters
roleAttribute role
Returns
Attribute value for a specific role

Definition at line 73 of file qwt_legend_data.cpp.

◆ values()

const QMap< int, QVariant > & QwtLegendData::values ( ) const
Returns
Legend attributes
See also
setValues()

Definition at line 42 of file qwt_legend_data.cpp.