QwtLegend - Man Page


QwtLegend —

The legend widget.  


#include <qwt_legend.h>

Public Types

enum LegendDisplayPolicy { NoIdentifier =  0, FixedIdentifier =  1, AutoIdentifier =  2 }
enum LegendItemMode { ReadOnlyItem, ClickableItem, CheckableItem }

Public Member Functions

void clear ()
const QWidget * contentsWidget () const
QWidget * contentsWidget ()
LegendDisplayPolicy displayPolicy () const
virtual bool eventFilter (QObject *, QEvent *)
QwtLegendItemManager * find (const QWidget *) const
QWidget * find (const QwtLegendItemManager *) const
virtual int heightForWidth (int w) const
QScrollBar * horizontalScrollBar () const
int identifierMode () const
void insert (const QwtLegendItemManager *, QWidget *)
bool isEmpty () const
uint itemCount () const
LegendItemMode itemMode () const
virtual QList< QWidget * > legendItems () const
QwtLegend (QWidget *parent=NULL)
void remove (const QwtLegendItemManager *)
void setDisplayPolicy (LegendDisplayPolicy policy, int mode)
void setItemMode (LegendItemMode)
virtual QSize sizeHint () const
QScrollBar * verticalScrollBar () const
virtual ~QwtLegend ()

Protected Member Functions

virtual void layoutContents ()
virtual void resizeEvent (QResizeEvent *)

Detailed Description

The legend widget.

The QwtLegend widget is a tabular arrangement of legend items. Legend items might be any type of widget, but in general they will be a QwtLegendItem.

See also:

QwtLegendItem, QwtLegendItemManager QwtPlot

Member Enumeration Documentation

enum QwtLegend::LegendDisplayPolicy

Display policy. .IP "·" 2 NoIdentifier
The client code is responsible how to display of each legend item. The Qwt library will not interfere.


All legend items are displayed with the QwtLegendItem::IdentifierMode to be passed in 'mode'.


Each legend item is displayed with a mode that is a bitwise or of


QwtLegendItem::ShowLine (if its curve is drawn with a line) and


QwtLegendItem::ShowSymbol (if its curve is drawn with symbols) and


QwtLegendItem::ShowText (if the has a title).

Default is AutoIdentifier.

See also:

setDisplayPolicy(), displayPolicy(), QwtLegendItem::IdentifierMode

enum QwtLegend::LegendItemMode

Interaction mode for the legend items. .IP "·" 2 ReadOnlyItem
The legend item is not interactive, like a label

  • ClickableItem
    The legend item is clickable, like a push button
  • CheckableItem
    The legend item is checkable, like a checkable button

Default is ReadOnlyItem.

See also:

setItemMode(), itemMode(), QwtLegendItem::IdentifierMode QwtLegendItem::clicked(), QwtLegendItem::checked(), QwtPlot::legendClicked(), QwtPlot::legendChecked()

Constructor & Destructor Documentation

QwtLegend::QwtLegend (QWidget *parent = NULL) [explicit] Constructor


parent Parent widget

QwtLegend::~QwtLegend () [virtual]


Member Function Documentation

void QwtLegend::clear ()

Remove all items.

QWidget * QwtLegend::contentsWidget () The contents widget is the only child of the viewport() and the parent widget of all legend items.

const QWidget * QwtLegend::contentsWidget () const The contents widget is the only child of the viewport() and the parent widget of all legend items.

QwtLegend::LegendDisplayPolicy QwtLegend::displayPolicy () const Returns

the legend display policy. Default is LegendDisplayPolicy::Auto.

See also:

setDisplayPolicy(), LegendDisplayPolicy

QWidget * QwtLegend::find (const QwtLegendItemManager *plotItem) const Find the widget that represents a plot item


plotItem Plot item


Widget on the legend, or NULL

QwtLegendItemManager * QwtLegend::find (const QWidget *legendItem) const Find the widget that represents a plot item


legendItem Legend item


Widget on the legend, or NULL

int QwtLegend::heightForWidth (intwidth) const [virtual] Returns

The preferred height, for the width w.


width Width

QScrollBar * QwtLegend::horizontalScrollBar () const Returns

Horizontal scrollbar

See also:


int QwtLegend::identifierMode () const Returns

the IdentifierMode to be used in combination with LegendDisplayPolicy::Fixed.

Default is ShowLine | ShowSymbol | ShowText.

void QwtLegend::insert (const QwtLegendItemManager *plotItem, QWidget *legendItem) Insert a new item for a plot item


plotItem Plot item
legendItem New legend item


The parent of item will be changed to QwtLegend::contentsWidget()

bool QwtLegend::isEmpty () const

Return true, if there are no legend items.

uint QwtLegend::itemCount () const

Return the number of legend items.

QwtLegend::LegendItemMode QwtLegend::itemMode () const See also


void QwtLegend::layoutContents () [protected, virtual] Adjust contents widget and item layout to the size of the viewport().

QList< QWidget * > QwtLegend::legendItems () const [virtual]

Return a list of all legend items.

void QwtLegend::remove (const QwtLegendItemManager *plotItem) Find the corresponding item for a plotItem and remove it from the item list.


plotItem Plot item

void QwtLegend::resizeEvent (QResizeEvent *e) [protected, virtual] Resize event


e Resize event

void QwtLegend::setDisplayPolicy (LegendDisplayPolicypolicy, intmode) Set the legend display policy to


policy Legend display policy
mode Identifier mode (or'd ShowLine, ShowSymbol, ShowText)

See also:

displayPolicy(), LegendDisplayPolicy

void QwtLegend::setItemMode (LegendItemModemode) See also


QSize QwtLegend::sizeHint () const [virtual]

Return a size hint.

QScrollBar * QwtLegend::verticalScrollBar () const Returns

Vertical scrollbar

See also:



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


Mon Aug 1 2011 Version 5.2.2 Qwt User's Guide