A class which draws a legend inside the plot canvas. More...

#include <qwt_plot_legenditem.h>

Inheritance diagram for QwtPlotLegendItem:

Public Types
enum	BackgroundMode { LegendBackground, ItemBackground }
	Background mode. More...

Public Types inherited from QwtPlotItem
enum	RttiValues { Rtti_PlotItem = 0, Rtti_PlotGrid, Rtti_PlotScale, Rtti_PlotLegend, Rtti_PlotMarker, Rtti_PlotCurve, Rtti_PlotSpectroCurve, Rtti_PlotIntervalCurve, Rtti_PlotHistogram, Rtti_PlotSpectrogram, Rtti_PlotSVG, Rtti_PlotTradingCurve, Rtti_PlotBarChart, Rtti_PlotMultiBarChart, Rtti_PlotShape, Rtti_PlotTextLabel, Rtti_PlotZone, Rtti_PlotUserItem = 1000 }
	Runtime type information. More...

enum	ItemAttribute { Legend = 0x01, AutoScale = 0x02, Margins = 0x04 }
	Plot Item Attributes. More...

enum	ItemInterest { ScaleInterest = 0x01, LegendInterest = 0x02 }
	Plot Item Interests. More...

enum	RenderHint { RenderAntialiased = 0x1 }
	Render hints. More...

typedef QFlags< ItemAttribute >	ItemAttributes
	Plot Item Attributes.

typedef QFlags< ItemInterest >	ItemInterests
	Plot Item Interests.

typedef QFlags< RenderHint >	RenderHints
	Render hints.

Public Member Functions
	QwtPlotLegendItem ()
	Constructor.

virtual	~QwtPlotLegendItem ()
	Destructor.

virtual int	rtti () const

void	setAlignment (Qt::Alignment)
	Set the alignmnet. More...

Qt::Alignment	alignment () const

void	setMaxColumns (uint)
	Limit the number of columns. More...

uint	maxColumns () const

void	setMargin (int)
	Set the margin around legend items. More...

int	margin () const

void	setSpacing (int)
	Set the spacing between the legend items. More...

int	spacing () const

void	setItemMargin (int)

int	itemMargin () const

void	setItemSpacing (int)

int	itemSpacing () const

void	setFont (const QFont &)

QFont	font () const

void	setBorderDistance (int numPixels)
	Set the margin between the legend and the canvas border. More...

int	borderDistance () const

void	setBorderRadius (double)

double	borderRadius () const

void	setBorderPen (const QPen &)

QPen	borderPen () const

void	setBackgroundBrush (const QBrush &)
	Set the background brush. More...

QBrush	backgroundBrush () const

void	setBackgroundMode (BackgroundMode)
	Set the background mode. More...

BackgroundMode	backgroundMode () const

void	setTextPen (const QPen &)
	Set the pen for drawing text labels. More...

QPen	textPen () const

virtual void	draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &rect) const

void	clearLegend ()
	Remove all items from the legend.

virtual void	updateLegend (const QwtPlotItem *, const QList< QwtLegendData > &)

virtual QRect	geometry (const QRectF &canvasRect) const

virtual QSize	minimumSize (const QwtLegendData &) const

virtual int	heightForWidth (const QwtLegendData &, int w) const

QList< const QwtPlotItem * >	plotItems () const

QList< QRect >	legendGeometries (const QwtPlotItem *) const

Public Member Functions inherited from QwtPlotItem
	QwtPlotItem (const QwtText &title=QwtText())

virtual	~QwtPlotItem ()
	Destroy the QwtPlotItem.

void	attach (QwtPlot *plot)
	Attach the item to a plot. More...

void	detach ()
	This method detaches a QwtPlotItem from any QwtPlot it has been associated with. More...

QwtPlot *	plot () const
	Return attached plot.

void	setTitle (const QString &title)

void	setTitle (const QwtText &title)

const QwtText &	title () const

void	setItemAttribute (ItemAttribute, bool on=true)

bool	testItemAttribute (ItemAttribute) const

void	setItemInterest (ItemInterest, bool on=true)

bool	testItemInterest (ItemInterest) const

void	setRenderHint (RenderHint, bool on=true)

bool	testRenderHint (RenderHint) const

void	setRenderThreadCount (uint numThreads)

uint	renderThreadCount () const

void	setLegendIconSize (const QSize &)

QSize	legendIconSize () const

double	z () const

void	setZ (double z)
	Set the z value. More...

void	show ()
	Show the item.

void	hide ()
	Hide the item.

virtual void	setVisible (bool)

bool	isVisible () const

void	setAxes (int xAxis, int yAxis)

void	setXAxis (int axis)

int	xAxis () const
	Return xAxis.

void	setYAxis (int axis)

int	yAxis () const
	Return yAxis.

virtual void	itemChanged ()

virtual void	legendChanged ()

virtual QRectF	boundingRect () const

virtual void	getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasSize, double &left, double &top, double &right, double &bottom) const
	Calculate a hint for the canvas margin. More...

virtual void	updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)
	Update the item to changes of the axes scale division. More...

QRectF	scaleRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the bounding scale rectangle of 2 maps. More...

QRectF	paintRect (const QwtScaleMap &, const QwtScaleMap &) const
	Calculate the bounding paint rectangle of 2 maps. More...

virtual QList< QwtLegendData >	legendData () const
	Return all information, that is needed to represent the item on the legend. More...

virtual QwtGraphic	legendIcon (int index, const QSizeF &) const

Protected Member Functions
virtual void	drawLegendData (QPainter painter, const QwtPlotItem , const QwtLegendData &, const QRectF &) const

virtual void	drawBackground (QPainter *, const QRectF &rect) const

Protected Member Functions inherited from QwtPlotItem
QwtGraphic	defaultIcon (const QBrush &, const QSizeF &) const
	Return a default icon from a brush. More...

Detailed Description

A class which draws a legend inside the plot canvas.

QwtPlotLegendItem can be used to draw a inside the plot canvas. It can be used together with a QwtLegend or instead of it to have more space for the plot canvas.

In opposite to QwtLegend the legend item is not interactive. To identify mouse clicks on a legend item an event filter needs to be installed catching mouse events ob the plot canvas. The geometries of the legend items are available using legendGeometries().

The legend item is aligned to plot canvas according to its alignment() flags. It might have a background for the complete legend ( usually semi transparent ) or for each legend item.

Note: An external QwtLegend with a transparent background on top the plot canvas might be another option with a similar effect.

Member Enumeration Documentation

enum QwtPlotLegendItem::BackgroundMode

Background mode.

Depending on the mode the complete legend or each item might have an background.

The default setting is LegendBackground.

See Also: setBackgroundMode(), setBackgroundBrush(), drawBackground()

Enumerator
LegendBackground	The legend has a background.
ItemBackground	Each item has a background.

Member Function Documentation

Qt::Alignment QwtPlotLegendItem::alignment ( ) const

Returns: Alignment flags

See Also: setAlignment()

QBrush QwtPlotLegendItem::backgroundBrush ( ) const

Returns: Brush is used to fill the background

See Also: setBackgroundBrush(), backgroundMode(), drawBackground()

QwtPlotLegendItem::BackgroundMode QwtPlotLegendItem::backgroundMode ( ) const

Returns: backgroundMode

See Also: setBackgroundMode(), backgroundBrush(), drawBackground()

int QwtPlotLegendItem::borderDistance ( ) const

Returns: Margin between the legend and the canvas border

See Also: margin()

QPen QwtPlotLegendItem::borderPen ( ) const

Returns: Pen for drawing the border

See Also: setBorderPen(), backgroundBrush()

double QwtPlotLegendItem::borderRadius ( ) const

Returns: Radius of the border

See Also: setBorderRadius(), setBorderPen()

void QwtPlotLegendItem::draw	(	QPainter *	painter,
		const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect
	)		const

virtual

Draw the legend

Parameters

painter	Painter
xMap	x Scale Map
yMap	y Scale Map
canvasRect	Contents rectangle of the canvas in painter coordinates

Implements QwtPlotItem.

void QwtPlotLegendItem::drawBackground	(	QPainter *	painter,
		const QRectF &	rect
	)		const

protectedvirtual

Draw a rounded rect

Parameters

painter	Painter
rect	Bounding rectangle

See Also: setBorderRadius(), setBorderPen(), setBackgroundBrush(), setBackgroundMode()

void QwtPlotLegendItem::drawLegendData	(	QPainter *	painter,
		const QwtPlotItem *	plotItem,
		const QwtLegendData &	data,
		const QRectF &	rect
	)		const

protectedvirtual

Draw an entry on the legend

Parameters

painter	Qt Painter
plotItem	Plot item, represented by the entry
data	Attributes of the legend entry
rect	Bounding rectangle for the entry

QFont QwtPlotLegendItem::font ( ) const

Returns: Font used for drawing the text label

See Also: setFont()

QRect QwtPlotLegendItem::geometry ( const QRectF & canvasRect ) const

virtual

Calculate the geometry of the legend on the canvas

Parameters

canvasRect Geometry of the canvas

Returns: Geometry of the legend

int QwtPlotLegendItem::heightForWidth	(	const QwtLegendData &	data,
		int	width
	)		const

virtual

Returns: The preferred height, for a width.

Parameters

data	Attributes of the legend entry
width	Width

int QwtPlotLegendItem::itemMargin ( ) const

Returns: Margin around each item

See Also: setItemMargin(), itemSpacing(), margin(), spacing()

int QwtPlotLegendItem::itemSpacing ( ) const

Returns: Spacing inside of each item

See Also: setItemSpacing(), itemMargin(), margin(), spacing()

QList< QRect > QwtPlotLegendItem::legendGeometries ( const QwtPlotItem * plotItem ) const

Returns: Geometries of the items of a plot item

Note: Usually a plot item has only one entry on the legend

int QwtPlotLegendItem::margin ( ) const

Returns: Margin around the legend items

See Also: setMargin(), spacing(), itemMargin(), itemSpacing()

uint QwtPlotLegendItem::maxColumns ( ) const

Returns: Maximum number of columns

See Also: maxColumns(), QwtDynGridLayout::maxColumns()

QSize QwtPlotLegendItem::minimumSize ( const QwtLegendData & data ) const

virtual

Minimum size hint needed to display an entry

Parameters

data	Attributes of the legend entry

Returns: Minimum size

QList< const QwtPlotItem * > QwtPlotLegendItem::plotItems ( ) const

Returns: All plot items with an entry on the legend

Note: A plot item might have more than one entry on the legend

int QwtPlotLegendItem::rtti ( ) const

virtual

Returns: QwtPlotItem::Rtti_PlotLegend

Reimplemented from QwtPlotItem.

void QwtPlotLegendItem::setAlignment ( Qt::Alignment alignment )

Set the alignmnet.

Alignment means the position of the legend relative to the geometry of the plot canvas.

Parameters

alignment Alignment flags

See Also: alignment(), setMaxColumns()

Note: To align a legend with many items horizontally the number of columns need to be limited

void QwtPlotLegendItem::setBackgroundBrush ( const QBrush & brush )

Set the background brush.

The brush is used to fill the background

Parameters

brush Brush

See Also: backgroundBrush(), setBackgroundMode(), drawBackground()

void QwtPlotLegendItem::setBackgroundMode ( BackgroundMode mode )

Set the background mode.

Depending on the mode the complete legend or each item might have an background.

The default setting is LegendBackground.

See Also: backgroundMode(), setBackgroundBrush(), drawBackground()

void QwtPlotLegendItem::setBorderDistance ( int distance )

Set the margin between the legend and the canvas border.

The default setting for the margin is 10 pixels.

Parameters

distance Margin in pixels

See Also: setMargin()

void QwtPlotLegendItem::setBorderPen ( const QPen & pen )

Set the pen for drawing the border

Parameters

pen	Border pen

See Also: borderPen(), setBackgroundBrush()

void QwtPlotLegendItem::setBorderRadius ( double radius )

Set the radius for the border

Parameters

radius A value <= 0 defines a rectangular border

See Also: borderRadius(), setBorderPen()

void QwtPlotLegendItem::setFont ( const QFont & font )

Change the font used for drawing the text label

Parameters

font	Legend font

See Also: font()

void QwtPlotLegendItem::setItemMargin ( int margin )

Set the margin around each item

Parameters

margin Margin

See Also: itemMargin(), setItemSpacing(), setMargin(), setSpacing()

void QwtPlotLegendItem::setItemSpacing ( int spacing )

Set the spacing inside of each item

Parameters

spacing Spacing

See Also: itemSpacing(), setItemMargin(), setMargin(), setSpacing()

void QwtPlotLegendItem::setMargin ( int margin )

Set the margin around legend items.

The default setting for the margin is 0.

Parameters

margin Margin in pixels

See Also: margin(), setSpacing(), setItemMargin(), setItemSpacing

void QwtPlotLegendItem::setMaxColumns ( uint maxColumns )

Limit the number of columns.

When aligning the legend horizontally ( Qt::AlignLeft, Qt::AlignRight ) the number of columns needs to be limited to avoid, that the width of the legend grows with an increasing number of entries.

Parameters

maxColumns Maximum number of columns. 0 means unlimited.