Base class for items on a polar plot. More...

#include <qwt_polar_item.h>

Inheritance diagram for QwtPolarItem:

Public Types
enum	RttiValues { Rtti_PolarItem = 0, Rtti_PolarGrid, Rtti_PolarMarker, Rtti_PolarCurve, Rtti_PolarSpectrogram, Rtti_PolarUserItem = 1000 }
	Runtime type information. More...

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

enum	RenderHint { RenderAntialiased = 0x01 }
	Render hints. More...

typedef QFlags< ItemAttribute >	ItemAttributes
	Item attributes.

typedef QFlags< RenderHint >	RenderHints
	Item attributes.

Public Member Functions
	QwtPolarItem (const QwtText &title=QwtText())

virtual	~QwtPolarItem ()
	Destroy the QwtPolarItem.

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

void	detach ()
	This method detaches a QwtPolarItem from the QwtPolarPlot it has been associated with. More...

QwtPolarPlot *	plot () const

void	setTitle (const QString &title)

void	setTitle (const QwtText &title)

const QwtText &	title () const

virtual int	rtti () const

void	setItemAttribute (ItemAttribute, bool on=true)

bool	testItemAttribute (ItemAttribute) const

void	setRenderHint (RenderHint, bool on=true)

bool	testRenderHint (RenderHint) const

void	setRenderThreadCount (uint numThreads)

uint	renderThreadCount () 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

virtual void	itemChanged ()

virtual void	legendChanged ()

virtual void	draw (QPainter *painter, const QwtScaleMap &azimuthMap, const QwtScaleMap &radialMap, const QPointF &pole, double radius, const QRectF &canvasRect) const =0
	Draw the item. More...

virtual QwtInterval	boundingInterval (int scaleId) const

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

virtual int	marginHint () const

void	setLegendIconSize (const QSize &)

QSize	legendIconSize () const

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

Detailed Description

Base class for items on a polar plot.

A QwtPolarItem is "something that can be painted on the canvas". It is connected to the QwtPolar framework by a couple of virtual methods, that are individually implemented in derived item classes.

QwtPolar offers an implementation of the most common types of items, but deriving from QwtPolarItem makes it easy to implement additional types of items.

Member Enumeration Documentation

enum QwtPolarItem::ItemAttribute

Plot Item Attributes.

See Also: setItemAttribute(), testItemAttribute()

Enumerator
Legend	The item is represented on the legend.
AutoScale	The boundingRect() of the item is included in the autoscaling calculation.

enum QwtPolarItem::RenderHint

Render hints.

See Also: setRenderHint(), testRenderHint()

Enumerator
RenderAntialiased	Enable antialiasing.

enum QwtPolarItem::RttiValues

Runtime type information.

RttiValues is used to cast plot items, without having to enable runtime type information of the compiler.

Enumerator
Rtti_PolarItem	Unspecific value, that can be used, when it doesn't matter.
Rtti_PolarGrid	For QwtPolarGrid.
Rtti_PolarMarker	For QwtPolarMarker.
Rtti_PolarCurve	For QwtPolarCurve.
Rtti_PolarSpectrogram	For QwtPolarSpectrogram.
Rtti_PolarUserItem	Values >= Rtti_PolarUserItem are reserved for plot items not implemented in the QwtPolar library.

Constructor & Destructor Documentation

QwtPolarItem::QwtPolarItem ( const QwtText & title = QwtText() )

explicit

Constructor

Parameters

title Item title, f.e used on a legend

See Also: setTitle()

Member Function Documentation

void QwtPolarItem::attach ( QwtPolarPlot * plot )

Attach the item to a plot.

This method will attach a QwtPolarItem to the QwtPolarPlot argument. It will first detach the QwtPolarItem from any plot from a previous call to attach (if necessary). If a NULL argument is passed, it will detach from any QwtPolarPlot it was attached to.

Parameters

plot	Plot widget

See Also: QwtPolarItem::detach()

QwtInterval QwtPolarItem::boundingInterval ( int scaleId ) const

virtual

Interval, that is necessary to display the item

This interval can be useful for operations like clipping or autoscaling For items ( like the grid ), where a bounding interval makes no sense an invalid interval is returned.

Parameters

scaleId Scale id ( QwtPolar::Scale )

Returns: Bounding interval of the plot item for a specific scale

Reimplemented in QwtPolarCurve, QwtPolarSpectrogram, and QwtPolarMarker.

void QwtPolarItem::detach ( )

This method detaches a QwtPolarItem from the QwtPolarPlot it has been associated with.

detach() is equivalent to calling attach( NULL )

See Also: attach()

virtual void QwtPolarItem::draw	(	QPainter *	painter,
		const QwtScaleMap &	azimuthMap,
		const QwtScaleMap &	radialMap,
		const QPointF &	pole,
		double	radius,
		const QRectF &	canvasRect
	)		const

pure virtual

Draw the item.

Parameters

painter	Painter
azimuthMap	Maps azimuth values to values related to 0.0, M_2PI
radialMap	Maps radius values into painter coordinates.
pole	Position of the pole in painter coordinates
radius	Radius of the complete plot area in painter coordinates
canvasRect	Contents rect of the canvas in painter coordinates

Implemented in QwtPolarGrid, QwtPolarCurve, QwtPolarSpectrogram, and QwtPolarMarker.

bool QwtPolarItem::isVisible ( ) const

Returns: true if visible

See Also: setVisible(), show(), hide()

void QwtPolarItem::itemChanged ( )

virtual

Update the legend and call QwtPolarPlot::autoRefresh for the parent plot.

See Also: updateLegend()

void QwtPolarItem::legendChanged ( )

virtual

Update the legend of the parent plot.

See Also: QwtPolarPlot::updateLegend(), itemChanged()

QList< QwtLegendData > QwtPolarItem::legendData ( ) const

virtual

Return all information, that is needed to represent the item on the legend.

Most items are represented by one entry on the legend showing an icon and a text.

QwtLegendData is basically a list of QVariants that makes it possible to overload and reimplement legendData() to return almost any type of information, that is understood by the receiver that acts as the legend.

The default implementation returns one entry with the title() of the item and the legendIcon().

See Also: title(), legendIcon(), QwtLegend

QwtGraphic QwtPolarItem::legendIcon	(	int	index,
		const QSizeF &	size
	)		const

virtual

Returns: Icon representing the item on the legend

The default implementation returns an invalid icon

Parameters

index	Index of the legend entry ( usually there is only one )
size	Icon size

See Also: setLegendIconSize(), legendData()

Reimplemented in QwtPolarCurve.

QSize QwtPolarItem::legendIconSize ( ) const

Returns: Legend icon size

See Also: setLegendIconSize(), legendIcon()

int QwtPolarItem::marginHint ( ) const

virtual

Some items like to display something (f.e. the azimuth axis) outside of the area of the interval of the radial scale. The default implementation returns 0 pixels

Returns: Hint for the margin

Reimplemented in QwtPolarGrid.

QwtPolarPlot * QwtPolarItem::plot ( ) const

Returns: Attached plot

uint QwtPolarItem::renderThreadCount ( ) const

Returns: Number of threads to be used for rendering. If numThreads() is set to 0, the system specific ideal thread count is used.

int QwtPolarItem::rtti ( ) const

virtual

Return rtti for the specific class represented. QwtPolarItem is simply a virtual interface class, and base classes will implement this method with specific rtti values so a user can differentiate them.

The rtti value is useful for environments, where the runtime type information is disabled and it is not possible to do a dynamic_cast<...>.

Returns: rtti value

See Also: RttiValues

Reimplemented in QwtPolarGrid, QwtPolarCurve, QwtPolarSpectrogram, and QwtPolarMarker.

void QwtPolarItem::setItemAttribute	(	ItemAttribute	attribute,
		bool	on = `true`
	)

Toggle an item attribute

Parameters

attribute	Attribute type
on	true/false

See Also: testItemAttribute(), ItemAttribute

void QwtPolarItem::setLegendIconSize ( const QSize & size )

Set the size of the legend icon

The default setting is 8x8 pixels

Parameters

size Size

See Also: legendIconSize(), legendIcon()

void QwtPolarItem::setRenderHint	(	RenderHint	hint,
		bool	on = `true`
	)

Toggle an render hint

Parameters

hint	Render hint
on	true/false

See Also: testRenderHint(), RenderHint

void QwtPolarItem::setRenderThreadCount ( uint numThreads )

On multi core systems rendering of certain plot item ( f.e QwtPolarSpectrogram ) can be done in parallel in several threads.

The default setting is set to 1.

Parameters

numThreads Number of threads to be used for rendering. If numThreads is set to 0, the system specific ideal thread count is used.

The default thread count is 1 ( = no additional threads )

void QwtPolarItem::setTitle ( const QString & title )

Set a new title

Parameters

title Title

See Also: title()

void QwtPolarItem::setTitle ( const QwtText & title )

Set a new title

Parameters

title Title

See Also: title()

void QwtPolarItem::setVisible ( bool on )

virtual

Show/Hide the item

Parameters

on	Show if true, otherwise hide

See Also: isVisible(), show(), hide()

void QwtPolarItem::setZ ( double z )

Set the z value.

Plot items are painted in increasing z-order.

Parameters

z Z-value

See Also: z(), QwtPolarItemDict::itemList()

bool QwtPolarItem::testItemAttribute ( ItemAttribute attribute ) const

Test an item attribute

Parameters

attribute Attribute type

Returns: true/false

See Also: setItemAttribute(), ItemAttribute

bool QwtPolarItem::testRenderHint ( RenderHint hint ) const

Test a render hint

Parameters

hint	Render hint

Returns: true/false

See Also: setRenderHint(), RenderHint

const QwtText & QwtPolarItem::title ( ) const

Returns: Title of the item

See Also: setTitle()

void QwtPolarItem::updateScaleDiv	(	const QwtScaleDiv &	azimuthScaleDiv,
		const QwtScaleDiv &	radialScaleDiv,
		const QwtInterval &	interval
	)

virtual

Update the item to changes of the axes scale division.

Update the item, when the axes of plot have changed. The default implementation does nothing, but items that depend on the scale division (like QwtPolarGrid()) have to reimplement updateScaleDiv()

Parameters

azimuthScaleDiv	Scale division of the azimuth-scale
radialScaleDiv	Scale division of the radius-axis
interval	The interval of the radius-axis, that is visible on the canvas

See Also: QwtPolarPlot::updateAxes()

Reimplemented in QwtPolarGrid.

double QwtPolarItem::z ( ) const

Plot items are painted in increasing z-order.

Returns: Z value

See Also: setZ(), QwtPolarItemDict::itemList()

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation