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

#include <qwt_polar_item.h>

Inheritance diagram for QwtPolarItem:

Classes
class	PrivateData

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...

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

virtual	~QwtPolarItem ()
	Destructor.

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

void	detach ()
	Detach the item from its plot.

QwtPolarPlot *	plot () const
	Get the attached plot.

void	setTitle (const QString &title)
	Set the title from a QString.

void	setTitle (const QwtText &title)
	Set the title from a QwtText.

const QwtText &	title () const
	Get the title.

virtual int	rtti () const
	Get the runtime type information.

void	setItemAttribute (ItemAttribute, bool on=true)
	Set an item attribute.

bool	testItemAttribute (ItemAttribute) const
	Test an item attribute.

void	setRenderHint (RenderHint, bool on=true)
	Set a render hint.

bool	testRenderHint (RenderHint) const
	Test a render hint.

void	setRenderThreadCount (uint numThreads)
	Set the number of render threads.

uint	renderThreadCount () const
	Get the number of render threads.

double	z () const
	Get the z value.

void	setZ (double z)
	Set the z value.

void	show ()
	Show the item.

void	hide ()
	Hide the item.

virtual void	setVisible (bool)
	Set the visibility.

bool	isVisible () const
	Get the visibility.

virtual void	itemChanged ()
	Update the item and trigger autoRefresh.

virtual void	legendChanged ()
	Update the legend.

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

virtual QwtInterval	boundingInterval (int scaleId) const
	Get the bounding interval for a scale.

virtual void	updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &, const QwtInterval &)
	Update the scale division.

virtual int	marginHint () const
	Get the margin hint.

void	setLegendIconSize (const QSize &)
	Set the legend icon size.

QSize	legendIconSize () const
	Get the legend icon size.

virtual QList< QwtLegendData >	legendData () const
	Get the legend data.

virtual QwtGraphic	legendIcon (int index, const QSizeF &) const
	Get the legend icon.

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

◆ ItemAttribute

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.

◆ RenderHint

enum QwtPolarItem::RenderHint

Render hints.

See also: setRenderHint(), testRenderHint()

Enumerator
RenderAntialiased	Enable antialiasing.

◆ RttiValues

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

explicit

Constructor.

Parameters

title Item title, f.e used on a legend

See also: setTitle()

Member Function Documentation

◆ attach()

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 nullptr argument is passed, it will detach from any QwtPolarPlot it was attached to.

Parameters

plot	Plot widget

See also: QwtPolarItem::detach()

◆ boundingInterval()

QwtInterval QwtPolarItem::boundingInterval ( int scaleId ) const

virtual

Get the bounding interval for a scale.

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, QwtPolarMarker, and QwtPolarSpectrogram.

◆ detach()

void QwtPolarItem::detach ( )

Detach the item from its plot.

Detach the item from its associated plot.

This method detaches a QwtPolarItem from the QwtPolarPlot it has been associated with. detach() is equivalent to calling attach( nullptr ).

See also: attach()

◆ draw()

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 QwtPolarCurve, QwtPolarGrid, QwtPolarMarker, and QwtPolarSpectrogram.

◆ isVisible()

bool QwtPolarItem::isVisible ( ) const

Get the visibility.

Check if the item is visible.

Returns: true if visible

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

◆ itemChanged()

void QwtPolarItem::itemChanged ( )

virtual

Update the item and trigger autoRefresh.

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

See also: updateLegend()

◆ legendChanged()

void QwtPolarItem::legendChanged ( )

virtual

Update the legend.

Update the legend of the parent plot.

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

◆ legendData()

QList< QwtLegendData > QwtPolarItem::legendData ( ) const

virtual

Get the legend data.

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().

Returns: List of legend data

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

◆ legendIcon()

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

virtual

Get the legend icon.

Get 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

Returns: Icon representing the item on the legend

See also: setLegendIconSize(), legendData()

Reimplemented in QwtPolarCurve.

◆ legendIconSize()

QSize QwtPolarItem::legendIconSize ( ) const

Get the legend icon size.

Returns: Legend icon size

See also: setLegendIconSize(), legendIcon()

◆ marginHint()

int QwtPolarItem::marginHint ( ) const

virtual

Get the margin hint.

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.

◆ plot()

QwtPolarPlot * QwtPolarItem::plot ( ) const

Get the attached plot.

Returns: Attached plot

◆ renderThreadCount()

uint QwtPolarItem::renderThreadCount ( ) const

Get the number of render threads.

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

◆ rtti()

int QwtPolarItem::rtti ( ) const

virtual

Get the runtime type information.

Get runtime type information 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 QwtPolarCurve, QwtPolarGrid, QwtPolarMarker, and QwtPolarSpectrogram.

◆ setItemAttribute()

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

Set an item attribute.

Toggle an item attribute.

Parameters

attribute	Attribute type
on	true/false

See also: testItemAttribute(), ItemAttribute

◆ setLegendIconSize()

void QwtPolarItem::setLegendIconSize ( const QSize & size )

Set the legend icon size.

Set the size of the legend icon.

The default setting is 8x8 pixels.

Parameters

size Size

See also: legendIconSize(), legendIcon()

◆ setRenderHint()

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

Set a render hint.

Toggle a render hint.

Parameters

hint	Render hint
on	true/false

See also: testRenderHint(), RenderHint

◆ setRenderThreadCount()

void QwtPolarItem::setRenderThreadCount ( uint numThreads )

Set the number of render threads.

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 ).

◆ setTitle() [1/2]

void QwtPolarItem::setTitle ( const QString & title )

Set the title from a QString.

Set a new title.

Parameters

title Title

See also: title()

◆ setTitle() [2/2]

void QwtPolarItem::setTitle ( const QwtText & title )

Set the title from a QwtText.

Set a new title.

Parameters

title Title

See also: title()

◆ setVisible()

void QwtPolarItem::setVisible ( bool on )

virtual

Set the visibility.

Show/Hide the item.

Parameters

on	Show if true, otherwise hide

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

◆ setZ()

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()

◆ testItemAttribute()

bool QwtPolarItem::testItemAttribute ( ItemAttribute attribute ) const

Test an item attribute.

Parameters

attribute Attribute type

Returns: true/false

See also: setItemAttribute(), ItemAttribute

◆ testRenderHint()

bool QwtPolarItem::testRenderHint ( RenderHint hint ) const

Test a render hint.

Parameters

hint	Render hint

Returns: true/false

See also: setRenderHint(), RenderHint

◆ title()

const QwtText & QwtPolarItem::title ( ) const

Get the title.

Get the title of the item.

Returns: Title of the item

See also: setTitle()

◆ updateScaleDiv()

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

virtual

Update the scale division.

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.

◆ z()

double QwtPolarItem::z ( ) const

Get the z value.

Plot items are painted in increasing z-order.

Returns: Z value

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

The documentation for this class was generated from the following files:

/home/runner/work/QWT/QWT/src/plot/qwt_polar_item.h
/home/runner/work/QWT/QWT/src/plot/qwt_polar_item.cpp

Classes

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ ItemAttribute

◆ RenderHint

◆ RttiValues

Constructor & Destructor Documentation

◆ QwtPolarItem()

Member Function Documentation

◆ attach()

◆ boundingInterval()

◆ detach()

◆ draw()

◆ isVisible()

◆ itemChanged()

◆ legendChanged()

◆ legendData()

◆ legendIcon()

◆ legendIconSize()

◆ marginHint()

◆ plot()

◆ renderThreadCount()

◆ rtti()

◆ setItemAttribute()

◆ setLegendIconSize()

◆ setRenderHint()

◆ setRenderThreadCount()

◆ setTitle() [1/2]

◆ setTitle() [2/2]

◆ setVisible()

◆ setZ()

◆ testItemAttribute()

◆ testRenderHint()

◆ title()

◆ updateScaleDiv()

◆ z()