A class for drawing symbols. More...

#include <qwt_symbol.h>

Classes
class	PrivateData

Public Types
enum	Style { NoSymbol = -1 , Ellipse , Rect , Diamond , Triangle , DTriangle , UTriangle , LTriangle , RTriangle , Cross , XCross , HLine , VLine , Star1 , Star2 , Hexagon , Path , Pixmap , Graphic , SvgDocument , UserStyle = 1000 }
	Symbol Style. More...

enum	CachePolicy { NoCache , Cache , AutoCache }
	Cache policy for symbol rendering. More...

Public Member Functions
	QwtSymbol (Style=NoSymbol)
	Default Constructor.

	QwtSymbol (Style, const QBrush &, const QPen &, const QSize &)

	QwtSymbol (const QPainterPath &, const QBrush &, const QPen &)

void	setCachePolicy (CachePolicy)
	Change the cache policy.

CachePolicy	cachePolicy () const
	Get the cache policy.

void	setSize (const QSize &)
	Set the symbol's size.

void	setSize (int width, int height=-1)
	Specify the symbol's size.

const QSize &	size () const
	Get the symbol's size.

void	setPinPoint (const QPointF &pos, bool enable=true)
	Set and enable a pin point.

QPointF	pinPoint () const
	Get pin point.

void	setPinPointEnabled (bool)
	Enable/disable the pin point alignment.

bool	isPinPointEnabled () const
	Check if pin point is enabled.

virtual void	setColor (const QColor &)
	Set the color of the symbol.

void	setBrush (const QBrush &)
	Assign a brush.

const QBrush &	brush () const
	Get the brush.

void	setPen (const QColor &, qreal width=0.0, Qt::PenStyle=Qt::SolidLine)
	Build and assign a pen.

void	setPen (const QPen &)
	Assign a pen.

const QPen &	pen () const
	Get the pen.

void	setStyle (Style)
	Specify the symbol style.

Style	style () const
	Get current symbol style.

void	setPath (const QPainterPath &)
	Set a painter path as symbol.

const QPainterPath &	path () const
	Get painter path for displaying the symbol.

void	setPixmap (const QPixmap &)
	Set a pixmap as symbol.

const QPixmap &	pixmap () const
	Get assigned pixmap.

void	setGraphic (const QwtGraphic &)
	Set a graphic as symbol.

const QwtGraphic &	graphic () const
	Get assigned graphic.

void	setSvgDocument (const QByteArray &)
	Set a SVG icon as symbol.

void	drawSymbol (QPainter *, const QRectF &) const
	Draw the symbol into a rectangle.

void	drawSymbol (QPainter *, const QPointF &) const
	Draw the symbol at a specified position.

void	drawSymbols (QPainter *, const QPolygonF &) const
	Draw symbols at the specified points.

void	drawSymbols (QPainter , const QPointF , int numPoints) const
	Render an array of symbols.

virtual QRect	boundingRect () const
	Calculate the bounding rectangle for a symbol at position (0,0)

void	invalidateCache ()
	Invalidate the cached symbol pixmap.

Protected Member Functions
virtual void	renderSymbols (QPainter , const QPointF , int numPoints) const
	Render the symbol to series of points.

Detailed Description

A class for drawing symbols.

Member Enumeration Documentation

◆ CachePolicy

enum QwtSymbol::CachePolicy

Cache policy for symbol rendering.

Depending on the render engine and the complexity of the symbol shape it might be faster to render the symbol to a pixmap and to paint this pixmap.

F.e. the raster paint engine is a pure software renderer where in cache mode a draw operation usually ends in raster operation with the the backing store, that are usually faster, than the algorithms for rendering polygons. But the opposite can be expected for graphic pipelines that can make use of hardware acceleration.

The default setting is AutoCache

See also: setCachePolicy(), cachePolicy()

Note: The policy has no effect, when the symbol is painted to a vector graphics format ( PDF, SVG ).

Warning: Since Qt 4.8 raster is the default backend on X11

Enumerator

NoCache

Don't use a pixmap cache.

Cache

Always use a pixmap cache.

AutoCache

Use a cache when one of the following conditions is true:

The symbol is rendered with the software renderer ( QPaintEngine::Raster )

◆ Style

enum QwtSymbol::Style

Symbol Style.

See also: setStyle(), style()

Enumerator
NoSymbol	No Style. The symbol cannot be drawn.
Ellipse	Ellipse or circle.
Rect	Rectangle.
Diamond	Diamond.
Triangle	Triangle pointing upwards.
DTriangle	Triangle pointing downwards.
UTriangle	Triangle pointing upwards.
LTriangle	Triangle pointing left.
RTriangle	Triangle pointing right.
Cross	Cross (+)
XCross	Diagonal cross (X)
HLine	Horizontal line.
VLine	Vertical line.
Star1	X combined with +.
Star2	Six-pointed star.
Hexagon	Hexagon.
Path	The symbol is represented by a painter path, where the origin ( 0, 0 ) of the path coordinate system is mapped to the position of the symbol. See also setPath(), path()
Pixmap	The symbol is represented by a pixmap. The pixmap is centered or aligned to its pin point. See also setPinPoint()
Graphic	The symbol is represented by a graphic. The graphic is centered or aligned to its pin point. See also setPinPoint()
SvgDocument	The symbol is represented by a SVG graphic. The graphic is centered or aligned to its pin point. See also setPinPoint()
UserStyle	Styles >= QwtSymbol::UserSymbol are reserved for derived classes of QwtSymbol that overload drawSymbols() with additional application specific symbol types.

Constructor & Destructor Documentation

◆ QwtSymbol()

QwtSymbol::QwtSymbol ( Style style = NoSymbol )

explicit

Default Constructor.

Parameters

style Symbol Style

The symbol is constructed with gray interior, black outline with zero width, no size and style 'NoSymbol'.

Constructor

Parameters

style	Symbol Style
brush	brush to fill the interior
pen	outline pen
size	size

See also: setStyle(), setBrush(), setPen(), setSize()

Constructor

The symbol gets initialized by a painter path. The style is set to QwtSymbol::Path, the size is set to empty ( the path is displayed unscaled ).

Parameters

path	painter path
brush	brush to fill the interior
pen	outline pen

See also: setPath(), setBrush(), setPen(), setSize()

Destructor

Member Function Documentation

◆ boundingRect()

QRect QwtSymbol::boundingRect ( ) const

virtual

Calculate the bounding rectangle for a symbol at position (0,0)

Returns: Bounding rectangle

See also: drawSymbols()

◆ brush()

const QBrush & QwtSymbol::brush ( ) const

Get the brush.

Returns: Current brush

See also: setBrush()

◆ cachePolicy()

QwtSymbol::CachePolicy QwtSymbol::cachePolicy ( ) const

Get the cache policy.

Returns: Cache policy

See also: CachePolicy, setCachePolicy()

◆ drawSymbol() [1/2]

void QwtSymbol::drawSymbol	(	QPainter *	painter,
		const QPointF &	pos
	)		const

inline

Draw the symbol at a specified position.

Parameters

painter	Painter
pos	Position of the symbol in screen coordinates

See also: drawSymbols()

◆ drawSymbol() [2/2]

void QwtSymbol::drawSymbol	(	QPainter *	painter,
		const QRectF &	rect
	)		const

Draw the symbol into a rectangle.

The symbol is painted centered and scaled into the target rectangle. It is always painted uncached and the pin point is ignored. This method is primarily intended for drawing a symbol to the legend.

Parameters

painter	Painter
rect	Target rectangle for the symbol

See also: drawSymbols()

◆ drawSymbols() [1/2]

void QwtSymbol::drawSymbols	(	QPainter *	painter,
		const QPointF *	points,
		int	numPoints
	)		const

Render an array of symbols.

Painting several symbols is more effective than drawing symbols one by one, as a couple of layout calculations and setting of pen/brush can be done once for the complete array.

Parameters

painter	Painter
points	Array of points
numPoints	Number of points

See also: drawSymbol()

◆ drawSymbols() [2/2]

void QwtSymbol::drawSymbols	(	QPainter *	painter,
		const QPolygonF &	points
	)		const

inline

Draw symbols at the specified points.

Parameters

painter	Painter
points	Positions of the symbols in screen coordinates

See also: drawSymbol()

◆ graphic()

const QwtGraphic & QwtSymbol::graphic ( ) const

Get assigned graphic.

Returns: Assigned graphic

See also: setGraphic()

◆ invalidateCache()

void QwtSymbol::invalidateCache ( )

Invalidate the cached symbol pixmap.

The symbol invalidates its cache, whenever an attribute is changed that has an effect on how to display a symbol. In case of derived classes with individual styles (>= QwtSymbol::UserStyle) it might be necessary to call invalidateCache() for attributes that are relevant for this style.

See also: CachePolicy, setCachePolicy(), drawSymbols()

◆ isPinPointEnabled()

bool QwtSymbol::isPinPointEnabled ( ) const

Check if pin point is enabled.

Returns: True when the pin point translation is enabled

See also: setPinPoint(), setPinPointEnabled()

◆ path()

const QPainterPath & QwtSymbol::path ( ) const

Get painter path for displaying the symbol.

Returns: Painter path for displaying the symbol

See also: setPath()

◆ pen()

const QPen & QwtSymbol::pen ( ) const

Get the pen.

Returns: Current pen

See also: setPen(), brush()

◆ pinPoint()

QPointF QwtSymbol::pinPoint ( ) const

Get pin point.

Returns: Current pin point

See also: setPinPoint(), setPinPointEnabled()

◆ pixmap()

const QPixmap & QwtSymbol::pixmap ( ) const

Get assigned pixmap.

Returns: Assigned pixmap

See also: setPixmap()

◆ renderSymbols()

void QwtSymbol::renderSymbols	(	QPainter *	painter,
		const QPointF *	points,
		int	numPoints
	)		const

protectedvirtual

Render the symbol to series of points.

Parameters

painter	Qt painter
points	Positions of the symbols
numPoints	Number of points

◆ setBrush()

void QwtSymbol::setBrush ( const QBrush & brush )

Assign a brush.

The brush is used to draw the interior of the symbol.

Parameters

brush Brush to assign

See also: brush()

◆ setCachePolicy()

void QwtSymbol::setCachePolicy ( QwtSymbol::CachePolicy policy )

Change the cache policy.

The default policy is AutoCache

Parameters

policy Cache policy

See also: CachePolicy, cachePolicy()

◆ setColor()

void QwtSymbol::setColor ( const QColor & color )

virtual

Set the color of the symbol.

Change the color of the brush for symbol types with a filled area. For all other symbol types the color will be assigned to the pen.

Parameters

color Color to set

See also: setBrush(), setPen(), brush(), pen()

◆ setGraphic()

void QwtSymbol::setGraphic ( const QwtGraphic & graphic )

Set a graphic as symbol.

Parameters

graphic Graphic

See also: graphic(), setPixmap()

Note: the style() is set to QwtSymbol::Graphic; brush() and pen() have no effect

◆ setPath()

void QwtSymbol::setPath ( const QPainterPath & path )

Set a painter path as symbol.

The symbol is represented by a painter path, where the origin (0, 0) of the path coordinate system is mapped to the position of the symbol. When the symbol has valid size the painter path gets scaled to fit into the size. Otherwise the symbol size depends on the bounding rectangle of the path.

Parameters

path	Painter path

Note: The style is implicitly set to QwtSymbol::Path.

See also: path(), setSize()

Example code defining a symbol drawing an arrow:

#include <qwt_symbol.h>
 
QwtSymbol *symbol = new QwtSymbol();
 
QPen pen( Qt::black, 2 );
pen.setJoinStyle( Qt::MiterJoin );
 
symbol->setPen( pen );
symbol->setBrush( Qt::red );
 
QPainterPath path;
path.moveTo( 0, 8 );
path.lineTo( 0, 5 );
path.lineTo( -3, 5 );
path.lineTo( 0, 0 );
path.lineTo( 3, 5 );
path.lineTo( 0, 5 );
 
QTransform transform;
transform.rotate( -30.0 );
path = transform.map( path );
 
symbol->setPath( path );
symbol->setPinPoint( QPointF( 0.0, 0.0 ) );
 
setSize( 10, 14 );

◆ setPen() [1/2]

void QwtSymbol::setPen	(	const QColor &	color,
		qreal	width = `0.0`,
		Qt::PenStyle	style = `Qt::SolidLine`
	)

Build and assign a pen.

In Qt5 the default pen width is 1.0 (0.0 in Qt4) what makes it non cosmetic (see QPen::isCosmetic()). This method has been introduced to hide this incompatibility.

Parameters

color	Pen color
width	Pen width
style	Pen style

See also: pen(), brush()

◆ setPen() [2/2]

void QwtSymbol::setPen ( const QPen & pen )

Assign a pen.

The pen is used to draw the symbol's outline.

Parameters

pen	Pen to assign

See also: pen(), setBrush()

◆ setPinPoint()

void QwtSymbol::setPinPoint	(	const QPointF &	pos,
		bool	enable = `true`
	)

Set and enable a pin point.

The position of a complex symbol is not always aligned to its center (e.g. an arrow, where the peak points to a position). The pin point defines the position inside of a Pixmap, Graphic, SvgDocument or PainterPath symbol where the represented point has to be aligned to.

Parameters

pos	Position
enable	Enable/disable the pin point alignment

See also: pinPoint(), setPinPointEnabled()

◆ setPinPointEnabled()

void QwtSymbol::setPinPointEnabled ( bool on )

Enable/disable the pin point alignment.

Parameters

on	Enabled when on is true

See also: setPinPoint(), isPinPointEnabled()

◆ setPixmap()

void QwtSymbol::setPixmap ( const QPixmap & pixmap )

Set a pixmap as symbol.

Parameters

pixmap Pixmap to set

See also: pixmap(), setGraphic()

Note: The style() is set to QwtSymbol::Pixmap; brush() and pen() have no effect

◆ setSize() [1/2]

void QwtSymbol::setSize ( const QSize & size )

Set the symbol's size.

Parameters

size	Size to set

See also: size(), setSize(int, int)

◆ setSize() [2/2]

void QwtSymbol::setSize	(	int	width,
		int	height = `-1`
	)

Specify the symbol's size.

If the 'height' parameter is left out or less than 0, and the 'width' parameter is greater than or equal to 0, the symbol size will be set to (width, width).

Parameters

width	Width
height	Height (defaults to -1)

See also: size(), setSize(const QSize&)

◆ setStyle()

void QwtSymbol::setStyle ( QwtSymbol::Style style )

Specify the symbol style.

Parameters

style Style to set

See also: style()

◆ setSvgDocument()

void QwtSymbol::setSvgDocument ( const QByteArray & svgDocument )

Set a SVG icon as symbol.

Parameters

svgDocument SVG icon data

See also: setGraphic(), setPixmap()

Note: The style() is set to QwtSymbol::SvgDocument; brush() and pen() have no effect

◆ size()

const QSize & QwtSymbol::size ( ) const

Get the symbol's size.

Returns: Current size

See also: setSize()

◆ style()

QwtSymbol::Style QwtSymbol::style ( ) const

Get current symbol style.

Returns: Current symbol style

See also: setStyle()

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

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

Classes

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ CachePolicy

◆ Style

Constructor & Destructor Documentation

◆ QwtSymbol()

Member Function Documentation

◆ boundingRect()

◆ brush()

◆ cachePolicy()

◆ drawSymbol() [1/2]

◆ drawSymbol() [2/2]

◆ drawSymbols() [1/2]

◆ drawSymbols() [2/2]

◆ graphic()

◆ invalidateCache()

◆ isPinPointEnabled()

◆ path()

◆ pen()

◆ pinPoint()

◆ pixmap()

◆ renderSymbols()

◆ setBrush()

◆ setCachePolicy()

◆ setColor()

◆ setGraphic()

◆ setPath()

◆ setPen() [1/2]

◆ setPen() [2/2]

◆ setPinPoint()

◆ setPinPointEnabled()

◆ setPixmap()

◆ setSize() [1/2]

◆ setSize() [2/2]

◆ setStyle()

◆ setSvgDocument()

◆ size()

◆ style()