QwtSymbol类 参考

A class for drawing symbols 更多...

#include <qwt_symbol.h>

类
class	PrivateData

Public 类型
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 更多...
enum	CachePolicy { NoCache , Cache , AutoCache }
	Cache policy for symbol rendering 更多...

Public 成员函数
	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 成员函数
virtual void	renderSymbols (QPainter *, const QPointF *, int numPoints) const
	Render the symbol to series of points

详细描述

A class for drawing symbols

成员枚举类型说明

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

参见

setCachePolicy(), cachePolicy()

注解

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

警告

Since Qt 4.8 raster is the default backend on X11

枚举值
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

参见

setStyle(), style()

枚举值
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. 参见 setPath(), path()
Pixmap	The symbol is represented by a pixmap. The pixmap is centered or aligned to its pin point. 参见 setPinPoint()
Graphic	The symbol is represented by a graphic. The graphic is centered or aligned to its pin point. 参见 setPinPoint()
SvgDocument	The symbol is represented by a SVG graphic. The graphic is centered or aligned to its pin point. 参见 setPinPoint()
UserStyle	Styles >= QwtSymbol::UserSymbol are reserved for derived classes of QwtSymbol that overload drawSymbols() with additional application specific symbol types.

构造及析构函数说明

QwtSymbol()

QwtSymbol::QwtSymbol ( Style  style = NoSymbol )

explicit

Default Constructor

参数

style

Symbol Style

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

Constructor

参数

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

参见

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 ).

参数

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

参见

setPath(), setBrush(), setPen(), setSize()

Destructor

成员函数说明

boundingRect()

QRect QwtSymbol::boundingRect ( ) const

virtual

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

返回

Bounding rectangle

参见

drawSymbols()

brush()

const QBrush & QwtSymbol::brush

(

)

const

Get the brush

返回

Current brush

参见

setBrush()

cachePolicy()

QwtSymbol::CachePolicy QwtSymbol::cachePolicy

(

)

const

Get the cache policy

返回

Cache policy

参见

CachePolicy, setCachePolicy()

drawSymbol() [1/2]

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

inline

Draw the symbol at a specified position

参数

painter	Painter
pos	Position of the symbol in screen coordinates

参见

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.

参数

painter	Painter
rect	Target rectangle for the symbol

参见

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.

参数

painter	Painter
points	Array of points
numPoints	Number of points

参见

drawSymbol()

drawSymbols() [2/2]

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

inline

Draw symbols at the specified points

参数

painter	Painter
points	Positions of the symbols in screen coordinates

参见

drawSymbol()

graphic()

const QwtGraphic & QwtSymbol::graphic

(

)

const

Get assigned graphic

返回

Assigned graphic

参见

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.

参见

CachePolicy, setCachePolicy(), drawSymbols()

isPinPointEnabled()

bool QwtSymbol::isPinPointEnabled

(

)

const

Check if pin point is enabled

返回

True when the pin point translation is enabled

参见

setPinPoint(), setPinPointEnabled()

path()

const QPainterPath & QwtSymbol::path

(

)

const

Get painter path for displaying the symbol

返回

Painter path for displaying the symbol

参见

setPath()

pen()

const QPen & QwtSymbol::pen

(

)

const

Get the pen

返回

Current pen

参见

setPen(), brush()

pinPoint()

QPointF QwtSymbol::pinPoint

(

)

const

Get pin point

返回

Current pin point

参见

setPinPoint(), setPinPointEnabled()

pixmap()

const QPixmap & QwtSymbol::pixmap

(

)

const

Get assigned pixmap

返回

Assigned pixmap

参见

setPixmap()

renderSymbols()

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

protectedvirtual

Render the symbol to series of points

参数

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.

参数

brush

Brush to assign

参见

brush()

setCachePolicy()

void QwtSymbol::setCachePolicy

(

QwtSymbol::CachePolicy

policy

)

Change the cache policy

The default policy is AutoCache

参数

policy

Cache policy

参见

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.

参数

color

Color to set

参见

setBrush(), setPen(), brush(), pen()

setGraphic()

void QwtSymbol::setGraphic

(

const QwtGraphic &

graphic

)

Set a graphic as symbol

参数

graphic

Graphic

参见

graphic(), setPixmap()

注解

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.

参数

path	Painter path

注解

The style is implicitly set to QwtSymbol::Path.

参见

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.

参数

color	Pen color
width	Pen width
style	Pen style

参见

pen(), brush()

setPen() [2/2]

void QwtSymbol::setPen

(

const QPen &

pen

)

Assign a pen

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

参数

pen	Pen to assign

参见

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.

参数

pos	Position
enable	Enable/disable the pin point alignment

参见

pinPoint(), setPinPointEnabled()

setPinPointEnabled()

void QwtSymbol::setPinPointEnabled

(

bool

on

)

Enable/disable the pin point alignment

参数

on	Enabled when on is true

参见

setPinPoint(), isPinPointEnabled()

setPixmap()

void QwtSymbol::setPixmap

(

const QPixmap &

pixmap

)

Set a pixmap as symbol

参数

pixmap

Pixmap to set

参见

pixmap(), setGraphic()

注解

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

参数

size	Size to set

参见

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).

参数

width	Width
height	Height (defaults to -1)

参见

size(), setSize(const QSize&)

setStyle()

void QwtSymbol::setStyle

(

QwtSymbol::Style

style

)

Specify the symbol style

参数

style

Style to set

参见

style()

setSvgDocument()

void QwtSymbol::setSvgDocument

(

const QByteArray &

svgDocument

)

Set a SVG icon as symbol

参数

svgDocument

SVG icon data

参见

setGraphic(), setPixmap()

注解

The style() is set to QwtSymbol::SvgDocument

brush() and pen() have no effect

size()

const QSize & QwtSymbol::size

(

)

const

Get the symbol's size

返回

Current size

参见

setSize()

style()

QwtSymbol::Style QwtSymbol::style

(

)

const

Get current symbol style

返回

Current symbol style

参见

setStyle()

---

该类的文档由以下文件生成:

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