A class to render labels. More...

#include <qgslabel.h>

Collaboration diagram for QgsLabel:

Classes
struct	labelpoint
Public Types
enum	LabelField { Text = 0, Family, Size, SizeType, Bold, Italic, Underline, Color, XCoordinate, YCoordinate, XOffset, YOffset, Angle, Alignment, BufferEnabled, BufferSize, BufferColor, BufferBrush, BorderWidth, BorderColor, BorderStyle, MultilineEnabled, StrikeOut, LabelFieldCount }
Public Member Functions
	QgsLabel (const QgsFields &fields)
	~QgsLabel ()
void	addRequiredFields (QgsAttributeList &fields) const
	add vector of required fields to existing list of fields
QgsFields &	fields ()
	Available vector fields.
QString	fieldValue (int attr, QgsFeature &feature)
	Get field value if : 1) field name is not empty 2) field exists 3) value is defined otherwise returns empty string.
QgsLabelAttributes *	labelAttributes ()
	Pointer to default attributes.
QString	labelField (int attr) const
	label field
float	maxScale () const
float	minScale () const
void	readXML (const QDomNode &node)
	Reads the renderer configuration from an XML file.
void	renderLabel (QgsRenderContext &renderContext, QgsFeature &feature, bool selected, QgsLabelAttributes *classAttributes=0)
	render label
bool	scaleBasedVisibility () const
void	setFields (const QgsFields &fields)
	Set available fields.
void	setLabelField (int attr, int fieldIndex)
	Set label field.
void	setMaxScale (float theMaxScale)
	Accessor and mutator for the maximum scale member.
void	setMinScale (float theMinScale)
	Accessor and mutator for the minimum scale member.
void	setScaleBasedVisibility (bool theVisibilityFlag)
	Accessor and mutator for the scale based visilibility flag.
void	writeXML (QDomNode &label_node, QDomDocument &document) const
	Writes the contents of the renderer to a configuration file.
Private Member Functions
void	labelPoint (std::vector< labelpoint > &, QgsFeature &feature)
	Get label point for simple feature in map units.
unsigned char *	labelPoint (labelpoint &point, unsigned char *wkb, size_t wkblen)
	Get label point for the given feature in wkb format.
bool	readLabelField (QDomElement &el, int attr, QString prefix)
void	renderLabel (QgsRenderContext &renderContext, QgsPoint point, QString text, QFont font, QPen pen, int dx, int dy, double xoffset, double yoffset, double ang, int width, int height, int alignment)
	Does the actual rendering of a label at the given point.
Private Attributes
QgsFields	mFields
	Available layer fields.
QgsLabelAttributes *	mLabelAttributes
	Default layer attributes.
std::vector< QString >	mLabelField
	Label fields.
std::vector< int >	mLabelFieldIdx
	Label field indexes.
float	mMaxScale
	Maximum scale at which this label should be displayed.
float	mMinScale
	Minimum scale at which this label should be displayed.
bool	mScaleBasedVisibility
	A flag that tells us whether to use the above vars to restrict the label's visibility.
QColor	mSelectionColor
	Color to draw selected features.

Detailed Description

A class to render labels.

Label rendering properties can be either specified directly or in most cases determined dynamically based on the value of an attribute.

Definition at line 52 of file qgslabel.h.

Member Enumeration Documentation

enum QgsLabel::LabelField

Enumerator:

Text
Family
Size
SizeType
Bold
Italic
Underline
Color
XCoordinate
YCoordinate
XOffset
YOffset
Angle
Alignment
BufferEnabled
BufferSize
BufferColor
BufferBrush
BorderWidth
BorderColor
BorderStyle
MultilineEnabled
StrikeOut
LabelFieldCount

Definition at line 60 of file qgslabel.h.

Constructor & Destructor Documentation

QgsLabel::QgsLabel ( const QgsFields & fields )

Definition at line 47 of file qgslabel.cpp.

References fields(), LabelFieldCount, mFields, mLabelAttributes, and mLabelFieldIdx.

QgsLabel::~QgsLabel ( )

Definition at line 61 of file qgslabel.cpp.

References mLabelAttributes.

Member Function Documentation

void QgsLabel::addRequiredFields ( QgsAttributeList & fields ) const

add vector of required fields to existing list of fields

Definition at line 463 of file qgslabel.cpp.

References LabelFieldCount, and mLabelFieldIdx.

Referenced by QgsVectorLayer::drawLabels().

QgsFields & QgsLabel::fields ( void )

Available vector fields.

Definition at line 490 of file qgslabel.cpp.

References mFields.

Referenced by QgsLabel(), and setFields().

QString QgsLabel::fieldValue	(	int	attr,
		QgsFeature &	feature
	)

Get field value if : 1) field name is not empty 2) field exists 3) value is defined otherwise returns empty string.

Definition at line 66 of file qgslabel.cpp.

References QgsFeature::attribute(), and mLabelFieldIdx.

Referenced by renderLabel().

QgsLabelAttributes * QgsLabel::labelAttributes ( void )

Pointer to default attributes.

Note:: this replaces the to-be-deprecated layerAttributes method.; introduced in QGIS 1.4

Definition at line 514 of file qgslabel.cpp.

References mLabelAttributes.

QString QgsLabel::labelField ( int attr ) const

label field

Definition at line 503 of file qgslabel.cpp.

References QgsFields::count(), LabelFieldCount, mFields, and mLabelFieldIdx.

Referenced by QgsVectorLayer::writeSymbology(), and writeXML().

void QgsLabel::labelPoint	(	std::vector< labelpoint > &	points,
		QgsFeature &	feature
	)		`[private]`

Get label point for simple feature in map units.

Definition at line 519 of file qgslabel.cpp.

References QgsGeometry::asWkb(), QgsFeature::geometry(), QgsDebugMsg, QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, QGis::WKBMultiPoint, QGis::WKBMultiPoint25D, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBPoint, QGis::WKBPoint25D, QGis::WKBPolygon, QGis::WKBPolygon25D, QgsGeometry::wkbSize(), and QgsGeometry::wkbType().

Referenced by renderLabel().

unsigned char * QgsLabel::labelPoint	(	labelpoint &	point,
		unsigned char *	wkb,
		size_t	wkblen
	)		`[private]`

Get label point for the given feature in wkb format.

Definition at line 567 of file qgslabel.cpp.

References QgsLabel::labelpoint::angle, QgsLabel::labelpoint::p, QgsDebugMsg, QgsPoint::set(), QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBPoint, QGis::WKBPoint25D, QGis::WKBPolygon, and QGis::WKBPolygon25D.

float QgsLabel::maxScale ( ) const

Definition at line 1401 of file qgslabel.cpp.

References mMaxScale.

Referenced by QgsVectorLayer::drawLabels(), and QgsVectorLayer::writeSymbology().

float QgsLabel::minScale ( ) const

Definition at line 1391 of file qgslabel.cpp.

References mMinScale.

Referenced by QgsVectorLayer::drawLabels(), and QgsVectorLayer::writeSymbology().

bool QgsLabel::readLabelField	(	QDomElement &	el,
		int	attr,
		QString	prefix = `"field"`
	)		`[private]`

Definition at line 698 of file qgslabel.cpp.

References QgsFields::count(), mFields, and mLabelFieldIdx.

Referenced by readXML().

void QgsLabel::readXML ( const QDomNode & node )

Reads the renderer configuration from an XML file.

Parameters:

node	the Dom node to read

Definition at line 733 of file qgslabel.cpp.

Referenced by QgsVectorLayer::readSymbology().

void QgsLabel::renderLabel	(	QgsRenderContext &	renderContext,
		QgsFeature &	feature,
		bool	selected,
		QgsLabelAttributes *	classAttributes = `0`
	)

render label

Parameters:

renderContext	the render context
feature	feature to render the label for
selected	feature is selected
classAttributes	attributes to create the label from

Note:: added in 1.2

Definition at line 76 of file qgslabel.cpp.

Referenced by QgsVectorLayer::drawLabels().

void QgsLabel::renderLabel	(	QgsRenderContext &	renderContext,
		QgsPoint	point,
		QString	text,
		QFont	font,
		QPen	pen,
		int	dx,
		int	dy,
		double	xoffset,
		double	yoffset,
		double	ang,
		int	width,
		int	height,
		int	alignment
	)		`[private]`