QgsLabel Class Reference
[QGIS core library]

A class to render labels. More...

#include <qgslabel.h>

Collaboration diagram for QgsLabel:

Collaboration graph
[legend]

List of all members.

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 QgsFieldMap &fields)
 ~QgsLabel ()
void renderLabel (QPainter *painter, const QgsRectangle &viewExtent, QgsCoordinateTransform *coordinateTransform, const QgsMapToPixel *transform, QgsFeature &feature, bool selected, QgsLabelAttributes *classAttributes=0, double sizeScale=1., double rasterScaleFactor=1.0)
 render label
void renderLabel (QgsRenderContext &renderContext, QgsFeature &feature, bool selected, QgsLabelAttributes *classAttributes=0)
 render label
void readXML (const QDomNode &node)
 Reads the renderer configuration from an XML file.
void writeXML (QDomNode &label_node, QDomDocument &document) const
 Writes the contents of the renderer to a configuration file.
void addRequiredFields (QgsAttributeList &fields) const
 add vector of required fields to existing list of fields
void setFields (const QgsFieldMap &fields)
 Set available fields.
QgsFieldMap & fields (void)
 Available vector fields.
QgsLabelAttributes * layerAttributes (void)
 Pointer to default attributes.
QgsLabelAttributes * labelAttributes (void)
 Pointer to default attributes.
void setLabelField (int attr, int fieldIndex)
 Set label field.
bool setLabelFieldName (int attr, QString name)
 Set label field by name.
QString labelField (int attr) const
 label field
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.
void setMinScale (float theMinScale)
 Accessor and mutator for the minimum scale member.
float minScale () const
void setMaxScale (float theMaxScale)
 Accessor and mutator for the maximum scale member.
float maxScale () const
void setScaleBasedVisibility (bool theVisibilityFlag)
 Accessor and mutator for the scale based visilibility flag.
bool scaleBasedVisibility () const

Private Member Functions

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.
bool readLabelField (QDomElement &el, int attr, QString prefix)
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.

Private Attributes

QColor mSelectionColor
 Color to draw selected features.
QgsLabelAttributes * mLabelAttributes
 Default layer attributes.
QgsFieldMap mField
 Available layer fields.
std::vector< QString > mLabelField
 Label fields.
std::vector< int > mLabelFieldIdx
 Label field indexes.
float mMinScale
 Minimum scale at which this label should be displayed.
float mMaxScale
 Maximum 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.

Classes

struct  labelpoint

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 QgsFieldMap &  fields  ) 

Definition at line 50 of file qgslabel.cpp.

References LabelFieldCount, mField, mLabelAttributes, and mLabelFieldIdx.

QgsLabel::~QgsLabel (  ) 

Definition at line 64 of file qgslabel.cpp.

References mLabelAttributes.

Member Function Documentation

void QgsLabel::renderLabel ( QPainter *  painter,
const QgsRectangle &  viewExtent,
QgsCoordinateTransform *  coordinateTransform,
const QgsMapToPixel *  transform,
QgsFeature &  feature,
bool  selected,
QgsLabelAttributes *  classAttributes = 0,
double  sizeScale = 1.,
double  rasterScaleFactor = 1.0 
) [inline]

render label

Parameters:
painter painter to render label in
viewExtent extent to render labels in
coordinateTransform coordinate transformation to use
transform transformation from coordinate to canvas pixels
feature feature to label
selected feature is selected
classAttributes attributes to create label from
sizeScale scale
rasterScaleFactor raster scale
Deprecated:

Definition at line 106 of file qgslabel.h.

References QgsCoordinateTransform::destCRS(), QgsRenderContext::setCoordinateTransform(), QgsRenderContext::setExtent(), QgsRenderContext::setMapToPixel(), QgsRenderContext::setPainter(), QgsRenderContext::setRasterScaleFactor(), QgsRenderContext::setScaleFactor(), and QgsCoordinateTransform::sourceCrs().

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

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 89 of file qgslabel.cpp.

References QgsLabelAttributes::alignment(), Alignment, QgsLabelAttributes::angle(), Angle, QgsLabelAttributes::angleIsAuto(), QgsLabelAttributes::bold(), Bold, QgsLabelAttributes::color(), Color, QgsLabelAttributes::family(), Family, fieldValue(), QgsLabelAttributes::italic(), Italic, labelPoint(), QgsRenderContext::mapToPixel(), QgsLabelAttributes::MapUnits, mLabelAttributes, QgsLabelAttributes::multilineEnabled(), QgsLabelAttributes::offsetType(), QgsLabelAttributes::PointUnits, QgsRenderContext::rasterScaleFactor(), renderLabel(), QgsRenderContext::scaleFactor(), QgsLabelAttributes::selectedOnly(), QgsPoint::setX(), QgsPoint::setY(), QgsLabelAttributes::size(), Size, QgsLabelAttributes::sizeType(), SizeType, QgsLabelAttributes::strikeOut(), StrikeOut, QgsLabelAttributes::text(), Text, QgsMapToPixel::transform(), QgsLabelAttributes::underline(), Underline, QgsPoint::x(), XCoordinate, QgsLabelAttributes::xOffset(), XOffset, YCoordinate, QgsLabelAttributes::yOffset(), and YOffset.

void QgsLabel::readXML ( const QDomNode &  node  ) 

Reads the renderer configuration from an XML file.

Parameters:
node the Dom node to read

Definition at line 745 of file qgslabel.cpp.

References Alignment, QgsLabelAttributes::alignmentCode(), Angle, Bold, BufferColor, BufferEnabled, BufferSize, Color, Family, Italic, mLabelAttributes, MultilineEnabled, QgsDebugMsg, readLabelField(), QgsLabelAttributes::setAlignment(), QgsLabelAttributes::setAngle(), QgsLabelAttributes::setAutoAngle(), QgsLabelAttributes::setBold(), QgsLabelAttributes::setBufferColor(), QgsLabelAttributes::setBufferEnabled(), QgsLabelAttributes::setBufferSize(), QgsLabelAttributes::setColor(), QgsLabelAttributes::setFamily(), QgsLabelAttributes::setItalic(), QgsLabelAttributes::setMultilineEnabled(), QgsLabelAttributes::setOffset(), QgsLabelAttributes::setSelectedOnly(), QgsLabelAttributes::setSize(), QgsLabelAttributes::setStrikeOut(), QgsLabelAttributes::setText(), QgsLabelAttributes::setUnderline(), Size, SizeType, StrikeOut, Text, Underline, QgsLabelAttributes::unitsCode(), XCoordinate, XOffset, YCoordinate, and YOffset.

Referenced by QgsVectorLayer::readSymbology().

void QgsLabel::writeXML ( QDomNode &  label_node,
QDomDocument &  document 
) const

Writes the contents of the renderer to a configuration file.

Definition at line 1038 of file qgslabel.cpp.

References Alignment, QgsLabelAttributes::alignment(), QgsLabelAttributes::alignmentIsSet(), QgsLabelAttributes::alignmentName(), Angle, QgsLabelAttributes::angle(), MathUtils::angle(), QgsLabelAttributes::angleIsAuto(), QgsLabelAttributes::angleIsSet(), Bold, QgsLabelAttributes::bold(), QgsLabelAttributes::boldIsSet(), BufferColor, QgsLabelAttributes::bufferColor(), QgsLabelAttributes::bufferColorIsSet(), BufferEnabled, QgsLabelAttributes::bufferEnabled(), BufferSize, QgsLabelAttributes::bufferSize(), QgsLabelAttributes::bufferSizeIsSet(), QgsLabelAttributes::bufferSizeType(), Color, QgsLabelAttributes::color(), QgsLabelAttributes::colorIsSet(), Family, QgsLabelAttributes::family(), QgsLabelAttributes::familyIsSet(), Italic, QgsLabelAttributes::italic(), QgsLabelAttributes::italicIsSet(), labelField(), mLabelAttributes, mLabelFieldIdx, MultilineEnabled, QgsLabelAttributes::multilineEnabled(), QgsLabelAttributes::offsetIsSet(), QgsLabelAttributes::offsetType(), QgsLabelAttributes::selectedOnly(), Size, QgsLabelAttributes::size(), QgsLabelAttributes::sizeIsSet(), QgsLabelAttributes::sizeType(), SizeType, StrikeOut, QgsLabelAttributes::strikeOut(), QgsLabelAttributes::strikeOutIsSet(), Text, QgsLabelAttributes::text(), QgsLabelAttributes::textIsSet(), Underline, QgsLabelAttributes::underline(), QgsLabelAttributes::underlineIsSet(), QgsLabelAttributes::unitsName(), XCoordinate, XOffset, QgsLabelAttributes::xOffset(), YCoordinate, YOffset, and QgsLabelAttributes::yOffset().

Referenced by QgsVectorLayer::writeSymbology().

void QgsLabel::addRequiredFields ( QgsAttributeList &  fields  )  const

add vector of required fields to existing list of fields

Definition at line 474 of file qgslabel.cpp.

References LabelFieldCount, and mLabelFieldIdx.

Referenced by QgsVectorLayer::drawLabels().

void QgsLabel::setFields ( const QgsFieldMap &  fields  ) 

Set available fields.

Definition at line 496 of file qgslabel.cpp.

References mField.

QgsFieldMap & QgsLabel::fields ( void   ) 

Available vector fields.

Definition at line 501 of file qgslabel.cpp.

References mField.

QgsLabelAttributes * QgsLabel::layerAttributes ( void   ) 

Pointer to default attributes.

Note:
this will be deprecated in version 2 as it is badly named. Rather use attributes.
See also:
labelAttributes method rather

Definition at line 528 of file qgslabel.cpp.

References mLabelAttributes.

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 523 of file qgslabel.cpp.

References mLabelAttributes.

Referenced by QgsQuickPrint::scaleTextLabels().

void QgsLabel::setLabelField ( int  attr,
int  fieldIndex 
)

Set label field.

Definition at line 506 of file qgslabel.cpp.

References LabelFieldCount, and mLabelFieldIdx.

bool QgsLabel::setLabelFieldName ( int  attr,
QString  name 
)

Set label field by name.

QString QgsLabel::labelField ( int  attr  )  const

label field

Definition at line 514 of file qgslabel.cpp.

References LabelFieldCount, mField, and mLabelFieldIdx.

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

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 69 of file qgslabel.cpp.

References QgsFeature::attributeMap(), and mLabelFieldIdx.

Referenced by renderLabel().

void QgsLabel::setMinScale ( float  theMinScale  ) 

Accessor and mutator for the minimum scale member.

Definition at line 1398 of file qgslabel.cpp.

References mMinScale.

Referenced by QgsVectorLayer::readSymbology().

float QgsLabel::minScale (  )  const

Definition at line 1403 of file qgslabel.cpp.

References mMinScale.

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

void QgsLabel::setMaxScale ( float  theMaxScale  ) 

Accessor and mutator for the maximum scale member.

Definition at line 1408 of file qgslabel.cpp.

References mMaxScale.

Referenced by QgsVectorLayer::readSymbology().

float QgsLabel::maxScale (  )  const

Definition at line 1413 of file qgslabel.cpp.

References mMaxScale.

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

void QgsLabel::setScaleBasedVisibility ( bool  theVisibilityFlag  ) 

Accessor and mutator for the scale based visilibility flag.

Definition at line 1388 of file qgslabel.cpp.

References mScaleBasedVisibility.

Referenced by QgsVectorLayer::readSymbology().

bool QgsLabel::scaleBasedVisibility (  )  const

Definition at line 1393 of file qgslabel.cpp.

References mScaleBasedVisibility.

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

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]

Does the actual rendering of a label at the given point.

Definition at line 385 of file qgslabel.cpp.

References QgsLabelAttributes::bufferColor(), QgsLabelAttributes::bufferColorIsSet(), QgsLabelAttributes::bufferEnabled(), QgsLabelAttributes::bufferSize(), QgsLabelAttributes::bufferSizeIsSet(), QgsRenderContext::coordinateTransform(), M_PI, QgsRenderContext::mapToPixel(), mLabelAttributes, QgsLabelAttributes::multilineEnabled(), QgsRenderContext::painter(), QgsDebugMsg, QgsRenderContext::rasterScaleFactor(), QgsRenderContext::scaleFactor(), QgsMapToPixel::transform(), QgsCoordinateTransform::transform(), QgsPoint::x(), and QgsPoint::y().

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

Definition at line 710 of file qgslabel.cpp.

References mField, and mLabelFieldIdx.

Referenced by readXML().

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

Get label point for simple feature in map units.

Definition at line 533 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 581 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.

Member Data Documentation

QColor QgsLabel::mSelectionColor [private]

Color to draw selected features.

Definition at line 208 of file qgslabel.h.

QgsLabelAttributes* QgsLabel::mLabelAttributes [private]

Default layer attributes.

Definition at line 211 of file qgslabel.h.

Referenced by labelAttributes(), layerAttributes(), QgsLabel(), readXML(), renderLabel(), writeXML(), and ~QgsLabel().

QgsFieldMap QgsLabel::mField [private]

Available layer fields.

Definition at line 214 of file qgslabel.h.

Referenced by fields(), labelField(), QgsLabel(), readLabelField(), and setFields().

std::vector<QString> QgsLabel::mLabelField [private]

Label fields.

Definition at line 217 of file qgslabel.h.

std::vector<int> QgsLabel::mLabelFieldIdx [private]

Label field indexes.

Definition at line 220 of file qgslabel.h.

Referenced by addRequiredFields(), fieldValue(), labelField(), QgsLabel(), readLabelField(), setLabelField(), and writeXML().

float QgsLabel::mMinScale [private]

Minimum scale at which this label should be displayed.

Definition at line 223 of file qgslabel.h.

Referenced by minScale(), and setMinScale().

float QgsLabel::mMaxScale [private]

Maximum scale at which this label should be displayed.

Definition at line 225 of file qgslabel.h.

Referenced by maxScale(), and setMaxScale().

bool QgsLabel::mScaleBasedVisibility [private]

A flag that tells us whether to use the above vars to restrict the label's visibility.

Definition at line 227 of file qgslabel.h.

Referenced by scaleBasedVisibility(), and setScaleBasedVisibility().

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