QgsLineSymbol Class Reference

A line symbol type, for rendering LineString and MultiLineString geometries. More...

#include <qgslinesymbol.h>

Inheritance diagram for QgsLineSymbol:

Public Member Functions
	QgsLineSymbol (const QgsSymbolLayerList &layers=QgsSymbolLayerList())
	Constructor for QgsLineSymbol, with the specified list of initial symbol layers.
QgsLineSymbol *	clone () const override
	Returns a deep copy of this symbol.
QgsProperty	dataDefinedWidth () const
	Returns data defined width for whole symbol (including all symbol layers).
void	renderPolyline (const QPolygonF &points, const QgsFeature *f, QgsRenderContext &context, int layer=-1, bool selected=false)
	Renders the symbol along the line joining points, using the given render context.
void	setDataDefinedWidth (const QgsProperty &property) const
	Set data defined width for whole symbol (including all symbol layers).
void	setWidth (double width) const
	Sets the width for the whole line symbol.
void	setWidthUnit (Qgis::RenderUnit unit) const
	Sets the width units for the whole symbol (including all symbol layers).
double	width () const
	Returns the estimated width for the whole symbol, which is the maximum width of all marker symbol layers in the symbol.
double	width (const QgsRenderContext &context) const
	Returns the symbol width, in painter units.
Public Member Functions inherited from QgsSymbol
virtual	~QgsSymbol ()
QgsSymbolAnimationSettings &	animationSettings ()
	Returns a reference to the symbol animation settings.
const QgsSymbolAnimationSettings &	animationSettings () const
	Returns a reference to the symbol animation settings.
bool	appendSymbolLayer (QgsSymbolLayer *layer)
	Appends a symbol layer at the end of the current symbol layer list.
QImage	asImage (QSize size, QgsRenderContext *customContext=nullptr)
	Returns an image of the symbol at the specified size.
Q_DECL_DEPRECATED QImage	bigSymbolPreviewImage (QgsExpressionContext *expressionContext=nullptr, int flags=static_cast< int >(Qgis::SymbolPreviewFlag::FlagIncludeCrosshairsForMarkerSymbols))
QImage	bigSymbolPreviewImage (QgsExpressionContext *expressionContext=nullptr, Qgis::SymbolPreviewFlags flags=Qgis::SymbolPreviewFlag::FlagIncludeCrosshairsForMarkerSymbols, const QgsScreenProperties &screen=QgsScreenProperties())
	Returns a large (roughly 100x100 pixel) preview image for the symbol.
QgsSymbolBufferSettings *	bufferSettings ()
	Returns the symbol buffer settings, which control an optional "halo" effect around the symbol.
const QgsSymbolBufferSettings *	bufferSettings () const
	Returns the symbol buffer settings, which control an optional "halo" effect around the symbol.
bool	canCauseArtifactsBetweenAdjacentTiles () const
	Returns true if the symbol rendering can cause visible artifacts across a single feature when the feature is rendered as a series of adjacent map tiles each containing a portion of the feature's geometry.
bool	changeSymbolLayer (int index, QgsSymbolLayer *layer)
	Deletes the current layer at the specified index and replaces it with layer.
bool	clipFeaturesToExtent () const
	Returns whether features drawn by the symbol will be clipped to the render context's extent.
QColor	color () const
	Returns the symbol's color.
QgsPropertyCollection &	dataDefinedProperties ()
	Returns a reference to the symbol's property collection, used for data defined overrides.
const QgsPropertyCollection &	dataDefinedProperties () const
	Returns a reference to the symbol's property collection, used for data defined overrides.
bool	deleteSymbolLayer (int index)
	Removes and deletes the symbol layer at the specified index.
void	drawPreviewIcon (QPainter *painter, QSize size, QgsRenderContext *customContext=nullptr, bool selected=false, const QgsExpressionContext *expressionContext=nullptr, const QgsLegendPatchShape *patchShape=nullptr, const QgsScreenProperties &screen=QgsScreenProperties())
	Draws an icon of the symbol that occupies an area given by size using the specified painter.
QString	dump () const
	Returns a string dump of the symbol's properties.
void	exportImage (const QString &path, const QString &format, QSize size)
	Export the symbol as an image format, to the specified path and with the given size.
Qgis::SymbolFlags	flags () const
	Returns flags for the symbol.
bool	forceRHR () const
	Returns true if polygon features drawn by the symbol will be reoriented to follow the standard right-hand-rule orientation, in which the area that is bounded by the polygon is to the right of the boundary.
bool	hasDataDefinedProperties () const
	Returns whether the symbol utilizes any data defined properties.
bool	insertSymbolLayer (int index, QgsSymbolLayer *layer)
	Inserts a symbol layer to specified index.
Q_DECL_DEPRECATED const QgsVectorLayer *	layer () const
QgsMapUnitScale	mapUnitScale () const
	Returns the map unit scale for the symbol.
qreal	opacity () const
	Returns the opacity for the symbol.
Qgis::RenderUnit	outputUnit () const
	Returns the units to use for sizes and widths within the symbol.
void	renderFeature (const QgsFeature &feature, QgsRenderContext &context, int layer=-1, bool selected=false, bool drawVertexMarker=false, Qgis::VertexMarkerType currentVertexMarkerType=Qgis::VertexMarkerType::SemiTransparentCircle, double currentVertexMarkerSize=0.0)
	Render a feature.
Qgis::SymbolRenderHints	renderHints () const
	Returns the rendering hint flags for the symbol.
void	setAnimationSettings (const QgsSymbolAnimationSettings &settings)
	Sets a the symbol animation settings.
void	setBufferSettings (QgsSymbolBufferSettings *settings)
	Sets a the symbol buffer settings, which control an optional "halo" effect around the symbol.
void	setClipFeaturesToExtent (bool clipFeaturesToExtent)
	Sets whether features drawn by the symbol should be clipped to the render context's extent.
void	setColor (const QColor &color) const
	Sets the color for the symbol.
void	setDataDefinedProperties (const QgsPropertyCollection &collection)
	Sets the symbol's property collection, used for data defined overrides.
void	setDataDefinedProperty (Property key, const QgsProperty &property)
	Sets a data defined property for the symbol.
void	setFlags (Qgis::SymbolFlags flags)
	Sets flags for the symbol.
void	setForceRHR (bool force)
	Sets whether polygon features drawn by the symbol should be reoriented to follow the standard right-hand-rule orientation, in which the area that is bounded by the polygon is to the right of the boundary.
Q_DECL_DEPRECATED void	setLayer (const QgsVectorLayer *layer)
void	setMapUnitScale (const QgsMapUnitScale &scale) const
	Sets the map unit scale for the symbol.
void	setOpacity (qreal opacity)
	Sets the opacity for the symbol.
void	setOutputUnit (Qgis::RenderUnit unit) const
	Sets the units to use for sizes and widths within the symbol.
void	setRenderHints (Qgis::SymbolRenderHints hints)
	Sets rendering hint flags for the symbol.
void	startFeatureRender (const QgsFeature &feature, QgsRenderContext &context, int layer=-1)
	Called before symbol layers will be rendered for a particular feature.
void	startRender (QgsRenderContext &context, const QgsFields &fields=QgsFields())
	Begins the rendering process for the symbol.
void	stopFeatureRender (const QgsFeature &feature, QgsRenderContext &context, int layer=-1)
	Called after symbol layers have been rendered for a particular feature.
void	stopRender (QgsRenderContext &context)
	Ends the rendering process.
QgsSymbolLayer *	symbolLayer (int layer)
	Returns the symbol layer at the specified index.
const QgsSymbolLayer *	symbolLayer (int layer) const
	Returns the symbol layer at the specified index, const variant.
int	symbolLayerCount () const
	Returns the total number of symbol layers contained in the symbol.
QgsSymbolLayerList	symbolLayers () const
	Returns the list of symbol layers contained in the symbol.
QgsSymbolRenderContext *	symbolRenderContext ()
	Returns the symbol render context.
QgsSymbolLayer *	takeSymbolLayer (int index)
	Removes a symbol layer from the list and returns a pointer to it.
void	toSld (QDomDocument &doc, QDomElement &element, QVariantMap props) const
	Converts the symbol to a SLD representation.
Qgis::SymbolType	type () const
	Returns the symbol's type.
QSet< QString >	usedAttributes (const QgsRenderContext &context) const
	Returns a list of attributes required to render this feature.
bool	usesMapUnits () const
	Returns true if the symbol has any components which use map unit based sizes.

Static Public Member Functions
static QgsLineSymbol *	createSimple (const QVariantMap &properties)
	Create a line symbol with one symbol layer: SimpleLine with specified properties.
Static Public Member Functions inherited from QgsSymbol
static QgsSymbol *	defaultSymbol (Qgis::GeometryType geomType)
	Returns a new default symbol for the specified geometry type.
static const QgsPropertiesDefinition &	propertyDefinitions ()
	Returns the symbol property definitions.
static Qgis::SymbolType	symbolTypeForGeometryType (Qgis::GeometryType type)
	Returns the default symbol type required for the specified geometry type.
static QString	symbolTypeToString (Qgis::SymbolType type)
	Returns a translated string version of the specified symbol type.

Additional Inherited Members
Public Types inherited from QgsSymbol
enum class	Property : int { Opacity }
	Data definable properties. More...
Protected Member Functions inherited from QgsSymbol
	QgsSymbol (Qgis::SymbolType type, const QgsSymbolLayerList &layers)
	Constructor for a QgsSymbol of the specified type.
QgsSymbolLayerList	cloneLayers () const
	Retrieve a cloned list of all layers that make up this symbol.
void	copyCommonProperties (const QgsSymbol *other)
	Copies common properties from an other symbol to this symbol.
void	renderUsingLayer (QgsSymbolLayer *layer, QgsSymbolRenderContext &context, Qgis::GeometryType geometryType=Qgis::GeometryType::Unknown, const QPolygonF *points=nullptr, const QVector< QPolygonF > *rings=nullptr)
	Renders a context using a particular symbol layer without passing in a geometry.
void	renderVertexMarker (QPointF pt, QgsRenderContext &context, Qgis::VertexMarkerType currentVertexMarkerType, double currentVertexMarkerSize)
	Render editing vertex marker at specified point.
Static Protected Member Functions inherited from QgsSymbol
static QPolygonF	_getLineString (QgsRenderContext &context, const QgsCurve &curve, bool clipToExtent=true)
	Creates a line string in screen coordinates from a QgsCurve in map coordinates.
static QPointF	_getPoint (QgsRenderContext &context, const QgsPoint &point)
	Creates a point in screen coordinates from a QgsPoint in map coordinates.
static void	_getPolygon (QPolygonF &pts, QVector< QPolygonF > &holes, QgsRenderContext &context, const QgsPolygon &polygon, bool clipToExtent=true, bool correctRingOrientation=false)
	Creates a polygon in screen coordinates from a QgsPolygonXYin map coordinates.
static QPolygonF	_getPolygonRing (QgsRenderContext &context, const QgsCurve &curve, bool clipToExtent, bool isExteriorRing=false, bool correctRingOrientation=false)
	Creates a polygon ring in screen coordinates from a QgsCurve in map coordinates.
Protected Attributes inherited from QgsSymbol
QgsSymbolAnimationSettings	mAnimationSettings
std::unique_ptr< QgsSymbolBufferSettings >	mBufferSettings
bool	mClipFeaturesToExtent = true
bool	mForceRHR = false
Q_DECL_DEPRECATED const QgsVectorLayer *	mLayer = nullptr
QgsSymbolLayerList	mLayers
qreal	mOpacity = 1.0
	Symbol opacity (in the range 0 - 1)
Qgis::SymbolRenderHints	mRenderHints
Qgis::SymbolFlags	mSymbolFlags = Qgis::SymbolFlags()
	Symbol flags.
Qgis::SymbolType	mType

Detailed Description

A line symbol type, for rendering LineString and MultiLineString geometries.

Definition at line 29 of file qgslinesymbol.h.

Constructor & Destructor Documentation

QgsLineSymbol()

QgsLineSymbol::QgsLineSymbol

(

const QgsSymbolLayerList &

layers = QgsSymbolLayerList()

)

Constructor for QgsLineSymbol, with the specified list of initial symbol layers.

Ownership of the layers are transferred to the symbol.

Definition at line 33 of file qgslinesymbol.cpp.

Member Function Documentation

clone()

QgsLineSymbol * QgsLineSymbol::clone ( ) const

overridevirtual

Returns a deep copy of this symbol.

Ownership is transferred to the caller.

Implements QgsSymbol.

Definition at line 304 of file qgslinesymbol.cpp.

createSimple()

QgsLineSymbol * QgsLineSymbol::createSimple ( const QVariantMap &  properties )

static

Create a line symbol with one symbol layer: SimpleLine with specified properties.

This is a convenience method for easier creation of line symbols.

Definition at line 22 of file qgslinesymbol.cpp.

dataDefinedWidth()

QgsProperty QgsLineSymbol::dataDefinedWidth

(

)

const

Returns data defined width for whole symbol (including all symbol layers).

Returns

data defined width, or invalid property if size is not set at the line level. Caller takes responsibility for deleting the returned object.

See also

setDataDefinedWidth

Definition at line 178 of file qgslinesymbol.cpp.

renderPolyline()

void QgsLineSymbol::renderPolyline	(	const QPolygonF &	points,
		const QgsFeature *	f,
		QgsRenderContext &	context,
		int	layer = -1,
		bool	selected = false
	)

Renders the symbol along the line joining points, using the given render context.

The f argument is used to pass the feature currently being rendered (when available).

If only a single symbol layer from the symbol should be rendered, it should be specified in the layer argument. A layer of -1 indicates that all symbol layers should be rendered.

If selected is true then the symbol will be drawn using the "selected feature" style and colors instead of the symbol's normal style.

Definition at line 232 of file qgslinesymbol.cpp.

setDataDefinedWidth()

void QgsLineSymbol::setDataDefinedWidth

(

const QgsProperty &

property

)

const

Set data defined width for whole symbol (including all symbol layers).

See also

dataDefinedWidth()

Definition at line 142 of file qgslinesymbol.cpp.

setWidth()

void QgsLineSymbol::setWidth

(

double

width

)

const

Sets the width for the whole line symbol.

Individual symbol layer sizes will be scaled to maintain their current relative size to the whole symbol size.

See also

width()

Definition at line 40 of file qgslinesymbol.cpp.

setWidthUnit()

void QgsLineSymbol::setWidthUnit

(

Qgis::RenderUnit

unit

)

const

Sets the width units for the whole symbol (including all symbol layers).

Parameters

unit	size units

Since

QGIS 3.16

Definition at line 83 of file qgslinesymbol.cpp.

width() [1/2]

double QgsLineSymbol::width

(

)

const

Returns the estimated width for the whole symbol, which is the maximum width of all marker symbol layers in the symbol.

Warning

This returned value is inaccurate if the symbol consists of multiple symbol layers with different width units. Use the overload accepting a QgsRenderContext argument instead for accurate sizes in this case.

See also

setWidth()

Definition at line 96 of file qgslinesymbol.cpp.

width() [2/2]

double QgsLineSymbol::width

(

const QgsRenderContext &

context

)

const

Returns the symbol width, in painter units.

This is the maximum width of all marker symbol layers in the symbol.

This method returns an accurate width by calculating the actual rendered width of each symbol layer using the provided render context.

See also

setWidth()

Since

QGIS 3.4.5

Definition at line 127 of file qgslinesymbol.cpp.

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

• /build/qgis-3.41.0+git20241110+fda2aa46e9a+99sid/src/core/symbology/qgslinesymbol.h
• /build/qgis-3.41.0+git20241110+fda2aa46e9a+99sid/src/core/symbology/qgslinesymbol.cpp