Class: QgsFeatureRenderer

class qgis.core.QgsFeatureRenderer(type: str)

Bases: sip.wrapper

Parameters

type

class Capabilities

Bases: sip.wrapper

QgsFeatureRenderer.Capabilities(Union[QgsFeatureRenderer.Capabilities, QgsFeatureRenderer.Capability]) QgsFeatureRenderer.Capabilities(QgsFeatureRenderer.Capabilities)

class Capability

Bases: int

Filter = 8
MoreSymbolsPerFeature = 4
ScaleDependent = 16
SymbolLevels = 1
accept(self, visitor: QgsStyleEntityVisitorInterface) → bool

Accepts the specified symbology visitor, causing it to visit all symbols associated with the renderer.

Returns True if the visitor should continue visiting other objects, or False if visiting should be canceled.

New in version 3.10.

Parameters

visitor (QgsStyleEntityVisitorInterface) –

Return type

bool

capabilities(self) → QgsFeatureRenderer.Capabilities

Returns details about internals of this renderer.

E.g. if you only want to deal with visible features:

if not renderer.capabilities().testFlag(QgsFeatureRenderer.Filter) or renderer.willRenderFeature(feature, context):
    deal_with_my_feature()
else:
    skip_the_curren_feature()
Return type

QgsFeatureRenderer.Capabilities

checkLegendSymbolItem(self, key: str, state: bool = True)

item in symbology was checked

New in version 2.5.

Parameters
  • key (str) –

  • state (bool = True) –

clone(self) → QgsFeatureRenderer

Create a deep copy of this renderer. Should be implemented by all subclasses and generate a proper subclass.

Return type

QgsFeatureRenderer

Returns

A copy of this renderer

convertSymbolRotation(symbol: QgsSymbol, field: str)

Note

this function is used to convert old rotations expressions to symbol level DataDefined angle

Parameters
convertSymbolSizeScale(symbol: QgsSymbol, method: QgsSymbol.ScaleMethod, field: str)

Note

this function is used to convert old sizeScale expressions to symbol level DataDefined size

Parameters
copyRendererData(self, destRenderer: QgsFeatureRenderer)

Clones generic renderer data to another renderer. Currently clones * Order By * Paint Effect

Parameters

destRenderer (QgsFeatureRenderer) – destination renderer for copied effect

defaultRenderer(geomType: QgsWkbTypes.GeometryType) → QgsFeatureRenderer

Returns a new renderer - used by default in vector layers

Parameters

geomType (QgsWkbTypes.GeometryType) –

Return type

QgsFeatureRenderer

dump(self) → str

Returns debug information about this renderer

Return type

str

embeddedRenderer(self) → QgsFeatureRenderer

Returns the current embedded renderer (subrenderer) for this feature renderer. The base class implementation does not use subrenderers and will always return None.

New in version 2.16.

Return type

QgsFeatureRenderer

filter(self, fields: QgsFields = QgsFields()) → str

If a renderer does not require all the features this method may be overridden and return an expression used as where clause. This will be called once after startRender() and before the first call to renderFeature(). By default this returns a null string and all features will be requested. You do not need to specify the extent in here, this is taken care of separately and will be combined with a filter returned from this method.

Return type

str

Returns

An expression used as where clause

Parameters

fields (QgsFields = QgsFields()) –

filterNeedsGeometry(self) → bool

Returns True if this renderer requires the geometry to apply the filter.

Return type

bool

forceRasterRender(self) → bool

Returns whether the renderer must render as a raster.

New in version 2.12.

Return type

bool

legendClassificationAttribute(self) → str

If supported by the renderer, return classification attribute for the use in legend

New in version 2.6.

Return type

str

legendKeysForFeature(self, feature: QgsFeature, context: QgsRenderContext) → Set[str]

Returns legend keys matching a specified feature.

New in version 2.14.

Parameters
Return type

Set[str]

legendSymbolItemChecked(self, key: str) → bool

items of symbology items in legend is checked

New in version 2.5.

Parameters

key (str) –

Return type

bool

legendSymbolItems(self) → List[QgsLegendSymbolItem]

Returns a list of symbology items for the legend

New in version 2.6.

Return type

List[QgsLegendSymbolItem]

legendSymbolItemsCheckable(self) → bool

items of symbology items in legend should be checkable

New in version 2.5.

Return type

bool

load(symbologyElem: QDomElement, context: QgsReadWriteContext) → QgsFeatureRenderer

create a renderer from XML element

Parameters
Return type

QgsFeatureRenderer

loadSld(node: QDomNode, geomType: QgsWkbTypes.GeometryType, errorMessage: str) → QgsFeatureRenderer

Create a new renderer according to the information contained in the UserStyle element of a SLD style document

Parameters
  • node (QDomNode) – the node in the SLD document whose the UserStyle element is a child

  • geomType (QgsWkbTypes.GeometryType) – the geometry type of the features, used to convert Symbolizer elements

  • errorMessage (str) – it will contain the error message if something went wrong

Return type

QgsFeatureRenderer

Returns

the renderer

modifyRequestExtent(self, extent: QgsRectangle, context: QgsRenderContext)

Allows for a renderer to modify the extent of a feature request prior to rendering

Parameters
  • extent (QgsRectangle) – reference to request’s filter extent. Modify extent to change the extent of feature request

  • context (QgsRenderContext) – render context

New in version 2.7.

orderBy(self) → QgsFeatureRequest.OrderBy

Gets the order in which features shall be processed by this renderer.

Note

this property has no effect if orderByEnabled() is False

See also

orderByEnabled()

New in version 2.14.

Return type

QgsFeatureRequest.OrderBy

orderByEnabled(self) → bool

Returns whether custom ordering will be applied before features are processed by this renderer.

See also

orderBy()

New in version 2.14.

Return type

bool

originalSymbolForFeature(self, feature: QgsFeature, context: QgsRenderContext) → QgsSymbol

Returns symbol for feature. The difference compared to symbolForFeature() is that it returns original symbol which can be used as an identifier for renderer’s rule - the former may return a temporary replacement of a symbol for use in rendering.

New in version 2.12.

Parameters
Return type

QgsSymbol

originalSymbolsForFeature(self, feature: QgsFeature, context: QgsRenderContext) → List[QgsSymbol]

Equivalent of originalSymbolsForFeature() call extended to support renderers that may use more symbols per feature - similar to symbolsForFeature()

New in version 2.12.

Parameters
Return type

List[QgsSymbol]

paintEffect(self) → QgsPaintEffect

Returns the current paint effect for the renderer.

Return type

QgsPaintEffect

Returns

paint effect

See also

setPaintEffect()

New in version 2.9.

renderFeature(self, feature: QgsFeature, context: QgsRenderContext, layer: int = -1, selected: bool = False, drawVertexMarker: bool = False) → bool

Render a feature using this renderer in the given context. Must be called between startRender() and stopRender() calls. Default implementation renders a symbol as determined by symbolForFeature() call. Returns True if the feature has been returned (this is used for example to determine whether the feature may be labelled).

If layer is not -1, the renderer should draw only a particula layer from symbols (in order to support symbol level rendering).

See also

startRender()

See also

stopRender()

Parameters
  • feature (QgsFeature) –

  • context (QgsRenderContext) –

  • layer (int = -1) –

  • selected (bool = False) –

  • drawVertexMarker (bool = False) –

Return type

bool

renderFeatureWithSymbol(self, feature: QgsFeature, symbol: QgsSymbol, context: QgsRenderContext, layer: int, selected: bool, drawVertexMarker: bool)

Render the feature with the symbol using context. Use layer to specify the symbol layer, selected to specify if it should be rendered as selected and drawVertexMarker to specify if vertex markers should be rendered.

Parameters
renderVertexMarker(self, pt: Union[QPointF, QPoint], context: QgsRenderContext)

render editing vertex marker at specified point

Parameters
renderVertexMarkerPolygon(self, pts: QPolygonF, rings: Iterable[QPolygonF], context: QgsRenderContext)

render editing vertex marker for a polygon

Parameters
  • pts (QPolygonF) –

  • rings (Iterable[QPolygonF]) –

  • context (QgsRenderContext) –

renderVertexMarkerPolyline(self, pts: QPolygonF, context: QgsRenderContext)

render editing vertex marker for a polyline

Parameters
save(self, doc: QDomDocument, context: QgsReadWriteContext) → QDomElement

store renderer info to XML element

Parameters
Return type

QDomElement

setEmbeddedRenderer(self, subRenderer: QgsFeatureRenderer)

Sets an embedded renderer (subrenderer) for this feature renderer. The base class implementation does nothing with subrenderers, but individual derived classes can use these to modify their behavior.

Parameters

subRenderer (QgsFeatureRenderer) – the embedded renderer. Ownership will be transferred.

New in version 2.16.

setForceRasterRender(self, forceRaster: bool)

Sets whether the renderer should be rendered to a raster destination.

Parameters

forceRaster (bool) – set to True if renderer must be drawn on a raster surface. This may be desirable for highly detailed layers where rendering as a vector would result in a large, complex vector output.

New in version 2.12.

setLegendSymbolItem(self, key: str, symbol: QgsSymbol)

Sets the symbol to be used for a legend symbol item.

Parameters
  • key (str) – rule key for legend symbol

  • symbol (QgsSymbol) – new symbol for legend item. Ownership is transferred to renderer.

New in version 2.14.

setOrderBy(self, orderBy: QgsFeatureRequest.OrderBy)

Define the order in which features shall be processed by this renderer.

Note

this property has no effect if orderByEnabled() is False

New in version 2.14.

Parameters

orderBy (QgsFeatureRequest.OrderBy) –

setOrderByEnabled(self, enabled: bool)

Sets whether custom ordering should be applied before features are processed by this renderer.

Parameters

enabled (bool) – set to True to enable custom feature ordering

See also

setOrderBy()

See also

orderByEnabled()

New in version 2.14.

setPaintEffect(self, effect: QgsPaintEffect)

Sets the current paint effect for the renderer.

Parameters

effect (QgsPaintEffect) – paint effect. Ownership is transferred to the renderer.

See also

paintEffect()

New in version 2.9.

setUsingSymbolLevels(self, usingSymbolLevels: bool)
Parameters

usingSymbolLevels (bool) –

setVertexMarkerAppearance(self, type: int, size: float)

Sets type and size of editing vertex markers for subsequent rendering

Parameters
  • type (int) –

  • size (float) –

startRender(self, context: QgsRenderContext, fields: QgsFields)

Must be called when a new render cycle is started. A call to startRender() must always be followed by a corresponding call to stopRender() after all features have been rendered.

Parameters
  • context (QgsRenderContext) – Additional information passed to the renderer about the job which will be rendered

  • fields (QgsFields) – The fields available for rendering

See also

stopRender()

Warning

This method is not thread safe. Before calling startRender() in a non-main thread, the renderer should instead be cloned and startRender()/stopRender() called on the clone.

stopRender(self, context: QgsRenderContext)

Must be called when a render cycle has finished, to allow the renderer to clean up.

Calls to stopRender() must always be preceded by a call to startRender().

Warning

This method is not thread safe. Before calling startRender() in a non-main thread, the renderer should instead be cloned and startRender()/stopRender() called on the clone.

See also

startRender()

Parameters

context (QgsRenderContext) –

symbolForFeature(self, feature: QgsFeature, context: QgsRenderContext) → QgsSymbol

To be overridden

Must be called between startRender() and stopRender() calls.

Parameters
Return type

QgsSymbol

Returns

returns pointer to symbol or 0 if symbol was not found

New in version 2.12.

symbols(self, context: QgsRenderContext) → List[QgsSymbol]

Returns list of symbols used by the renderer.

Parameters

context (QgsRenderContext) – render context

New in version 2.12.

Return type

List[QgsSymbol]

symbolsForFeature(self, feature: QgsFeature, context: QgsRenderContext) → List[QgsSymbol]

Returns list of symbols used for rendering the feature. For renderers that do not support MoreSymbolsPerFeature it is more efficient to use symbolForFeature()

New in version 2.12.

Parameters
Return type

List[QgsSymbol]

toSld(self, doc: QDomDocument, element: QDomElement, props: Dict[str, str] = {})

used from subclasses to create SLD Rule elements following SLD v1.1 specs

Parameters
  • doc (QDomDocument) –

  • element (QDomElement) –

  • props (Dict[str) –

type(self) → str
Return type

str

usedAttributes(self, context: QgsRenderContext) → Set[str]

Returns a list of attributes required by this renderer. Attributes not listed in here may not have been requested from the provider at rendering time.

Return type

Set[str]

Returns

A set of attributes

Parameters

context (QgsRenderContext) –

usingSymbolLevels(self) → bool
Return type

bool

willRenderFeature(self, feature: QgsFeature, context: QgsRenderContext) → bool

Returns whether the renderer will render a feature or not. Must be called between startRender() and stopRender() calls. Default implementation uses symbolForFeature().

New in version 2.12.

Parameters
Return type

bool

writeSld(self, doc: QDomDocument, styleName: str, props: Dict[str, str] = {}) → QDomElement

create the SLD UserStyle element following the SLD v1.1 specs with the given name

New in version 2.8.

Parameters
  • doc (QDomDocument) –

  • styleName (str) –

  • props (Dict[str) –

Return type

QDomElement