Class: QgsFeatureRenderer¶
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class
qgis.core.
QgsFeatureRenderer
(type: str)¶ Bases:
sip.wrapper
Enums
Methods
Returns details about internals of this renderer.
item in symbology was checked
Create a deep copy of this renderer.
Clones generic renderer data to another renderer.
Returns a new renderer - used by default in vector layers
Returns debug information about this renderer
Returns the current embedded renderer (subrenderer) for this feature renderer.
If a renderer does not require all the features this method may be overridden and return an expression used as where clause.
Returns true if this renderer requires the geometry to apply the filter.
Returns whether the renderer must render as a raster.
If supported by the renderer, return classification attribute for the use in legend
Returns legend keys matching a specified feature.
items of symbology items in legend is checked
Returns a list of symbology items for the legend
items of symbology items in legend should be checkable
create a renderer from XML element
Create a new renderer according to the information contained in the UserStyle element of a SLD style document
Allows for a renderer to modify the extent of a feature request prior to rendering
Gets the order in which features shall be processed by this renderer.
Returns whether custom ordering will be applied before features are processed by this renderer.
Returns symbol for feature.
Equivalent of originalSymbolsForFeature() call extended to support renderers that may use more symbols per feature - similar to symbolsForFeature()
Returns the current paint effect for the renderer.
Render a feature using this renderer in the given context.
Render the
feature
with thesymbol
usingcontext
.render editing vertex marker at specified point
render editing vertex marker for a polygon
render editing vertex marker for a polyline
store renderer info to XML element
Sets an embedded renderer (subrenderer) for this feature renderer.
Sets whether the renderer should be rendered to a raster destination.
Sets the symbol to be used for a legend symbol item.
Define the order in which features shall be processed by this renderer.
Sets whether custom ordering should be applied before features are processed by this renderer.
Sets the current paint effect for the renderer.
Sets type and size of editing vertex markers for subsequent rendering
Must be called when a new render cycle is started.
Must be called when a render cycle has finished, to allow the renderer to clean up.
To be overridden
Returns list of symbols used by the renderer.
Returns list of symbols used for rendering the feature.
used from subclasses to create SLD Rule elements following SLD v1.1 specs
Returns a list of attributes required by this renderer.
Returns whether the renderer will render a feature or not.
create the SLD UserStyle element following the SLD v1.1 specs with the given name
Signals
Attributes
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class
Capabilities
¶ Bases:
sip.wrapper
QgsFeatureRenderer.Capabilities(Union[QgsFeatureRenderer.Capabilities, QgsFeatureRenderer.Capability]) QgsFeatureRenderer.Capabilities(QgsFeatureRenderer.Capabilities)
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class
Capability
¶ Bases:
int
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Filter
= 8¶
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MoreSymbolsPerFeature
= 4¶
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ScaleDependent
= 16¶
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SymbolLevels
= 1¶
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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()
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checkLegendSymbolItem
(self, key: str, state: bool = True)¶ item in symbology was checked
New in version 2.5.
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clone
(self) → QgsFeatureRenderer¶ Create a deep copy of this renderer. Should be implemented by all subclasses and generate a proper subclass.
- Returns
A copy of this renderer
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convertSymbolRotation
(symbol: QgsSymbol, field: str)¶ Note
this function is used to convert old rotations expressions to symbol level DataDefined angle
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convertSymbolSizeScale
(symbol: QgsSymbol, method: QgsSymbol.ScaleMethod, field: str)¶ Note
this function is used to convert old sizeScale expressions to symbol level DataDefined size
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copyRendererData
(self, destRenderer: QgsFeatureRenderer)¶ Clones generic renderer data to another renderer. Currently clones * Order By * Paint Effect
- Parameters
destRenderer – destination renderer for copied effect
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defaultRenderer
(geomType: QgsWkbTypes.GeometryType) → QgsFeatureRenderer¶ Returns a new renderer - used by default in vector layers
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dump
(self) → str¶ Returns debug information about this renderer
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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 null.
See also
New in version 2.16.
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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.
- Returns
An expression used as where clause
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filterNeedsGeometry
(self) → bool¶ Returns true if this renderer requires the geometry to apply the filter.
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forceRasterRender
(self) → bool¶ Returns whether the renderer must render as a raster.
See also
New in version 2.12.
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legendClassificationAttribute
(self) → str¶ If supported by the renderer, return classification attribute for the use in legend
New in version 2.6.
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legendKeysForFeature
(self, feature: QgsFeature, context: QgsRenderContext) → Set[str]¶ Returns legend keys matching a specified feature.
New in version 2.14.
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legendSymbolItemChecked
(self, key: str) → bool¶ items of symbology items in legend is checked
New in version 2.5.
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legendSymbolItems
(self) → object¶ Returns a list of symbology items for the legend
New in version 2.6.
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legendSymbolItemsCheckable
(self) → bool¶ items of symbology items in legend should be checkable
New in version 2.5.
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load
(symbologyElem: QDomElement, context: QgsReadWriteContext) → QgsFeatureRenderer¶ create a renderer from XML element
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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 – the node in the SLD document whose the UserStyle element is a child
geomType – the geometry type of the features, used to convert Symbolizer elements
errorMessage – it will contain the error message if something went wrong
- Returns
the renderer
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modifyRequestExtent
(self, extent: QgsRectangle, context: QgsRenderContext)¶ Allows for a renderer to modify the extent of a feature request prior to rendering
- Parameters
extent – reference to request’s filter extent. Modify extent to change the extent of feature request
context – render context
New in version 2.7.
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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
New in version 2.14.
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orderByEnabled
(self) → bool¶ Returns whether custom ordering will be applied before features are processed by this renderer.
See also
See also
New in version 2.14.
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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.
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originalSymbolsForFeature
(self, feature: QgsFeature, context: QgsRenderContext) → object¶ Equivalent of originalSymbolsForFeature() call extended to support renderers that may use more symbols per feature - similar to symbolsForFeature()
New in version 2.12.
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paintEffect
(self) → QgsPaintEffect¶ Returns the current paint effect for the renderer.
- Returns
paint effect
See also
New in version 2.9.
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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
See also
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renderFeatureWithSymbol
(self, feature: QgsFeature, symbol: QgsSymbol, context: QgsRenderContext, layer: int, selected: bool, drawVertexMarker: bool)¶ Render the
feature
with thesymbol
usingcontext
. Uselayer
to specify the symbol layer,selected
to specify if it should be rendered as selected anddrawVertexMarker
to specify if vertex markers should be rendered.
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renderVertexMarker
(self, pt: Union[QPointF, QPoint], context: QgsRenderContext)¶ render editing vertex marker at specified point
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renderVertexMarkerPolygon
(self, pts: QPolygonF, rings: Iterable[QPolygonF], context: QgsRenderContext)¶ render editing vertex marker for a polygon
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renderVertexMarkerPolyline
(self, pts: QPolygonF, context: QgsRenderContext)¶ render editing vertex marker for a polyline
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save
(self, doc: QDomDocument, context: QgsReadWriteContext) → QDomElement¶ store renderer info to XML element
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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 – the embedded renderer. Ownership will be transferred.
See also
New in version 2.16.
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setForceRasterRender
(self, forceRaster: bool)¶ Sets whether the renderer should be rendered to a raster destination.
- Parameters
forceRaster – 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.
See also
New in version 2.12.
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setLegendSymbolItem
(self, key: str, symbol: QgsSymbol)¶ Sets the symbol to be used for a legend symbol item.
- Parameters
key – rule key for legend symbol
symbol – new symbol for legend item. Ownership is transferred to renderer.
New in version 2.14.
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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
See also
New in version 2.14.
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setOrderByEnabled
(self, enabled: bool)¶ Sets whether custom ordering should be applied before features are processed by this renderer.
- Parameters
enabled – set to true to enable custom feature ordering
See also
See also
New in version 2.14.
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setPaintEffect
(self, effect: QgsPaintEffect)¶ Sets the current paint effect for the renderer.
- Parameters
effect – paint effect. Ownership is transferred to the renderer.
See also
New in version 2.9.
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setUsingSymbolLevels
(self, usingSymbolLevels: bool)¶
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setVertexMarkerAppearance
(self, type: int, size: float)¶ Sets type and size of editing vertex markers for subsequent rendering
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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 – Additional information passed to the renderer about the job which will be rendered
fields – The fields available for rendering
See also
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.
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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
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symbolForFeature
(self, feature: QgsFeature, context: QgsRenderContext) → QgsSymbol¶ To be overridden
Must be called between startRender() and stopRender() calls.
- Parameters
feature – feature
context – render context
- Returns
returns pointer to symbol or 0 if symbol was not found
New in version 2.12.
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symbols
(self, context: QgsRenderContext) → object¶ Returns list of symbols used by the renderer.
- Parameters
context – render context
New in version 2.12.
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symbolsForFeature
(self, feature: QgsFeature, context: QgsRenderContext) → object¶ 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.
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toSld
(self, doc: QDomDocument, element: QDomElement, props: Dict[str, str] = {})¶ used from subclasses to create SLD Rule elements following SLD v1.1 specs
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type
(self) → str¶
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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.
- Returns
A set of attributes
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usingSymbolLevels
(self) → bool¶
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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.
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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.
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class