Class: QgsCategorizedSymbolRenderer

class qgis.core.QgsCategorizedSymbolRenderer(attrName: str = '', categories: Iterable[QgsRendererCategory] = [])

Bases: QgsFeatureRenderer

Constructor for QgsCategorizedSymbolRenderer.

The attrName argument specifies the layer’s field name, or expression, which the categories will be matched against.

A list of renderer categories can optionally be specified. If no categories are specified in the constructor, they can be added later by calling addCategory().

Methods

accept

param visitor:

addCategory

Adds a new category to the renderer.

capabilities

rtype:

QgsFeatureRenderer.Capabilities

categories

Returns a list of all categories recognized by the renderer.

categoryIndexForLabel

Returns the index of the category with the specified label (or -1 if the label was not found, or is not unique).

categoryIndexForValue

Returns the index for the category with the specified value (or -1 if not found).

checkLegendSymbolItem

param key:

classAttribute

Returns the class attribute for the renderer, which is the field name or expression string from the layer which will be matched against the renderer categories.

clone

rtype:

QgsCategorizedSymbolRenderer

convertFromRenderer

Creates a new QgsCategorizedSymbolRenderer from an existing renderer.

convertSymbolRotation

convertSymbolSizeScale

create

Creates a categorized renderer from an XML element.

createCategories

Create categories for a list of values.

dataDefinedSizeLegend

Returns configuration of appearance of legend when using data-defined size for marker symbols.

deleteAllCategories

Deletes all existing categories from the renderer.

deleteCategory

Deletes the category with the specified index from the renderer.

dump

rtype:

str

filter

param fields:

filterNeedsGeometry

rtype:

bool

legendClassificationAttribute

rtype:

str

legendKeysForFeature

param feature:

legendSymbolItemChecked

param key:

legendSymbolItems

rtype:

List[QgsLegendSymbolItem]

legendSymbolItemsCheckable

rtype:

bool

matchToSymbols

Replaces category symbols with the symbols from a style that have a matching name and symbol type.

moveCategory

Moves an existing category at index position from to index position to.

originalSymbolForFeature

param feature:

rebuildHash

hashtable for faster access to symbols

renderFeatureWithSymbol

Render the feature with the symbol using context.

renderVertexMarker

render editing vertex marker at specified point

renderVertexMarkerPolygon

render editing vertex marker for a polygon

renderVertexMarkerPolyline

render editing vertex marker for a polyline

save

param doc:

saveRendererData

Saves generic renderer data into the specified element.

setClassAttribute

Sets the class attribute for the renderer, which is the field name or expression string from the layer which will be matched against the renderer categories.

setDataDefinedSizeLegend

Configures appearance of legend when renderer is configured to use data-defined size for marker symbols.

setLegendSymbolItem

param key:

setSourceColorRamp

Sets the source color ramp.

setSourceSymbol

Sets the source symbol for the renderer, which is the base symbol used for the each categories' symbol before applying the categories' color.

skipRender

sortByLabel

Sorts the existing categories by their label.

sortByValue

Sorts the existing categories by their value.

sourceColorRamp

Returns the source color ramp, from which each categories' color is derived.

sourceSymbol

Returns the renderer's source symbol, which is the base symbol used for the each categories' symbol before applying the categories' color.

startRender

param context:

stopRender

param context:

symbolForFeature

param feature:

symbolForValue

Returns the matching symbol corresponding to an attribute value.

symbolForValue2

Returns the matching symbol corresponding to an attribute value.

symbols

param context:

toSld

param doc:

updateCategoryLabel

Changes the label for the category with the specified index.

updateCategoryRenderState

Changes the render state for the category with the specified index.

updateCategorySymbol

Changes the symbol for the category with the specified index.

updateCategoryValue

Changes the value for the category with the specified index.

updateColorRamp

Update the color ramp used and all symbols colors.

updateSymbols

Update all the symbols but leave categories and colors.

usedAttributes

param context:

accept(self, visitor: QgsStyleEntityVisitorInterface) bool
Parameters:

visitor (QgsStyleEntityVisitorInterface) –

Return type:

bool

addCategory(self, category: QgsRendererCategory)

Adds a new category to the renderer.

See also

categories()

Parameters:

category (QgsRendererCategory) –

capabilities(self) QgsFeatureRenderer.Capabilities
Return type:

QgsFeatureRenderer.Capabilities

categories(self) List[QgsRendererCategory]

Returns a list of all categories recognized by the renderer.

Return type:

List[QgsRendererCategory]

categoryIndexForLabel(self, val: str) int

Returns the index of the category with the specified label (or -1 if the label was not found, or is not unique).

New in version 2.5.

Parameters:

val (str) –

Return type:

int

categoryIndexForValue(self, val: Any) int

Returns the index for the category with the specified value (or -1 if not found).

Parameters:

val (Any) –

Return type:

int

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

  • state (bool = True) –

classAttribute(self) str

Returns the class attribute for the renderer, which is the field name or expression string from the layer which will be matched against the renderer categories.

Return type:

str

clone(self) QgsCategorizedSymbolRenderer
Return type:

QgsCategorizedSymbolRenderer

convertFromRenderer(renderer: QgsFeatureRenderer, layer: QgsVectorLayer = None) QgsCategorizedSymbolRenderer

Creates a new QgsCategorizedSymbolRenderer from an existing renderer.

Since QGIS 3.20, the optional layer parameter is required for conversions of some renderer types.

Return type:

QgsCategorizedSymbolRenderer

Returns:

a new renderer if the conversion was possible, otherwise None.

New in version 2.5.

Parameters:
convertSymbolRotation(symbol: QgsSymbol, field: str)

Note

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

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

Note

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

create(element: QDomElement, context: QgsReadWriteContext) QgsFeatureRenderer

Creates a categorized renderer from an XML element.

Parameters:
Return type:

QgsFeatureRenderer

createCategories(values: Iterable[Any], symbol: QgsSymbol, layer: QgsVectorLayer = None, fieldName: str = '') List[QgsRendererCategory]

Create categories for a list of values. The returned symbols in the category list will be a modification of symbol.

If layer and fieldName are specified it will try to find nicer values to represent the description for the categories based on the respective field configuration.

New in version 3.6.

Parameters:
Return type:

List[QgsRendererCategory]

dataDefinedSizeLegend(self) QgsDataDefinedSizeLegend

Returns configuration of appearance of legend when using data-defined size for marker symbols. Will return None if the functionality is disabled.

New in version 3.0.

Return type:

QgsDataDefinedSizeLegend

deleteAllCategories(self)

Deletes all existing categories from the renderer.

See also

deleteCategory()

deleteCategory(self, catIndex: int) bool

Deletes the category with the specified index from the renderer.

Parameters:

catIndex (int) –

Return type:

bool

dump(self) str
Return type:

str

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

fields (QgsFields = QgsFields()) –

Return type:

str

filterNeedsGeometry(self) bool
Return type:

bool

legendClassificationAttribute(self) str
Return type:

str

legendKeysForFeature(self, feature: QgsFeature, context: QgsRenderContext) Set[str]
Parameters:
Return type:

Set[str]

legendSymbolItemChecked(self, key: str) bool
Parameters:

key (str) –

Return type:

bool

legendSymbolItems(self) List[QgsLegendSymbolItem]
Return type:

List[QgsLegendSymbolItem]

legendSymbolItemsCheckable(self) bool
Return type:

bool

matchToSymbols(self, style: QgsStyle, type: Qgis.SymbolType, caseSensitive: bool = True, useTolerantMatch: bool = False) Tuple[int, List[Any], List[str]]

Replaces category symbols with the symbols from a style that have a matching name and symbol type.

The unmatchedCategories list will be filled with all existing categories which could not be matched to a symbol in style.

The unmatchedSymbols list will be filled with all symbol names from style which were not matched to an existing category.

If caseSensitive is False, then a case-insensitive match will be performed. If useTolerantMatch is True, then non-alphanumeric characters in style and category names will be ignored during the match.

Returns the count of symbols matched.

New in version 3.4.

Parameters:
  • style (QgsStyle) –

  • type (Qgis.SymbolType) –

  • caseSensitive (bool = True) –

  • useTolerantMatch (bool = False) –

Return type:

Tuple[int, List[Any], List[str]]

moveCategory(self, from_: int, to: int)

Moves an existing category at index position from to index position to.

Parameters:
  • from (int) –

  • to (int) –

originalSymbolForFeature(self, feature: QgsFeature, context: QgsRenderContext) QgsSymbol
Parameters:
Return type:

QgsSymbol

rebuildHash(self)

hashtable for faster access to symbols

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.

renderVertexMarker(self, pt: QPointF | QPoint, context: QgsRenderContext)

render editing vertex marker at specified point

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

render editing vertex marker for a polygon

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

render editing vertex marker for a polyline

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

QDomElement

saveRendererData(self, doc: QDomDocument, element: QDomElement, context: QgsReadWriteContext)

Saves generic renderer data into the specified element.

This method should be called in a subclass’ save() implementation in order to store all common base class properties in the DOM element.

New in version 3.22.

setClassAttribute(self, attr: str)

Sets the class attribute for the renderer, which is the field name or expression string from the layer which will be matched against the renderer categories.

See also

classAttribute()

Parameters:

attr (str) –

setDataDefinedSizeLegend(self, settings: QgsDataDefinedSizeLegend)

Configures appearance of legend when renderer is configured to use data-defined size for marker symbols. This allows configuring for which values (symbol sizes) should be shown in the legend, whether to display different symbol sizes collapsed in one legend node or separated across multiple legend nodes etc.

When renderer does not use data-defined size or does not use marker symbols, these settings will be ignored. Takes ownership of the passed settings objects. None is a valid input that disables data-defined size legend.

New in version 3.0.

Parameters:

settings (QgsDataDefinedSizeLegend) –

setLegendSymbolItem(self, key: str, symbol: QgsSymbol)
Parameters:
setSourceColorRamp(self, ramp: QgsColorRamp)

Sets the source color ramp.

Parameters:

ramp (QgsColorRamp) – color ramp. Ownership is transferred to the renderer

setSourceSymbol(self, sym: QgsSymbol)

Sets the source symbol for the renderer, which is the base symbol used for the each categories’ symbol before applying the categories’ color.

Parameters:

sym (QgsSymbol) – source symbol, ownership is transferred to the renderer

See also

sourceSymbol()

skipRender(self) QgsSymbol

Deprecated since version No: longer used, will be removed in QGIS 4.0

Return type:

QgsSymbol

sortByLabel(self, order: Qt.SortOrder = Qt.AscendingOrder)

Sorts the existing categories by their label.

See also

sortByValue()

Parameters:

order (Qt.SortOrder = Qt.AscendingOrder) –

sortByValue(self, order: Qt.SortOrder = Qt.AscendingOrder)

Sorts the existing categories by their value.

See also

sortByLabel()

Parameters:

order (Qt.SortOrder = Qt.AscendingOrder) –

sourceColorRamp(self) QgsColorRamp

Returns the source color ramp, from which each categories’ color is derived.

See also

sourceSymbol()

Return type:

QgsColorRamp

sourceSymbol(self) QgsSymbol

Returns the renderer’s source symbol, which is the base symbol used for the each categories’ symbol before applying the categories’ color.

Return type:

QgsSymbol

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

context (QgsRenderContext) –

symbolForFeature(self, feature: QgsFeature, context: QgsRenderContext) QgsSymbol
Parameters:
Return type:

QgsSymbol

symbolForValue(self, value: Any) QgsSymbol

Returns the matching symbol corresponding to an attribute value.

Deprecated since version use: variant which takes a second bool argument instead.

Parameters:

value (Any) –

Return type:

QgsSymbol

symbolForValue2(self, value: Any) Tuple[QgsSymbol, bool]

Returns the matching symbol corresponding to an attribute value.

Will return None if no matching symbol was found for value, or if the category corresponding to value is currently disabled (see QgsRendererCategory.renderState()).

If foundMatchingSymbol is specified then it will be set to True if a matching category was found. This can be used to differentiate between None returned as a result of no matching category vs None as a result of disabled categories.

Note

available in Python bindings as symbolForValue2

Parameters:

value (Any) –

Return type:

Tuple[QgsSymbol, bool]

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

context (QgsRenderContext) –

Return type:

List[QgsSymbol]

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

  • element (QDomElement) –

  • props (Dict[str) –

updateCategoryLabel(self, catIndex: int, label: str) bool

Changes the label for the category with the specified index.

A category’s label is used to represent the category within legends and the layer tree.

Parameters:
  • catIndex (int) –

  • label (str) –

Return type:

bool

updateCategoryRenderState(self, catIndex: int, render: bool) bool

Changes the render state for the category with the specified index.

The render state indicates whether or not the category will be rendered, and is reflected in whether the category is checked with the project’s layer tree.

New in version 2.5.

Parameters:
  • catIndex (int) –

  • render (bool) –

Return type:

bool

updateCategorySymbol(self, catIndex: int, symbol: QgsSymbol) bool

Changes the symbol for the category with the specified index.

Ownership of symbol is transferred to the renderer.

Parameters:
Return type:

bool

updateCategoryValue(self, catIndex: int, value: Any) bool

Changes the value for the category with the specified index.

If value is a list, then the category will match any of the values from this list.

Parameters:
  • catIndex (int) –

  • value (Any) –

Return type:

bool

updateColorRamp(self, ramp: QgsColorRamp)

Update the color ramp used and all symbols colors.

Parameters:

ramp (QgsColorRamp) – color ramp. Ownership is transferred to the renderer

New in version 2.5.

updateSymbols(self, sym: QgsSymbol)

Update all the symbols but leave categories and colors. This method also sets the source symbol for the renderer.

Parameters:

sym (QgsSymbol) – source symbol to use for categories. Ownership is not transferred.

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

context (QgsRenderContext) –

Return type:

Set[str]