Class: QgsAbstractMeshLayerLabeling

Abstract base class - its implementations define different approaches to the labeling of a mesh layer.

Added in version 3.36.

Note

This is an abstract class, with methods which must be implemented by a subclass.

The following methods must be implemented: clone(), hasNonDefaultCompositionMode(), requiresAdvancedEffects(), save(), setSettings(), settings(), type()

Class Hierarchy

Subclasses

QgsMeshLayerSimpleLabeling

Basic implementation of the labeling interface for mesh layers.

Abstract Methods

clone	Returns a new copy of the object
hasNonDefaultCompositionMode	Returns True the labeling requires a non-default composition mode.
requiresAdvancedEffects	Returns True if drawing labels requires advanced effects like composition modes, which could prevent it being used as an isolated cached image or exported to a vector format.
save	Returns labeling configuration as XML element
setSettings	Set pal settings for a specific provider (takes ownership).
settings	Gets associated label settings.
type	Unique type string of the labeling configuration implementation

Virtual Methods

In PyQGIS, only methods marked as virtual can be safely overridden in a Python subclass of QgsAbstractMeshLayerLabeling. See the FAQ for more details.

accept	Accepts the specified symbology visitor, causing it to visit all symbols associated with the labeling.
multiplyOpacity	Multiply opacity by opacityFactor.
subProviders	Gets list of sub-providers within the layer's labeling.
toSld	Writes the SE 1.1 TextSymbolizer element based on the current layer labeling settings

Static Methods

create	Try to create instance of an implementation based on the XML data
defaultSettingsForLayer	Returns the default layer settings to use for the specified mesh layer.

class qgis.core.QgsAbstractMeshLayerLabeling

Bases: object

virtual accept(self, visitor: QgsStyleEntityVisitorInterface | None) → bool

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

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

Parameters:

visitor (Optional[QgsStyleEntityVisitorInterface])

Return type:

bool

abstract clone(self) → QgsAbstractMeshLayerLabeling | None

Returns a new copy of the object

Return type:

Optional[QgsAbstractMeshLayerLabeling]

static create(element: QDomElement, context: QgsReadWriteContext) → QgsAbstractMeshLayerLabeling | None

Try to create instance of an implementation based on the XML data

Parameters:

• element (QDomElement)

• context (QgsReadWriteContext)

Return type:

Optional[QgsAbstractMeshLayerLabeling]

static defaultSettingsForLayer(layer: QgsMeshLayer | None) → QgsPalLayerSettings

Returns the default layer settings to use for the specified mesh layer.

Parameters:

layer (Optional[QgsMeshLayer])

Return type:

QgsPalLayerSettings

abstract hasNonDefaultCompositionMode(self) → bool

Returns True the labeling requires a non-default composition mode.

This method is pessimistic, in that it will return True in cases where composition modes cannot be easily determined in advance (e.g. when data-defined overrides are in place for composition modes).

The default composition mode is QPainter.CompositionMode_SourceOver.

Added in version 3.44.

Return type:

bool

virtual multiplyOpacity(self, opacityFactor: float)

Multiply opacity by opacityFactor.

This method multiplies the opacity of the labeling elements (text, shadow, buffer etc.) by opacity effectively changing the opacity of the whole labeling elements.

Parameters:

opacityFactor (float)

abstract requiresAdvancedEffects(self) → bool

Returns True if drawing labels requires advanced effects like composition modes, which could prevent it being used as an isolated cached image or exported to a vector format.

Return type:

bool

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

Returns labeling configuration as XML element

Parameters:

• doc (QDomDocument)

• context (QgsReadWriteContext)

Return type:

QDomElement

abstract setSettings(self, settings: QgsPalLayerSettings | None, providerId: str | None = '')

Set pal settings for a specific provider (takes ownership).

Parameters:

• settings (Optional[QgsPalLayerSettings]) – Pal layer settings

• providerId (Optional[str] = '') – The id of the provider

abstract settings(self, providerId: str | None = '') → QgsPalLayerSettings

Gets associated label settings. In case of multiple sub-providers with different settings, they are identified by their ID.

Parameters:

providerId (Optional[str] = '')

Return type:

QgsPalLayerSettings

virtual subProviders(self) → List[str]

Gets list of sub-providers within the layer’s labeling.

Return type:

List[str]

virtual toSld(self, parent: QDomNode, props: Dict[str, Any])

Writes the SE 1.1 TextSymbolizer element based on the current layer labeling settings

Parameters:

• parent (QDomNode)

• props (Dict[str, Any])

abstract type(self) → str

Unique type string of the labeling configuration implementation

Return type:

str