QgsPointClusterRenderer class

A renderer that automatically clusters points with the same geographic position.

Base classes

class QgsPointDistanceRenderer: An abstract base class for distance based point renderers (e.g., clusterer and displacement renderers).

static auto convertFromRenderer(const QgsFeatureRenderer* renderer) -> QgsPointClusterRenderer*: Creates a QgsPointClusterRenderer from an existing renderer.
static auto create(QDomElement& symbologyElem, const QgsReadWriteContext& context) -> QgsFeatureRenderer*: Creates a renderer from XML element.

auto clone() const -> QgsPointClusterRenderer* override: Create a deep copy of this renderer.
auto clusterSymbol() -> QgsMarkerSymbol*: Returns the symbol used for rendering clustered groups (but not ownership of the symbol).
auto save(QDomDocument& doc, const QgsReadWriteContext& context) -> QDomElement override: store renderer info to XML element
void setClusterSymbol(QgsMarkerSymbol* symbol): Sets the symbol for rendering clustered groups.
void startRender(QgsRenderContext& context, const QgsFields& fields) override: Must be called when a new render cycle is started.
void stopRender(QgsRenderContext& context) override: Must be called when a render cycle has finished, to allow the renderer to clean up.
auto usedAttributes(const QgsRenderContext& context) const -> QSet<QString> override: Returns a list of attributes required by this renderer.

Creates a QgsPointClusterRenderer from an existing renderer.

Returns	a new renderer if the conversion was possible, otherwise nullptr.

Create a deep copy of this renderer.

Returns	A copy of this renderer

Should be implemented by all subclasses and generate a proper subclass.

Returns the symbol used for rendering clustered groups (but not ownership of the symbol).

Sets the symbol for rendering clustered groups.

Parameters
symbol	new cluster symbol. Ownership is transferred to the renderer.

Must be called when a new render cycle is started.

Parameters
context	Additional information passed to the renderer about the job which will be rendered
fields	The fields available for rendering

A call to startRender() must always be followed by a corresponding call to stopRender() after all features have been rendered.

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().

Returns a list of attributes required by this renderer.

Returns	A set of attributes

Attributes not listed in here may not have been requested from the provider at rendering time.