Class: QgsDiagramRenderer

Evaluates and returns the diagram settings relating to a diagram for a specific feature.

Class Hierarchy

Subclasses

QgsLinearlyInterpolatedDiagramRenderer	Alters the size of rendered diagrams using a linear scaling.
QgsSingleCategoryDiagramRenderer	Renders the diagrams for all features with the same settings
QgsStackedDiagramRenderer	Renders diagrams using mixed diagram render types. The size of the rendered diagram is given by a combination of subrenderers.

Methods

attributeLegend	Returns True if renderer will show legend items for diagram attributes.
clone	Returns new instance that is equivalent to this one
convertSizeToMapUnits	Converts size from mm to map units
diagram
diagramAttributes	Returns attribute indices needed for diagram rendering
diagramSettings	Returns list with all diagram settings in the renderer
diagramSize	Returns size of the diagram (in painter units) or an invalid size in case of error
legendItems	Returns list of legend nodes for the diagram
readXml	Reads diagram state from a DOM element.
referencedFields	Returns the set of any fields required for diagram rendering
renderDiagram	Renders the diagram for a specified feature at a specific position in the passed render context.
rendererName
setAttributeLegend	Sets whether the renderer will show legend items for diagram attributes.
setDiagram
sizeMapUnits	Returns size of the diagram for a feature in map units.
writeXml	Writes diagram state to a DOM element.

Static Methods

dpiPaintDevice

Returns the paint device dpi (or -1 in case of error

class qgis.core.QgsDiagramRenderer

Bases: object

attributeLegend(self) → bool

Returns True if renderer will show legend items for diagram attributes.

See also

setAttributeLegend()

Return type:

bool

clone(self) → QgsDiagramRenderer | None

Returns new instance that is equivalent to this one

Return type:

Optional[QgsDiagramRenderer]

convertSizeToMapUnits(self, size: QSizeF, context: QgsRenderContext)

Converts size from mm to map units

Parameters:

• size (QSizeF)

• context (QgsRenderContext)

diagram(self) → QgsDiagram | None

Return type:

Optional[QgsDiagram]

diagramAttributes(self) → List[str]

Returns attribute indices needed for diagram rendering

Return type:

List[str]

diagramSettings(self) → List[QgsDiagramSettings]

Returns list with all diagram settings in the renderer

Return type:

List[QgsDiagramSettings]

diagramSettings(self, feature: QgsFeature, c: QgsRenderContext, s: QgsDiagramSettings) → bool

Returns diagram settings for a feature (or False if the diagram for the feature is not to be rendered). Used internally within renderDiagram()

Parameters:

• feature (QgsFeature) – the feature

• c (QgsRenderContext) – render context

• s (QgsDiagramSettings) – out: diagram settings for the feature

Return type:

bool

diagramSize(self, feature: QgsFeature, c: QgsRenderContext) → QSizeF

Returns size of the diagram (in painter units) or an invalid size in case of error

Parameters:

• feature (QgsFeature) – the feature

• c (QgsRenderContext) – render context

Return type:

QSizeF

static dpiPaintDevice(a0: QPainter | None) → int

Returns the paint device dpi (or -1 in case of error

Parameters:

a0 (Optional[QPainter])

Return type:

int

legendItems(self, nodeLayer: QgsLayerTreeLayer | None) → List[QgsLayerTreeModelLegendNode]

Returns list of legend nodes for the diagram

Note

caller is responsible for deletion of QgsLayerTreeModelLegendNodes

Parameters:

nodeLayer (Optional[QgsLayerTreeLayer])

Return type:

List[QgsLayerTreeModelLegendNode]

readXml(self, elem: QDomElement, context: QgsReadWriteContext)

Reads diagram state from a DOM element. Subclasses should ensure that

Parameters:

• elem (QDomElement)

• context (QgsReadWriteContext)

QgsDiagramRenderer.readXml() is called by their readXml implementation to restore the

readXml() is called by their readXml implementation to restore the general QgsDiagramRenderer settings.

See also

writeXml()

Parameters:

• elem (QDomElement)

• context (QgsReadWriteContext)

referencedFields(self, context: QgsExpressionContext = QgsExpressionContext()) → Set[str]

Returns the set of any fields required for diagram rendering

Parameters:

context (QgsExpressionContext = QgsExpressionContext()) – expression context the diagrams will be drawn using

Return type:

Set[str]

renderDiagram(self, feature: QgsFeature, c: QgsRenderContext, pos: QPointF | QPoint, properties: QgsPropertyCollection = QgsPropertyCollection())

Renders the diagram for a specified feature at a specific position in the passed render context.

Parameters:

• feature (QgsFeature)

• c (QgsRenderContext)

• pos (Union[QPointF, QPoint])

• properties (QgsPropertyCollection = QgsPropertyCollection())

rendererName(self) → str

Return type:

str

setAttributeLegend(self, enabled: bool)

Sets whether the renderer will show legend items for diagram attributes.

Parameters:

enabled (bool) – set to True to show diagram attribute legend

See also

attributeLegend()

setDiagram(self, d: QgsDiagram | None)

Parameters:

d (Optional[QgsDiagram])

sizeMapUnits(self, feature: QgsFeature, c: QgsRenderContext) → QSizeF

Returns size of the diagram for a feature in map units. Returns an invalid QSizeF in case of error

Parameters:

• feature (QgsFeature)

• c (QgsRenderContext)

Return type:

QSizeF

writeXml(self, layerElem: QDomElement, doc: QDomDocument, context: QgsReadWriteContext)

Writes diagram state to a DOM element. Subclasses should ensure that

Parameters:

• layerElem (QDomElement)

• doc (QDomDocument)

• context (QgsReadWriteContext)

QgsDiagramRenderer.writeXml() is called by their writeXml implementation to save the

writeXml() is called by their writeXml implementation to save the general QgsDiagramRenderer settings.

See also

readXml()

Parameters:

• layerElem (QDomElement)

• doc (QDomDocument)

• context (QgsReadWriteContext)