QgsDiagramLayerSettings class

Stores the settings for rendering of all diagrams for a layer.

Reference

QgsDiagramSettings stores the settings related to rendering the individual diagrams themselves, while QgsDiagramLayerSettings stores settings which control how ALL diagrams within a layer are rendered.

Public types

enum LinePlacementFlag { OnLine = 1, AboveLine = 1 << 1, BelowLine = 1 << 2, MapOrientation = 1 << 4 }: Line placement flags for controlling line based placements.
enum Property { BackgroundColor, StrokeColor, StrokeWidth, PositionX, PositionY, Distance, Priority, ZIndex, IsObstacle, Show, AlwaysShow, StartAngle }: Data definable properties.

Public static functions

static auto propertyDefinitions() -> const QgsPropertiesDefinition&: Returns the diagram property definitions.

Constructors, destructors, conversion operators

QgsDiagramLayerSettings(): Constructor for QgsDiagramLayerSettings.
QgsDiagramLayerSettings(const QgsDiagramLayerSettings& rh): Copy constructor.

Public functions

auto coordinateTransform() const -> QgsCoordinateTransform: Returns the coordinate transform associated with the layer, or an invalid transform if no transformation is required.
auto dataDefinedProperties() -> QgsPropertyCollection&: Returns a reference to the diagram's property collection, used for data defined overrides.
auto dataDefinedProperties() const -> const QgsPropertyCollection&: Returns a reference to the diagram's property collection, used for data defined overrides.
auto distance() const -> double: Returns the distance between the diagram and the feature (in mm).
auto isObstacle() const -> bool: Returns whether the feature associated with a diagram acts as an obstacle for other labels or diagrams.
auto linePlacementFlags() const -> LinePlacementFlags: Returns the diagram placement flags.
auto placement() const -> Placement: Returns the diagram placement.
auto prepare(const QgsExpressionContext& context = QgsExpressionContext()) const -> bool: Prepares the diagrams for a specified expression context.
auto priority() const -> int: Returns the diagram priority.
void readXml(const QDomElement& elem): Reads the diagram settings from a DOM element.
auto referencedFields(const QgsExpressionContext& context = QgsExpressionContext()) const -> QSet<QString>: Returns the set of any fields referenced by the layer's diagrams.
auto renderer() -> QgsDiagramRenderer*: Returns the diagram renderer associated with the layer.
auto renderer() const -> const QgsDiagramRenderer*: Returns the diagram renderer associated with the layer.
void setCoordinateTransform(const QgsCoordinateTransform& transform): Sets the coordinate transform associated with the layer.
void setDataDefinedProperties(const QgsPropertyCollection& collection): Sets the diagram's property collection, used for data defined overrides.
void setDistance(double distance): Sets the distance between the diagram and the feature.
void setIsObstacle(bool isObstacle): Sets whether the feature associated with a diagram acts as an obstacle for other labels or diagrams.
void setLinePlacementFlags(LinePlacementFlags flags): Sets the the diagram placement flags.
void setPlacement(Placement value): Sets the diagram placement.
void setPriority(int value): Sets the diagram priority.
void setRenderer(QgsDiagramRenderer* diagramRenderer): Sets the diagram renderer associated with the layer.
void setShowAllDiagrams(bool showAllDiagrams): Sets whether the layer should show all diagrams, including overlapping diagrams.
void setZIndex(double index): Sets the diagram z-index.
auto showAllDiagrams() const -> bool: Returns whether the layer should show all diagrams, including overlapping diagrams.
void writeXml(QDomElement& layerElem, QDomDocument& doc) const: Writes the diagram settings to a DOM element.
auto zIndex() const -> double: Returns the diagram z-index.

Enum documentation

enum QgsDiagramLayerSettings::Property

Data definable properties.

Enumerators
BackgroundColor	Diagram background color.
StrokeColor	Stroke color.
StrokeWidth	Stroke width.
PositionX
PositionY	x-coordinate data defined diagram position
Distance	y-coordinate data defined diagram position
Priority	Distance to diagram from feature.
ZIndex	Diagram priority (between 0 and 10)
IsObstacle	Z-index for diagram ordering.
Show	Whether diagram features act as obstacles for other diagrams/labels.
AlwaysShow	Whether to show the diagram.
StartAngle	Whether the diagram should always be shown, even if it overlaps other diagrams/labels.

Function documentation

static const QgsPropertiesDefinition& QgsDiagramLayerSettings::propertyDefinitions()

Returns the diagram property definitions.

QgsCoordinateTransform QgsDiagramLayerSettings::coordinateTransform() const

Returns the coordinate transform associated with the layer, or an invalid transform if no transformation is required.

QgsPropertyCollection& QgsDiagramLayerSettings::dataDefinedProperties()

Returns a reference to the diagram's property collection, used for data defined overrides.

const QgsPropertyCollection& QgsDiagramLayerSettings::dataDefinedProperties() const

Returns a reference to the diagram's property collection, used for data defined overrides.

double QgsDiagramLayerSettings::distance() const

Returns the distance between the diagram and the feature (in mm).

bool QgsDiagramLayerSettings::isObstacle() const

Returns whether the feature associated with a diagram acts as an obstacle for other labels or diagrams.

LinePlacementFlags QgsDiagramLayerSettings::linePlacementFlags() const

Returns the diagram placement flags.

These are only used if the diagram placement is set to a line type.

Placement QgsDiagramLayerSettings::placement() const

Returns the diagram placement.

bool QgsDiagramLayerSettings::prepare(const QgsExpressionContext& context = QgsExpressionContext()) const

Prepares the diagrams for a specified expression context.

Calling prepare before rendering multiple diagrams allows precalculation of expensive setup tasks such as parsing expressions. Returns true if preparation was successful.

int QgsDiagramLayerSettings::priority() const

Returns the diagram priority.

Returns	diagram priority, where 0 = low and 10 = high

void QgsDiagramLayerSettings::readXml(const QDomElement& elem)

Reads the diagram settings from a DOM element.

QSet<QString> QgsDiagramLayerSettings::referencedFields(const QgsExpressionContext& context = QgsExpressionContext()) const

Returns the set of any fields referenced by the layer's diagrams.

Parameters
context	expression context the diagrams will be drawn using

QgsDiagramRenderer* QgsDiagramLayerSettings::renderer()

Returns the diagram renderer associated with the layer.

const QgsDiagramRenderer* QgsDiagramLayerSettings::renderer() const

Returns the diagram renderer associated with the layer.

void QgsDiagramLayerSettings::setCoordinateTransform(const QgsCoordinateTransform& transform)

Sets the coordinate transform associated with the layer.

Parameters
transform	coordinate transform. Ownership is transferred to the object.

void QgsDiagramLayerSettings::setDataDefinedProperties(const QgsPropertyCollection& collection)

Sets the diagram's property collection, used for data defined overrides.

Parameters
collection	property collection. Existing properties will be replaced.

void QgsDiagramLayerSettings::setDistance(double distance)

Sets the distance between the diagram and the feature.

Parameters
distance	distance in mm

void QgsDiagramLayerSettings::setIsObstacle(bool isObstacle)

Sets whether the feature associated with a diagram acts as an obstacle for other labels or diagrams.

Parameters
isObstacle	set to true for feature to act as obstacle

void QgsDiagramLayerSettings::setLinePlacementFlags(LinePlacementFlags flags)

Sets the the diagram placement flags.

Parameters
flags	placement value

These are only used if the diagram placement is set to a line type.

void QgsDiagramLayerSettings::setPlacement(Placement value)

Sets the diagram placement.

Parameters
value	placement value

void QgsDiagramLayerSettings::setPriority(int value)

Sets the diagram priority.

Parameters
value	priority, where 0 = low and 10 = high

void QgsDiagramLayerSettings::setRenderer(QgsDiagramRenderer* diagramRenderer)

Sets the diagram renderer associated with the layer.

Parameters
diagramRenderer	diagram renderer. Ownership is transferred to the object.

void QgsDiagramLayerSettings::setShowAllDiagrams(bool showAllDiagrams)

Sets whether the layer should show all diagrams, including overlapping diagrams.

Parameters
showAllDiagrams	set to true to show all diagrams

void QgsDiagramLayerSettings::setZIndex(double index)

Sets the diagram z-index.

Parameters
index	diagram z-index

Diagrams (or labels) with a higher z-index are drawn over diagrams with a lower z-index.

bool QgsDiagramLayerSettings::showAllDiagrams() const

Returns whether the layer should show all diagrams, including overlapping diagrams.

void QgsDiagramLayerSettings::writeXml(QDomElement& layerElem, QDomDocument& doc) const

Writes the diagram settings to a DOM element.

double QgsDiagramLayerSettings::zIndex() const

Returns the diagram z-index.