QgsLayoutObject class

A base class for objects which belong to a layout.

Reference

Base classes

class QgsExpressionContextGenerator: Abstract interface for generating an expression context.

Derived classes

class QgsLayoutItem: Base class for graphical items within a QgsLayout.
class QgsLayoutItemMapItem: An item which is drawn inside a QgsLayoutItemMap, e.g., a grid or map overview.
class QgsLayoutMultiFrame: Abstract base class for layout items with the ability to distribute the content to several frames (QgsLayoutFrame items).

Public types

enum DataDefinedProperty { NoProperty = 0, AllProperties, TestProperty, PresetPaperSize, PaperWidth, PaperHeight, NumPages, PaperOrientation, PageNumber, PositionX, PositionY, ItemWidth, ItemHeight, ItemRotation, Transparency, Opacity, BlendMode, ExcludeFromExports, FrameColor, BackgroundColor, MapRotation, MapScale, MapXMin, MapYMin, MapXMax, MapYMax, MapAtlasMargin, MapLayers, MapStylePreset, MapLabelMargin, PictureSource, PictureSvgBackgroundColor, PictureSvgStrokeColor, PictureSvgStrokeWidth, SourceUrl, LegendTitle, LegendColumnCount, ScalebarFillColor, ScalebarFillColor2, ScalebarLineColor, ScalebarLineWidth, AttributeTableSourceLayer }: Data defined properties for different item types.
enum PropertyValueType { EvaluatedValue = 0, OriginalValue }: Specifies whether the value returned by a function should be the original, user set value, or the current evaluated value for the property.

Public static functions

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

Constructors, destructors, conversion operators

QgsLayoutObject(QgsLayout* layout) explicit: Constructor for QgsLayoutObject, with the specified parent layout.

Public functions

auto createExpressionContext() const -> QgsExpressionContext override: Creates an expression context relating to the objects' current state.
auto customProperties() const -> QStringList: Returns list of keys stored in custom properties for the object.
auto customProperty(const QString& key, const QVariant& defaultValue = QVariant()) const -> QVariant: Read a custom property from the object.
auto dataDefinedProperties() -> QgsPropertyCollection&: Returns a reference to the object's property collection, used for data defined overrides.
auto dataDefinedProperties() const -> const QgsPropertyCollection&: Returns a reference to the object's property collection, used for data defined overrides.
auto layout() const -> const QgsLayout*: Returns the layout the object is attached to.
auto layout() -> QgsLayout*: Returns the layout the object is attached to.
void removeCustomProperty(const QString& key): Remove a custom property from the object.
void setCustomProperty(const QString& key, const QVariant& value): Set a custom property for the object.
void setDataDefinedProperties(const QgsPropertyCollection& collection): Sets the objects's property collection, used for data defined overrides.

Signals

void changed(): Emitted when the object's properties change.

Public slots

void refresh() virtual: Refreshes the object, causing a recalculation of any property overrides.

Protected functions

auto readObjectPropertiesFromElement(const QDomElement& parentElement, const QDomDocument& document, const QgsReadWriteContext& context) -> bool: Sets object properties from a DOM element.
auto writeObjectPropertiesToElement(QDomElement& parentElement, QDomDocument& document, const QgsReadWriteContext& context) const -> bool: Stores object properties within an XML DOM element.

Protected variables

QgsObjectCustomProperties mCustomProperties: Custom properties for object.

Enum documentation

enum QgsLayoutObject::DataDefinedProperty

Data defined properties for different item types.

Enumerators
NoProperty	No property.
AllProperties	All properties for item.
TestProperty	Dummy property with no effect on item.
PresetPaperSize	Preset paper size for composition.
PaperWidth	Paper width (deprecated)
PaperHeight	Paper height (deprecated)
NumPages	Number of pages in composition (deprecated)
PaperOrientation	Paper orientation.
PageNumber	Page number for item placement.
PositionX	X position on page.
PositionY	Y position on page.
ItemWidth	Width of item.
ItemHeight	Height of item.
ItemRotation	Rotation of item.
Transparency	Item transparency (deprecated)
Opacity	Item opacity.
BlendMode	Item blend mode.
ExcludeFromExports	Exclude item from exports.
FrameColor	Item frame color.
BackgroundColor	Item background color.
MapRotation	Map rotation.
MapScale	Map scale.
MapXMin	Map extent x minimum.
MapYMin	Map extent y minimum.
MapXMax	Map extent x maximum.
MapYMax	Map extent y maximum.
MapAtlasMargin	Map atlas margin.
MapLayers	Map layer set.
MapStylePreset	Layer and style map theme.
MapLabelMargin	Map label margin.
PictureSource	Picture source url.
PictureSvgBackgroundColor	SVG background color.
PictureSvgStrokeColor	SVG stroke color.
PictureSvgStrokeWidth	SVG stroke width.
SourceUrl	Html source url.
LegendTitle	Legend title.
LegendColumnCount	Legend column count.
ScalebarFillColor	Scalebar fill color.
ScalebarFillColor2	Scalebar secondary fill color.
ScalebarLineColor	Scalebar line color.
ScalebarLineWidth	Scalebar line width,.
AttributeTableSourceLayer	Attribute table source layer.

enum QgsLayoutObject::PropertyValueType

Specifies whether the value returned by a function should be the original, user set value, or the current evaluated value for the property.

This may differ if a property has a data defined expression active.

Enumerators
EvaluatedValue	Return the current evaluated value for the property.
OriginalValue	Return the original, user set value.

Function documentation

QgsLayoutObject::QgsLayoutObject(QgsLayout* layout) explicit

Constructor for QgsLayoutObject, with the specified parent layout.

QgsExpressionContext QgsLayoutObject::createExpressionContext() const override

Creates an expression context relating to the objects' current state.

The context includes scopes for global, project and layout properties.

QStringList QgsLayoutObject::customProperties() const

Returns list of keys stored in custom properties for the object.

QVariant QgsLayoutObject::customProperty(const QString& key, const QVariant& defaultValue = QVariant()) const

Read a custom property from the object.

Parameters
key	property key
defaultValue	default value to return if property with matching key does not exist
Returns	value of matching property

QgsPropertyCollection& QgsLayoutObject::dataDefinedProperties()

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

const QgsPropertyCollection& QgsLayoutObject::dataDefinedProperties() const

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

void QgsLayoutObject::removeCustomProperty(const QString& key)

Remove a custom property from the object.

Parameters
key	property key

void QgsLayoutObject::setCustomProperty(const QString& key, const QVariant& value)

Set a custom property for the object.

Parameters
key	property key. If a property with the same key already exists it will be overwritten.
value	property value

void QgsLayoutObject::setDataDefinedProperties(const QgsPropertyCollection& collection)

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

Parameters
collection	property collection. Existing properties will be replaced.

bool QgsLayoutObject::readObjectPropertiesFromElement(const QDomElement& parentElement, const QDomDocument& document, const QgsReadWriteContext& context) protected

Sets object properties from a DOM element.

Parameters
parentElement	is the parent DOM element for the object
document	DOM document
context	read write context
Returns	true if read was successful

bool QgsLayoutObject::writeObjectPropertiesToElement(QDomElement& parentElement, QDomDocument& document, const QgsReadWriteContext& context) const protected

Stores object properties within an XML DOM element.

Parameters
parentElement	is the parent DOM element to store the object's properties in
document	DOM document
context	read write context
Returns	true if write was successful