Implementation of legend node interface for displaying preview of vector symbols and their labels and allowing interaction with the symbol / renderer. More...

#include <qgslayertreemodellegendnode.h>

Inheritance diagram for QgsSymbolLegendNode:

[legend]

Public Member Functions
	QgsSymbolLegendNode (QgsLayerTreeLayer nodeLayer, const QgsLegendSymbolItem &item, QObject parent=nullptr)
	Constructor for QgsSymbolLegendNode.

	~QgsSymbolLegendNode ()

QgsExpressionContextScope *	createSymbolScope () const
	Create an expression context scope containing symbol related variables.

QgsSymbol *	customSymbol () const
	Returns the node's custom symbol.

QVariant	data (int role) const override
	Returns data associated with the item. Must be implemented in derived class.

QSizeF	drawSymbol (const QgsLegendSettings &settings, ItemContext *ctx, double itemHeight) const override
	Draws symbol on the left side of the item.

QString	evaluateLabel (const QgsExpressionContext &context=QgsExpressionContext(), const QString &label=QString())
	Evaluates and returns the text label of the current node.

QJsonObject	exportSymbolToJson (const QgsLegendSettings &settings, const QgsRenderContext &context) const override
	Adds a symbol in base64 string within a JSON object with the key "icon".

Qt::ItemFlags	flags () const override
	Returns item flags associated with the item. Default implementation returns Qt::ItemIsEnabled.

QSize	iconSize () const

void	invalidateMapBasedData () override
	Notification from model that information from associated map view has changed.

bool	isScaleOK (double scale) const override

QSize	minimumIconSize () const
	Calculates the minimum icon size to prevent cropping.

QSize	minimumIconSize (QgsRenderContext *context) const
	Calculates the minimum icon size to prevent cropping.

QgsLegendPatchShape	patchShape () const
	Returns the symbol patch shape to use when rendering the legend node symbol.

void	setCustomSymbol (QgsSymbol *symbol)
	Sets the node's custom symbol.

bool	setData (const QVariant &value, int role) override
	Sets some data associated with the item. Default implementation does nothing and returns `false`.

void	setEmbeddedInParent (bool embedded) override

void	setIconSize (QSize sz)
	Set the icon size.

void	setPatchShape (const QgsLegendPatchShape &shape)
	Sets the symbol patch shape to use when rendering the legend node symbol.

void	setSymbol (QgsSymbol *symbol)
	Sets the symbol to be used by the legend node.

void	setTextOnSymbolLabel (const QString &label)
	Sets label of text to be shown on top of the symbol.

void	setTextOnSymbolTextFormat (const QgsTextFormat &format)
	Sets format of text to be shown on top of the symbol.

void	setUserLabel (const QString &userLabel) override

const QgsSymbol *	symbol () const
	Returns the symbol used by the legend node.

QString	symbolLabel () const
	Label of the symbol, user defined label will be used, otherwise will default to the label made by QGIS.

QString	textOnSymbolLabel () const
	Returns label of text to be shown on top of the symbol.

QgsTextFormat	textOnSymbolTextFormat () const
	Returns text format of the label to be shown on top of the symbol.

Public Member Functions inherited from QgsLayerTreeModelLegendNode
virtual bool	columnBreak () const
	Returns whether a forced column break should occur before the node.

virtual ItemMetrics	draw (const QgsLegendSettings &settings, ItemContext *ctx)
	Entry point called from QgsLegendRenderer to do the rendering.

virtual QSizeF	drawSymbolText (const QgsLegendSettings &settings, ItemContext *ctx, QSizeF symbolSize) const
	Draws label on the right side of the item.

QJsonObject	exportToJson (const QgsLegendSettings &settings, const QgsRenderContext &context)
	Entry point called from QgsLegendRenderer to do the rendering in a JSON object.

virtual bool	isEmbeddedInParent () const

QgsLayerTreeLayer *	layerNode () const
	Returns pointer to the parent layer node.

QgsLayerTreeModel *	model () const
	Returns pointer to model owning this legend node.

virtual void	setColumnBreak (bool breakBeforeNode)
	Sets whether a forced column break should occur before the node.

virtual void	setUserPatchSize (QSizeF size)
	Sets the user (overridden) size for the legend node.

virtual QString	userLabel () const

virtual QSizeF	userPatchSize () const
	Returns the user (overridden) size for the legend node.

Static Public Attributes
static double	MAXIMUM_SIZE = -1.0

static double	MINIMUM_SIZE = -1.0

Additional Inherited Members
Public Types inherited from QgsLayerTreeModelLegendNode
enum class	CustomRole : int { RuleKey = Qt::UserRole , ParentRuleKey , NodeType , IsDataDefinedSize }
	Legend node data roles. More...

enum	NodeTypes { SimpleLegend , SymbolLegend , RasterSymbolLegend , ImageLegend , WmsLegend , DataDefinedSizeLegend , EmbeddedWidget , ColorRampLegend }
	Types of legend nodes. More...

Public Slots inherited from QgsLayerTreeModelLegendNode
void	checkAllItems ()
	Checks all checkable items belonging to the same layer as this node.

void	toggleAllItems ()
	Toggle all checkable items belonging to the same layer as this node.

void	uncheckAllItems ()
	Unchecks all checkable items belonging to the same layer as this node.

Signals inherited from QgsLayerTreeModelLegendNode
void	dataChanged ()
	Emitted on internal data change so the layer tree model can forward the signal to views.

void	sizeChanged ()
	Emitted when the size of this node changes.

Protected Member Functions inherited from QgsLayerTreeModelLegendNode
	QgsLayerTreeModelLegendNode (QgsLayerTreeLayer nodeL, QObject parent=nullptr)
	Construct the node with pointer to its parent layer node.

QgsRenderContext *	createTemporaryRenderContext () const
	Returns a temporary context or `nullptr` if legendMapViewData are not valid.

Protected Attributes inherited from QgsLayerTreeModelLegendNode
bool	mColumnBreakBeforeNode = false

bool	mEmbeddedInParent

QgsLayerTreeLayer *	mLayerNode = nullptr

QgsLegendPatchShape	mPatchShape

QString	mUserLabel

QSizeF	mUserSize

Detailed Description

Implementation of legend node interface for displaying preview of vector symbols and their labels and allowing interaction with the symbol / renderer.

Definition at line 399 of file qgslayertreemodellegendnode.h.

Constructor & Destructor Documentation

◆ QgsSymbolLegendNode()

QgsSymbolLegendNode::QgsSymbolLegendNode	(	QgsLayerTreeLayer *	nodeLayer,
		const QgsLegendSymbolItem &	item,
		QObject *	parent = `nullptr`
	)

Constructor for QgsSymbolLegendNode.

Parameters

nodeLayer	layer node
item	the legend symbol item
parent	attach a parent QObject to the legend node.

Definition at line 321 of file qgslayertreemodellegendnode.cpp.

◆ ~QgsSymbolLegendNode()

QgsSymbolLegendNode::~QgsSymbolLegendNode ( )

default

Member Function Documentation

◆ createSymbolScope()

QgsExpressionContextScope * QgsSymbolLegendNode::createSymbolScope ( ) const

Create an expression context scope containing symbol related variables.

The caller takes ownership of the returned object.

Since: QGIS 3.36

Definition at line 966 of file qgslayertreemodellegendnode.cpp.

◆ customSymbol()

QgsSymbol * QgsSymbolLegendNode::customSymbol ( ) const

Returns the node's custom symbol.

If a non-nullptr value is returned, then this symbol will be used for rendering the legend node instead of the default symbol().

See also: setCustomSymbol()

Since: QGIS 3.14

Definition at line 451 of file qgslayertreemodellegendnode.cpp.

◆ data()

QVariant QgsSymbolLegendNode::data ( int role ) const

overridevirtual

Returns data associated with the item. Must be implemented in derived class.

Implements QgsLayerTreeModelLegendNode.

Definition at line 545 of file qgslayertreemodellegendnode.cpp.

◆ drawSymbol()

QSizeF QgsSymbolLegendNode::drawSymbol	(	const QgsLegendSettings &	settings,
		ItemContext *	ctx,
		double	itemHeight
	)		const

overridevirtual

Draws symbol on the left side of the item.

Parameters

settings	Legend layout configuration
ctx	Context for rendering - may be `nullptr` if only doing layout without actual rendering
itemHeight	Minimal height of the legend item - used for correct positioning when rendering

Returns: Real size of the symbol (may be bigger than "normal" symbol size from settings)

Reimplemented from QgsLayerTreeModelLegendNode.

Definition at line 649 of file qgslayertreemodellegendnode.cpp.

◆ evaluateLabel()

QString QgsSymbolLegendNode::evaluateLabel	(	const QgsExpressionContext &	context = `QgsExpressionContext()`,
		const QString &	label = `QString()`
	)

Evaluates and returns the text label of the current node.

Parameters

context	extra QgsExpressionContext to use for evaluating the expression
label	text to evaluate instead of the layer layertree string

Since: QGIS 3.10

Definition at line 930 of file qgslayertreemodellegendnode.cpp.

◆ exportSymbolToJson()

QJsonObject QgsSymbolLegendNode::exportSymbolToJson	(	const QgsLegendSettings &	settings,
		const QgsRenderContext &	context
	)		const

overridevirtual

Adds a symbol in base64 string within a JSON object with the key "icon".

Parameters

settings	Legend layout configuration
context	Rendering context

Since: QGIS 3.8

Reimplemented from QgsLayerTreeModelLegendNode.

Definition at line 816 of file qgslayertreemodellegendnode.cpp.

◆ flags()

Qt::ItemFlags QgsSymbolLegendNode::flags ( ) const

overridevirtual

Returns item flags associated with the item. Default implementation returns Qt::ItemIsEnabled.

Reimplemented from QgsLayerTreeModelLegendNode.

Definition at line 352 of file qgslayertreemodellegendnode.cpp.

◆ iconSize()

QSize QgsSymbolLegendNode::iconSize ( ) const

inline

Definition at line 437 of file qgslayertreemodellegendnode.h.

◆ invalidateMapBasedData()

void QgsSymbolLegendNode::invalidateMapBasedData ( )

overridevirtual

Notification from model that information from associated map view has changed.

Default implementation does nothing.

Reimplemented from QgsLayerTreeModelLegendNode.

Definition at line 885 of file qgslayertreemodellegendnode.cpp.

◆ isScaleOK()

bool QgsSymbolLegendNode::isScaleOK ( double scale ) const

inlineoverridevirtual

Reimplemented from QgsLayerTreeModelLegendNode.

Definition at line 429 of file qgslayertreemodellegendnode.h.

◆ minimumIconSize() [1/2]

QSize QgsSymbolLegendNode::minimumIconSize ( ) const

Calculates the minimum icon size to prevent cropping.

When evaluating the size for multiple icons it is more efficient to create a single render context in advance and use the variant which accepts a QgsRenderContext argument.

Definition at line 361 of file qgslayertreemodellegendnode.cpp.

◆ minimumIconSize() [2/2]

QSize QgsSymbolLegendNode::minimumIconSize ( QgsRenderContext * context ) const

Calculates the minimum icon size to prevent cropping.

When evaluating the size for multiple icons it is more efficient to create a single render context in advance and call this method instead of minimumIconSize().

Definition at line 367 of file qgslayertreemodellegendnode.cpp.