Command to draw labels for a feature. More...

#include <luciad/layers/features/FeatureCanvas.h>

Public Member Functions
virtual	~LabelDrawCommand ()=default

virtual LabelDrawCommand &	anchor (std::shared_ptr< Geometry > anchor)=0
	Sets the anchor of the label. More...

virtual LabelDrawCommand &	anchorDraped (bool draped)=0
	Specify whether the anchor is draped or not. More...

virtual LabelDrawCommand &	icon (std::shared_ptr< IIcon > icon)=0
	Sets the icon to use for the label. More...

virtual LabelDrawCommand &	inPath ()=0
	Configure the LabelDrawCommand to paint the label inside the anchor. More...

virtual LabelDrawCommand &	labelGroup (LabelGroup labelGroup)=0
	Set the `LabelGroup` for label decluttering. More...

virtual LabelDrawCommand &	onPath (OnPathLabelStyle onPathLabelStyle)=0
	Configure the LabelDrawCommand to position a single label along a line. More...

virtual LabelDrawCommand &	onPath (PathLabelPosition verticalPosition, double additionalVerticalOffset)=0
	Configure the LabelDrawCommand to position a single label along a line. More...

virtual LabelDrawCommand &	pinStyle (PinStyle pinStyle)=0
	This method enables pins for labels and defines their styling. More...

virtual LabelDrawCommand &	pointPositions (std::vector< RelativePosition > positions)=0
	Specifies the possible positions to place a Point label. More...

virtual LabelDrawCommand &	priority (Priority priority)=0
	Sets the priority that is used to determine the order in which labels are placed. More...

virtual LabelDrawCommand &	queryable (bool queryable)=0
	Indicates whether or not the label should be considered when a `Map::queryFeatures` is requested. More...

virtual void	submit ()=0
	Submits this draw command. More...

virtual LabelDrawCommand &	text (std::string text)=0
	Sets the text to use for the label. More...

virtual LabelDrawCommand &	text (std::vector< std::string > text, HorizontalAlignment alignment=HorizontalAlignment::Left)=0
	Sets the text to use for the label. More...

virtual LabelDrawCommand &	text (TextBlock text)=0
	Sets the text block to use for the label. More...

virtual LabelDrawCommand &	textStyle (TextStyle textStyle)=0
	Sets the styling for the text. More...

Detailed Description

Command to draw labels for a feature.

It is mandatory to specify at least the following:

The anchor geometry to which the label is attached
The label content

Label content

The label content can be

A single line of text: see text(std::string)
Multiple lines text: see text(std::vector<std::string>,HorizontalAlignment alignment)
A text block: see text(TextBlock)
An icon: see icon

It is mandatory to call at least one of these methods. If not, an exception will be thrown when submitting this label draw command. If these methods are called multiple times, only the last one is used.

Label positions

It is possible to explicitly specify a label position. This can be done using one of the following methods:

the pointPositions method: to anchor a label to a Point geometry
the onPath method: to place a label along a line
the inPath method: to place a label inside an area

If these methods are called multiple times, only the last one is used. If none of these methods is called, a default label positions is chosen using the LabelDrawCommand::anchor geometry.

Label decluttering

Labels that are added using this class are automatically decluttered:

Multiple label locations are tried to avoid overlapping labels
Labels for which no good location can be found (i.e. that would always overlap with an other label) are dropped.

See the related guide for a more extensive overview of the labeling API.

Since: 2020.2

Constructor & Destructor Documentation

◆ ~LabelDrawCommand()

virtual luciad::FeatureCanvas::LabelDrawCommand::~LabelDrawCommand ( )

virtualdefault

Member Function Documentation

◆ anchor()

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::anchor ( std::shared_ptr< Geometry > anchor )

pure virtual

Sets the anchor of the label.

This property is mandatory.

Parameters

anchor the anchor of the label, cannot be nullptr.

Returns: this

Exceptions

luciad::NullArgumentException if the anchor is nullptr.

◆ anchorDraped()

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::anchorDraped ( bool draped )

pure virtual

Specify whether the anchor is draped or not.

If this method is not invoked, the draping status will be the same as when rendering the anchor: if all Z components equal to 0, draping is enabled and the label will be on the ground. Otherwise, the label will be placed at anchor elevation.

Parameters

draped whether the anchor is draped or not.

Returns: this

◆ icon()

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::icon ( std::shared_ptr< IIcon > icon )

pure virtual

Sets the icon to use for the label.

This property is optional, though it is mandatory that at least one method is used to specify the label content. See the class documentation for more info.

Parameters

icon	the icon to use for the label, cannot be `nullptr`

Returns: this

Exceptions

luciad::NullArgumentException when the icon is nullptr.

◆ inPath()

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::inPath ( )

pure virtual

Configure the LabelDrawCommand to paint the label inside the anchor.

The anchor is used as follows:

The anchor must be a closed ring or a surface, or contain one. If it's not the case, an exception is thrown in the submit method.
If the anchor is a multi geometry, only the biggest one is considered.
If the anchor is an extruded one, the base geometry is considered.
If the anchor is a Patch, the base geometry is considered.
For other geometries, the label is positioned in such a way that it's inside the anchor geometry.

Calling this method is optional. See LabelDrawCommand for more information.

Returns: this LabelDrawCommand

◆ labelGroup()

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::labelGroup ( LabelGroup labelGroup )

pure virtual

Set the LabelGroup for label decluttering.

A label declutter group is a collection of labels that are positioned independently from other label declutter groups. I.e. labels from one group will never affect labels from other groups. This also means that labels from different groups are allowed to overlap.

Parameters

labelGroup declutter group for this label. See LabelGroup for more information.

Returns: this LabelDrawCommand

Since: 2021.0

◆ onPath() [1/2]

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::onPath ( OnPathLabelStyle onPathLabelStyle )

pure virtual

Configure the LabelDrawCommand to position a single label along a line.

Depending on how the given OnPathLabelStyle is configured, it can be located

somewhere along the line, but also within the view extent
at a specific location along the line, for example exactly in the middle

When this method is called, the anchor must be a Curve.

If an anchor is specified that is not supported by this labeling method, an exception will be thrown when the label command is submitted.

Calling this method is optional. See LabelDrawCommand for more information.

Parameters

onPathLabelStyle specifies all parameters needed to place the label at a specific location along the line, cannot be nullptr.

Returns: this LabelDrawCommand

Since: 2021.0

◆ onPath() [2/2]

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::onPath	(	PathLabelPosition	verticalPosition,
		double	additionalVerticalOffset
	)

pure virtual

Configure the LabelDrawCommand to position a single label along a line.

The label will also be placed within the view extent if possible.

When this method is called, the anchor must be a Curve or consist of one in case of:

Also Bounds geometries are supported.

If an anchor is specified that is not supported by this labeling method, an exception will be thrown when the label command is submitted.

Calling this method is optional. See LabelDrawCommand for more information.

Parameters

verticalPosition specifies where the label is placed wrt to a position on the line.

additionalVerticalOffset an additional perpendicular offset from the position on the line at which a label will be placed. This offset is expressed in pixels. If the value is positive, the label position is moved away from the line. If the value is negative, the label positions is moved towards the line. There is no maximum limit to the negative values, but keep in mind that large negative values will push the label to the opposite side of the line. The default offset is 0.

Returns: this LabelDrawCommand

◆ pinStyle()

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::pinStyle ( PinStyle pinStyle )

pure virtual

This method enables pins for labels and defines their styling.

By default, there's no pin for labels.

Pins are only supported when a label is attached to a point. No pin will be painted when onPath or inPath label positioning is used.

Parameters

pinStyle the styling for the pin. See PinStyle::newBuilder. This property is optional. By default, there's no pin for labels.

Returns: this

◆ pointPositions()

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::pointPositions ( std::vector< RelativePosition > positions )

pure virtual

Specifies the possible positions to place a Point label.

If the anchor is not a point geometry, an exception is thrown in the submit method.

Calling this method is optional. See LabelDrawCommand for more information.

Parameters

positions the possible positions for a point label. If empty, an exception is thrown.

Returns: this LabelDrawCommand

Exceptions

luciad::InvalidArgumentException if the list of positions is empty.

◆ priority()

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::priority ( Priority priority )

pure virtual

Sets the priority that is used to determine the order in which labels are placed.

Using a high priority will make it more likely for a label to be placed.
Using a low priority will make it more likely for the label to be omitted during label placement, because other labels with a higher priority may already occupy its space.

Label priorities work across layers. This means that it is possible to give a high priority to a label, regardless of where the layer is located in the Map's LayerList.

This property is optional. The default is Priority::normal().

Parameters

priority the priority for this label

Returns: this

◆ queryable()

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::queryable ( bool queryable )

pure virtual

Indicates whether or not the label should be considered when a Map::queryFeatures is requested.

The default is true.

Parameters

queryable true if the label should be considered.

Returns: this TextDrawCommand.

Since: 2020.2

◆ submit()

virtual void luciad::FeatureCanvas::LabelDrawCommand::submit ( )

pure virtual

Submits this draw command.

Nothing will be painted if the draw command is not submitted.

Exceptions

LogicException if anchor is not a luciad::Point and the pointPositions method is used.

◆ text() [1/3]

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::text ( std::string text )

pure virtual

Sets the text to use for the label.

This property is optional, though it is mandatory that at least one method is used to specify the label content. See the class documentation for more info.

Parameters

text	the text to use for the label.

Returns: this

◆ text() [2/3]

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::text	(	std::vector< std::string >	text,
		HorizontalAlignment	alignment = `HorizontalAlignment::Left`
	)

pure virtual

Sets the text to use for the label.

Each string in this vector is rendered as a separate line.

This property is optional, though it is mandatory that at least one method is used to specify the label content. See the class documentation for more info.

Parameters

text	the text to use for the label.
alignment	side where text is aligned. By default text is aligned on the left.

Returns: this

◆ text() [3/3]

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::text ( TextBlock text )

pure virtual

Sets the text block to use for the label.

A text block is composed of multiple texts with different styling each. See TextBlock and TextBlock::Builder.

This property is optional, though it is mandatory that at least one method is used to specify the label content. See the class documentation for more info.

Parameters

text	the text block to use for the label.

Returns: this

Since: 2021.0

◆ textStyle()

virtual LabelDrawCommand & luciad::FeatureCanvas::LabelDrawCommand::textStyle ( TextStyle textStyle )

pure virtual

Sets the styling for the text.

This property is optional. See the text style builder for the default values.

Parameters

textStyle the styling for the text.

Returns: this

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ ~LabelDrawCommand()

Member Function Documentation

◆ anchor()

◆ anchorDraped()

◆ icon()

◆ inPath()

◆ labelGroup()

◆ onPath() [1/2]

◆ onPath() [2/2]

◆ pinStyle()

◆ pointPositions()

◆ priority()

◆ queryable()

◆ submit()

◆ text() [1/3]

◆ text() [2/3]

◆ text() [3/3]

◆ textStyle()