FreeNodeLabelModel

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This node label model can be used to specify any position and orientation of a label.

Inheritance Hierarchy

FreeNodeLabelModel

Implemented Interfaces

ILabelModel

Remarks

The position of the label is stored relative to the layout of the node the label belongs to.

Type Details

yFiles module: view

Methods

createParameter

(layoutRatio: Point, layoutOffset: Point, labelRatio: Point, labelOffset?: Point, angle?: number) : FreeNodeLabelModelParameter

Creates a parameter instance that anchors the label to the node at a given position.

Remarks

The parameter will use the ratio and offset values to determine a point on both the label and the node. It will place the label in such a way that both points coincide.

ParametersOptions Overload

options - Object
A map of options to pass to the method.

layoutRatio - Point: The ratio that describes the point on the node's layout relative to its upper-left corner. A value of (0,0) describes the upper-left corner, while (1,1) is the lower-right corner.
layoutOffset - Point: The absolute offset to apply to the point on the node after the ratio has been determined.
labelRatio - Point: The ratio that describes the point on the label's layout relative to its upper-left corner. A value of (0,0) describes the upper-left corner, while (1,1) is the lower-right corner.
labelOffset - Point: The absolute offset to apply to the point on the label after the ratio has been determined. This defaults to (0,0), representing no further offset.
angle - number: The angle by which the label should be rotated around the point described using the ratio and offset, measured in radians. The default is 0.

Returns

↪FreeNodeLabelModelParameter: A parameter that exactly fits the described location.

Throws

Exception({ name: 'ArgumentError' }): layoutRatio, layoutOffset, labelRatio or labelOffset contains one or more NaN values.

Sample Graphs

createParameterForLayouts

(nodeLayout: Rect, labelLayout: IOrientedRectangle, referenceLocation?: Point) : FreeNodeLabelModelParameter

Creates a parameter instance that anchors the labelLayout relative to the nodeLayout.

Remarks

This method ultimately delegates to createParameter so its main purpose is to calculate the appropriate node and label layout ratio and offset parameters.

These parameters are calculated in the following way: Each coordinate axis is considered independently. If the reference point coordinate is within the node layout interval, its relative location specifies the layout ratio for this coordinate. Otherwise, the absolute distance of the reference point and the node layout interval specifies the layout offset and the layout ratio is either 0.0 or 1.0. The parameters for the label ratio and label offset are calculated the same way. If no reference point is provided, the reference point is determined automatically in the following way: For each coordinate, if the node layout and label layout do not overlap, the reference is the label corner that is closest to the node. If they overlap and if in addition the start or end coordinate of the label matches the start, center, or end coordinate of the node, that coordinate is the reference. Otherwise, the center of the label specifies the reference.

Parameters

options - Object
A map of options to pass to the method.

nodeLayout - Rect: The node layout.
labelLayout - IOrientedRectangle: The label layout.
referenceLocation - Point: A reference location that influences the ratio and offset calculation for the createParameter call.

Returns

↪FreeNodeLabelModelParameter: The canonical parameter for the specified node and label layout.

Throws

Exception({ name: 'ArgumentError' }): nodeLayout or referenceLocation contains one or more NaN values.

findBestParameter

(label: ILabel, layout: IOrientedRectangle) : ILabelModelParameter

Tries to find a parameter that best matches the given layout for the provided label instance.

Remarks

This implementation will match the provided layout perfectly.

Parameters

options - Object
A map of options to pass to the method.

label - ILabel: The label to find a parameter for.
layout - IOrientedRectangle: The anticipated layout for the label.

Returns

↪ILabelModelParameter: A non-null parameter that can be used for the label to approximate the provided layout.

getContext

(label: ILabel) : ILookup

Provides a lookup context for the given label.

Parameters

options - Object
A map of options to pass to the method.

label - ILabel: The label to use in the context.

Returns

↪ILookup: An implementation of the ILookup interface that can be used to query additional aspects of the label.

Implements

ILabelModel

getGeometry

(label: ILabel, layoutParameter: ILabelModelParameter) : IOrientedRectangle

Calculates the geometry of the given label using the given model parameter.

Parameters

options - Object
A map of options to pass to the method.

label - ILabel: The label to calculate the geometry for.
layoutParameter - ILabelModelParameter: A parameter that is compatible with this model. Typically, this is a parameter that has been created by this model, and its property model returns this instance.

Returns

↪IOrientedRectangle: An IOrientedRectangle that describes the geometry of the label. This is typically designed as a flyweight, therefore clients should not cache the instance but store the values if they need a snapshot for later use.

Implements

ILabelModel

Constants

CENTER

: FreeNodeLabelModelParameter

A predefined parameter instance that places the label anchored at the node center and has no rotation

INSTANCE

: FreeNodeLabelModel

A shared public instance that can be used to obtain parameters.