OpenLIME

Class: Annotation

Annotation

Represents an annotation that can be drawn as an overlay on a canvas. An annotation is a decorative element (text, graphics, glyph) that provides additional context or information for interpreting underlying drawings.

Each annotation includes:

  • A unique identifier
  • Optional metadata (description, category, code, label)
  • Visual representation (SVG, image, or element collection)
  • Spatial information (region or bounding box)
  • Style and state properties

Annotations can be serialized to/from JSON-LD format for interoperability with Web Annotation standards.

new Annotation( [options])

Creates a new Annotation instance.

Parameters:
Name Type Argument Description
options Object <optional>

Configuration options for the annotation.

Properties
Name Type Argument Default Description
id string <optional>

Unique identifier for the annotation. Auto-generated if not provided.
code string <optional>

A code identifier for the annotation.
label string <optional>
 ''

Display label for the annotation.
description string <optional>

HTML text containing a comprehensive description.
class string <optional>

Category or classification of the annotation.
target string <optional>

Target element or area this annotation refers to.
svg string <optional>

SVG content for the annotation.
image Object <optional>

Image data associated with the annotation.
region Object <optional>

Region coordinates {x, y, w, h} for the annotation.
data Object <optional>
 {}

Additional custom data for the annotation.
style Object <optional>

Style configuration for rendering.
bbox BoundingBox <optional>

Bounding box of the annotation.
visible boolean <optional>
 true

Visibility state of the annotation.
state Object <optional>

State variables for the annotation.
ready boolean <optional>
 false

Indicates if SVG conversion is complete.
needsUpdate boolean <optional>
 true

Indicates if annotation needs updating.
editing boolean <optional>
 false

Indicates if annotation is being edited.
Source:

Methods

getBBoxFromElements()

Calculates and returns the bounding box of the annotation based on its elements or region. The coordinates are always relative to the top-left corner of the canvas.

Source:
Returns:

The calculated bounding box of the annotation.

Type
BoundingBox

toJsonLd()

Converts the annotation to a JSON-LD format object.

Source:
Returns:

A JSON-LD representation of the annotation.

Type
Object

<static> fromJsonLd(entry)

Creates an Annotation instance from a JSON-LD format object.

Parameters:
Name Type Description
entry Object

The JSON-LD object representing an annotation.
Source:
Throws:

If the entry is not a valid JSON-LD annotation or contains unsupported selectors.

Type
Error
Returns:

A new Annotation instance.

Type
Annotation