SpecDefinition referenceView source

Image Variable

An image source: any Asset (an 'asset:<id>' reference, HTTPS URL, data URI, relative or local path, or an object with src, alt and metadata). Reference it whole as 'var:<id>' in an image, asset or src field; '{{<id>}}' inserts the source string.

Metadata

Definition: #/$defs/ImageVariable
Form: object
Source: spec/schemas/opf.schema.json

Field index

Field	Type	Req.	Description
type	const	yes	Variable kind. One of color, text, number, date, image, url or list. `type` · Allowed values `"image"`
value	ref:Asset	—	Image source this variable resolves to.
required	boolean	—	Whether the variable must be filled. Defaults to true: a variable with no 'value' is unfilled, and an unfilled required variable is an error in a normal deck and expected in a template. Set false for an optional slot: an unfilled optional variable resolves to empty text (inline tokens) or the field that references it is omitted.
label	string	—	Optional short human label for forms and fill panels.
description	string	—	Optional prose describing what the variable is for, surfaced by pickers, fill forms and agents.
example	ref:Asset	—	Illustrative image source shown in fill forms and used when a template is previewed with examples. Never written to output.

`type`

typeconstrequiredyesdefault—

Variable kind. One of color, text, number, date, image, url or list.

type · Allowed values: "image"

Field fragment · type.json

{
  "type": "image"
}

`value`

typeref:Assetrequirednodefault—

Image source this variable resolves to.

`required`

typebooleanrequirednodefaulttrue

Whether the variable must be filled. Defaults to true: a variable with no 'value' is unfilled, and an unfilled required variable is an error in a normal deck and expected in a template. Set false for an optional slot: an unfilled optional variable resolves to empty text (inline tokens) or the field that references it is omitted.

`label`

typestringrequirednodefault—

Optional short human label for forms and fill panels.

`description`

typestringrequirednodefault—

Optional prose describing what the variable is for, surfaced by pickers, fill forms and agents.

`example`

typeref:Assetrequirednodefault—

Illustrative image source shown in fill forms and used when a template is previewed with examples. Never written to output.

Complete definition constraints

Exact schema constraints

{
  "type": "object",
  "required": [
    "type"
  ],
  "additionalProperties": false,
  "properties": {
    "type": {
      "type": "string",
      "const": "image",
      "description": "Variable kind. One of color, text, number, date, image, url or list."
    },
    "value": {
      "$ref": "#/$defs/Asset",
      "description": "Image source this variable resolves to."
    },
    "required": {
      "type": "boolean",
      "default": true,
      "description": "Whether the variable must be filled. Defaults to true: a variable with no 'value' is unfilled, and an unfilled required variable is an error in a normal deck and expected in a template. Set false for an optional slot: an unfilled optional variable resolves to empty text (inline tokens) or the field that references it is omitted."
    },
    "label": {
      "type": "string",
      "description": "Optional short human label for forms and fill panels."
    },
    "description": {
      "type": "string",
      "description": "Optional prose describing what the variable is for, surfaced by pickers, fill forms and agents."
    },
    "example": {
      "$ref": "#/$defs/Asset",
      "description": "Illustrative image source shown in fill forms and used when a template is previewed with examples. Never written to output."
    }
  },
  "description": "An image source: any Asset (an 'asset:<id>' reference, HTTPS URL, data URI, relative or local path, or an object with src, alt and metadata). Reference it whole as 'var:<id>' in an image, asset or src field; '{{<id>}}' inserts the source string."
}