Interface StorymapOverlayLayer

Extra attribution fragment, listed while the overlay is visible

CSS mix-blend-mode for the layer container (needs className)

CSS class for the layer container. OpenLayers paints every layer with the same class into one shared div/canvas, so a distinct class isolates this layer (e.g. for blend modes). The class replaces the default wholesale, so keep the ol-layer token (e.g. "ol-layer historic-sheet") unless you know why not.

false hides the row from the control without removing the overlay.

Clip box [west, south, east, north] in lon/lat (mercator maps)

IIIF Georeference Extension placement instead of a tile source. The ground control points are fitted affinely and the image is placed on the geographic map, so this is the manifest-side equivalent of a georeferenced raster overlay.

Control row label for the layer switcher (show_layers_control). Defaults to map_type. A function is re-invoked on every refreshLabels() for host i18n — but only when the entry comes from constructor options: mergeData() overwrites option keys with the storymap JSON, so a document carrying overlays replaces function labels with its own strings.

Render the row checked and disabled: an overlay the visitor may add back but not remove (e.g. a georeferenced scan the story is built on). The control never toggles a locked entry.

Any map_type value the tile layer factory accepts. Required unless the entry carries a georeference (a placed IIIF image instead of a tile source).

Layer opacity 0..1 (default 1)

Initial visibility (default true)