OptionalfallbackThe aspect-ratio for Content Display Areas to use as fallback if the publication has no cover image. Defined as (width / height).
Optional ExperimentalinsetsConfigures insets that reserve space along the edges of the ReaderView, typically set to match
the device's safe area insets to keep content clear of camera notches, rounded corners, or system UI elements.
For paginated renderers, publication content will not be rendered in the inset areas except when zooming in.
For scrolling renderers, the vertical (top and bottom) insets do not limit the content display area. Instead, they add extra space at the top and bottom of the scrolling container. This ensures that content can be scrolled fully into view within the safe area. The horizontal (left and right) insets will still constrain the content display area.
Percentage values are based on the ReaderView's dimensions. Any value higher than 40% of the ReaderView's width or height will be clamped to 40%.
Defaults to 0 for all sides.
Identifies the type of Content Display Area options.
Content Display Areas are based on the aspect-ratio derived from the publication's fixed-layout documents, if any exist. Otherwise, the aspect ratio is derived from the publication's cover image.
When the publication lacks both fixed-layout pages and cover image, the configurable fallback value is used instead.
Note: When this type is used, additional publication data might need to be fetched. This may negatively impact the time until first page rendered if the publication is streamed over the internet.