Some books, such as Manga, are designed for content to be presented in one continuous scroll without white space or gaps. Vertical scrolling allows the reader to view and read the content from top-to-bottom. Apple Books presents the content documents in the order listed in the <spine> element, which defines the linear reading order of the book. By specifying vertical scrolling, Apple Books presents the content continuously without any space between content documents.
For books designed for content using top-to-bottom reading, keep the following guidelines in mind:
Vertical scrolling fixed-layout books are optimized for portrait mode, which provides a gapless, top-to-bottom reading experience for content such as Manga.
When creating vertical scrolling fixed-layout books, a book must have scrolled-continuous in the <meta property="rendition:flow"> tag in the <metadata> element within the OPF file. See Defining Book Layout Metadata for more information annotations.
<metadata xmlns="http://www.idpf.org/2007/opf" xmlns:dc="http://purl.org/dc/elements/1.1/" >
<dc:title>Fixed-Layout Book</dc:title>
<dc:identifier id="bookid">0123456789</dc:identifier>
<dc:language>en</dc:language>
<meta property="rendition:layout">pre-paginated</meta>
<meta property="rendition:spread">portrait</meta>
<meta property="rendition:flow">scrolled-continuous</meta>
</metadata>
Readers can turn on Vertical Scrolling Mode by selecting it in font preferences.
Images inside fixed-layout books must not exceed 5.6 million pixels. You can calculate whether an image inside the book file exceeds 5.6 million pixels by multiplying the height and width of the image. See Optimizing Images in Fixed-Layout Books for details.