Changes in the iBooks Asset Guide 5.1.2

The section that describes how to design books with JavaScript interactivity has been modified to include design and technical considerations necessary for both macOS and iOS. See the section Books with JavaScript Interactivity for more information.

In vertical writing mode, characters are rotated automatically based on the font sets and the glyphs that are available to iBooks. The following lists the system-provided fonts you should use for Japanese text:

Important: If you want to use a Japanese font that is available in macOS or iOS, it is strongly recommended that you use Hiragino Kaku ProN and Hiragino Mincho ProN as both are pre-installed for the reader. YuGothic, YuMincho, and Hiragino Maru Gothic ProN require the reader to download the font from the iBooks Font menu before the font is available for use.

If you create a new version of a book, keep in mind that the idrefs in the OPF should always refer to the same content across different versions of the book. For example, ID "html9" should refer to the same chapter in both versions of the book, even if the actual name of the HTML file or the order of the elements in the spine may have changed. By keeping the idrefs the same, the annotations a customer made in a chapter in one version of the book will remain with the correct chapter when synced to the newer version. If you do not keep the idrefs the same, the annotations end up in the wrong chapter in the new version.

By default, Japanese and Chinese books scroll horizontally, while all other languages scroll vertically. You can redefine the scroll direction using the "ibooks:scroll-axis" property in the OPF .opf file. See Scrolling in Flowing Books for an example.

The book’s cover art that appears on the store (also known as the marketing image) is the image delivered alongside the book asset and does not refer to the cover image included in the book asset.

The book’s cover art must use RGB color mode and should be at least 1400 pixels along the shorter axis. For best results, a good rule of thumb is to use an image that is a minimum of 300 dpi.

The pixel limit for the interior cover, as with all interior book images, has been increased to 3.2 million pixels from 2 million pixels.

The sizes of the new iPad screenshots with the status bar removed have been corrected. Below, all screenshots are listed and the sizes are shown width by height. When the screenshots are cropped to remove the status bar, those pixels come off the height.

Previous versions of this guide did not specify what is meant by “beginning of the book” when describing how iBooks uses the percentage of words method to cut a sample for preview. Where the sample begins can vary depending on how the book has been structured. The words on which the percentage is calculated are counted from the beginning of the book. For flowing books, the beginning is determined by finding the first landmark where the epub:type attribute is "bodymatter". If that attribute is specified, iBooks starts cutting the sample from the publication component in the spine item referenced by the href attribute in the landmark. If the "bodymatter" attribute is not specified, iBooks looks for the first landmark where the epub:type attribute is not one of the following: "cover", "frontmatter", "toc", "foreword", "introduction", or "dedication" and starts with the spine items immediately following the component referenced in the prior "cover", "frontmatter", "toc", "foreword", "introduction", or "dedication" landmark.

For example, if the Landmarks structure included epub:type attributes of "cover", "frontmatter", "page1", and "bibliography", iBooks searches the spine for the component referenced in the "frontmatter" landmark and starts the sample cutting with the spine item immediately following it.

Note: It is recommended that the publication component referenced by the attribute in the landmark be listed close to the last item on the list of items. When cutting the sample based on percentage of words, iBooks could potentially include publication components that precede the referenced spine item, which could result in iBooks including the entire book in the sample. href"bodymatter"notspine

Corrected typos in the Book Versioning section, and in the Table of Contents and Ambient Soundtrack sections in the fixed-layout books chapter. In these sections, a space was missing between ibooks: and http:// in the prefix examples. Note that the space between ibooks: and http:// is important; it needs to be a single, regular space character and not a return, non-breaking space, or any other kind of whitespace.