Purpose and Scope
EPUB® documents, unlike print books or PDF files, are designed to change. The content
flows, or reflows, to fit the screen and to fit the needs of the reader. The EPUB
3.0 Specification says that “content presentation should adapt to the user rather
than the user having to adapt to a particular representation of content.”
But this principle doesn’t work for all types of documents. Sometimes content and
design are so intertwined they cannot be separated. Any change in appearance risks
changing the meaning, or losing all meaning. Fixed-layout documents give content creators greater control over presentation, when a reflowable EPUB is
not suitable for the content.
This document, EPUB 3 Fixed-Layout Documents, defines a set of metadata properties
to allow declarative expression of intended rendering behaviors of fixed-layout documents
in the context of EPUB 3. It also defines mechanisms to express the intended rendering
dimensions of fixed-layout XHTML and SVG [ContentDocs30] content, as well as bitmap images.
NOTE EPUB 3 affords multiple mechanisms for representing fixed-layout content in EPUB 3 documents. When fixed-layout content is necessary, the author's choice of mechanism willdepend on many factors including desired degree of precision, file size, accessibility, etc. This document does not attempt to dictate the author's choice of mechanism.