Although it may be possible to create fixed-layout EPUB publications that conform to WCAG 2.0, conforming to the latest versions of the standard is much more difficult due to the reflow requirement that was added in 2.1.
The following table identifies some of the most common level A and AA success criteria that fail due to the use of fixed layouts.
|Success Criterion||Required for WCAG||Problems|
|1.1.1 Non-text Content (A)||2.0+||
Image-based fixed layouts, such as comics and manga, typically fail this requirement as alternative text and descriptions cannot capture all of the story conveyed through the imagery. A separate serialization of the story is often required.
|1.3.1 Info and Relationships (A)||2.0+||
Generic elements, like
|1.3.2 Meaningful Sequence (A)||2.0+||
Because content elements can be visually placed wherever needed, care is not always taken to ensure that a logical sequence is maintained in the markup. When an assistive technology reads such a work, information and dialogue are rendered out of sequence.
In the case where content is laid out over two pages, the logical sequence may require a visual reader to move back and forth from page to page. This type of sequence cannot be represented in the markup.
|1.3.4 Orientation (AA)||2.0+||
Fixed-layout pages are usually designed to be rendered in a specific orientation, and authors may indicate that reading systems should only render the content in that orientation.
To meet WCAG 2.0, however, the orientation of the content must not affect its readability.
|1.4.3 Contrast (Minimum) (AA)||2.0+||
The overlaying of text on images in fixed layouts can cause insufficient contrast, making it difficult for readers to perceive the text.
|1.4.4 Resize Text (AA)||2.0+||
Users are typically prevented by reading systems from changing the fonts of fixed-layout publications to ensure the content is rendered how the author designed it.
|1.4.5 Images of Text (AA)||2.0+||
Images of text are often used to prevent users from changing the font and altering the design of fixed-layout pages.
|1.4.10 Reflow (AA)||2.1+||
Due to the fixed dimensions of a fixed-layout page, the zoom requirement of this success criterion typically results in the user having to scroll both axes to read the content.
|1.4.12 Text Spacing (AA)||2.1+||
Even if users are allowed to change the appearance, adding spacing can force text to exceed the boundaries of its container element and/or page. In this case, the overflow text is often hidden from sight.