Mobile device users can zoom text in message viewers and editors, as well as some list components.
Zooming can mean different things depending on the type of content:
Adjusting text size
Adjusting the size of all content
Users should be able to adjust font size for text content without a strict layout, such as e-mail. When text size is changed, the text is wrapped to fit the width of the view. Seeing all content may require more vertical scrolling, but the intention is to avoid the need to scroll horizontally. The number of available text size levels may differ from application to application.
If the content does not allow reformatting, such as images, maps, PDF documents, and many Web pages, zooming changes the size of all content, while preserving its aspect ratio. Since the layout does not change, users may have to scroll both vertically and horizontally to see all content.
When an application starts, the default settings for text and content size are applied. Zooming by users is temporary, which means that the adjustments are discarded when the application exits.