This specification defines a media feature to match the different visual presentation modes that can be applied to web applications and thereby apply different styling based on these different modes using CSS Media Queries [[!MEDIAQ]].

Introduction

Web applications, be they widgets or in-browser, can on most platforms be run in multiple visual modes. At times they may occupy the entire screen, at others they may be minimized to a specific docking area; at times they may have chrome that matches the operating system's style while at others they may be providing their own controls in order to provide for a more immersive experience.

The user is generally in control of at least several aspects of these modalities, and it is therefore important for authors to be able to react to these in order to provide different styling to their applications. In order to achieve this, this specification defines a media feature that allows different CSS style rules to be applied depending on whether a given media query [[!MEDIAQ]] matches.

Design Goals and Requirements

The design goals and requirements for this specification are documented in the Requirements for Standardizing Widgets [[WIDGETS-REQS]].

This document addresses one requirement from "User Experience":

  1. Display Modes

This specification defines conformance criteria that apply to a single product: user agents that implement the view modes that it contains.

Security considerations

An application could be designed to trick users into performing actions they do not wish to or to capture data that they did not intend to provide. Examples of situations in which the user could be tricked include, but are not limited to:

Implementers are encouraged to take these issues into consideration and to provide limitations to what a Web application may do in order to ensure that the user is exposed to minimal risk.

Definitions

View mode
The view mode is the manner in which a Web application is presented to a user that corresponds to the metaphors and functionalities in use on a given platform. This specification defines a number of view modes that a user agent is expected to match to comparable platform-specific situations.
Chrome
The chrome comprises the visible parts of the user agent that do not depend on the content (e.g. window decorations, tool bars, title bars, menus).
Immersive
A user interface is said to be immersive when its controls and components are created to match the specific style of the application instead of using the chrome and widgets of the platform.
Media feature
The term media feature is defined in [[!MEDIAQ]].
Screen area
The area of the screen that is generally available for applications, excluding parts that the system generally keeps to itself (e.g. a bar at the top for menus, time, or context, or at the bottom with a list of running applications).
Web application
A Web application is an application built and shipped using Web technology that may be running inside of a browser, as a widget, or in another type of container designed for this purpose.
Widgets
The term widget is defined in [[WIDGETS]].
Viewport
The term viewport is defined in [[CSS21]].

The 'view-mode' media feature

The view-mode media feature describes the mode in which the Web application is being shown as a running application on the platform.

Value:
windowed | floating | fullscreen | maximized | minimized
Applies to:
visual media types
Accepts min/max prefixes:
No

A user agent SHOULD make a best-effort attempt at matching the great variety of platform conventions in which it may be running a Web application to the list of view modes defined in this specification so that the view-mode media feature may describe common situations in a manner that is useful to authors. Each view mode is defined to be exclusive of the others.

View modes

The view-mode media feature accepts the following enumerated values:

windowed
Describes a Web application running in a windowed manner, which is to say with chrome and without occupying the entire screen area.
floating
Describes a Web application providing a more immersive interface, running in a windowed manner but without chrome, and with the viewport's initial background being transparent such that other system items (other applications, the display's background...) can be seen through parts of the viewport that are not being painted to.
fullscreen
Describes a Web application that is occupying the entirety of the display, including the parts normally excluded from the screen area (e.g. a fullscreen video) and without any chrome.
maximized
Describes a Web application that is occupying the entirety of the screen area but with chrome.
minimized
Describes a Web application docked or otherwise minimized, but with a dynamic graphical representation being available nevertheless (i.e. the application isn't entirely hidden, or maybe its icon is still shown and it has control over what it contains). This may correspond for instance to a thumbnail of the application's content being shown.

Examples

A simple example in CSS: 

@media handheld and (view-mode: floating) and (orientation: landscape) {
  // ...
}
@media tv and (view-mode: windowed) {
  // ...
}
@media handheld and (view-mode: fullscreen) {
  // ...
}

Acknowledgements

Daniel Herzog, Arve Bersvendsen, Arthur Barstow, Jochen Cichon, Sebastian Markbåge, Cameron McCormack, David Rogers, Richard Tibbett, Scott Wilson, Boris Zbarsky, Kenneth Christiansen, Daniel Glazman, Tab Atkins Jr, Josh Soresh, Marcin Hanclik, the CSS WG.