Difference between revisions of "User Context/Requirements"

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(Preliminary version submitted by Jason White)
 
m (Linebreak cleanup)
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== Mechanism ==
 
== Mechanism ==
A user agent creates and maintains a profile of the user's needs and
+
 
preferences. This profile can be interrogated by Web content using a
+
A user agent creates and maintains a profile of the user's needs and preferences. This profile can be interrogated by Web content using a specified API, subject to constraints intended to preserve the user's privacy (see requirements below).
specified API, subject to constraints intended to preserve the user's
+
privacy (see requirements below).
+
  
 
The needs and preferences can be represented as key/value pairs.
 
The needs and preferences can be represented as key/value pairs.
  
The user agent populates the profile by obtaining information from
+
The user agent populates the profile by obtaining information from one or more sources. No restriction is placed on the sources that may be used, but depending on the implementation these may include:  
one or more sources. No restriction is placed on the sources that may
+
* The configuration of the user agent.  
be used, but depending on the implementation these may include:
+
* The configuration of the operating system.  
* The configuration of the user agent.
+
* Assistive technologies (via available API calls).  
* The configuration of the operating system.
+
* The location and physical environment of the hardware, via sensors, positioning technology and other mechanisms.  
* Assistive technologies (via available API calls).
+
* Need/preference profiles retrieved from the Web in any format that the user agent supports (GPII, for example).  
* The location and physical environment of the hardware, via sensors,
+
positioning technology and other mechanisms.
+
* Need/preference profiles retrieved from the Web in any format that
+
the user agent supports (GPII, for example).
+
 
* Inferences drawn from any of the above.
 
* Inferences drawn from any of the above.
  
[Editorial note: should there be a hierarchy of sources, e.g., the
+
[Editorial note: should there be a hierarchy of sources, e.g., the user's explicit preferences override information gathered from the environment, or should this be left completely unspecified? It is undecided whether needs/preferences not readily available from the first two items above (and possibly also the assistive technology item) should be excluded from the first version of the specification.]
user's explicit preferences override information gathered from the
+
environment, or should this be left completely unspecified? It is
+
undecided whether needs/preferences not readily available from the
+
first two items above (and possibly also the assistive technology
+
item) should be excluded from the first version of the specification.]
+
  
The user agent updates the profile in response to changes in any of
+
The user agent updates the profile in response to changes in any of the information sources that it supports. An event is dispatched to notify Web content of such updates.
the information sources that it supports. An event is dispatched to
+
notify Web content of such updates.
+
  
 
== Access Control ==
 
== Access Control ==
There is a basic set of keys in the need/preference profile that may
 
be queried by all Web content using the API. The remaining keys may
 
not be queried unless the user grants permission to do so. The user
 
agent provides in its user interface a mechanism whereby the user can
 
grant or withhold permission. (This is a user agent conformance
 
requirement.) Once granted or denied, the permission applies to the
 
browsing context as defined in HTML 5.
 
  
Grants and denials of permission may be maintained in persistent
+
There is a basic set of keys in the need/preference profile that may be queried by all Web content using the API. The remaining keys may not be queried unless the user grants permission to do so. The user agent provides in its user interface a mechanism whereby the user can grant or withhold permission. (This is a user agent conformance requirement.) Once granted or denied, the permission applies to the browsing context as defined in HTML 5.
storage by the user agent and retrieved in subsequent interactions.
+
  
[Editorial note: It is undecided at what level of granularity the
+
Grants and denials of permission may be maintained in persistent storage by the user agent and retrieved in subsequent interactions.
permission is granted or denied, e.g., for individual keys, for
+
 
defined categories of keys or for all keys.]
+
[Editorial note: It is undecided at what level of granularity the permission is granted or denied, e.g., for individual keys, for defined categories of keys or for all keys.]
  
 
== Extensions ==
 
== Extensions ==
The API allows values to be retrieved for keys not defined in the
 
specification. Such implementation-defined keys are distinguished (for
 
example, by a namespace mechanism) from keys defined in the
 
specification.
 
  
[Editorial note: the extension mechanism is distinct from the question
+
The API allows values to be retrieved for keys not defined in the specification. Such implementation-defined keys are distinguished (for example, by a namespace mechanism) from keys defined in the specification.
of whether the specification itself should define a core of common
+
 
keys and one or more modules that not every implementation is required
+
[Editorial note: the extension mechanism is distinct from the question of whether the specification itself should define a core of common keys and one or more modules that not every implementation is required to support.]
to support.]
+
  
 
== Specifiable Components of a User's Profile ==
 
== Specifiable Components of a User's Profile ==
This section identifies contextual items (needs, preferences
+
 
etc.), which have been proposed for inclusion in the specification.
+
This section identifies contextual items (needs, preferences etc.), which have been proposed for inclusion in the specification.
  
 
[Editorial note: use cases need to be added to the subsections below.]
 
[Editorial note: use cases need to be added to the subsections below.]
  
 
=== General ===
 
=== General ===
* The user's current point-of-regard. [Note: this isn't really a need
+
 
or preference but it is part of the "context".]
+
* The user's current point-of-regard. [Note: this isn't really a need or preference but it is part of the "context".]  
* Whether the user's keyboard settings allow all interactive elements
+
* Whether the user's keyboard settings allow all interactive elements to receive focus.  
to receive focus.
+
* Whether the display colors are currently inverted by the operating system or user agent.
* Whether the display colors are currently inverted by the operating
+
system or user agent.
+
  
 
=== Type Settings ===
 
=== Type Settings ===
* The user's default font size.
+
 
* The user's minimum font size limit.
+
* The user's default font size.  
* The user's preferred letter spacing.
+
* The user's minimum font size limit.  
 +
* The user's preferred letter spacing.  
 
* The user's preferred line height.
 
* The user's preferred line height.
  
 
=== Display Settings ===
 
=== Display Settings ===
* The user's required display contrast.
+
 
* Whether the user's display requires grayscale or supports full
+
* The user's required display contrast.  
color.
+
* Whether the user's display requires grayscale or supports full color.  
* Whether a lightly colored foreground text on a dark background, or
+
* Whether a lightly colored foreground text on a dark background, or dark text on a light background, is preferred.
dark text on a light background, is preferred.
+
  
 
=== Media Alternative Settings ===
 
=== Media Alternative Settings ===
* Whether captions/subtitles should be presented.
+
 
* Which languages are preferred for captions/subtitles (giving an order of preference).
+
* Whether captions/subtitles should be presented.  
* Whether captions/subtitles for the deaf and hard of hearing, or
+
* Which languages are preferred for captions/subtitles (giving an order of preference).  
spoken-language subtitles only, should be provided.
+
* Whether captions/subtitles for the deaf and hard of hearing, or spoken-language subtitles only, should be provided.  
* Whether closed captions should be used. [Editorial note: this item
+
* Whether closed captions should be used. [Editorial note: this item may be redundant.]  
may be redundant.]
+
* Whether a text transcript of audio or video is preferred.  
* Whether a text transcript of audio or video is preferred.
+
* Whether audio or video media  should be presented simultaneously with the transcript (implies that a transcript is required).  
* Whether audio or video media  should be presented simultaneously with the transcript (implies that a transcript is required).
+
* Whether a video of sign language (i.e., a sign language translation) is desired.  
* Whether a video of sign language (i.e., a sign language translation)
+
* Which sign languages are preferred (in order of preference). * Whether an audio description of video is desired.  
is desired.
+
* Whether visual resources should be replaced or augmented by textual alternatives (e.g., images by descriptions).  
* Which sign languages are preferred (in order of preference).
+
* Whether visual resources should be replaced or augmented by long descriptions.  
* Whether an audio description of video is desired.
+
* Whether replacement or augmentation is preferred, i.e., simultaneous presentation of the visual content and the description, or substitution of the description for the visual material.  
* Whether visual resources should be replaced or augmented by textual alternatives
+
* Whether auditory resources should be replaced by visual alternatives (e.g., sounds by visual notifications).  
(e.g., images by descriptions).
+
* Whether text, visual content, or both should be replaced by spoken content (e.g., recorded or synthetic speech delivered as audio).  
* Whether visual resources should be replaced or augmented by long descriptions.
+
* Whether synthetic speech or human speech is preferred.  
* Whether replacement or augmentation is preferred, i.e., simultaneous presentation of the visual content and the description, or substitution of the description for the visual material.
+
* Whether speech should always commence at the beginning of a recording or from the point at which it was last interrupted.  
* Whether auditory resources should be replaced by visual alternatives
+
* Whether spoken alternatives should be substituted only for directive content [Editorial note: definition required.]  
(e.g., sounds by visual notifications).
+
* Whether tactile content should be augmented or replaced by textual alternatives, and whether augmentation or replacement is preferred.  
* Whether text, visual content, or both should be replaced by spoken
+
* Whether tactile content should be augmented or replaced by visual content, and whether to augment or replace.  
content (e.g., recorded or synthetic speech delivered as audio).
+
* Whether tactile content should be augmented or replaced by auditory content, and whether to augment or replace.  
* Whether synthetic speech or human speech is preferred.
+
* Whether auditory content should be replaced or augmented by tactile content, and whether to augment or replace.  
* Whether speech should always commence at the beginning of a
+
* Whether visual content should be augmented or replaced by tactile content, and whether to augment or replace.  
recording or from the point at which it was last interrupted.
+
* Whether visual content that flashes more than three times per second should be suppressed.  
* Whether spoken alternatives should be substituted only for directive
+
* Whether content that simulates motion should be suppressed.  
content [Editorial note: definition required.]
+
* Whether tactile content should be augmented or replaced by textual alternatives, and whether augmentation or replacement is preferred.
+
* Whether tactile content should be augmented or replaced by visual content, and whether to augment or replace.
+
* Whether tactile content should be augmented or replaced by auditory content, and whether to augment or replace.
+
* Whether auditory content should be replaced or augmented by tactile content, and whether to augment or replace.
+
* Whether visual content should be augmented or replaced by tactile content, and whether to augment or replace.
+
* Whether visual content that flashes more than three times per second should be suppressed.
+
* Whether content that simulates motion should be suppressed.
+
 
* Whether sounds that can cause seizures should be suppressed.
 
* Whether sounds that can cause seizures should be suppressed.
  
 
=== Presentational Modality Settings ===
 
=== Presentational Modality Settings ===
* Whether textual content should be augmented or replaced by visual content, and whether augmentation or replacement is preferred.
+
 
* Whether textual content should be augmented or replaced by audio content, and whether to augment or replace.
+
* Whether textual content should be augmented or replaced by visual content, and whether augmentation or replacement is preferred.  
 +
* Whether textual content should be augmented or replaced by audio content, and whether to augment or replace.  
 
* Whether textual content should be augmented or replaced by tactile content, and whether to augment or replace.
 
* Whether textual content should be augmented or replaced by tactile content, and whether to augment or replace.
  
 
=== Assistive Technology Settings ===
 
=== Assistive Technology Settings ===
* Whehter a screen reader is active.
 
* Whether a screen magnifier is active.
 
* The name of each active assistive technology.
 
* The version of each active assistive technology.
 
* Screen magnifier properties, including zoom level, zoom window size and center point.
 
* Whether content is required to be compatible with screen readers and
 
other assistive technologies.
 
* With which accessibility APIs or versions thereof the content is
 
required to be compatible (e.g., Web or operating system-specific APIs).
 
  
[Editorial note: the desirability of some of the requirements in this
+
* Whehter a screen reader is active.
section has been questioned. It has not been decided whether to
+
* Whether a screen magnifier is active.
disclose which assistive technology a user is running to Web
+
* The name of each active assistive technology.
applications, and further analysis of the issue is necessary in order to reach consensus.]
+
* The version of each active assistive technology.
 +
* Screen magnifier properties, including zoom level, zoom window size and center point.
 +
* Whether content is required to be compatible with screen readers and other assistive technologies.
 +
* With which accessibility APIs or versions thereof the content is required to be compatible (e.g., Web or operating system-specific APIs).
 +
 
 +
[Editorial note: the desirability of some of the requirements in this section has been questioned. It has not been decided whether to disclose which assistive technology a user is running to Web applications, and further analysis of the issue is necessary in order to reach consensus.]
  
 
=== User Interface Organization and Complexity Settings ===
 
=== User Interface Organization and Complexity Settings ===
* Whether a simple user interface is required.
+
 
* Whether the number of user interface elements presented simultaneously should be limited.
+
* Whether a simple user interface is required.  
* Whether the text included in the content should use simple
+
* Whether the number of user interface elements presented simultaneously should be limited.  
language or be suitable for a given reading level.
+
* Whether the text included in the content should use simple language or be suitable for a given reading level.  
* Whether the options and functionality available to the user should
+
* Whether the options and functionality available to the user should be restricted to those essential to the primary purpose of the interaction.  
be restricted to those essential to the primary purpose of the interaction.
+
* Whether symbols (in symbol systems used by persons with cognitive disabilities) should be substituted for text.
* Whether symbols (in symbol systems used by persons with cognitive
+
disabilities) should be substituted for text.
+

Revision as of 13:52, 27 June 2013

Mechanism

A user agent creates and maintains a profile of the user's needs and preferences. This profile can be interrogated by Web content using a specified API, subject to constraints intended to preserve the user's privacy (see requirements below).

The needs and preferences can be represented as key/value pairs.

The user agent populates the profile by obtaining information from one or more sources. No restriction is placed on the sources that may be used, but depending on the implementation these may include:

  • The configuration of the user agent.
  • The configuration of the operating system.
  • Assistive technologies (via available API calls).
  • The location and physical environment of the hardware, via sensors, positioning technology and other mechanisms.
  • Need/preference profiles retrieved from the Web in any format that the user agent supports (GPII, for example).
  • Inferences drawn from any of the above.

[Editorial note: should there be a hierarchy of sources, e.g., the user's explicit preferences override information gathered from the environment, or should this be left completely unspecified? It is undecided whether needs/preferences not readily available from the first two items above (and possibly also the assistive technology item) should be excluded from the first version of the specification.]

The user agent updates the profile in response to changes in any of the information sources that it supports. An event is dispatched to notify Web content of such updates.

Access Control

There is a basic set of keys in the need/preference profile that may be queried by all Web content using the API. The remaining keys may not be queried unless the user grants permission to do so. The user agent provides in its user interface a mechanism whereby the user can grant or withhold permission. (This is a user agent conformance requirement.) Once granted or denied, the permission applies to the browsing context as defined in HTML 5.

Grants and denials of permission may be maintained in persistent storage by the user agent and retrieved in subsequent interactions.

[Editorial note: It is undecided at what level of granularity the permission is granted or denied, e.g., for individual keys, for defined categories of keys or for all keys.]

Extensions

The API allows values to be retrieved for keys not defined in the specification. Such implementation-defined keys are distinguished (for example, by a namespace mechanism) from keys defined in the specification.

[Editorial note: the extension mechanism is distinct from the question of whether the specification itself should define a core of common keys and one or more modules that not every implementation is required to support.]

Specifiable Components of a User's Profile

This section identifies contextual items (needs, preferences etc.), which have been proposed for inclusion in the specification.

[Editorial note: use cases need to be added to the subsections below.]

General

  • The user's current point-of-regard. [Note: this isn't really a need or preference but it is part of the "context".]
  • Whether the user's keyboard settings allow all interactive elements to receive focus.
  • Whether the display colors are currently inverted by the operating system or user agent.

Type Settings

  • The user's default font size.
  • The user's minimum font size limit.
  • The user's preferred letter spacing.
  • The user's preferred line height.

Display Settings

  • The user's required display contrast.
  • Whether the user's display requires grayscale or supports full color.
  • Whether a lightly colored foreground text on a dark background, or dark text on a light background, is preferred.

Media Alternative Settings

  • Whether captions/subtitles should be presented.
  • Which languages are preferred for captions/subtitles (giving an order of preference).
  • Whether captions/subtitles for the deaf and hard of hearing, or spoken-language subtitles only, should be provided.
  • Whether closed captions should be used. [Editorial note: this item may be redundant.]
  • Whether a text transcript of audio or video is preferred.
  • Whether audio or video media should be presented simultaneously with the transcript (implies that a transcript is required).
  • Whether a video of sign language (i.e., a sign language translation) is desired.
  • Which sign languages are preferred (in order of preference). * Whether an audio description of video is desired.
  • Whether visual resources should be replaced or augmented by textual alternatives (e.g., images by descriptions).
  • Whether visual resources should be replaced or augmented by long descriptions.
  • Whether replacement or augmentation is preferred, i.e., simultaneous presentation of the visual content and the description, or substitution of the description for the visual material.
  • Whether auditory resources should be replaced by visual alternatives (e.g., sounds by visual notifications).
  • Whether text, visual content, or both should be replaced by spoken content (e.g., recorded or synthetic speech delivered as audio).
  • Whether synthetic speech or human speech is preferred.
  • Whether speech should always commence at the beginning of a recording or from the point at which it was last interrupted.
  • Whether spoken alternatives should be substituted only for directive content [Editorial note: definition required.]
  • Whether tactile content should be augmented or replaced by textual alternatives, and whether augmentation or replacement is preferred.
  • Whether tactile content should be augmented or replaced by visual content, and whether to augment or replace.
  • Whether tactile content should be augmented or replaced by auditory content, and whether to augment or replace.
  • Whether auditory content should be replaced or augmented by tactile content, and whether to augment or replace.
  • Whether visual content should be augmented or replaced by tactile content, and whether to augment or replace.
  • Whether visual content that flashes more than three times per second should be suppressed.
  • Whether content that simulates motion should be suppressed.
  • Whether sounds that can cause seizures should be suppressed.

Presentational Modality Settings

  • Whether textual content should be augmented or replaced by visual content, and whether augmentation or replacement is preferred.
  • Whether textual content should be augmented or replaced by audio content, and whether to augment or replace.
  • Whether textual content should be augmented or replaced by tactile content, and whether to augment or replace.

Assistive Technology Settings

  • Whehter a screen reader is active.
  • Whether a screen magnifier is active.
  • The name of each active assistive technology.
  • The version of each active assistive technology.
  • Screen magnifier properties, including zoom level, zoom window size and center point.
  • Whether content is required to be compatible with screen readers and other assistive technologies.
  • With which accessibility APIs or versions thereof the content is required to be compatible (e.g., Web or operating system-specific APIs).

[Editorial note: the desirability of some of the requirements in this section has been questioned. It has not been decided whether to disclose which assistive technology a user is running to Web applications, and further analysis of the issue is necessary in order to reach consensus.]

User Interface Organization and Complexity Settings

  • Whether a simple user interface is required.
  • Whether the number of user interface elements presented simultaneously should be limited.
  • Whether the text included in the content should use simple language or be suitable for a given reading level.
  • Whether the options and functionality available to the user should be restricted to those essential to the primary purpose of the interaction.
  • Whether symbols (in symbol systems used by persons with cognitive disabilities) should be substituted for text.