W3C Working Draft 7 July 2000
CMN This section is good
CMN I am a bit concerned about the generality of this - it is not
clear in the guidelines what is a required functionality and what is
subject to applicability. In addition, or perhaps as a consequence, it is
not clear what a User Agent needs to support. For example, should it be a
requirement that a User Agent can render images, or that a user can follow
links, in order for the User Agent to be accessible to people regardless of
disability? In particular, this would seem to allow a User Agent to conform
on the basis that it doesn't implement APIs, so those checkpoints are not
applicable (and similarly for other requirements).
Not every checkpoint or guideline is applicable to every user agent.
Generally, a user agent must adhere to checkpoints that ensure accessibility of
functionalities that it offers to users and it must implement required
functionalities
natively. If the user agent supports keyboard input, it must support
accessible keyboard input. If the user agent supports images, it must ensure
access to each image or an equivalent alternative specified by the author. If a
user agent supports style sheets, it must implement the accessibility features
of the style sheet language. If the user agent supports frames, it must ensure
access to frame alternatives specified by the author. In short, if a user agent
offers a functionality, it must ensure that people with disabilities have
access to that functionality or an equivalent alternative.
Not all user agents support every content type, markup language feature,
input or output device interface, etc. When a content type, feature, or device
interface is not supported, checkpoints with requirements related to it do not
apply to the user agent. Thus, if a user agent supports style sheets at all,
all checkpoints related to style sheet accessibility apply. If a user agent
does not support style sheets at all, the checkpoints do not apply.
Checkpoints for communication with other software:
-
1.1 Ensure that every functionality available through the
user interface is also available through
every input API implemented by the user agent. This
checkpoint does not require developers to reimplement the input methods
associated with the keyboard, pointing device, voice, and other input APIs. The device-independence required by this
checkpoint applies to the functionalities described by the other checkpoints in
this document (e.g., installation, documentation, user agent user interface configuration, etc.).
[Priority 1]
- 1.2
Use the standard input and output device APIs of the
operating system. Do not bypass the standard output
APIs when rendering information. [Priority 1]
- 1.3 Implement the standard keyboard API of the operating system
and ensure that every functionality available through the user interface is
available through this API. This checkpoint always applies
on systems with a standard keyboard API.
[Priority 1]
CMN See my notes on applicability for my concerns with this checkpoint
Checkpoints for content accessibility:
- 3.3
Allow the user to configure
the user agent to render animated or blinking text as motionless text. [Priority 1]
-
3.4 Allow the user to configure
the user agent to render animations or blinking images as motionless images.
[Priority 1]
CMN It should be noted that these (especially the second) are related to the checkpoints on control of video
Checkpoints for fonts and colors:
- 4.1
Allow the user to configure and
control the size of text.
If this is done by allowing the user to
configure font size, make available the range of system font sizes. [Priority 1]
Checkpoints for visual and auditory presentations:
- 4.5 Allow the user to slow the
presentation rate of audio, video, and animations. For a visual track, provide
at least one setting between 40% and 60% of the original speed. For a
pre-recorded auditory track including stand-alone audio presentations, provide
at least one setting between 75% - 80% of the original speed. For a
synchronized multimedia presentation where the visual track may be slowed from
100% to to 80% of its original speed, synchronize the visual and auditory
tracks. Below 80%, the user agent is not required to render the auditory track.
[Priority 1]
CMN So if the User Agent only includes a video slowed to 50% it is not necessary to provide an audio that is synchronised. Do we mean this (I can live with it).
Checkpoints for user interface accessibility:
- 4.16 Allow the user to configure the user agent so that after one viewport is open, no other viewports open
except as the result of explicit user request.
[Priority 2]
CMN The frames case is an interesting one. Not presenting frames can
benefit people who have difficulty in using them, and would prefer to use a noframes version,
but can also disorient people
Checkpoints for communication with other software:
- 5.1 Provide programmatic read access to
HTML and XML
content by conforming to the W3C Document Object Model (DOM) Level 2 Core and
HTML modules and exporting the interfaces they define. [Priority 1]
CMN These three checkpoints could be combined (with a special case if
necessary for DOM. Basically they require standard APIs (again) and in particular
the implementation of applicable parts of DOM (again - see "use applicable W3C technologies)
- 5.2 If the user can modify
HTML and XML content
through the user
interface, provide the same functionality programmatically by
conforming to the W3C Document Object Model (DOM) Level 2 Core and
HTML modules and exporting the interfaces they define. [Priority 1]
- 5.3 For markup languages other than
HTML and XML, provide programmatic access to content using standard
APIs (e.g., platform-independent APIs and
standard APIs for the operating system). [Priority 1]
- 5.4 Provide programmatic read and write
access to user
agent user interface controls using standard
APIs (e.g., platform-independent APIs
such as the W3C DOM, standard APIs for the operating system,
and conventions for programming languages, plug-ins, virtual machine
environments, etc.) [Priority 1]
Checkpoints for user interface accessibility:
-
7.2 For user agents that offer a browsing history mechanism, when
the user returns to a previous viewport, restore the point of
regard in the viewport.
[Priority 1]
CMN The question of having a history mechanism is already currently satisfied by
the applcability rule isn't it?