WCAG 2.1 勧告候補 (Candidate Recommendation)

W3C が勧告している WCAG (Web Content Accessibility Guidelines) 2.0 の次期バージョンである WCAG 2.1 が、Candidate Recommendation (勧告候補) として2018年1月30日に開示されました

勧告候補ということで、盛り込まれる達成基準の内容は概ねこれでフィックスされ、あとは最終的な勧告 (2018年6月予定) の前に、個々の達成基準の実効性を最終確認する段階となります。この記事では取り急ぎ、WCAG 2.1 で追加される (であろう) 新達成基準を一覧としてまとめてみましたので、共有したいと思います。

先に最終ワーキングドラフトに対してコメントを提出し、それに対する W3C Accessibility Guidelines Working Group からの公式見解をいただいていたので、この勧告候補の内容自体は概ね想定どおりでしたが、これまでになかった内容として一点、達成基準 1.4.10 (Reflow) において、横方向にスクロールするコンテンツに対する規定が追加されているのが要注目かと思います (日本語の縦書きページに影響しそう、という点で)。

個人的には、タッチターゲットサイズに対する規定がレベル AAA のみになってしまったのは、少し寂しい気がしました。最終ワーキングドラフトにあったタッチターゲットサイズの規定 (レベル AA) に対して私自身コメントしたことも遠因になってしまったかもしれませんが、個人的には達成基準 2.5.3 をレベル AA にしていいのでは?という気がしないでもありません。


# 達成基準 レベル 詳細 フォーカス
1.3.4 Identify Common Purpose AA The meaning of each input field collecting information about the user can be programmatically determined when:
  • The input field has a meaning that maps to the HTML 5.2 Autofill field names; and
  • The content is implemented using technologies with support for identifying the expected meaning for form input data.
1.3.5 Identify Purpose AAA In content implemented using markup languages, the purpose of User Interface Components, icons, and regions can be programmatically determined. 認知/学習
1.4.10 Reflow AA Content can be presented without loss of information or functionality, and without requiring scrolling in two dimensions for:
  • Vertical scrolling content at a width equivalent to 320 CSS pixels;
  • Horizontal scrolling content at a height equivalent to 256 CSS pixels;
Except for parts of the content which require two-dimensional layout for usage or meaning.
1.4.11 Non-text Contrast AA The visual presentation of the following have a contrast ratio of at least 3:1 against adjacent color(s):
User Interface Components:
Visual information used to indicate states and boundaries of user interface components, except for inactive components or where the appearance of the component is determined by the user agent and not modified by the author;
Graphical Objects:
Parts of graphics required to understand the content, except when a particular presentation of graphics is essential to the information being conveyed.
1.4.12 Text Spacing AA In content implemented using markup languages that support the following text style properties, no loss of content or functionality occurs by setting all of the following and by changing no other style property:
  • Line height (line spacing) to at least 1.5 times the font size;
  • Spacing following paragraphs to at least 2 times the font size;
  • Letter spacing (tracking) to at least 0.12 times the font size;
  • Word spacing to at least 0.16 times the font size.
Exception: Human languages and scripts which do not make use of one or more of these text style properties in written text can conform using only the properties that are used.
1.4.13 Content on Hover or Focus AA Where receiving and removing pointer hover or keyboard focus triggers additional content to become visible and hidden, respectively, the following are true:
A mechanism is available to dismiss the additional content without moving pointer hover or keyboard focus, unless the additional content communicates an input error or does not obscure or replace other content;
If pointer hover can trigger the additional content, then the pointer can be moved over the additional content without the additional content disappearing;
The additional content remains visible until the hover or focus trigger is removed, the user dismisses it, or its information is no longer valid.
Exception: The visual presentation of the additional content is controlled by the user agent and is not modified by the author.
2.2.6 Timeouts AAA Users are warned of the duration of any user inactivity that could cause data loss, unless the data is preserved for more than 20 hours when the user does not take any actions. 認知/学習
2.2.7 Animation from Interactions AAA Motion animation triggered by interaction can be disabled, unless the animation is essential to the functionality or the information being conveyed. 認知/学習
2.4.11 Character Key Shortcuts A If a keyboard shortcut is implemented in content using only letter (including upper- and lower-case letters), punctuation, number, or symbol characters, then at least one of the following is true:
Turn off:
A mechanism is available to turn the shortcut off;
A mechanism is available to remap the shortcut to use one or more non-printable keyboard characters (e.g. Ctrl, Alt, etc).
Active only on focus:
The keyboard shortcut for a user interface component is only active when that component has focus.
2.4.12 Label in Name A For user interface components with labels that include text or images of text, the name contains the text presented visually. モバイル
2.5.1 Pointer Gestures A All functionality that uses multipoint or path-based gestures for operation can be operated with a single pointer without a path-based gesture, unless a multipoint or path-based gesture is essential. モバイル
2.5.2 Pointer Cancellation A For functionality that can be operated using a single pointer, at least one of the following is true:
No Down-Event:
The down-event of the pointer is not used to execute any part of the function;
Abort or Undo:
Completion of the function is on the up-event, and a mechanism is available to abort the function before completion or undo the function after completion;
Up Reversal:
The up-event reverses any outcome of the preceding down-event;
Completing the function on the down-event is essential.
2.5.3 Target Size AAA The size of the target for pointer inputs is at least 44 by 44 CSS pixels except when:
The target is available through an equivalent link or control on the same page that is at least 44 by 44 CSS pixels;
The target is in a sentence or block of text;
User Agent Control:
The size of the target is determined by the user agent and is not modified by the author.
A particular presentation of the target is essential to the information being conveyed;
2.5.4 Concurrent Input Mechanisms AAA Web content does not restrict use of input modalities available on a platform except where the restriction is essential, required to ensure the security of the content, or required to respect user settings. モバイル
2.6.1 Motion Actuation A Functionality that can be operated by device motion or user motion can also be operated by user interface components and responding to the motion can be disabled to prevent accidental actuation, except when:
Supported Interface:
The motion is used to operate functionality through an accessibility supported interface;
The motion is essential for the function and doing so would invalidate the activity.
2.6.2 Orientation AA Content does not restrict its view and operation to a single display orientation, such as portrait or landscape, unless a specific display orientation is essential. モバイル
3.2.6 Status Changes AA In content implemented using markup languages, status messages can be programmatically determined through role or properties such that they can be presented to the user by assistive technologies without receiving focus. モバイル