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Subject: Re: [office-accessibility] Revised alternative text proposal (includesaddressing Chieko's issue on hypertext hints)
Rich,
Please check the following points.
> 3.0 General wording to be added
>
> Where <draw:param> is specified it should be indicated that <svg:
> desc> is not to be used for accessibility.
>
<draw:param> does not include <svg:desc>, so we do not need to mention
about <draw:param>.
---------
Chieko Asakawa, Ph.D.
Accessibility Research
Tokyo Research Laboratory, IBM Research
E-mail: chie@jp.ibm.com
Tel: +81-46(215)4633 Fax: +81-46(274)4282
Richard
Schwerdtfeger
<schwer@us.ibm.co To
m> office-accessibility@lists.oasis-op
en.org, Chieko
2006/04/27 07:16 Asakawa/Japan/IBM@IBMJP, Hironobu
Takagi/Japan/IBM@IBMJP, Nathaniel S
Borenstein <nborenst@us.ibm.com>
cc
Subject
[office-accessibility] Revised
alternative text proposal (includes
addressing Chieko's issue on
hypertext hints)
Executive Summary of proposed changes addressing alternative text for
non-text elements and hypertext links:
An accessibility gap in the ODF specification is alternative text support
for non-text objects. Additionally, the specification does not allow for
alternative "hint" text for hypertext links. These is also a key
accessbility requirement in the W3C Web Content Accessibility Guidelines.
In order to address this, the subteam has decided we need provisioning for
alternative text and long descriptions for these types of ODF elements. We
had considered the use of draw:name and office:name (hyperlink) properties
for alternative text however feedback from some TC members indicated that
this already had "legitimate uses and its reuse was inappropriate."
Subsequently, the subteam recommends the use of the <svg:title> element,
from SVG, for alternative text and
the <svg:desc> element, from SVG for the long description. We have also
decided that ODF captions do not follow standard XML in that the captioning
<text:p> does not show a normative relationship, in the specification, to
the drawing object being captioned. As a result we will be introducing a
new draw:describedBy attribute to apply to objects being captioned.
Furthermore, we will be asking that the appropriate text be added to the
ODF specification to indicate how this accessibility meta data is mapped by
the authoring tool to platform accessibility API as well as their
accessibility applicability in the specification.
Requirements:
1.0 image-map elements
The <svg:title> element must be provided as an optional attribute to the
following:
draw:area-rectangle
draw:area-circle
draw:area-polygon
Text should be added to these elements as follows:
<svg:title> is used as a short accessible name for alternative text. When
transcoding from another document format to ODF the alt text shall be
mapped to the <svg:title> element.
<svg:desc> Is used for the long description in support of accessibility.
2.0 Drawing layer
The <svg:desc> attribute must be provided as an optional attribute to the
<draw:layer>. This attribute must apply to all ODF document formats for
which <draw:layer> is used.
Text should be added as follows:
<svg:title> is used as a short accessible name for alternative text. When
transcoding from another document format to ODF the alt text shall be
mapped to the <svg:title> element.
<svg:desc> Is used for the long description in support of accessibility.
Note: when transcoding from another document format to ODF the alt text
shall be mapped to the contents of the <svg:title> element.
3.0 General wording to be added
Where <draw:param> is specified it should be indicated that <svg:desc> is
not to be used for accessibility.
4.0 Drawing shapes (line 5926 of spec.)
The <svg:title> and <svg:desc> elements must be provided as an optional
attribute to all drawing shape elements defined below for all ODF document
formats for which these drawing shapes are used.
The following are the drawing shape elements:
<draw-rect>
<draw:line>
<draw:polyline>
<draw:polygon>
<draw:regular-polygon>
<draw:path>
<draw:circle>
<draw:ellipse>
<draw:g>
<draw:page-thumbnail>
<draw:frame>
<draw:measure>
<draw:caption>
<draw:connector>
<draw:control>
<dr3d:scene>
<draw-custom-shape>
Text should be added to these elements as follows:
<svg:title> is used as a short accessible name for alternative text. When
transcoding from another document format to ODF the alt text shall be
mapped to the <svg:title> element.
<svg:desc> Is used for the long description in support of accessibility.
User agents supporting platform accessibility APIs should follow the
following conventions for supporting the accessible name, accessible
description (accessible help on Windows systems), and describedBy
relationships:
If an <svg:title> element is provided it should map to the accessible name.
If not, the name should use the text referenced the text element identified
by the draw:describedby attribute. <svg:desc> must be used to support the
accessible description. User agents shall not manufacture names for the
<svg:title> element, such as using the drawing object followed by a
cardinal number in a string as it is used for accessibility. Name
assignments such as these provide no semantic meaning to the user.
Guidance for authors:
Authors should not assign names to objects having no semantic value. If no
name is assigned the caption text will be used in its place. <svg:title>
shall take precedence over the caption text for accessible name assignment
by the user agent.
Assignment of the long description should only be necessary when a drawing
object is significantly complex and the user needs more information to
describe it. Long descriptions would be more applicable to drawing
groupings than basic drawing shapes.
Authoring tool responsibility for presenting and prompting for the
<svg:title> and <svg:desc>:
Authoring tools should provide an option from an objects context menu to
allow the user to enter the text for either of these elements as a minimum.
More proactive authoring tools should have a facility for prompting the
author for this text. Since <svg:desc> is a long description, a text area
vs. a text field should be used to prompt the user accordingly in GUI-based
authoring tools like Workplace and Open Office.
Navigation tools, such as in Workplace and Open Office, used to list the
objects in the view should provide
the type of object followed by the contents of <svg:title>. The title must
have been entered by the author.
Fore <draw:g> elements the drawing objects who are members of the group
should visible only when the group is expanded.
(Embedded image moved to file: pic12969.gif)
5.0 Establish clear relationship between a drawing objects and its caption
by including a new optional draw:describedby attribute to the following
drawing objects:
<draw-rect>
<draw:line>
<draw:polyline>
<draw:polygon>
<draw:regular-polygon>
<draw:path>
<draw:circle>
<draw:ellipse>
<draw:g>
<draw:page-thumbnail>
<draw:measure>
<draw:caption>
<draw:connector>
<draw:control>
<dr3d:scene>
<draw-custom-shape>
<dr3d:scene>
<draw:frame>
draw:describedby shall take a value of IDREF. The value for describedBy
attribute shall be the target id assigned to the <text:p> used to represent
the corresponding caption. As text:p is an XML element it may have an ID
assigned by default. The following attribute list should be included as
optional to the above drawing objects:
<define name="common-draw-describedby-attlist" combine="interleave">
<attribute name="draw:desribedby">
<ref name="IDREF"/>
</attribute>
</define>
When a caption is assigned by a user agent, an id must be assigned to the
element containing the text used to caption a drawing element. The drawing
element being captioned must then be assigned the draw:describedby
attribute with an IDEF equivalent to the id of the captioning text thus
establishing a relationship between the captioned text and the object
captioned as needed for accessibility. Removing the caption should result
in removing the describedBy attribute of the object that was being
captioned.
If the user agent supports a platform which provides a describedby
relationship in its accessibility API, this relationship for captions
should be used to fulfill the relationship.
6.0 Establish alternative text hints for hypertext links
The <svg:title> element must be provided as an optional attribute to
<text:a>
<svg:title> is used as a short accessible description for hint text. When
transcoding from another document format to ODF the alt text shall be
mapped to the <svg:title> element. When exporting ODF documents to HTML,
the contents of title text should be mapped to alt text in HTML. As a
minimum, authoring tools should provide a mechanism to provide the
alternative text. When moving the mouse over they hypertext, the hint text
should be displayed if provided otherwise the hyperlink URI should be
provided.
Rich Schwerdtfeger
Distinguished Engineer, SWG Accessibility Architect/Strategist
Chair, IBM Accessibility Architecture Review Board
blog: http://www-106.ibm.com/developerworks/blogs/dw_blog.jspa?blog=441
"Two roads diverged in a wood, and I -
I took the one less traveled by, and that has made all the difference.",
Frost
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