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Action-630 proposal

From: Jim Allan <jimallan@tsbvi.edu>
Date: Thu, 17 May 2012 11:38:08 -0500
Message-ID: <CA+=z1W=eN2KhSWjk5vJFF19a3gdd-_OKT03_-j20T-Se-28O-g@mail.gmail.com>
To: WAI-ua <w3c-wai-ua@w3.org>
There is no current wording. The proposal below incorporates the
discussion of the thread beginning at
http://lists.w3.org/Archives/Public/w3c-wai-ua/2011OctDec/0057.html

Proposed:

1.8.z Maintain Point of Regard: By default, when the user changes
viewport or content size the point of regard remains at the same
relative location within the visible portion of the viewport.

{removed the words 'rendering size', not sure what that means. the
user can change the viewport size (change the dimensions of the
bounding window. the user can change the content size but using the
zoom feature, changing the default font size setting, or changing the
font size (at least for IE) on a site}

Intent of Success Criteria 1.8.z
It can be disorienting and confusing when a user changes the viewport
size or zooms the content and the current content shifts out of the
viewport causing different content on the same page to be displayed in
the viewport. Starting with the base assumption that regardless of
other content that may have focus, or be selected, the current point
of regard is that information that is visible to the user with the
bounds of the viewport (user agent content area).

There are at least three cases where the user agent may have to take
action to keep the point of regard in essentially the same location
within the visible portion of the viewport: (a) the viewport is
resized; (b) the zoom/scale on the content is changed; or (c) the
formatting of some or all of the content changes (e.g. font or text
size, causing content to change height and/or rewrap).

In these cases the user agent should maintain the same top-left
(top-right for RTL) corner UNLESS there is a focussed/selected content
INSIDE the pre-zoomed viewport, in which case the focused/selected
content remains in the post-zoom viewport.
Note: "Content" and "selected" are used because there may be cases
where the viewport is zooming into just part of an element (e.g. if I
select a few words of text that are part of a <p> and zoom in)

(thought of adding this as as the 2nd sentence in the intent. it
serves as an alternate example to try to get the point across. "Just
as the location in audio does not change when the user increases the
volume, the current point of regard should not change when the user
changes the size of the window or zooms the content.")

Examples of Success Criteria 1.8.z
- A user with a distraction disorder (not the best term) is trying to
read a text disclaimer (fine print - a smaller font that the default
font size) on a page. The disclaimer starts in the top left corner of
viewport. The user makes the font size bigger using the zoom feature
of the browser. The fonts and images get larger and the top left
corner of the content remains the same. The user has a known
recognized reference point from which to read the disclaimer.
- A user with low vision is trying to read a text disclaimer (fine
print a smaller font that the default font size) on a page. The
selects (highlights) the disclaimer in the viewport. The user makes
the font size bigger using the zoom feature of the browser. The fonts
and images get larger. The content shifts as it gets larger to keep
the top left portion (at least 5 characters) of the selected content
within the viewport The user has a known reference point from which to
continue reading the disclaimer.


reworded the definition...changed the order of the examples to put
graphical window first. added reference to this proper SC

point of regard
The point of regard is the position in rendered content that the user
is presumed to be viewing. The dimensions of the point of regard may
vary. For example, it may be a two-dimensional area (e.g. content
rendered through a two-dimensional graphical viewport), or a point
(e.g. a moment during an audio rendering or a cursor position in a
graphical rendering), or a range of text (e.g. focused text). The
point of regard is almost always within the viewport, but it may
exceed the spatial or temporal dimensions of the viewport (see the
definition of rendered content for more information about viewport
dimensions). The point of regard may also refer to a particular moment
in time for content that changes over time (e.g. an audio-only
presentation). User agents may determine the point of regard in a
number of ways, including based on viewport position in content,
keyboard focus, and selection. The stability of the point of regard is
addressed by 1.8.z


-- 
Jim Allan, Accessibility Coordinator & Webmaster
Texas School for the Blind and Visually Impaired
1100 W. 45th St., Austin, Texas 78756
voice 512.206.9315    fax: 512.206.9264  http://www.tsbvi.edu/
"We shape our tools and thereafter our tools shape us." McLuhan, 1964
Received on Thursday, 17 May 2012 16:38:41 GMT

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