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Re: Test needs specification of window size and criteria for compliance

From: Loretta Guarino Reid <lorettaguarino@google.com>
Date: Wed, 23 Mar 2011 16:12:26 -0700
Message-ID: <AANLkTika7=cCo5c6KSPmYpQAuDxOdmcRwAQWHaM9qpT2@mail.gmail.com>
To: fischer@dias.de
Cc: public-comments-wcag20@w3.org
On Mon, Jan 17, 2011 at 11:51 PM, <noreply@w3.org> wrote:

> Name: Detlev Fischer
> Email: fischer@dias.de
> Affiliation: DIAS GmbH
> Document: TD
> Item Number: G178
> Part of Item: Tests
> Comment Type: technical
> Summary of Issue: Test needs specification of window size and criteria for
> compliance
> Comment (Including rationale for any proposed change):
> The test as it stands is not particularly useful as it does not specify the
> viewport size, which will have an effect on scalability and occurrence of
> clipped text and text overlapping. It also does not specify what it means
> that "text size can be increased to 200% of the original size" - is the
> requirement that ther text is still legible / not clipped?
> Proposed Change:
> If the test is to determin whethe renlarged text is still usable / legible
> (and this is the only meaningful test), the viewport / window size to be
> used in the test must be specified (WAT and Web developer toolbar allow the
> setting of the window to 1024 x 768 px, for example), and criteria for
> compliance must be goven (e.g. "the text is still fully legible (i.e. no
> parts are clipped, boxed do not overlap).
> ================================
Response from the Working Group
Good points.

The goal is to increase the text size in the expected viewport size, that
is, the viewport size for which the content was designed. Of course, this
will depend on the designer's expectations of the devices available to the
user. However, the tester has no way to reliably determine those
expectations. Using a viewport size that is smaller than expected can
produce incorrect failures.

For testing purposes, we have selected "1024 x 768 or larger" as the
expected viewport size, so the initial step in the procedure will be

"Set the viewport size to 1024px x 768px or larger".

Note that this does not ensure legibility of the text. Depending upon the
characteristics of the device and the design of the page, text many be very
small physically. However, it gives us a basis on which to compare
functionality with the enlarged text version.

We are also adding an additional test step to clarified what must be true
after increasing the text size:

"Check that after increasing the text size to 200% of the original size,
there is no loss of content or functionality (e.g. no parts of the text are
clipped, boxes do not overlap, controls are not obscured or separated from
their labels, etc)"

Loretta Guarino Reid, WCAG WG Co-Chair
Gregg Vanderheiden, WCAG WG Co-Chair
Michael Cooper, WCAG WG Staff Contact

On behalf of the WCAG Working Group
Received on Wednesday, 23 March 2011 23:12:59 UTC

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