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Re: Your comments on WCAG 2.0 Public Working Draft of May, 2007

From: Liam McGee <liam@communis.co.uk>
Date: Tue, 06 Nov 2007 14:46:51 +0000
Message-ID: <47307E5B.4040505@communis.co.uk>
To: public-comments-WCAG20@w3.org
CC: EOWG <w3c-wai-eo@w3.org>

Dear Loretta, thanks for your response to my comment.

The change does not deal with the problem raised in my original comment, 
thus I continue to be dissatisfied with this SC. I have modified my 
comments in the light of the revision you have made and re-presented 
them below. Hope they make sense... please email if clarification is 
required.

The new SC 1.4.7 referred to in your response (appended at the end of 
this email); 1.4.8 in the Nov 2007 editor's draft; requires that for the 
visual presentation of blocks of text, a mechanism available to achieve 
the following:

  "text is resized without assistive technology up to 200
  percent in a way that does not require the user to scroll horizontally
  to read a line of text "

Problem 1:
----------
Horizontal scrolling is not an accessibility issue (or, at least, I have 
no evidence that this is the case from experience with users with 
disabilities) - horizontal scrolling does not prevent a user from 
accessing information any more than vertical scrolling does. I am well 
used to scrolling all over the viewport when using screen magnification 
software, for example. This *is* a usability issue, but it does not 
prevent access to information.

More critically, the need for horizontal scrolling depends on the 
pixel-width of the viewport, and this is *impossible for the designer to 
control*. A moderately long word (or a URL) on a PDA will easily fail 
this - and some languages have a lot of long words.


Proposed Change:
----------------
Suggested change: replace "in a way that does not require the user
to scroll horizontally" with "while remaining readable to the user"


Problem 2:
----------
"line spacing is at least space-and-a-half within paragraphs,
and paragraph spacing is larger than line spacing [LC- 569]"

Query:
------
I am interested in the research basis for this requirement.

Leading/line height/line spacing is important to legibility but optimal 
leading is proportional to line length, and excessive leading has been 
shown to *diminish* legibility (Burt C. (1955): A Psychological Study of 
Typography; Cambridge University Press, Cambridge). Rehe's research 
suggested optimal leading ranges of 1 to 4 points, with heavier 
typefaces requiring more leading (Rehe RF (1974). Typography: how to 
make it most legible. Indiana: Design Research International).
Many reviews of the area simply conclude that evidence is sketchy at 
best, and that more robust research (especially into on-screen 
legibility) is required.

If we consider Rehe's argument that increasing beyond 1.4 reduces 
legibility, then 1.5 seems a funny number to pick. Of course, you may 
have some fantastic research to back up the 1.5 choice, but I'd be 
interested to know what it was.


Many thanks, and keep up the good work

Liam McGee


Loretta Guarino Reid wrote:
> ----------------------------------------------------------
> Comment 1: Preferment of liquid over elastic design for accessibility reasons
> Source: http://lists.w3.org/Archives/Public/public-comments-wcag20/2007Jul/0231.html
> (Issue ID: 2356)
> ----------------------------
> Original Comment:
> ----------------------------
> 
> Firstly, the need for horizontal scrolling depends on the pixel-width
> of the viewport. This is not under the designer's control
> 
> Secondly, this is in any case problematic as a long word (or a URL) in
> a columnar layout will easily fail this (loss of content as the layout
> breaks). This may be even worse in languages where long words are a
> common occurrence. In a layout context, it is saying "a word may not
> be more than half the width of a column".
> 
> Thirdly, horizontal scrolling is certainly a usability issue, but not
> an accessibility issue - horizontal scrolling does not prevent a user
> from accessing info (or at least, no more than vertical scrolling
> does). I would rather scroll horizontally then have headings and URLs
> become unreadable - which really is an accessibility issue. I am well
> used to scrolling all over the viewport when using screen mag
> software, for example.
> 
> Proposed Change:
> Suggested change: remove "and in a way that does not require the user
> to scroll horizontally"
> 
> ---------------------------------------------
> Response from Working Group:
> ---------------------------------------------
> 
> We have addressed this problem in a different way. We have removed SC
> 1.4.7 (Reflow). All the techniques from the success criterion are also
> sufficient techniques for SC 1.4.4 (Resize text) and are listed there.
> The other aspects of SC 1.4.7 are covered by a new success criterion
> that addresses readability of text:
> 
> "For the visual presentation of blocks of text, a mechanism is
> available to achieve the following: (Level AAA)
> 
>         * foreground and background colors can be selected by the user
>         * width is no more than 80 characters
>         * text is not aligned on both the left and the right [LC-1253]
> [LC-569 (add)]
>         * line spacing is at least space-and-a-half within paragraphs,
> and paragraph spacing is larger than line spacing [LC- 569]
>         * text is resized without assistive technology up to 200
> percent in a way that does not require the user to scroll horizontally
> to read a line of text "
Received on Tuesday, 6 November 2007 14:47:04 UTC

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