W3C home > Mailing lists > Public > www-svg@w3.org > November 2002

Re: svg textLength issue (and a little thing about use...)

From: Jim Ley <jim@jibbering.com>
Date: Wed, 13 Nov 2002 12:43:25 -0000
To: www-svg@w3.org
Message-ID: <aqthk0$2mn$1@main.gmane.org>


"Chris Lilley" <chris@w3.org> wrote in message
news:15663032281.20021113121936@w3.org...
>
> Hello Jim, www-svg,
>
> You said
> http://lists.w3.org/Archives/Public/www-svg/2002Aug/0028.html
>
> [two things, one about circular references that was cleared up by the
> mention from the 1.1 spec "URI references that directly or indirectly
> reference themselves are treated as invalid circular references."

Yes, this was resolved, thanks.

> > The textLength attribute on SVG's textLength causes accesibility
> > problems for users who use their own stylesheets to overide author
> > selections.
>
> This is incorrect. There are several related but distinct things here:

No, it's clearly correct, the demonstration at
http://jibbering.com/2002/8/svg-textlength.svg
shows it clearly.

> - variations in font metrics between platforms can result in slightly
> overlaping text, a problem that textLength takes care of

Certainly, one solution to our problems would be to limit textLength to
+/-20% of the viewers calculated length, that would still mean that the
text characters did not overlap each other.

> Yes. And if there was no textLength specified, they would also get a
> decrease in legibility because of overlap with other text or graphics.
>
> They should not do that, but should use zoom instead.

In discussing my original problem with a member of the WAI working group,
she made it clear that zoom everything was not an acceptable solution in
the general case (unfortunately it seems the archive isn't available), I
assume the WG took input from WAI during discussion of the issue, can it
be explained why zoom all is appropriate?

> Systems that do not do reflow cannot use the font-size property to
> make text larger for increased legibility. They need other methods
> that prevent overlap, such as zoom.

I take this means that the SVG Working Group are removing the ability for
users to use a user stylesheet to overide the sizing of text?  If a user
should not do it, why is it a requirement?

However I do not agree that users do not need to do it, also, resources
such as:
http://www.w3.org/TR/SVG-access/
state:

| This makes it easier for a user to override styles for different
| classes of elements when necessary. For instance, users with
| low vision or with color deficiencies might need to override
| style properties to read the text.

Which gives clear indication that users styling text is appropriate.

There are 3 solutions to the issue that I can see:

1. Provide a way to overide textLength in CSS.
2. Remove the ability to have a user stylesheet set the size of fonts,
and include a zoom: css attribute, to replace the functionality.  (or
make it a conformance requirement to make the same available via menus, I
prefer the css approach as a more unified one.)
3. Limit text lengths power to be +/-20% of the viewers calculated length
(20% is a guess whatever is appropriate)

Marking the issue as "incorrect" is not an appropriate response.

Jim.
Received on Wednesday, 13 November 2002 07:48:41 GMT

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