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Re: Action-902 Units of measure for 1.4.3

From: Jeanne Spellman <jeanne@w3.org>
Date: Mon, 07 Oct 2013 18:06:58 -0400
Message-ID: <52533082.2010009@w3.org>
To: Jim Allan <jimallan@tsbvi.edu>, UAWG <w3c-wai-ua@w3.org>
I agree that 0 is confusing with O depending on the font, but 0 is a 
very different width from M and that will put us in conflict with CSS 
which uses 0.  I am pretty sure that other technologies also use 0 as 
the defining character for width.  I suggest we put "0 (zero)" in the 
proposal.

On 10/7/2013 5:38 PM, Jim Allan wrote:
> References (for 1.4.3 in IER)
> http://www.w3.org/TR/CSS2/visudet.html#leading
>   http://www.w3.org/wiki/CSS/Properties/line-height
> http://www.w3.org/TR/CSS2/text.html#spacing-props
> http://www.w3.org/TR/CSS2/fonts.html#font-styling
> http://www.w3.org/TR/CSS2/fonts.html#font-boldness
> http://www.w3.org/TR/CSS2/text.html#lining-striking-props
> http://www.w3.org/TR/CSS2/text.html#alignment-prop
>
> Table of all CSS properties http://www.w3.org/TR/CSS2/propidx.html
>
> adding a Note to 1.4.3
> Note: The unit of measure will vary by the technology. For the purposes of
> UAAG 2.0, the font height should be considered to be equal to 1. The font
> width of the character M (or other character commonly accepted in the
> typography for that language) should be considered to be equal to 1.
>
> <jim in the note, 0 was confusing (as it is a zero, not an O), I changed to
> an M
> I added the word and character spacing, justification, bold, etc references>
>
> any other comments, additions, smithing???
>
>
> On Fri, Oct 4, 2013 at 2:22 PM, Jeanne Spellman <jeanne@w3.org> wrote:
>
>> As per my action item, I followed up on the text customization proposal to
>> see what unit of measure was intended for 1.4.3 on line height (leading),
>> character and word spacing.
>>
>> Results:  No unit of measure was specified deliberately, because no unit
>> of measure is proper usage. Examples were given of CSS and Word, which both
>> accept a number without a unit of measure.
>>
>> I personally disagree with this. While my typography experience is quite
>> dated, I have always used a unit of measure in typography.  While this (no
>> unit of measure) is allowed in CSS, the examples make clear that CSS2
>> considers no unit of measure as em. The calculation of line-height in CSS
>> 2.1 is quite complex, and I think we should avoid it ourselves, and refer
>> people to appropriate documentation.
>> http://www.w3.org/TR/CSS2/**visudet.html#leading<http://www.w3.org/TR/CSS2/visudet.html#leading>
>>
>> References (which I think we should include in the References section of
>> 1.4.3 IER)
>> http://www.w3.org/TR/CSS2/**visudet.html#leading<http://www.w3.org/TR/CSS2/visudet.html#leading>
>>   http://www.w3.org/wiki/CSS/**Properties/line-height<http://www.w3.org/wiki/CSS/Properties/line-height>(some useful language here, IMO.)
>> Table of all CSS properties http://www.w3.org/TR/CSS2/**propidx.html<http://www.w3.org/TR/CSS2/propidx.html>
>> The spec for CSS3 is not complete and should not be referenced.  The
>> latest working draft (for your info) is http://www.w3.org/TR/css3-**
>> text/#word-spacing <http://www.w3.org/TR/css3-text/#word-spacing>
>>
>> I propose adding a Note to 1.4.3
>> Note: The unit of measure will vary by the technology. For the purposes of
>> UAAG 2.0, the font height should be considered to be equal to 1. The font
>> width of the character 0 (or other character commonly accepted in the
>> typography for that language) should be considered to be equal to 1.
>>
>>
>
>

-- 
_______________________________
Jeanne Spellman
W3C Web Accessibility Initiative
jeanne@w3.org
Received on Monday, 7 October 2013 22:07:06 UTC

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