Re: Changing definition of "Large text" to use px rather than pt

On 27/04/2016 00:05, Gregg Vanderheiden RTF wrote:
> I think we are using points was because LARGE TEXT applied only to text.
>   And all current regulations for LARGE TEXT are specified in points.

Points may be used in regulations for *print* (which as a medium has a 
guaranteed physical output size, therefore "18 pt" in print always will 
be "18 pt" - with some minor variations due to printer settings etc if 
we're talking home printing, rather than commercial printing), but this 
does not apply as readily to digital/on-screen presentation in a world 
with a myriad potential screen sizes, dpi, viewport adjustments, etc.

> Also for most authors, font sizes are specified in Pts not pixels.

And this is where I (and many others) strongly disagree, based on my 
years in the industry and the amount of head scratching that seems to be 
common across developers when they encounter the wording in this part of 
WCAG 2 as it stands. Developers in the wild most often use px or avoid 
setting any measure and instead use % or em. Use of pt (and pc, in, cm, 
mm) - with the exception of explicit print media styles - is a rarity 
for web-based content.

I don't have any giant data analysis/web crawler capability myself, but 
I'm willing to bet that if we analyse the CSS of the top 1000 sites with 
the most traffic, you won't find any significant use of font definitions 
in pt.

> But as long as there is a conversion back and forth - there is no
> substantial problem.  no?

Well that has been my argument from the start, yes. To me it's an 
editorial, rather than a substantive, change (as long as the converted 
value in px is the same - though it *may* benefit from some rounding for 
very awkward fractional pixel sizes). But the important part as well is 
that the spec needs to clarify (in an informative note, at the very 
least) that it refers to CSS units of measure, and not any form of 
physical real world rendering size which simply cannot be guaranteed by 
authors with past and current technology in a way that works 
consistently across devices/screen sizes/OSs/UAs (which note 3 seems to 
do, but perhaps not clearly).

In any case, I'll see if I can make a more tangible pull 
request/proposal that addresses both these issues.

P
-- 
Patrick H. Lauke

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Received on Tuesday, 26 April 2016 23:31:57 UTC