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

On 25/04/2016 23:24, Gregg Vanderheiden wrote:
> I’m not sure what you are referring to by "Changing definition of "Large
> text" to use px rather than pt"
>
> Definitions in WCAG are normative.    They cannot be changed without
> changing the standard.

As pt as a unit, when working with all past and current user agents with 
a screen (as opposed to print - and even there, some initial testing 
seems to show that it's the same problem) is anchored on px (and does 
NOT refer to actual physical size), all I'm proposing is to change the 
wording, but not the meaning, of the spec - translate the advice given 
in pt to the same (or as close as possible) value but expressed in px 
(as 1pt = 1.333px in all scenarios I've tested, consistently, across 
user agents).

So this is not a change, more of a rewording.

> We can provide an advisory - but we can’t change the definition.

That would perhaps also work in the interim, not sure.

> If we are defining it differently in an extension - then that too seems
> to are problematical

No, this pertains to core WCAG 2.0. In the mobile a11y TF work, the 
subject came up and was (I believe) circumvented by going directly to 
defining things like touch/activation targets in px rather than pt.

> If we are creating a  NEW version of WCAG  - the we could change it —
> but there will be some confusion.
>
> Why is it needed?

The confusion is actually present right now (and has been for as long as 
I can remember), as "pt" is not a unit that is actually used by web 
developers. The base unit for anybody working with on-screen content is 
(for the most part anyway) px, and having normative language reference a 
unit that is

a) not commonly used
b) often leads to confusion (with some developers simply treating 1pt = 
1px, which is wrong)
c) often leads to false assumptions that it somehow actually expresses 
real-world physical sizes, as would be measured on a screen with a ruler 
(which is impossible for an author to actually control, for all the 
factors listed in this discussion)

is what's actually causing confusion - even among actual list members here.


P
-- 
Patrick H. Lauke

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Received on Monday, 25 April 2016 22:51:15 UTC