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

I agree that the user agent size is the base. That gives us REM. Users
don't care how W3 measures points or pixels. To them the concept of
perceivable font-size is defined by the dimensions of their eye. At present
both screen physical size and eye size are imponderables for software. Lack
of knowledge of screen size is not a necessity, but new hardware
requirements would be needed to correct that problem.

So, where do we stand.  What is large print. At present it is 24 / 16 = 1.5
times the REM that is usually 16px.  For now large print is 1.5xREM.

The issue of matching font size to eyeballs. Is a little more tricky.  Each
individual can learn their critical print size (CPS), the minimum highly
legible font size. The user agents will choose the average user CPS by
trial and error, because they want normal users to use their browser.
Other users will need adjustments. Clearly setting the user agent REM
should be available to users who are not average and content should respond
to a wide range of REM.

Wayne





On Tue, Apr 26, 2016 at 8:19 AM, Gregg Vanderheiden <
gregg@raisingthefloor.org> wrote:

> read the definition in the Glossary
>
> it explains it there
>
> *gregg*
>
> On Apr 26, 2016, at 2:49 AM, Patrick H. Lauke <redux@splintered.co.uk>
> wrote:
>
> On 26/04/2016 01:42, Gregg Vanderheiden wrote:
>
> Notes are NOT normative.
> You are correct
>
> but in definitions…  hmmmm..
>
> pts are defined in inches — so they are an absolute number.
>
> pixels are not — or do you have some absolute definition of px meaning a
> fraction of an inch (or mm)?
>
>
> Gregg, are you seriously suggesting that WCAG 2.0 actually meant "14pt
> bold / 18pt" *as measured on the screen with a ruler* all along? Rather
> than CSS "pt", which are by definition 1.333px (see
> http://codepen.io/patrickhlauke/pen/zqabMR) ?
>
> What did the actual testing procedure for "large text" look like then?
> "Open the page on your browser, take a ruler, and measure the size of the
> text as rendered on the screen"?
>
> If you *are* meaning that WCAG 2.0 meant actual physical sizes all along,
> then...I'm sorry, but we're back to the problem that it is impossible for
> an author to actually guarantee at what physical size anything is rendered
> on every user's screen. So the normative language for WCAG 2.0 includes a
> requirement that cannot be absolutely tested, as it depends on each
> individual user's physical screen size, resolution, zoom factor, dpi, etc.
>
> Or are there any techniques that you can point to on how an author can
> guarantee, on every device, in every browser, that something will render at
> a particular size? I'd love to see them - but suspect they do not exist, as
> this is an impossibility, since it varies so heavily across devices. Is
> WCAG 2.0 requiring a magic pony?
>
> P
> --
> Patrick H. Lauke
>
> www.splintered.co.uk | https://github.com/patrickhlauke
> http://flickr.com/photos/redux/ | http://redux.deviantart.com
> twitter: @patrick_h_lauke | skype: patrick_h_lauke
>
>
>