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Re: User Agents Do Not Implement Absolute Length Units, Places Responsive Design in Jeopardy

From: Felix Miata <mrmazda@earthlink.net>
Date: Fri, 21 Oct 2011 17:54:02 -0400
Message-ID: <4EA1E9FA.3010702@earthlink.net>
To: www-style@w3.org
On 2011/10/21 16:10 (GMT-0400) Brian Blakely composed:

> in most cases authors will want
> to use linear physical data, to then arrive at their own design conclusions
> about legibility and appropriate use.

This is the root of the problem originally created by CSS1, that authors were 
given the px unit to size however and whatever they please, as though they 
were designing for print media, decades before a material distinction between 
device px and CSS was offered by user agents, or _at_all_. Even assuming only 
CSS px exist, which is still way off in the distant future, if ever, there's 
still no predictable relationship between sizes suitable for any particular 
site visitor and sizes deemed suitable by a site designer. IOW, 
author/designers are _never_ in position to choose the optimal base sizing 
unit for anywhere but the displays they're viewing.

What standards should be pushing for is for authors for the vast majority of 
pages to choose only proportions among object sizes without regard to 
absolute size, and for the users of the user agents to choose the appropriate 
base sizes for each's own environment. We already have appropriate base 
sizes, although support for the best of them will remain short of universal 
for some time to come. I'm referring of course to the original em unit, and 
its putatively superior replacement, the rem unit.

The dominant text size on virtually every page should be 1rem. Virtually 
everything that needs to be some other size should be sized as some multiple 
or fraction of that user-defined base size. Authors get to choose 
proportions. Users get to define the actual sizes that those proportions 
produce as displayed results, at least for media types other than print.

De minimus use of the px unit could be retained, as for narrow margins, 
paddings and borders, by limiting its _valid_ use to single digits or bitmap 
image sizing, and _never_ allowing its use for text. Otherwise, until 
widespread use of screen densities of 300 DPI or more has been reached, legal 
use of the px unit in standards mode should be eliminated. Or maybe a third 
browser rendering mode (called "userrespect" maybe?) could be introduced, to 
preserve what little usability ever possessed by the vast mass of naively 
designed pages that caused the death of absolute units in mainstream browsers.

Were this to take place, user agents would actually become agents of users, 
rather than tools used by authors to make the web unnecessarily difficult for 
ordinary and mildly challenged users to actually use. The built-in 
adaptability of user agents encompasses the inherent advantage of the web 
over print, which most unfortunately remains little more than a potential 
advantage ever since CSS1 and its px unit were unleashed.

A consequence were this to happen would be that genuine traditional physical 
units could be preserved for special circumstances design, like when a page 
serves little or no purpose in the absence of reasonably or totally accurate 
absolute lengths, and for print media.
"The wise are known for their understanding, and pleasant
words are persuasive." Proverbs 16:21 (New Living Translation)

  Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***  http://fm.no-ip.com/
Received on Friday, 21 October 2011 21:55:10 UTC

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