Re: [css-values] The length unit 'Q' (quarter of millimeter)

On 2013-11-18 12:39 (GMT-0800) Tab Atkins Jr. composed:

> On Mon, Nov 18, 2013 at 12:23 PM, Felix Miata <mrmazda@earthlink.net> wrote:

>> The pt unit no longer exists except in old browsers, Konqueror when
>> configured to use the KHTML engine, or any other browser that may exist that
>> uses the KHTML engine.

> Yes it does.

Pt means point, a centuries old universally familiar *physical* measuring 
unit that web spec authors want morphed into a logical unit of variable 
physical size in same manner as computer developers tried to usurp prefixes 
for decimal multiples for use with binary numbers[1]. It caused, causes and 
will continue to cause unnecessary confusion as long as the hijacking 
continues in web specs and design practice.

[1] http://physics.nist.gov/cuu/Units/binary.html 
http://en.wikipedia.org/wiki/Binary_prefix

>> Pt for quite some time has been a synonym for px in
>> Blink, Gecko, Trident and WebKit.

> No it's not.  1pt = 4/3px.  In easier terms, 12pt == 16px.

A pt is a physical unit, while a px is a unit whose size varies widely 
according to screen density. You can claim a pt is a logical unit all you 
want, but that doesn't make it so except in a limited context needlessly 
divergent from all historical contexts and non-web current contexts.

> Try this in any browser you want:

> <!DOCTYPE html>
[deleted]

Better to try a linked real web page that actually demonstrates the damage 
that results from morphing a physical unit into a logical unit.

http://fm.no-ip.com/Auth/Font/fonts-ptdemo.html (source used in screenshot)
http://fm.no-ip.com/SS/W3/dpi-samp-cssvalues-Qunit1.png (contextual 
screenshot of several browsers rendering the above, and their environment. 
Proper viewing requires use of a viewer that can adjust image size so that 
the 25.4mm blocks in fact measure 25.4mm with a ruler.)

You may note the date on the page isn't very old. It was originally created 
before IE7 existed, and needed subsequently to be modified to use mozmm units 
so that users of Gecko browsers could continue to enjoy competent rendering, 
same as users of old browsers and KHTML Konqueror users.

Note how poorly the newest browser there used, the one entirely unable to 
size in physical units (Chrome), fits within its environment. Everything 
about it is undersized compared to everything else. That's because within its 
environment sizing is specified in physical pt units of uniform nominal 1/72" 
dimension, *accurate* in every case where the environment is accurately 
configured to match physical display characteristics.

> Please do not attempt to hijack this thread with discussion of physical units.

$SUBJECT is about another long existing *physical* length unit. I don't see 
any point in adding more logical units to any web standards, particularly any 
named exactly the same as any physical length unit. If a Q unit is to be 
added, it should have the exact same meaning as it currently does among 
typesetters, a physical dimension, not another (il)logical one inanely 
designed to make incompetently designed web pages seem to be competently 
designed, and make learning competent web design even more difficult than it 
already has become. Logical CSS units desperately need names that clearly 
distinguish them from physical units, and the already usurped physical names 
restored to use as genuine physical units.
-- 
"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 Tuesday, 19 November 2013 12:08:15 UTC