W3C home > Mailing lists > Public > www-style@w3.org > February 2012

Re: [css3-values] Physical length units

From: Matthew Wilcox <elvendil@gmail.com>
Date: Wed, 22 Feb 2012 08:45:32 +0000
Message-ID: <CAMCRKi+qQiJBkk2FnSxmnBP4Tf+SKx9QQ3X-BZDn-oy5bWrYyA@mail.gmail.com>
To: Felix Miata <mrmazda@earthlink.net>
Cc: www-style@w3.org
Well that's never going to happen. Designers size text, and I think
it's their moral responsibility to do so in fact. The browser can
re-scale what we designers feel is an appropriate default, so there is
no loss for anyone.
Consider fonts where the x-height is considerably different. I know a
few where the default '16px' browsers use is visually far too small to
be comparable with the standard fonts. It's my duty to adjust that. I
do it by editing font sizes on html, and it would be wrong of me not
to.

On 22 February 2012 02:48, Felix Miata <mrmazda@earthlink.net> wrote:
> On 2012/02/21 19:52 (GMT) Matthew Wilcox composed:
>
>
>> Felix, it sounds like you're arguing designers should never set font
>> size/line height on<html>?
>
>
> With the usual reservations on the use of the word "never", and WRT size,
> absolutely. Those needing to support old IE versions need to "set" 100% on
> html and/or body in order to avoid one of its worst and well known bugs. And
> there are situations where the designer has complete knowledge and/or
> control over the hardware and viewing environment, e.g. POS kiosks or
> classrooms. But outside a limited set of special cases, deviating from the
> browser default size at the base level (body and/or html) needs to be
> considered a major first level no-no. It should be a top priority in WCAG
> rather than missing virtually altogether.
>
> Executive summary:
> Web designers need necessarily be free to contextually size similarly to
> designing for print, but visitors' defaults normally must define the context
> - the base size, which necessarily is 1em/medium/100%, as long as respecting
> visitors is the right thing to do. Setting some other size on body or html
> is antithetical to this priority.
>
> Line-height, while not altogether unimportant, plays a rather small role in
> legibility or reading comfort when text is comfortably sized. More leading
> when lines are longish certainly can be helpful, but usually the better fix
> is to adjust the lines, not diddle with leading, and certainly not to make
> it resemble a middle-schooler's double spaced term paper. Most web font
> designers really have done a decent job setting default leading for their
> fonts when they are used in lines of reasonable length at a comfortable
> size.
>
>
> For a sighted visitor audience, legibility is job one. Period. To anyone who
> can't read text comfortably, nothing else a designer's CSS can or can't do
> to the end of maximizing legibility matters more than ensuring the user's
> preference for base text size be respected.
>
> Setting some size other than medium/1em/100% at the root level is telling
> the visitor he doesn't deserve your respect, that the designer somehow knows
> better than he or the supplier of the unpersonalized environment he's using
> that his presumptively perfect default font size isn't.
>
> The print world and the web each have their strengths and their weaknesses,
> some of which overlap, some which don't:
>
> Overlap:
> The designer gets to choose the spatial relationships, how big the figure is
> compared to the paragraph, where foo goes in relation to bar, how many words
> make an appropriate line length, whether menus go to one side or over the
> top or even to have any, how many columns, how much smaller "fine print" or
> superscripts, how much bigger main heading and subheadings, whether caption
> text or blockquotes should be oblique or monospace or a different face or
> size than paragraph text, etc.
>
> Differences:
> Print: once it's done it's done. Little to no adaptability is possible short
> of complete redesign, certainly not instantly.
>
> Web: Powerful powerful advantage in natural built-in adaptability of the
> _user_ agent to conform content to the users' environments. Those who don't
> read books, newspapers or magazines because they only come in one size are
> not so limited on the web. Web users get to personalize their personal
> computing devices, and make things bigger if that's how they like them or
> need them, or smaller if that's their preference. And even after they've
> done that personalization, the user agents will nevertheless continue, if
> unconstrained by designer styles, to adapt the content to fit the space
> actually available. The web could be a panacea if only web stylists weren't
> insistent on using CSS to make web pages look like Sears catalog pages,
> pharmaceutical ads in magazines or miniature TV commercials.
>
> Designer knows how big the paper, billboard, kiosk or jumbotron is.
> vs.
> Designer has no way to know most of the many variables that go into how big
> the visitor needs or wants things to end up:
>        actual device pixel density
>        physical viewport metrics
>        viewing distance
>        visual acuity
>        backlighting
>        ambient light
>        health or other chronic distractions
>
> Remember too that the difference between a default size change and a zoom
> level change differs rather little. The most obvious difference is temporal,
> that is, default is done in advance. The other is that it's applied
> globally. Zoom is done after the fact, a defensive measure applied when an
> offense is encountered. WRT text-only zoom, usually there's no apparent
> difference in effect of zoom application vs. default effect on layout in
> maximally compliant browsers. Saying zooming needs to be embraced without
> saying default size needs be respected is like saying it's OK to sell
> peaches by the pound but not oranges because oranges need to have their
> noxious skin removed before eating while peaches don't, an orthogonal
> distinction.
>
> --
> "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 Wednesday, 22 February 2012 08:46:01 GMT

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