[thelist] A pixel is not a pixel

Arlen.P.Walker at jci.com Arlen.P.Walker at jci.com
Mon Jun 18 13:36:14 CDT 2001


>Of course, if all browsers choose to go over to the real W3C standards in
>every particular, the de-facto standard will change. If that is the case,
>we'll all have to change our CSS tricks with it. But I won't do it before
>this actually happens.

I feel a little like Baron Xeno as I type this but....before all browsers
can choose to follow the W3C standards, some browsers must choose to do so.
And before some, one must choose. And that's where we are now, with Opera
choosing to follow the standard. What happens next is open to speculation,
but I'd be in favor of revising the standard, personally. What I've been
saying on this thread is that I think Opera got the standard right, but
that the standard was wrong to say what it does.

>>Type specified at 10px, according to the CSS standard, should render at
the
>>exact same visible height, regardless of the size and resolution of the
>>monitor.
>
>Now this I don't believe. If you're right, we basically cannot choose a
>resolution for our monitors any more, because everything will show up the
>same size anyway, so it's useless. We're forced to abide by the resolution

>the monitor vendor has chosen for us.

I think you lost me there. The idea is that 10px type (and anything else
specified in pixels, for that matter) will render as if the monitor were
set to 90ppi. You can choose any resolution for your monitor you wish; the
larger the ppi you set, the more detailed will be the edges of the letters,
etc. But the letter will remain the same height. Example: a monitor which
delivers 180ppi will have 4x (2x high and 2x wide) as many pixels in a 10px
letter as a monitor at 90ppi.

>The main problem is that this is simply too complicated for most people
>(including myself).

That was one of the reasons I faulted the W3C for calling it a pixel, when
they were clearly *not* referring to a hardware pixel. Better to invent a
new term.

>In my mind, you're treating monitors as if they were print: you want to
say
>exactly how large your font will show up, while the current trend is
towards
>user choice (by adjusting monitor resolution, or, in some browsers, by
>adjusting the font size overruling the style sheet)

Adjusting font size by overruling the style will still be supported. The
idea was simply to treat monitors and printers the same way, as the trend
is for monitors to soon have the resultion that printers have enjoyed for
years. Yes, it's complicated. Yes, there were other ways to do it, which
weren't as prone to confusion. But the W3C chose this one, so for the
moment we're stuck with it.

Given the tech staff at Opera (most of what I know about CSS came from
Lie/Bos "Cascading Style Sheets: Designing For The Web" -- highly
recommended, BTW -- and Lie works there) I have been less willing to
classify this as a misreading/misunderstanding of the standard than as an
incomplete first step towards fully implementing the standard as written.
There's a lot to recommend the theory behind it; I just wish they'd used a
different name for it than "pixel," as that's where most of the heartburn
is coming from.

Were I king (a statement sure to cause an instant insurrection) I would
have reserved "pixel" for an absolute hardware measurement, and insisted
that it treat printers exactly same way it treats monitors: 1 pixel = 1 dot
on the printer, and used point (or made up a new term, like the Frohicke,
to avoid confusion) as the measurement that scaled to compensate for the
resolution of the output device, whether monitor or printer, and any
browser that failed to do both would be classed as "non-compliant." As a
workaround for lying OS's, the current W3C recommendation of selecting the
default font base unit (96ppi/72ppi) would then be applied across the
board. I'd even suggest a variable user-controlled base unit: that way a
user could reduce/enlarge the entire page proportionally, as an
accesibility feature.

Yes, we need a screen measurement that is consistent over all resolutions.
This is a necessary condition for good typography. Pixels shouldn't be it,
because of the confusion factor, but it's what the W3C chose. Points would
be best, but they were subverted from the start by MS. Perhaps inventing a
new unit would have been better.

Have fun,
Arlen
Chief Managing Director In Charge, Department of Redundancy Department
DNRC 224

Arlen.P.Walker at JCI.Com
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