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Re: Making pt a non-physical unit

From: Robert O'Callahan <robert@ocallahan.org>
Date: Wed, 6 Jan 2010 23:14:22 +1300
Message-ID: <11e306601001060214n42e5848cy173718661a69f344@mail.gmail.com>
To: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Cc: www-style <www-style@w3.org>
On Wed, Jan 6, 2010 at 10:52 PM, Giuseppe Bilotta <
giuseppe.bilotta@gmail.com> wrote:

> Or we could fix Webkit and IE to do the right thing, and push for a
> web that does the right thing.

Please go ahead and persuade Webkit and IE people to change. Once you
succeed, I promise Gecko will follow suit.

If a fixed px/pt ratio is chosen as the preferred solution for the
> mess of mixing absolute and relative units of measure, I would rather
> see px defined in terms of pts (and thus of inches) as suggested
> elsewhere in this thread, rather than the other way around, and have
> the UAs query the display dpi to adjust for the physical px size.

I explained previously why this is impossible.

Rendering speed might suffer a hit on very low end hardware, but to my
> knowledge this would only affect older hardware that is at 96dpi
> already, i.e. not needing any 'conversion factor'.

It's a measurable performance hit on any shipping browser on any hardware.
Also, very few screens are actually 96dpi, even on "older hardware".

Also, for
> performance and quality reasons, UAs could clip the dpi ratios to
> round factors (e.g. assuming a 120dpi on a 133dpi display, thus
> achieving a zoom factor of 125% rather than 138.54%)

That doesn't help performance or quality at all. All scale factors other
than 1.0 are much slower.

"He was pierced for our transgressions, he was crushed for our iniquities;
the punishment that brought us peace was upon him, and by his wounds we are
healed. We all, like sheep, have gone astray, each of us has turned to his
own way; and the LORD has laid on him the iniquity of us all." [Isaiah
Received on Wednesday, 6 January 2010 10:14:55 UTC

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