W3C home > Mailing lists > Public > www-style@w3.org > January 2010

Re: Making pt a non-physical unit

From: Robert O'Callahan <robert@ocallahan.org>
Date: Wed, 6 Jan 2010 09:23:05 +1300
Message-ID: <11e306601001051223n11568549j203a59913d54aede@mail.gmail.com>
To: fantasai <fantasai.lists@inkedblade.net>
Cc: Alex Mogilevsky <alexmog@microsoft.com>, www-style <www-style@w3.org>, Melinda Grant <Melinda.Grant@gmx.com>
On Wed, Jan 6, 2010 at 8:45 AM, fantasai <fantasai.lists@inkedblade.net>wrote:

> What about locking things the other way, 1px == 3/4pt? That seems
> less drastic, because at least you're keeping the 1pt = 1/72in.
>

We can't allow px to vary just because the screen DPI changed. Our
experience shows that even for very large DPIs that is not what users want.
Platforms have developed their own user-controllable settings (e.g. UI
scaling on Mac, "font DPI" on Windows) for controlling how content gets
scaled, and that's what should control the px-to-screen-pixel ratio. Also,
making 1px not be a single screen pixel whenever the screen is not exactly
96dpi would cause serious performance degredation.

I'm wondering how this will play out for other media, like print.


We can make print behave differently. However, the same sorts of problems
would show up when printing these problematic sites, so for those sites, we
probably do need to lock the pt/px ratio.

Rob
-- 
"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
53:5-6]
Received on Tuesday, 5 January 2010 20:23:38 GMT

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