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

Re: Making pt a non-physical unit

From: Jonathan Kew <jonathan@jfkew.plus.com>
Date: Thu, 7 Jan 2010 16:40:08 +0000
Cc: Boris Zbarsky <bzbarsky@mit.edu>
Message-Id: <4E7D1971-45AF-497B-B4D7-40D258F4A259@jfkew.plus.com>
To: www-style list <www-style@w3.org>
On 7 Jan 2010, at 15:43, Boris Zbarsky wrote:

> On 1/7/10 10:38 AM, Ambrose LI wrote:
>> I don't understand why we are stressing the importance of physical
>> accuracy in projections. Do people expect units to measure as spec'd
>> when projected?
> 
> I have no idea, but the spec says they should at the moment.  Just like it says they should measure as spec'd on an iPhone.  Or on an eye-glasses display.  Or a contact lens display.  That's what makes the physical units physical.
> 
> That's also what makes them clearly nonsense for anything where you don't control the device; 12pt font on a contact lens display would be ... interesting.
> 
>> When we spec 12pt on PowerPoint does it result in 12pt type on the projection
>> screen which looks like a tiny dot 15 ft away? No.
> 
> That's precisely how Webkit and IE treat pt in general and how Robert is proposing Gecko treat pt.  It's a clear violation of what the CSS spec says to do with pt at the moment.

Right. And (despite some initial reluctance) I'm inclined to agree. My request now is that if we're going to change the spec to match this actual practice, we should do so for all the units, not just for pt. And then IF there's a need to specify units that are NOT treated in the same way but "bypass" the default scaling of the device, we should create a clearly distinct class of units for this purpose.

JK
Received on Thursday, 7 January 2010 16:40:46 GMT

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