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Re: [css3-values] define 'dot' to be a device pixel

From: Chris Lilley <chris@w3.org>
Date: Sun, 6 May 2012 09:26:12 +0200
Message-ID: <100638440.20120506092612@w3.org>
To: Edward O'Connor <eoconnor@apple.com>
CC: www-style@w3.org
On Tuesday, April 24, 2012, 11:36:13 PM, Edward wrote:

EOC> Hi,

EOC> So far as I can tell, the closest thing to a definition for "dot" in
EOC> CSS3 Values is in the caption of Figure 2:

EOC>     "Showing that more device pixels (dots) are needed to cover a 1px by
EOC>     1px area on a high-resolution device than on a low-res one"

EOC> I think it would be good if this definition were raised out of the
EOC> caption to be its own statement in normative prose somewhere.

Yes.

The term dot needs to be defined. Whether 'device pixel' is a good definition is less clear - it applies to displays, but applies less clearly to printer dots, where it relates to the screening resolution.

Note that we also added some clarifying text on resolution to Media Queries, which mentions dots:

4.11. resolution
For printers, this corresponds to the screening resolution (the resolution for printing dots of arbitrary color). 
http://www.w3.org/TR/2012/PR-css3-mediaqueries-20120426/#resolution

Note that screens for different inks are rotated relative to each other, so they don't really correspond to device pixels. Note too that the 'dots of arbitrary color' and 'smallest possible dots' are different, the former being composed of clumps of the latter.

-- 
 Chris Lilley   Technical Director, Interaction Domain                 
 W3C Graphics Activity Lead, Fonts Activity Lead
 Co-Chair, W3C Hypertext CG
 Member, CSS, WebFonts, SVG Working Groups
Received on Sunday, 6 May 2012 07:26:14 GMT

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