ISSUE-1: px units

px units

Raised by:
Elika Etemad
Opened on:
It seems to be an unwritten assumption, that CSS 'px' units should map to
a whole number of device pixels. E.g. the examples in the spec all assume
rounding to a whole number of device pixels. But there is no normative
text that suggests this interpretation.

Proposed change:

"the user agent should rescale pixel values"
"the user agent should rescale pixel units to a different whole number
of device pixels"


Insert before
"It is recommended that the reference pixel be..."
the sentence
"It is recommended that the pixel unit refer to the whole number of
device pixels that best approximates the reference pixel."
Related Actions Items:
Related emails:
  1. Re: [css-grid] Summary of Abspos Issues (from on 2015-05-12)
  2. [css-grid] Summary of Abspos Issues (from on 2015-05-09)
  3. Re: [css-grid] Absolutely positioned items and static position (from on 2015-05-08)
  4. Agenda request CR for CSS Masking 1 (from on 2014-06-23)
  5. [CSSWG] Minutes Paris F2F 2013-09-13 Fri I: CSS Masking, Display Tree or DOM, Flexbox (from on 2013-09-30)
  6. [CSSWG] Minutes Tucson F2F 2013-02-14 Tue AM I: Paged Media 4, Flexbox (from on 2013-02-14)
  7. Re: [css3-speech] status (from on 2011-12-04)
  8. Re: [css3-speech] status (from on 2011-12-04)
  9. [CSSWG] Minutes and Resolutions Telecon 2011-11-30 (from on 2011-11-30)
  10. Re: [css3-speech] status (from on 2011-11-30)
  11. Minutes, 22 November FX taskforce call (from on 2010-11-22)
  12. [CSSWG] Minutes and Resolutions 2008-04-09 (from on 2008-04-10)
  13. RE: [CSS21] [css3-values] px and device pixels (from on 2008-03-25)
  14. ISSUE-1: [CSS2.1] (from on 2008-03-22)
  15. Re: [CSS21] [css3-values] px and device pixels (from on 2008-03-21)

Related notes:

Second proposal accepted 2008-04-09

Elika Etemad, 16 Apr 2008, 01:00:06

Display change log ATOM feed

Peter Linss <>, Daniel Glazman <>, Chairs, Chris Lilley <>, Bert Bos <>, Staff Contacts
Tracker: documentation, (configuration for this group), originally developed by Dean Jackson, is developed and maintained by the Systems Team <>.
$Id: index.php,v 1.325 2014-09-10 21:42:02 ted Exp $