[CSS21] [css3-values] px and device pixels

• From: fantasai <fantasai.lists@inkedblade.net>
• Date: Fri, 21 Mar 2008 19:54:40 -0700
• To: www-style@w3.org
• Message-ID: <47E474F0.7010708@inkedblade.net>

I always thought it was in the spec, but it seems to be an unwritten
assumption, that CSS 'px' units should map to a whole number of device
pixels. The examples in the spec all assume rounding to a whole number
of device pixels. And while I don't think we should absolutely require
this (I know on printers defining "device pixel" is not straightforward),
I think it should be recommended as something to aim for.

Proposed change:

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

OR

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."

~fantasai

Received on Saturday, 22 March 2008 02:55:14 UTC