- From: Bert Bos <bert@w3.org>
- Date: Fri, 22 Jan 2010 21:31:44 +0100
- To: www-validator-css@w3.org
Here is one for the wish list:
A common error in style sheets is to use the 'pt' unit in style sheets
meant for the screen. That is nearly always a mistake, especially when
the style sheet also uses 'px' in other places. Depending on the dot
pitch of the screen, the size of a pt may vary between as much as 1 and
2 px, thus if precise alignment is desired, it will fail on some
screens, typically on higher-resolution screens with 100 to 200 dpi.
I did a quick check with a random sample of style sheets and found that
most often people use 'pt' for 'font-size'. Maybe there is a (false)
believe that fonts must be specified in points...
(Of the style sheets that used 'pt', quite a few had just a single rule
with 'pt', nearly always a 'font-size', while other rules in the style
sheets, including other 'font-size', used relative units. My guess is
that those style sheets were originally made by designers, and then
later somebody else made a local change...)
It would be nice if the validator gave a warning (not an error,
obviously) when it found any absolute units
('pt', 'mm', 'in', 'cm', 'pc'). The warning should say something about
using absolute and relative units together and that they scale
differently depending on the screen's dpi. Almost certainly the style
sheet should use 'px' or 'em' instead.
Such a warning should not be given when it is known that the style sheet
is only used for print.
Bert
--
Bert Bos ( W 3 C ) http://www.w3.org/
http://www.w3.org/people/bos W3C/ERCIM
bert@w3.org 2004 Rt des Lucioles / BP 93
+33 (0)4 92 38 76 92 06902 Sophia Antipolis Cedex, France
Received on Friday, 22 January 2010 20:32:16 UTC