W3C home > Mailing lists > Public > www-style@w3.org > February 2004

RE: [css3-page] LCWD issue 22 -- [22] Section 3.3.2 <length>

From: Ernest Cline <ernestcline@mindspring.com>
Date: Tue, 17 Feb 2004 16:52:15 -0500
Message-ID: <410-220042217215215515@mindspring.com>
To: "BIGELOW,JIM (HP-Boise,ex1)" <jim.bigelow@hp.com>, "Boris Zbarsky" <bzbarsky@MIT.EDU>
Cc: "W3C CSS List" <www-style@w3.org>

> [Original Message]
> From: BIGELOW,JIM (HP-Boise,ex1) <jim.bigelow@hp.com>
> To: Boris Zbarsky <bzbarsky@MIT.EDU>
> Boris wrote:
> > Actually, if I understand the definition of "pixel" in CSS 
> > correctly, that is precisely what should NOT happen if pixels 
> > are implemented correctly.  In CSS "pixel" does not refer to 
> > a dot but rather to a solid angle in the field of view.  
> > Therefore a "300px" image should have the same physical 
> > dimensions (as measured with a ruler) no matter what the 
> > medium, as long as the viewing distance is held constant 
> > (modulo the possily low resolution of the imaging device, actually).
>  Thank you, I stand corrected.

Close, but not quite.  What should happen is that 1px should be
selected so that it is an integral multiple of the device pixel that
comes closest to having the desired size of the reference pixel,
which also depends upon the desired 

Thus for example, both CSS2.1 and CSS3 Values suggest that
a 300dpi printer should use 1px = 3dots  while a 600dpi printer
should use 1px = 5dots.
Received on Tuesday, 17 February 2004 16:52:19 UTC

This archive was generated by hypermail 2.3.1 : Monday, 2 May 2016 14:27:11 UTC