- From: Peter Moulder <peter.moulder@monash.edu>
- Date: Thu, 01 Jul 2010 06:37:18 +1000
- To: "www-style@w3.org" <www-style@w3.org>
On Wed, Jun 16, 2010 at 06:32:37PM -0700, fantasai wrote: > | The reference pixel is the visual angle of one pixel on a device with > | a pixel density of 96dpi and a distance from the reader of an arm's > | length. For a nominal arm's length of 28 inches, the visual angle is > | therefore about 0.0213 degrees. For reading at arm's length, 1px thus > | corresponds to about 0.26 mm (1/96 inch). Somehow, the existing CSS2.1 text defining a px seems to cause problems for people: they don't have a good feel for how many px there should be to an inch on paper or on a handheld computer or on a billboard. Not just estimating how the distance compares to the usual distance of a desktop monitor, but even whether a shorter viewing distance should result in more or less than 96 px per inch. "Subtending the same the visual angle as a 96dpi pixel does when it's 28in away" is rather indirect. Somewhere in the text, I suggest pointing out that 2688 reference px should equal the usual viewing distance (so 672 reference px is a quarter of the expected viewing distance). pjrm.
Received on Wednesday, 30 June 2010 20:37:49 UTC