- From: Simon Sapin <simon.sapin@kozea.fr>
- Date: Mon, 28 Jan 2013 20:20:09 +0100
- To: François REMY <francois.remy.dev@outlook.com>
- CC: "www-style@w3.org" <www-style@w3.org>
Le 28/01/2013 20:00, François REMY a écrit : >> For instance, if we say the viewing distance is about half an arms >> length then the size of a reference pixel would be about 1/128 >> physical inches. Given 312 device pixels per physical inch, this >> gives 312/128 = 2.4375 device pixels per reference pixel. > Thanks for the clarification. Is there an online calculator that > gives the optimal size of a pixel (or the DPI) given the viewing > distance? The reference pixel is a visual angle (of about 0.0213 degrees) that projects to 1/96 inch at a distance of 28 inches. So at a viewing distance D, the reference pixel is (1/96) * D / 28 = D/2688. http://dev.w3.org/csswg/css3-values/#absolute-lengths Of course real devices pick some approximation of that for their actual CSS pixels, and the actual viewing distance is often unknown and variable. -- Simon Sapin
Received on Monday, 28 January 2013 19:20:33 UTC