- From: Felix Miata <mrmazda@earthlink.net>
- Date: Thu, 08 May 2014 02:50:29 -0400
- To: w3c-wai-ig@w3.org
On 2014-05-03 02:06 (GMT+0100) Patrick H. Lauke composed: > Well, as we're talking retina versus non-retina...have a look at this shot Actually we weren't. The mention of Retina was an offer of proof of a real 220DPI device people could buy and use as opposed to some arbitrary "non-standard setup". > http://i.imgur.com/q76abmy.jpg And if I had selected the non-Mac 235 DPI M3800 Dell instead?.... > MacBook Pro with Retina display on the left, MacBook Pro with non-Retina > on the right. At same viewing distance all the text looks exactly the > same size...because the OS compensates for the higher pixel density. So > your example screenshots don't actually reflect the reality in this > particular case. My screenshots don't purport to address any ability or not of any DE to in any manner vary the physical size of a CSS px to match or emulate some specification. That's a whole other subject orthogonal to the reasons why I wrote and write in this thread. I write because using the px unit, among other things: 1-for setting text size wholly and utterly disregards user-determined optimal text size as registered by the visitor's UA default size. Translation: disrespect for users (aka rude); negative accessibility impact. 2-for setting container size and/or leading can cause an assortment of problems when text size is forced by the user to deviate from the stylist's CSS "suggestion" toward or reaching user-optimal, including but not limited to: hidden text, overlapping text, uncomfortably or inanely short line lengths, and misinterpretation due to unexpected text position. 3-is absolutely unnecessary to effectuate the perspectives inherent in any particular web page design, unnecessarily reducing accessibility > In fact, this is consistent with the reference px definition: at the > same viewing distance, the CSS reference pixel dimension needs to remain > the same, regardless of actual physical device pixels. If I follow the > rationale of your viewing instructions, you seem to imply that a viewer > should adapt their viewing distance in order to keep the ratio of the > dimension of a *physical* pixel and the viewing distance constant, > whereas the CSS px reference definition is based on the ratio of the > dimension of a *CSS* pixel and the viewing distance. For the same > type/class of device, with same screen size, I should not adjust my > viewing distance at all...it's the OS that needs to adjust its mapping > of CSS pixels to physical pixels. [Addressed by my 2014-05-08 01:11 (GMT-0400) thread post.] >> Have you never noticed that as the price of PC >> equipment goes up, that pixel density, on average, goes up too, meaning >> everything shrinks > No it doesn't, see above. You missed the part about "on average". A Macbook Pro is anything but average. An OS or DE may or may not provide a reasonable compensation, if any at all, for display pixel densities that deviate modestly or moderately from the standard 96 assumption. e.g. on Windows 8 DPI must reach 140 in order for it to scale, and to scale further 180 must be reached. http://blogs.msdn.com/b/b8/archive/2012/03/21/scaling-to-different-screens.aspx ....On the 235DPI M3800 Dell, according to that blog URL, Windows would be applying 180DPI scaling to a 235DPI device, a 23.4% nominal shortfall, a 41.3% shortfall WRT real size (a function of squares, it takes only a 41.4% increase in height and width to produce twice the px in total. A 1920x1200 screen's px count is 12.5% greater than a doubling of the px count of a 1280x800 screen. An em block twice the physical *size* of a 16px em block if it could exist would be 22.6275px.). -- "The wise are known for their understanding, and pleasant words are persuasive." Proverbs 16:21 (New Living Translation) Team OS/2 ** Reg. Linux User #211409 ** a11y rocks! Felix Miata *** http://fm.no-ip.com/
Received on Thursday, 8 May 2014 06:50:53 UTC