On 2014-03-15 21:14 (GMT-0400) Crest Christopher composed:
Felix, what do you mean by DE DPI ?
The term DE DPI refers to logical pixel density, as opposed to physical (device) pixel density.
DPI is dots per inch, which most think of as pixels per inch, a measure of display pixel density. DPI is often used interchangeably with display resolution, but wrong so used. Display resolution is a measure of pixels wide by pixels high regardless of actual physical width or height. 3840x2160 might sound like high resolution, but applied to cover a 3 meter wide wall its physical density (32.5 DPI) is very much lower than is a 40" HDTV screen's (55.1 DPI), a 24" 1920x1200 screen (94.3 DPI), or a 2880X1800 15.4" Retina laptop (220 DPI). Density is what matters, not of itself "resolution".
DE means desktop environment. In Windows and Mac, DEs are traditionally not options, while in Linux, quite a number of desktop environments exist, among them, Gnome, IceWM, KDE, LXDE, Mate, Unity & XFCE. DEs for desktop systems (and the software than runs on them, including web browsers) almost universally by default assume a display density of 96 DPI (or PPI), same as the CSS reference px unit. As densities are assumed by the display environment software, they are logical as opposed to physical, except when assumed and physical happen to coincide, as is typically the case for a '17"' 1280x1024 LCD (within ~1% or so), but not for very many other common sizes.
In Geckos, variations in assumed DPI have no impact on its 16px OEM default size, which physically speaking is 12pt whenever the DPI is in fact 96. If you adjust the DE's logical DPI upward on account of use of a high density display device, you get no change in px size of fonts within its viewport, while in IE, you do get bigger fonts in the viewport (as well as in its, and Gecko's, UI). To get bigger fonts in px from Geckos requires either settings personalization, zoom, or bigger CSS size declarations, all of which are effective in IE as well, but often obviated from necessity because IE's default automatically goes up as DE DPI goes up, e.g., default @120 DPI being 20px instead of the 16px that it is @96, or 24px when DPI is 144.
I thought doing fonts in EM was a good thing ? :)
The reason it's ostensibly a good thing is because there is positive non-zero rational relationship between a CSS size declaration in em, and to optimal as reflected by the browser default size, which does not exist for a px unit.
In actual practice em is typically better than px only in theory, the difference being that a size in px is 100% arbitrary, disregarding optimal entirely, while stylists typically declare an arbitrary fraction of the optimal size, often 62.5%, .76em or 80%, as the base CSS font size. What makes em sometimes better in practice is that as display density increases, the px unit decreases in physical size (to a point, after which it doubles, and then at another point, after which it in effect will have tripled, etc.), while the em unit remains at the arbitrary fraction declared, which enjoys some likelihood to have been either manually or automatically adjusted to compensate for a "high" physical device pixel density.
-- "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/ ______________________________________________________________________ css-discuss [css-d@lists.css-discuss.org] http://www.css-discuss.org/mailman/listinfo/css-d List wiki/FAQ -- http://css-discuss.incutio.com/ List policies -- http://css-discuss.org/policies.html Supported by evolt.org -- http://www.evolt.org/help_support_evolt/
