- From: Patrick H. Lauke via GitHub <sysbot+gh@w3.org>
- Date: Mon, 14 Nov 2016 16:33:05 +0000
- To: public-css-archive@w3.org
patrickhlauke has just created a new issue for https://github.com/w3c/csswg-drafts: == [css-values] clarify that most (all?) high-dpi devices anchor on pixel, rather than physical, unit == The section on absolute lengths https://drafts.csswg.org/css-values/#absolute-lengths currently contains the following: > For print media and similar high-resolution devices, the anchor unit should be one of the standard physical units (inches, centimeters, etc). For lower-resolution devices, and devices with unusual viewing distances, it is recommended instead that the anchor unit be the pixel unit. For such devices it is recommended that the pixel unit refer to the whole number of device pixels that best approximates the reference pixel. In essence, this splits devices into "print and high resolution" on one side, and "lower-resolution and unusual viewing distances". However, most (all?) high-dpi devices (including recent desktop monitors, laptops, mobile/tablet devices) currently also anchor on the pixel unit. It seems that it's really only print media that (try to) anchor on physical units (unless I'm missing some non-print device that does this?). I think it would be important to either rewrite this section to change the distinction, or to leave the above as is but then include a note straight after clarifying that currently even high-resolution desktops/laptops/mobiles/tablets are anchored on the pixel unit. The reason for bringing this up is that this issue seems to constantly rear its head in discussions around being able to use absolute measures like "mm" to actually map to physical size of elements *as rendered on a device* (most recently I had this discussion in the mobile accessibility task force https://www.w3.org/WAI/GL/mobile-a11y-tf/wiki/Summary_of_Research_on_Touch/Pointer_Target_Size#Comparison_of_web_content_sized_in_px_and_physical_size_of_rendered_content_on_common_device_screens which led to having to demonstrate this practically using http://codepen.io/patrickhlauke/full/zqabMR/ ... and I'm aware of similar discussions under WICG in relation to large screen / TV environments) Happy to draft a PR if this sounds like a reasonable request. Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/708 using your GitHub account
Received on Monday, 14 November 2016 16:33:11 UTC