- From: Charles Pritchard <chuck@jumis.com>
- Date: Wed, 22 Feb 2012 20:08:41 -0800
- To: "www-style@w3.org" <www-style@w3.org>
This list hit a bit of a dead-end on discussing how to represent physical dimensions: I'm going to widen my gaze. Now seems like a fantastic time to talk about device units and viewing distance. Can we pull off a media query that says: (viewing-distance: 8ft)? When there's on person in the room, it's becoming feasible to judge how far the person is from the screen. Does it make sense to consider "target-distance" ? If we are considering overlays on contact lenses are steradians something we want to consider? When I am animating, if I'm following WCAG, should I try to handle the flashing guideline: "the combined area of flashes occurring concurrently occupies no more than a total of .006 steradians within any 10 degree visual field on the screen (25% of any 10 degree visual field on the screen) at typical viewing distance"? http://www.w3.org/TR/WCAG/#general-thresholddef Is it reasonable to enable MyFancyWebApp (tm) to change its appearance as the user moves further away? The boundaries of UA and Web App will continue to shrink as we give more power to application authors. Usually, this kind of flexibility is left up to the UA. viewing-distance and viewing-angle may have some interesting uses for motion parallax, and implicit "zoom". logical and device pixel ratios are really important for bitmaps to meet the high quality of the display device. 1. We've got full screen now, an interesting semantic. When an element is now in full screen, it seems reasonable that CSS could do all sorts of strange and wonderful things. 2. We've got Microsoft's contextual zoom semantics. Pretty cool stuff for touch screens. 3. We've got Microsoft's logical and device pixel measurements in CSSOM (window.screen). 4. We have device-pixel-ratio working with CSS selectors in Mozilla's product. Eh. At some point we may even have the height and width of the display device. It's frequently the case that the OS has this information. There is no real consensus on devicePixelRatio. There's no real consensus on how to express browser zoom on the desktop. As far as I can tell, we don't even have consensus on what (min-width: 480px) should do. http://www.w3.org/TR/css3-mediaqueries/ Bitmap images have a naturalHeight and naturalWidth. Canvas elements have a bitmap backing size, and it's usually 1:1 with the width/height attribute. SVG can be rasterized onto a fixed height/width. Bandwidth matters. Video looks better at higher resolution, but with visual media elements, a high resolution might cost too much in bandwidth or in cpu usage. And it may be overkill if the screen is small. I don't need to render my Canvas animation to meet the devicePixelRatio if the user is 8 feet from the screen. I could, but it's not an issue. I don't need to render the full animation (I can use clip) when the user has occluded the screen through zoom, such as on a mobile phone. Any chance of synthesizing all of this into a coherent proposal for media queries? I see no reason why I can't as an author, support projection displays, heads up displays, 3d focus tracking, and so forth.. I don't see why I couldn't do it efficiently, adjusting my pixel ratios and other such things. I'd like to gain consensus amongst vendors that we can setup standard names and a coherent system to fix these existing issues in exposing access to available information. -Charles
Received on Thursday, 23 February 2012 04:09:04 UTC