<div dir="ltr">Hi-DPI displays and resolution independence are two completely different problems. You don't get resolution independence by scaling, it needs separate design and a responsive layout. The scale is simply for displays where the pixel density is double or triple other displays. </div><div class="gmail_extra"> <div class="gmail_quote">On Thu, Mar 12, 2015 at 9:08 AM, microcai <<a href="mailto:microcai@fedoraproject.org" target="_blank">microcai@fedoraproject.org</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">on Monday 09 March 2015 08:59:35，Jasper St. Pierre wrote： > You misunderstood what pq said. > > You work in "logical pixels". On a hi-DPI display, with twice the pixel > density, each "logical pixel" is backed by 4 device pixels. Your actual > backing surface containing the pixels is in "device pixels". assume we design for 72DPI screen, then , yes, we are working on logical pixels even when we use 12point font, because 1point=1pixel on 72DPI screen. then the point became the "logical pixel". Just look at android, we have 4" screen range from 320p to 1080p, they don't really do 2x scale. but people still expect the *same* UI size. if you force only 2x scale, the you are lost in the real world. you simply can not run on 1080p screen when you have your app design for 720p screen, even then they share the same physical size, and people expect the same UI element sizes on the same physical sized screen. <div class="HOEnZb"><div class="h5"> > > So, if you have an window that is 800x600 logical pixels, when you drag it > to a low-DPI display, your backing buffer is 800x600 device pixels. When > you drag it to a hi-DPI display, your backing buffer is 1600x1200 device > pixels. > > When you submit your buffer, you tell the compositor what the ratio of > device pixels to logical pixels is, in the perhaps misnamed > "set_buffer_scale" request. So, for the low-DPI buffer, you submit "1", > since 800x600 / 800x600 = 1. When you submit your hi-DPI buffer, you submit > "2", since 1600x1200 / 800x600 = 2. > > If you submit "1" and you are on a low-DPI display, it all matches and > things are fine. If you submit "1" and you are on a hi-DPI display, the > compositor scales up your buffer to match. If you submit "2" and you are on > a hi-DPI display, it all matches up and things are fine. If you submit "2" > and you are on a low-DPI display, the compositor scales down your buffer to > match. > > On Mon, Mar 9, 2015 at 6:19 AM, microcai <<a href="mailto:microcai@fedoraproject.org">microcai@fedoraproject.org</a>> wrote: > > 在 2015年3月9日 Monday 10:39:20，您写道： > > > > > Hi, > > > > > > On Monday, March 9, 2015, microcai <<a href="mailto:microcai@fedoraproject.org">microcai@fedoraproject.org</a>> wrote: > > > > so we are forcing two code pathes in APP? or just support non-integer > > > > scale? > > > > > > Scaling is a specific fallback for legacy/non-DPI-aware clients, to get > > > them to show anything at all. Other clients will render at the > > > > appropriate > > > > > resolution already. > > > > That's not the story I was told. pg says scale is the *only way* to > > support > > HiDPI. > > > > > Any plan that relies on integer scaling means you're wasting pixels on > > > > your > > > > > lovely dense display. Any plan that relies on non-integer scaling makes > > > your text blurry to the point of unreadable - again, a waste of pixels > > > on > > > such lovely displays. Just render at the correct scale to begin with. > > > > > > Cheers, > > > Daniel > > > > _______________________________________________ > > wayland-devel mailing list > > <a href="mailto:wayland-devel@lists.freedesktop.org">wayland-devel@lists.freedesktop.org</a> > > <a href="http://lists.freedesktop.org/mailman/listinfo/wayland-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/wayland-devel</a> _______________________________________________ wayland-devel mailing list <a href="mailto:wayland-devel@lists.freedesktop.org">wayland-devel@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/wayland-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/wayland-devel</a> </div></div></blockquote></div> -- <div class="gmail_signature"> Jasper </div> </div>