On 10/21/2016 03:31 PM, Adam Williamson wrote: >> There was a lot of kerfuffle around the GTK (and Wayland) decision to >> only support integer scales, searching for it will give you some background. > > I don't recall that...do you have any specific references? At the time > hidpi was first added to GNOME, IIRC, only OS X was really doing it, > and it only did it in integers (because, as you say, they just make > sure that's all the hardware they ship needs). I think this thread was the start of the discussion: https://lists.freedesktop.org/archives/wayland-devel/2013-May/009073.html There were several after that. Sometimes they are quite difficult to follow, as the concepts of fractional scaling, and scaling based on EDID DPI are often mixed up, although they are orthogonal. Even more so because until recently, Qt still used EDID DPI scaling (as of 5.6, it supports a mode like Windows where it assumes 96dpi and supports fractional scale factors) There are technical issues with drawing natively at fractional scales, such as choosing sizes of Xembeds or Wayland subsurfaces, which are always snapped to the nearest pixel. Qt and Firefox manage, but probably because neither really uses Xembeds, and both have to work on Windows. There are also personal preferences, as integer scales with legacy applications can use nearest neighbor resampling leading to sharp but pixelated images, and fractional scaling usually uses bicubic or lanczos which leads to soft images. I think it would be great to improve the out of box experience for these displays that sit at awkward scaling steps, with the tools that we currently have. I'm not exactly sure of the best approach, though. For example, Firefox could be changed to pick up a fractional scaling from the gnome-tweak-tool's font scaling, but that means its widget sizes don't quite line up with other GTK3 apps. You can also achieve Mac-style 2x->1.5x or 3x->2x scaling via xrandr plane scaling - maybe a UI could be created for that (but with the performance caveats). > Still, now I got curious and looked it up, it's a bit difficult to > interpret Windows' history here. I can at least tell that Windows 7 and > 8 had 100%, 125% and 150% scaling settings, and 8.1 and 10 have up to > 200% and per-display scaling, but I haven't found any references as to > exactly how this is implemented for each release - whether it's really > interface scaling, complete with high-resolution interface assets in > the OS so the scaled display actually looks sharp, or if it's just text > scaling like GNOME's 'text scaling factor'... I have a Windows 10 machine right next to me (being used by a coworker). It appears to have full interface scaling, with high resolution assets, for apps that indicate support. It's currently set to 1.5x scaling with a 4k monitor. For multiple displays, the app can only have one scaling at a time, but it does change per monitor. Moving an app across screens causes a sudden "snap" in its scale factor once it's over halfway to the other screen. _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx
