> On 21 Jun 2016, at 15:24, Samuel Stirtzel via Development > <[email protected]> wrote: > > 2016-06-21 14:15 GMT+02:00 Shawn Rutledge <[email protected]>: >> >>> On 20 Jun 2016, at 18:09, Thiago Macieira <[email protected]> wrote: >>> 160x90 mm is a valid screen size, correspoding to a 7.2" monitor. >> >> Of course, it’s just suspicious (being a fallback value, apparently), but >> not impossible. > > Unfortunately it's not a fallback value, instead TV manufacturers > commonly only set the aspect ratio (in cm) because one EDID for all > devices is cheaper. > See bullet point d of Adam Jacksons mail about the EDID -> DPI topic: > https://lists.fedoraproject.org/pipermail/devel/2011-October/157671.html >
I would also like to add that even if you _do_ get a trustable screen size, using physical DPI as a general purpose solution has flaws: * Physical sizes do not account for viewing distance, logical DPI/scale usually do. For example, a 2x iPhone has a higher pixel density than a 2x MacBook. The base Android DPI is 160. * You actually want some amount of quantization, at least for the general desktop use case. I use two 1x class screens with slightly different physical DPI. What happens when you move a window from one screen to another? If content size is based on physical DPI you get a shift in content logical size, and possibly a resize of the window, which is unexpected. Similarly windows scaling happens in 25% increments. Physical DPI is fine as a special purpose solution where the user or developer is in complete control of the hardware. For Qt I think this translates to that we can support using physical DPI, but it can’t be the default. Morten _______________________________________________ Development mailing list [email protected] http://lists.qt-project.org/mailman/listinfo/development
