[Development] Revisiting high-DPI configuration options

[Morten Sorvig]

> On 19 Jul 2016, at 14:58, Shawn Rutledge <Shawn.Rutledge at qt.io> wrote:
> 
> 
> I agree that most apps should have a means of scaling.  Control-mousewheel and control+/- are common on the desktop, so maybe it ought to be universal.  So far we have browsers, image and drawing viewers and editors, text editors (like Creator’s) and terminals which have the feature, but many other applications don’t.  

This would be a "document scaling” feature. Notice that the application UI
does not scale when using and control+/-. So this is orthogonal to the
current high-DPI support and can’t reuse that implementation.


> I got a 4K display at work, so now I want to use konsole instead of urxvt, because of this feature: I need to zoom it depending on the use case, and which screen it’s on.  (On the Mac though, I wouldn’t need it so urgently.  The window has a similar physical size as I move it from one screen to another; whereas on Linux, the non-highdpi-aware window manager will keep the same pixel dimensions as I move it across.  So it’s a much smaller window on the 4K screen, regardless whether the content inside gets scaled or not.  Is that right or wrong?  Are we waiting for window managers to catch up here?  I don’t think resizing the window is necessarily Qt’s problem, although sometimes the layout does drive the minimum window size.)  

Yes, we are waiting :) Display pixel density is a rendering detail and should
not affect layouts or window sizes. Some windowing systems are not there yet
and in those cases we may be in the business of resising on screen change.


> I want smaller fonts on the 4K display, but I want to be able to choose the scale, and fractional scaling works so badly now.  Widget styles seem to need some re-design to be scalable.

You may be in a minority here. I think the most common case is similarly
sized fonts (visually) on different displays. 

> 
> There are also cases when accurate calibration is important though.  Some people are actually still engaged in preparing print media, for example.  They will appreciate having 100% zoom result in the same scale as it will be on paper.  And such people should either buy monitors which have correct EDID, or know how to correct it in their OSes.


This is also in the “document” domain. It’s OK if the application UI is not exactly physically calibrated.

Morten