Various Resize/DPI improvements with the user interface and the cursor

[ehfd]

• When the size of the screen gets resized to become larger than what we traditionally worked with (over QHD/4K), the DPI behavior of desktop environments becomes strange, where the interfaces become much smaller than comfort and only applications are in the intended size.

Example (from #99):

While this issue is, of course, a problem with the DPI scaling of the Xfce desktop environment, we would still need to identify closely how the interface can be made better in higher resolutions.

• While dynamic cursor size has been implemented earlier on, we frequently see issues where the client cursor shows the intended cursor size, but when remote cursor mode is activated using full screen or Ctrl+Shift+LeftClick, the cursor size becomes much smaller. This means that the remote host is not honoring the cursor size that we want.

The remote cursor size is about 1.5 to 2 times smaller than the client cursor.

Moreover, we need to also consider resolution scaling when Scale to fit window is used.

Need to investigate both Selkies and the desktop environments (KDE, Xfce).

[PMohanJ]

According to the https://wiki.archlinux.org/title/HiDPI#Xfce, by setting up the following two properties and leaving the DPI to default value(96) seems to set everything to their aspect ratios except the window title

$ xfconf-query -c xsettings -p /Gdk/WindowScalingFactor -s 2
$ xfconf-query -c xfwm4 -p /general/theme -s Default-xhdpi

[ehfd]

This needs to be done on a case-by-case basis per desktop environment. https://wiki.archlinux.org/title/HiDPI explains a lot.

Similar phenomenon with the tray exists in KDE as well.

[ehfd]

In Xvfb, this might explain things:

https://github.com/Xpra-org/xpra/blob/master/docs/Usage/Xdummy.md
https://xpra.org/trac/ticket/10
Xpra-org/xpra#10

[ehfd]

It's pretty okay in Xfce nowadays in main.

[ehfd]

Strange cursor size issue was fixed in #142. DPI issue is yet to go.

[ehfd]

XDummy might be a solution to this problem.

https://github.com/Xpra-org/xpra/blob/master/docs/Usage/Xdummy.md

[ehfd]

#158 should have also fixed a part of this issue.