hidpi: Allow individual scaling for applications

[kaueraal]

Some applications, especially X11 applications, support hidpi, but currently do not support waylands internal scaling protocol for signaling this to wlm/sway. It would be nice to be able to set individual scaling or disable it altogether for certain windows on wlms side to get sharp scaled rendering nevertheless.
This would allow a smoother transition to sway/wlm/wayland for hidpi-users, especially as this affects both chromium and firefox.

See also swaywm/sway#1047.

[ddevault]

I said in my issue (and you failed to communicate here) that per-application DPI is not possible for Xwayland views. I asked you to open an issue asking if we could set the DPI for Xwayland globally at startup.

[kaueraal]

Where did you say that? At least on the issue I opened you didn't comment. Still, that limitation would make this feature relatively useless :-/

[edrex]

A global option to set the xwayland buffer_scale would be very helpful. Users willing to configure the various X scaling options (Xresource etc) could then have a blur-free Wayland experience with xwayland apps by setting the xwayland buffer scale equal to the output scale of their largest display. Seems like this could be a small change in wlc? Junior job?

[ddevault]

Probably.

https://github.com/Cloudef/wlc/blob/master/src/xwayland/xwayland.c#L310