The original !111 automatically sets the global scale factor to the maximum scale factor of all outputs. This PR allows the wayland compositor to explicitly set the scale factor via a newly introduced
XWAYLAND X protocol instead. This has a some advantages:
- More flexibility for the compositor:
- If the compositor wants to automatically set the scale to the max of all outputs, it can still do it himself.
- Alternatively, it can leave the configuration to the user. For example, a user may want to optimize text quality for a lower-DPI monitor.
- The original !111 added a
--max-factor-rescalecommand line flag so that the compositor can advertise support. This flag is no longer needed, because compositors without xwayland scaling support won't set a scale. The default scale is 1, which is equivalent to the old behavior. Therefore this change is backwards compatible without having to add the flag.