This is really up to Tixati to fix. HiDPI is a massive PITA for everyone involved but Tixati has got to support different platforms, including Windows XP (well basically none of that) and Linux. For the developer and Linux users here's a good blog post to read:
http://wok.oblomov.eu/tecnologia/mixed-dpi-x11/
PS: It is possible to set up virtual resolutions aka "custom resolutions" to display e.g. a 4K picture on a 1080p monitor for testing and other purposes. No need to actually buy a 4K monitor just to test for these issues.
Virtual resolution: commonly referred to a method where the GPU renders the full resolution but downscales it
Custom resolution: it is the ancient method where the GPU renders and sends the full resolution for the monitor to downscale it. This required tweaking resolution settings etc.