@hurlbz said:
@Bromeo does your solution work (while flux is running) for your external monitor? I am in a very similar situation to you.
Yes, it is completely independent of f.lux. Using ddcctl to send the monitor adjustment commands over the DDC protocol is the same as adjusting the monitor backlight brightness and contrast through the on-screen menu system of the monitor itself.
ddcctl is more of a proof-of-concept, if anything. It does require development experience to acquire the source via GitHub, build, and install. There are dire warnings that the app can crash your Mac. It uses deprecated / undocumented API calls. So, not all good news.
There is only a command-line interface to it with very simple parameters, like:
ddcctl -d 1 -b 50 -c 75
Which attempts to set Display #1's brightness (backlight) to 50%, and contrast to 75%. I also found the parameters for volume, mute, and input work on my LG monitor. In fact, adjusting volume via ddcctl brings up the mini on-screen display for volume as if I had reached up and adjusted it on the monitor itself.
As a side note, this LG monitor has various modes, including Reader that is similar to f.lux, but manually triggered.
For now I will probably just make a couple of shell scripts or an Apple Script to toggle day/night settings on this monitor... for my own sanity.