How can I set custom units in Photoshop?
For example I want to see all distances in dp, where
100.00dp = 150.00px
I've tried to set it in
Edit -> Preferences -> Unit & Rulers, but there I could set only predefined units.
I'm not aware that you can, however you could always set a grid in the preferences to 150px with 10 subdivisions.
Then turn your grid on with CTRL or CMD + '