I’m trying to make a disk image, friendly both to dark and light system modes. I don’t see the way to do it in DropDMG, so I actually wonder if that’s currently possible. There are two obstacles:
1. The disk image should have a custom background in the window (icon view) when it mounts. So, I created an image with the transparent background, hoping that Finder’s icon view background would be visible underneath to automatically get light/dark mode. However, the window background underneath the image is always white. Even if I remove the background image completely, the background of the window stays white.
2. File names text are always black (and match always white window background from 1). I don’t see any option to make them match the system colour mode (that is, to let the Finder do the its things with text colour).
It should always be friendly in the sense that the text is readable (not black on black), but there’s no way to make a custom background auto-switch. You can either use a custom background picture, in which case Finder will always treat that window as if it’s in light mode; or you can omit the background, in which case the background and text color will both switch when the user chooses light/dark.
Yeah, I never expected there’d be a way to auto-switch background picture on system colour mode change, but I didn’t expect Finder to always treat a window as if it’s in light mode if the background picture is present. That certainly sounds like a bug (sort of) in Finder to me. Anyway, that means my idea with a background picture with transparent background won’t work
I think it’s intentional because in general there’s no way for Finder to know whether the background will work in both modes. It’s safer to assume it was designed for light.
