Is it possible to (programmatically) set wallpapers for each separate "space"/desktop in macOS?

Question

I'm making a small app for myself to change the desktop background image periodically.

My program contains this block of code:

let screen = NSScreen.main()!
let newWallpaperURL = URL(/* ... */)
// ...
try! NSWorkspace.shared().setDesktopImageURL(newWallpaperURL, for: screen, options: [:])

This works, but only for the current "space" the keyboard is focused on.

e.g. if I'm in a fullscreen app, only the background of the Space occupied fullscreen app will be changed (not the background of my normal desktop). If I have two Spaces/desktops, it only changes the background image of one of them.

Is it possible to individually set wallpapers for each space programmatically?

Answer 1

Use this in Xcode 8.x:

if let screens = NSScreen.screens() {
    let newWallpaperURL = URL(/* ... */))
    for screen in screens {
        try? NSWorkspace.shared().setDesktopImageURL(newWallpaperURL, for: screen, options: [:])
    }
}

Unlike other solutions posted here this one will work in the current Xcode 8. NSScreen.screens is a class var in Xcode 9 (currently beta) but a class func in Xcode 8 which is why you need to put .screens() instead of .screens. Also, screens returns an optional so you need to safely unwrap it before passing it to the for loop.

Answer 2

You can get all the screens and set all of them.

let screens = NSScreen.screens
let newWallpaperURL = URL(/* ... */)
for i in screens {
    try! NSWorkspace.shared().setDesktopImageURL(newWallpaperURL, for: i, options: [:])
}