Get the current wallpaper in Cocoa

Question

I\'m using this code to get the current wallpaper:

NSURL *imageURL = [[NSWorkspace sharedWorkspace] desktopImageURLForScreen:[NSScreen mainScreen]];
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Answer 1

There is another way to get the image by taking a screenshot of the current wallpaper.

extension NSImage {

    static func desktopPicture() -> NSImage {

        let windows = CGWindowListCopyWindowInfo(
            CGWindowListOption.OptionOnScreenOnly,
            CGWindowID(0))! as NSArray

        var index = 0
        for var i = 0; i < windows.count; i++  {
            let window = windows[i]

            // we need windows owned by Dock
            let owner = window["kCGWindowOwnerName"] as! String
            if owner != "Dock" {
                continue
            }

            // we need windows named like "Desktop Picture %"
            let name = window["kCGWindowName"] as! String
            if !name.hasPrefix("Desktop Picture") {
                continue
            }

            // wee need the one which belongs to the current screen
            let bounds = window["kCGWindowBounds"] as! NSDictionary
            let x = bounds["X"] as! CGFloat
            if x == NSScreen.mainScreen()!.frame.origin.x {
                index = window["kCGWindowNumber"] as! Int
                break
            }
        }

        let cgImage = CGWindowListCreateImage(
            CGRectZero,
            CGWindowListOption(arrayLiteral: CGWindowListOption.OptionIncludingWindow),
            CGWindowID(index),
            CGWindowImageOption.Default)!

        let image = NSImage(CGImage: cgImage, size: NSScreen.mainScreen()!.frame.size)
        return image
    }        
}

This approach looks much simpler IMHO, if you need the picture, not the url.

Note that wallpaper is no longer defined in the com.apple.dektop plist: starting from Mavericks, the setting is moved to ~/Library/Application Support/Dock/desktoppicture.db. This is SQLite file, and the "data" table contains the url.