cocoa - 获取 Cocoa 中的当前壁纸

Question

我使用此代码来获取当前壁纸:

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

这工作正常，但是当我将图片文件夹设置为壁纸时(如图所示)，imageURL是一个目录，那么我如何获取当前壁纸的USURL这种情况？

Answer 1

还有另一种获取图像的方法，即截取当前壁纸的屏幕截图。

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
    }        
}

如果您需要图片而不是网址，则这种方法看起来要简单得多。

请注意，壁纸不再在 com.apple.dektop plist 中定义:从 Mavericks 开始，该设置已移至 ~/Library/Application Support/Dock/desktoppicture.db。这是 SQLite 文件，“数据”表包含 url。