将 SwiftUI 视图导出为图像 macOS

Question

I want to export a SwiftUI View on macOS. I have code that works on iOS, but it uses UIKit. I can't find another example to do it without UIKit.

Does anybody know how to do it?

fileprivate extension View {
    func snapshot(device: Device) -> UIImage {
        let controller = UIHostingController(rootView: self)
        let view = controller.view

        let targetSize = controller.view.intrinsicContentSize
        view?.bounds = CGRect(origin: .zero, size: targetSize)
        view?.backgroundColor = .clear
        
        let exportWidth = device.width / UIScreen.main.scale
        let exportHeight = device.height / UIScreen.main.scale

        let renderer = UIGraphicsImageRenderer(size: CGSize(width: exportWidth, height: exportHeight))

        return renderer.image { _ in
            view?.drawHierarchy(in: CGRect(x: 0, y: 0, width: exportWidth, height: exportHeight), afterScreenUpdates: true)
        }
    }
}

I know I can create a NSHostingController , but I think I need some alternative for UIGraphicsImageRenderer .

Thanks in advance

Answer 1

In NSView there are two methods:

func bitmapImageRepForCachingDisplay(in: NSRect) -> NSBitmapImageRep?

and

func cacheDisplay(in: NSRect, to: NSBitmapImageRep)

Once you have the NSBitmapImageRep , you can ask for the image in a number of formats using its:

func representation(using storageType: NSBitmapImageRep.FileType, 
     properties: [NSBitmapImageRep.PropertyKey : Any]) -> Data?

(the NSView to draw is the one owned by the hosting controller if that wasn't clear)