如何打印 SwiftUI 视图

Question

我想使用 SwiftUI View 在 macOS (Ventura) 上打印标签之类的东西。但这会导致一张白纸：

func startPrinting() {
    let printView = NSHostingView(rootView: Text("I want to print"))
    printView.frame.size = CGSize(width: 200, height: 200)

    let printInfo = NSPrintInfo()
    printInfo.topMargin = 0
    printInfo.leftMargin = 0
    printInfo.bottomMargin = 0
    printInfo.rightMargin = 0

    let printOperation = NSPrintOperation(view: printView, printInfo: printInfo)
    printOperation.run()
}

当我将

Text

切换到

TextField

时，会打印出来，但我不知道为什么。

如何打印 SwiftUI 视图？

Answer 1

我还想打印 SwiftUI 视图。就我而言，是带注释的地图视图。网上好像没有太多建议。我添加了提供的函数来尝试使用 Xcode 14 和 Xcode 15 打印 ContentView，结果类似，但没有完整的解决方案。

import SwiftUI

func startPrinting() {
    let printView = NSHostingView(rootView: ContentView())
    printView.frame.size = CGSize(width: 200, height: 200)

    let printInfo = NSPrintInfo()
    printInfo.topMargin = 0
    printInfo.leftMargin = 0
    printInfo.bottomMargin = 0
    printInfo.rightMargin = 0

    let printOperation = NSPrintOperation(view: printView, printInfo: printInfo)
    printOperation.run()
}

// 来自：如何打印 SwiftUI 视图

struct ContentView: View {
    
    @State var someText = "Text here"
    
    var body: some View {
        VStack {
            Image(systemName: "globe")
                .imageScale(.large)
                .foregroundColor(.accentColor)
            Text(someText)
            TextField("A textfield", text: $someText)
            Button("Print this View") {
                startPrinting()
            }
        }
        .padding()
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

更改 rootView 允许打印 ContentView 中的某些元素。不是地球仪。不是在文本字段中输入的文本。它确实包括文本内容、文本字段提示和出现的打印预览窗格中的按钮文本。

Answer 2

@vadian 我能够添加一个按钮来打印地图视图，但到目前为止还没有注释。

            Button("Print Map") {
                let options = MKMapSnapshotter.Options()
                options.region = centerRegion // defined above
                options.size = CGSize(width: 600, height: 800)
                
                let mapSnapshotter = MKMapSnapshotter(options: options)
                mapSnapshotter.start { (snapshot, error) -> Void in
                    
                let imageView = NSImageView()
                imageView.frame = NSRect(origin: CGPoint(x: 0, y: 0), size: CGSize(width: 600, height: 800))
                imageView.image = image
                
                let info = NSPrintInfo.shared
                info.horizontalPagination = .fit
                info.verticalPagination = .fit
                let operation = NSPrintOperation(view: imageView, printInfo: info)
                
                operation.showsPrintPanel = true
                operation.run()
            }
        }
    }.buttonStyle(.borderedProminent)
    
// Under Signing and Capabilities > App Sandbox > Hardware > Printing checked