ios - 斯威夫特：试图打印“双面” UIPrintInfo.Duplex.longEdge 但不工作

Question

我正在尝试在 iOS 应用程序中打印 PDF 双面，设置 printInfo.duplex = UIPrintInfo.Duplex.longEdge，但是当我使用 UIPrintInteractionController 打印时它被忽略

    printInfo.printerID = "c890E8700000.local"
    printInfo.jobName = lastPathComponent
    printInfo.duplex = UIPrintInfo.Duplex.longEdge
    printInfo.orientation = UIPrintInfo.Orientation.portrait
    printInfo.outputType = UIPrintInfo.OutputType.general
    
    
    print(printInfo.dictionaryRepresentation)


    // this is what I see in debug print
    Optional([
      AnyHashable("UIPrintInfoPrinterIDKey"): c890E8700000.local,
      AnyHashable("UIPrintInfoJobNameKey"): 02180830225_bg.pdf
    ])