printer example fix in ios15

gistfile1.txt

        WKWebView * webView = [[WKWebView alloc] initWithFrame:CGRectZero];
        [webView loadHTMLString:markup baseURL:nil]; // assuming some html loaded into markup for the printer

        UIViewPrintFormatter *formatter = webView.viewPrintFormatter;
        UIPrintInteractionController *printInteractionController = [UIPrintInteractionController sharedPrintController];
        [printInteractionController setPrintFormatter:formatter];

        UIPrintInfo *printInfo = [UIPrintInfo printInfo];
        printInfo.duplex = UIPrintInfoDuplexNone;
        printInfo.outputType = UIPrintInfoOutputPhotoGrayscale;

        self.printer = [UIPrinter printerWithURL:url]; // assuming you already have the printer url
        
        [printInteractionController setDelegate:self];
        [printInteractionController setPrintInfo:printInfo];
        [self.printer contactPrinter:^(BOOL available) {
            if (!available) {
                [self printFailed]; // private handler
            } else {
                [printInteractionController printToPrinter:self.printer
                   completionHandler:^(UIPrintInteractionController *controller, BOOL completed, NSError *error) {
                       if ( error ) {
                           NSLog(@"Airprint error: %@", error);
                           [self printFailed]; // private handler
                       } else {
                           // success case here
                       }
                      controller.delegate = nil;
                   }];
            }
        }];