Open Radar

 
Summary:
When one attempts to AirPrint a PDF open in WKWebView using [WKWebView viewPrintFormatter], the previews and the printed output are blank. 
Note that Safari on iOS prints normally.

Steps to Reproduce:
Unzip attached project, build & run. A pdf document will be loaded, and once it's loaded, the print dialog will open.

Expected Results:
Preview in print dialog shows a small PDF preview. PDF prints normally.

Actual Results:
Previews in print dialog shows a blank page. Printed page is blank.

Version:
iOS 9.1

Configuration:
iPhone 6s, also simulator

Attachments:
'TestPrint.zip' was successfully uploaded. Since attachments are not available on openradar, you need to do the following:
1. create a "Single View" project
2. Replace ViewController.m with the following:
#import "ViewController.h"

#import <MobileCoreServices/MobileCoreServices.h>
#import <WebKit/WebKit.h>

@interface ViewController () <WKNavigationDelegate>
@property(nonatomic, weak) WKWebView* webView;
@end

@implementation ViewController

- (void) viewDidAppear:(BOOL)animated {
  [super viewDidAppear:animated];
  
  NSString* pdfLink = @"http://www.cbu.edu.zm/downloads/pdf-sample.pdf";
  NSURL* pdfURL = [NSURL URLWithString:pdfLink];
  
  WKWebView* webView = [[WKWebView alloc] init];
  [self.view addSubview:webView];
  webView.frame = self.view.bounds;
  webView.navigationDelegate = self;
  [webView loadRequest:[NSURLRequest requestWithURL:pdfURL]];
  self.webView = webView;
}

- (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecified WKNavigation *)navigation {
  // Start printing
  UIPrintInfo* printInfo = [UIPrintInfo printInfo];
  printInfo.outputType = UIPrintInfoOutputGrayscale;
  printInfo.jobName = @"PDF Sample";

  UIPrintInteractionController* printController = [UIPrintInteractionController sharedPrintController];
  [printController setPrintInfo:printInfo];
  [printController setPrintFormatter:[self.webView viewPrintFormatter]];
  [printController presentAnimated:YES completionHandler:nil];
}

@end

3. Add WebKit and MobileCoreServices frameworks to linked frameworks section.