Screenshot.m

- (void)saveScreenshotToDocumentsDirectory
{
  CGSize imageSize = [[UIScreen mainScreen] bounds].size;
  if (NULL != UIGraphicsBeginImageContextWithOptions)
    UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
  else UIGraphicsBeginImageContext(imageSize);

  CGContextRef context = UIGraphicsGetCurrentContext();
  for (UIWindow *window in [[UIApplication sharedApplication] windows]) {
    if (![window respondsToSelector:@selector(screen)] || [window screen] == [UIScreen mainScreen]) {
      CGContextSaveGState(context);
      CGContextTranslateCTM(context, [window center].x, [window center].y);
      CGContextConcatCTM(context, [window transform]);
      CGContextTranslateCTM(context, -[window bounds].size.width * [[window layer] anchorPoint].x, -[window bounds].size.height * [[window layer] anchorPoint].y);
      [[window layer] renderInContext:context];
      CGContextRestoreGState(context);
    }
  }
  UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();

  NSData *imageData = UIImagePNGRepresentation(image);
  NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
  NSString *imagePath = [documentsPath stringByAppendingPathComponent:@"Screenshot.png"];
  [[NSFileManager defaultManager] createFileAtPath:imagePath contents:imageData attributes:nil];
}