title: iOS 7 Core Image QR Code generation too blur
body: <p>here's my code for generating QRCode image</p>
  
  <pre><code>+ (UIImage *)generateQRCodeWithString:(NSString *)string {
      NSData *stringData = [string dataUsingEncoding:NSUTF8StringEncoding];
      CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
      [filter setValue:stringData forKey:@"inputMessage"];
      [filter setValue:@"M" forKey:@"inputCorrectionLevel"];
      return [UIImage imageWithCIImage:filter.outputImage];
  }
  </code></pre>
  
  <p>The result is too blur. Is it possible to set the size of the generated qr code? </p>