Core Image Detectors

gistfile1.cs

using System;
using MonoTouch.CoreImage;
using MonoTouch.UIKit;

namespace CIDetectorsDemo
{
    public class DetectorController : UIViewController
    {
        UIImageView imageView;

        public override void ViewDidLoad ()
        {
            base.ViewDidLoad ();
     
            var imageIn = UIImage.FromBundle("card.jpg");
            //var imageIn = UIImage.FromBundle("qrcode.png");

            var context = CIContext.FromOptions (null);

            var options = new CIDetectorOptions {
                Accuracy = FaceDetectorAccuracy.High
            };

            var detector = CIDetector.CreateRectangleDetector (context, options);
            //var detector = CIDetector.CreateQRDetector (context, options);
            var ciImage = CIImage.FromCGImage (imageIn.CGImage);
            var features = detector.FeaturesInImage (ciImage);

            var overlay = CIImage.ImageWithColor (CIColor.FromRgba (1.0f, 0.0f, 0.0f, 0.7f));
            overlay = overlay.ImageByCroppingToRect (features [0].Bounds);   
            var ciImageWithOverlay = overlay.CreateByCompositingOverImage (ciImage);

            var imageOut = UIImage.FromImage (ciImageWithOverlay);

            imageView = new UIImageView (imageOut);
            imageView.Frame = View.Frame;

            Add (imageView);
        }
    }
}