dafuq.cs

using System;
using MonoTouch.UIKit;
using com.google.zxing;
using MonoTouch.AVFoundation;
using MonoTouch.CoreFoundation;
using MonoTouch.CoreVideo;
using System.Collections;
using MonoTouch.CoreMedia;
using System.Runtime.InteropServices;
using com.google.zxing.common;

namespace FdvWeb
{
    // based on https://github.com/xamarin/monotouch-samples/blob/master/AVCaptureFrames/Main.cs
    public class QRScanViewController : UIViewController
    {

        public event Action<Result> Scan;

        AVCaptureSession session;
        AVCaptureVideoPreviewLayer previewLayer;
        AVCaptureDevice captureDevice;
        UIImageView overlayView;
        UIButton buttonCancel;
        UIButton buttonFlash;
        DispatchQueue queue;
        ZxingScanner scanner;

        public override void LoadView ()
        {
            base.LoadView ();

            if (!SetupCaptureSession ())
                throw new NotSupportedException ("Unable to setup camera for scan");

            previewLayer.Frame = UIScreen.MainScreen.Bounds;
            View.Layer.AddSublayer (previewLayer);
        }

        public override void ViewDidLoad ()
        {
            overlayView = new UIImageView (UIScreen.MainScreen.Bounds);
            //Use your own overlay image here
            //overlayView.Image = UIImage.FromFile("Images/BarCodeOverlay.png");
            this.View.AddSubview (overlayView);

            buttonCancel = new UIButton ();
            //buttonCancel.ButtonType = UIButtonType.RoundedRect;
            buttonCancel.Frame = new System.Drawing.RectangleF (20, 20, 130, 30);
            buttonCancel.SetTitle ("Cancel", UIControlState.Normal);
            buttonCancel.Alpha = 0.3f;
            buttonCancel.SetTitleColor (UIColor.White, UIControlState.Normal);
            buttonCancel.TintColor = UIColor.Gray;
            buttonCancel.TouchUpInside += (sender, e) => {
                this.Scan (null);
            };

            this.View.AddSubview (buttonCancel);

            buttonFlash = new UIButton ();
            //buttonFlash.ButtonType = UIButtonType.RoundedRect;
            buttonFlash.Frame = new System.Drawing.RectangleF (170, 20, 130, 30);
            buttonFlash.SetTitle ("Flash On", UIControlState.Normal);
            buttonFlash.Alpha = 0.3f;
            buttonFlash.TintColor = UIColor.Gray;
            buttonFlash.SetTitleColor (UIColor.White, UIControlState.Normal);
            //buttonFlash.HorizontalAlignment = UIControlContentHorizontalAlignment.Right;
            buttonFlash.TouchUpInside += (sender, e) => {
                if (captureDevice != null) {
                    if (captureDevice.TorchAvailable) {
                        MonoTouch.Foundation.NSError err = null;

                        captureDevice.LockForConfiguration (out err);

                        if (captureDevice.TorchMode == AVCaptureTorchMode.Auto || captureDevice.TorchMode == AVCaptureTorchMode.Off)
                            captureDevice.TorchMode = AVCaptureTorchMode.On;
                        else
                            captureDevice.TorchMode = AVCaptureTorchMode.Off;

                        captureDevice.UnlockForConfiguration ();

                        this.BeginInvokeOnMainThread (() => {
                            if (buttonFlash.CurrentTitle == "Flash On")
                                buttonFlash.SetTitle ("Flash Off", UIControlState.Normal);
                            else
                                buttonFlash.SetTitle ("Flash On", UIControlState.Normal);
                        }
                        );
                    }
                }
            };
            this.View.AddSubview (buttonFlash);

        }

        bool SetupCaptureSession ()
        {
            // configure the capture session for low resolution, change this if your code
            // can cope with more data or volume
            session = new AVCaptureSession () {
                SessionPreset = AVCaptureSession.PresetMedium
            };

            // create a device input and attach it to the session
            captureDevice = AVCaptureDevice.DefaultDeviceWithMediaType (AVMediaType.Video);
            var input = AVCaptureDeviceInput.FromDevice (captureDevice);
            if (input == null) {
                // No input device
                return false;
            }
            session.AddInput (input);

            // create a VideoDataOutput and add it to the sesion
            var output = new AVCaptureVideoDataOutput () {
                VideoSettings = new AVVideoSettings (CVPixelFormatType.CV32BGRA)
            };


            // configure the output
            queue = new DispatchQueue ("myQueue");
            scanner = new ZxingScanner (this);
            output.SetSampleBufferDelegateAndQueue (scanner, queue);
            session.AddOutput (output);

            previewLayer = new AVCaptureVideoPreviewLayer (session);
            previewLayer.Orientation = AVCaptureVideoOrientation.Portrait;
            previewLayer.VideoGravity = "AVLayerVideoGravityResizeAspectFill";

            session.StartRunning ();
            return true;
        }

        class ZxingScanner : AVCaptureVideoDataOutputSampleBufferDelegate
        {
            bool gotResult = false;
            QRScanViewController parent;
            MultiFormatReader reader;
            byte[] bytes;

            public ZxingScanner (QRScanViewController parent)
            {
                this.parent = parent;
                this.reader = new MultiFormatReader {
                    Hints = new Hashtable {
                        { DecodeHintType.POSSIBLE_FORMATS, new ArrayList {
                            /*BarcodeFormat.UPC_A, BarcodeFormat.UPC_E , BarcodeFormat.CODE_128,
                            BarcodeFormat.CODE_39, BarcodeFormat.EAN_13, BarcodeFormat.EAN_8,*/ BarcodeFormat.QR_CODE
                        } }
                    }
                };
            }

            public override void DidOutputSampleBuffer (AVCaptureOutput captureOutput, CMSampleBuffer sampleBuffer, AVCaptureConnection connection)
            {
                try {

                    if (!gotResult) {
                        LuminanceSource luminance;
                        connection.VideoOrientation = AVCaptureVideoOrientation.Portrait;

                        using (var pixelBuffer = sampleBuffer.GetImageBuffer () as CVPixelBuffer) {

                            if (bytes == null)
                                bytes = new byte [pixelBuffer.Height * pixelBuffer.BytesPerRow];

                            pixelBuffer.Lock (0);
                            Marshal.Copy (pixelBuffer.BaseAddress, bytes, 0, bytes.Length);

                            luminance = new RGBLuminanceSource (bytes, pixelBuffer.Width, pixelBuffer.Height);


                            pixelBuffer.Unlock (0);
                        }

                        var binarized = new BinaryBitmap (new HybridBinarizer (luminance));
                        var result = reader.decodeWithState (binarized);

                        //parent.session.StopRunning ();

                        gotResult = true;

                        if (parent.Scan != null) {
                            //MonoTouch.AudioToolbox.SystemSound.FromFile ("Sounds/beep.wav").PlayAlertSound ();
                            parent.Scan (result);
                        }
                    }

                } catch (ReaderException) {
                    // ignore this exception; it happens every time there is a failed scan
                } catch (Exception e) {
                    // TODO: this one is unexpected.. log or otherwise handle it
                    throw;
                } finally {
                    try {
                        // lamest thing, but seems that this throws :(
                        sampleBuffer.Dispose ();
                    } catch {
                    }
                }
            }
        }
    }
}