iot/projects/Demo/Demo.iOS/IosDecoder.cs

using CameraPreview;
using CameraPreview.iOS;
using CoreGraphics;
using CoreVideo;
using System.IO;
using UIKit;

namespace Demo.iOS
{
    public class IosDecoder : DefaultDecoderBase
    {
        private readonly FaceDecoder _faceDecoder = new FaceDecoder();

        public override IScanResult Decode(CVPixelBuffer pixelBuffer)
        {
            pixelBuffer.Lock(CVPixelBufferLock.None);
            var flags = CGBitmapFlags.PremultipliedFirst | CGBitmapFlags.ByteOrder32Little;
            using (var cs = CGColorSpace.CreateDeviceRGB())
            {
                using (var context = new CGBitmapContext(pixelBuffer.BaseAddress,
                    pixelBuffer.Width,
                    pixelBuffer.Height,
                    8,
                    pixelBuffer.BytesPerRow,
                    cs,
                    (CGImageAlphaInfo)flags))
                {
                    using (var cgImage = context.ToImage())
                    {
                        pixelBuffer.Unlock(CVPixelBufferLock.None);
                        var uiImage = UIImage.FromImage(cgImage);
                        using (var stream = new MemoryStream())
                        {
                            uiImage.AsJPEG().AsStream().CopyTo(stream);
                            this._faceDecoder.Decode(stream.ToArray());
                        }
                    }
                }
            }
            return base.Decode(pixelBuffer);
        }
    }
}