iot/projects/Demo/Demo.Android/Controls/PreviewCallback.cs

using Android.Hardware;
using SkiaSharp.Views.Android;
using System;
using System.IO;

namespace Demo.Droid.Controls
{
    public class PreviewCallback : Java.Lang.Object, Camera.IPreviewCallback
    {
        private int width;
        private int height;
        private Android.Graphics.ImageFormatType previewFormat;

        public PreviewCallback(int width, int height, Android.Graphics.ImageFormatType previewFormat)
        {
            this.width = width;
            this.height = height;
            this.previewFormat = previewFormat;
        }

        public void OnPreviewFrame(byte[] data, Camera camera)
        {
            //byte[] rotatedData = new byte[bytes.Length];
            //for (int y = 0; y < height; y++)
            //{
            //    for (int x = 0; x < width; x++)
            //    {
            //        rotatedData[x * height + height - y - 1] = bytes[x + y * width];
            //    }
            //}
            var jpegBytes = this.ConvertYuvToJpeg(data);
            var droidBitmap = Android.Graphics.BitmapFactory.DecodeByteArray(jpegBytes, 0, jpegBytes.Length);
            var skBitmap = droidBitmap.ToSKBitmap();
            var base64 = Convert.ToBase64String(jpegBytes);
        }

        private byte[] ConvertYuvToJpeg(byte[] yuvData, int quality = 80)
        {
            var yuv = new Android.Graphics.YuvImage(yuvData, previewFormat, width, height, null);
            var ms = new MemoryStream();
            yuv.CompressToJpeg(new Android.Graphics.Rect(0, 0, width, height), quality, ms);
            var jpegData = ms.ToArray();
            ms.Close();
            return jpegData;
        }
    }
}