.net core使用ZXing.Net识别图片中的二维码或条型码

.net core 3.1 识别图片中的二维码或条型码

安装扩展ZXing.Net.Bindings.ZKWeb.System.Drawing

  

命名空间： 

   using System;
   using System.IO;
   using System.DrawingCore;
   using ZXing.Common;
   using ZXing;
   using ZXing.QrCode;
   using ZXing.ZKWeb;
   using System.Net;
   using System.Threading;
   using System.DrawingCore.Imaging;

 

    public static class CodeHelper
    {
        /// <summary>
        /// 读取二维码或者条形码（通过http路径）
        /// </summary>
        /// <param name="url">http路径</param>
        /// <returns>returns</returns>
        public static string ReadFromImage(string url)
        {
            var tryCount = 1;
            Console.WriteLine($"正在识别：url={url}");
            while (tryCount <= 3)
            {// 偶尔识别不出时重试
                try
                {
                    if (string.IsNullOrWhiteSpace(url))
                    {
                        return "";
                    }

                    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                    request.Method = "GET";
                    using (WebResponse response = request.GetResponse())
                    {
                        using (var stream = response.GetResponseStream())
                        {
                            using (var image = Image.FromStream(stream))
                            {
                                using (Bitmap bmp = Resizer(image, 2000))
                                {// 因有些图片较模糊，故放大比较容易识别。可不放大 Bitmap bmp = new Bitmap(image);

                                    // 该类名称为BarcodeReader,可以读二维码和条形码
                                    var zzb = new ZXing.ZKWeb.BarcodeReader();
                                    zzb.Options = new DecodingOptions
                                    {
                                        CharacterSet = "UTF-8"
                                    };
                                    Result r = zzb.Decode(bmp);
                                    string resultText = null;
                                    if (r != null)
                                    {
                                        resultText = r.Text;
                                    }

                                    if (!string.IsNullOrWhiteSpace(resultText))
                                    {
                                        Console.WriteLine($"识别结果：{resultText}");
                                    }

                                    tryCount = 10;
                                    return resultText;
                                }
                            }
                        }
                    }
                }
                catch (Exception ex)
                {                   
                    Console.WriteLine($"ReadFromImage异常，url={url}，异常消息：{ex.Message}\r\n");
                    tryCount++;
                    if (tryCount <= 3)
                    {
                        Console.WriteLine($"0.5秒后将重试");
                        Thread.Sleep(500);
                    }
                }
            }

            return "";
        }

        /// <summary>
        /// 按宽度放大
        /// </summary>
        /// <param name="bmp">bmp</param>
        /// <param name="width">width</param>
        /// <returns>returns</returns>
        private static Bitmap Resizer(this Image bmp, int width)
        {
            if (bmp.Width >= width)
            {
                return new Bitmap(bmp);
            }

            Bitmap ob = new Bitmap(width, bmp.Height * width / bmp.Width);

            using (var g = Graphics.FromImage(ob))
            {
                g.Clear(Color.WhiteSmoke);
                g.DrawImage(bmp, new Rectangle(0, 0, ob.Width, ob.Height), 0, 0, bmp.Width, bmp.Height, GraphicsUnit.Pixel);
            }

            return ob;
        }

        /// <summary>
        /// 读取二维码或者条形码（通过物理路径）
        /// </summary>
        /// <param name="imgFile">物理路径</param>
        /// <returns>returns</returns>
        public static string ReadFromImage2(string imgFile)
        {
            if (string.IsNullOrWhiteSpace(imgFile))
            {
                return "";
            }

            Image img = Image.FromFile(imgFile);
            Bitmap b = new Bitmap(img);

            // 该类名称为BarcodeReader,可以读二维码和条形码
            var zzb = new ZXing.ZKWeb.BarcodeReader();
            zzb.Options = new DecodingOptions
            {
                CharacterSet = "UTF-8"
            };
            Result r = zzb.Decode(b);
            string resultText = null;
            if (r != null)
            {
                resultText = r.Text;
            }

            b.Dispose();
            img.Dispose();

            return resultText;
        }
    }