二维码识别（C#、WEB）

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二维码识别（C#）

ZXing.Net

添加依赖

Nuget下载依赖ZXing.Net

image-20220809155234941

注意

在做答题卡识别的时候不用用二值化的图片进行二维码的识别，识别率会大大下降。

生成二维码

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public static Bitmap createQRImage(string str)
{
  QrCodeEncodingOptions options = new QrCodeEncodingOptions();
  options.CharacterSet = "UTF-8";
  options.DisableECI = true; // Extended Channel Interpretation (ECI) 主要用于特殊的字符集。并不是所有的扫描器都支持这种编码。
  options.ErrorCorrection = ZXing.QrCode.Internal.ErrorCorrectionLevel.H; // 纠错级别
  options.Width = 300;
  options.Height = 300;
  options.Margin = 1;
  BarcodeWriter writer = new BarcodeWriter();
  writer.Format = BarcodeFormat.QR_CODE;
  writer.Options = options;

  Bitmap bmp = writer.Write(str);
  return bmp;
}

纠错级别：

L - 约 7% 纠错能力。
M - 约 15% 纠错能力。
Q - 约 25% 纠错能力。
H - 约 30% 纠错能力。

生成条形码

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public static Bitmap create128Image(string str)
{
  QrCodeEncodingOptions options = new QrCodeEncodingOptions();
  options.CharacterSet = "UTF-8";
  options.Width = 300;
  options.Height = 50;
  options.Margin = 1;
  options.PureBarcode = false; // 是否是纯码，如果为 false，则会在图片下方显示数字

  BarcodeWriter writer = new BarcodeWriter();
  writer.Format = BarcodeFormat.CODE_128;
  writer.Options = options;

  Bitmap bmp = writer.Write(str);
  return bmp;
}

识别二维码、条形码

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public static string readCode(string imagePath)
{
  string str = "";
  BarcodeReader reader = new BarcodeReader();
  reader.Options.CharacterSet = "UTF-8";
  using (Bitmap bmp = new Bitmap(imagePath))
  {
    try
    {
      Result result = reader.Decode(bmp);
      if (result != null)
      {
        str = result.Text;
      }
    }
    catch (Exception)
    {
      return str;
    }
  }

  return str;
}

工具类

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namespace Z.Utils.Common
{
    using System;
    using System.Drawing;

    using ZXing;
    using ZXing.QrCode;

    public class ZQrcodeUtil
    {
        /// <summary>
        /// 创建二维码
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static Bitmap CreateQrImage(string str)
        {
            QrCodeEncodingOptions options = new QrCodeEncodingOptions();
            options.CharacterSet = "UTF-8";
            options.DisableECI = true; // Extended Channel Interpretation (ECI) 主要用于特殊的字符集。并不是所有的扫描器都支持这种编码。
            options.ErrorCorrection = ZXing.QrCode.Internal.ErrorCorrectionLevel.H; // 纠错级别
            options.Width = 300;
            options.Height = 300;
            options.Margin = 1;
            BarcodeWriter writer = new BarcodeWriter();
            writer.Format = BarcodeFormat.QR_CODE;
            writer.Options = options;

            Bitmap bmp = writer.Write(str);
            return bmp;
        }

        /// <summary>
        /// 识别二维码
        /// </summary>
        /// <param name="bmp"></param>
        /// <returns></returns>
        public static string ReadCode(Bitmap bmp)
        {
            string str = "";
            BarcodeReader reader = new BarcodeReader();
            reader.Options.CharacterSet = "UTF-8";
            try
            {
                Result result = reader.Decode(bmp);
                if (result != null)
                {
                    str = result.Text;
                }
            }
            catch (Exception)
            {
                return str;
            }

            return str;
        }

        /// <summary>
        /// 识别二维码
        /// </summary>
        /// <param name="imagePath"></param>
        /// <returns></returns>
        public static string ReadCode(string imagePath)
        {
            string str = "";
            BarcodeReader reader = new BarcodeReader();
            reader.Options.CharacterSet = "UTF-8";
            using (Bitmap bmp = new Bitmap(imagePath))
            {
                try
                {
                    Result result = reader.Decode(bmp);
                    if (result != null)
                    {
                        str = result.Text;
                    }
                }
                catch (Exception)
                {
                    return str;
                }
            }

            return str;
        }
    }
}

QRCoder

安装

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Install-Package QRCoder -Version 1.3.9

网址https://github.com/codebude/QRCoder/

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namespace SchoolClient.Utils
{
    using System;
    using System.Drawing;
    using System.Runtime.InteropServices;
    using System.Windows;
    using System.Windows.Media;
    using System.Windows.Media.Imaging;

    using QRCoder;

    using Z.Utils.Common;

    public class ZqrCodeUtil
    {
        public static ImageSource CreateQr
        (
            string str,
            int pixelsPerModule = 20
        )
        {
            System.Drawing.Color qrColor = System.Drawing.Color.Black;
            System.Drawing.Color qrBackgroundColor = System.Drawing.Color.White;
            IntPtr hBitmap = IntPtr.Zero;
            ImageSource wpfBitmap = null;
            try
            {
                QRCodeGenerator qrGenerator = new QRCodeGenerator();
                QRCodeData qrCodeData = qrGenerator.CreateQrCode(
                    str,
                    QRCodeGenerator.ECCLevel.Q
                );
                QRCode qrCode = new QRCode(qrCodeData);
                Bitmap qrCodeImage = qrCode.GetGraphic(
                    pixelsPerModule,
                    qrColor,
                    qrBackgroundColor,
                    true
                );
                hBitmap = qrCodeImage.GetHbitmap();
                wpfBitmap = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
                    hBitmap,
                    IntPtr.Zero,
                    Int32Rect.Empty,
                    BitmapSizeOptions.FromEmptyOptions()
                );
            }
            catch (Exception ex)
            {
                ZLogHelper.Logerror.Error(
                    "生成二维码",
                    ex
                );
            }
            finally
            {
                // Ensure that the HBitmap is properly released
                try
                {
                    if (hBitmap != IntPtr.Zero)
                    {
                        DeleteObject(hBitmap);
                    }
                }
                catch (Exception)
                {
                    // ignored
                }
            }
            return wpfBitmap;
        }

        // Import the DeleteObject method from the GDI library
        [DllImport("gdi32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool DeleteObject(IntPtr hObject);
    }
}

注意

pixelsPerModule不是图片的大小，保持默认20即可，设置过大可能导致在部分电脑上图片显示异常。

Bitmap=>ImageSource

方式1

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public static ImageSource GetImageSourceByBitmap(Bitmap bm)
{
    IntPtr hBitmap = IntPtr.Zero;
    ImageSource imageSource = null;
    try
    {
        hBitmap = bm.GetHbitmap();
        BitmapSource bitmapSource = Imaging.CreateBitmapSourceFromHBitmap(
            hBitmap,
            IntPtr.Zero,
            Int32Rect.Empty,
            BitmapSizeOptions.FromEmptyOptions()
        );

        // Convert BitmapSource to ImageSource
        imageSource = (ImageSource)new ImageSourceConverter().ConvertFrom(bitmapSource);
    }
    finally
    {
        // Ensure that the HBitmap is properly released
        if (hBitmap != IntPtr.Zero)
        {
            DeleteObject(hBitmap);
        }
    }
    return imageSource;
}

// Import the DeleteObject method from the GDI library
[DllImport("gdi32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern bool DeleteObject(IntPtr hObject);

方式2

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public static ImageSource GetImageSourceByBitmap2(Bitmap bm)
{
    IntPtr hBitmap = IntPtr.Zero;
    ImageSource imageSource = null;
    try
    {
        hBitmap = bm.GetHbitmap();
        imageSource = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
            hBitmap,
            IntPtr.Zero,
            Int32Rect.Empty,
            BitmapSizeOptions.FromEmptyOptions()
        );
    }
    finally
    {
        // Ensure that the HBitmap is properly released
        if (hBitmap != IntPtr.Zero)
        {
            DeleteObject(hBitmap);
        }
    }
    return imageSource;
}

// Import the DeleteObject method from the GDI library
[DllImport("gdi32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern bool DeleteObject(IntPtr hObject);

两种方法都可以将Bitmap转换为ImageSource，并且都可以正常工作。

然而，推荐使用第二种方法GetImageSourceByBitmap2，它使用的是System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap方法。

这是因为CreateBitmapSourceFromHBitmap方法是WPF提供的一个直接的API，用于从HBITMAP句柄创建BitmapSource对象。

与第一种方法相比，它更简洁且更直接，在性能上也更高效。

所以，GetImageSourceByBitmap2方法是更好的选择。

WEB二维码生成

方式1

https://www.npmjs.com/package/qrcode#usage

引用

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<script src="https://cdn.jsdelivr.net/npm/qrcode/build/qrcode.min.js"></script>

或者

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npm install --save qrcode

import QRCode from 'qrcode'

调用

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let that = this;
var opts = {
  errorCorrectionLevel: 'H',
  type: 'image/jpeg',
  quality: 0.9,
  margin: 0,
  color: {
    dark: "#000000",
    light: "#ffffff"
  }
};
QRCode.toDataURL(
  "https://www.psvmc.cn",
  opts,
  function (err, url) {
    that.qrcode_url = url;
  });

注意

要转换的内容必须是字符串，不能是数字，否则会报错。

方式2

https://www.npmjs.com/package/qrcodejs2

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let qrcodes = this.$refs["qrcode"];
for (const qrcode of qrcodes) {
  new QRCode(qrcode, {
    text: "https://www.psvmc.cn",
    width: 128,
    height: 128,
    colorDark: "#000000",
    colorLight: "#ffffff",
    correctLevel: QRCode.CorrectLevel.M
  });
}

更新二维码

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qrcode.clear();
qrcode.makeCode("https://www.psvmc.cn");