Google ZXing

Google ZXing是目前一个常用的基于Java实现的多种格式的1D/2D条码图像处理库，出于其开源的特性其现在已有多平台版本。比如今天要用到的ZXing.Net就是针对微软.Net平台的版本。

使用Google ZXing生成和识别二维码

使用Zxing制作二维码需要提供最少包括①是否使用ECI编码段——QrCodeEncodingOptions.DisableECI；②内容编码格式（一般为UTF-8）——QrCodeEncodingOptions.CharacterSet；③二维码的宽高（以像素计）——QrCodeEncodingOptions. Width和QrCodeEncodingOptions. Height；④二维码的边距（以像素计）——QrCodeEncodingOptions. Margin；⑤需承载的内容——String字符串。共计5种参数。 

下面的代码为基于C#.Net Winform窗体使用Zxing.Net类库生成的标准二维码。

//以一个函数调用，text为需要生成的内容
public void Normal(string text)
{
    //调用saveFileDialog选择导出二维码保存位置
    string filename = saveFileDialog.FileName;
    //初始化
    BarcodeWriter writer = new BarcodeWriter();
    writer.Format = BarcodeFormat.QR_CODE;
    QrCodeEncodingOptions options = new QrCodeEncodingOptions();
    //禁用ECI
    options.DisableECI = true;
    //内容编码格式
    options.CharacterSet = cbx_code.Text;
    //二维码的宽高
    options.Width = int.Parse(tbx_width.Text);
    options.Height = int.Parse(tbx_height.Text);
    //二维码边距
    options.Margin = int.Parse(tbx_margin.Text);
    writer.Options = options;
    //导出图片
    Bitmap p = writer.Write(text);
    p.Save(filename, System.Drawing.Imaging.ImageFormat.Png);
    p.Dispose();
    //在程序中加载导出的二维码
    pictureBox.ImageLocation = filename;
}

除去生成标准的二维码，还可以生成中间带有Logo的个性化二维码，如下图。 

以下是实现代码。

public void GenerateWithLogo(string text)
        {
            //调用openFileDialog选择要插入的Logo
            openFileDialog.ShowDialog();
            Bitmap logo = new Bitmap(openFileDialog.FileName);
            //调用saveFileDialog选择保存位置
            saveFileDialog.ShowDialog();
            //初始化
            MultiFormatWriter writer = new MultiFormatWriter();
            Dictionary<EncodeHintType, object> hint = new Dictionary<EncodeHintType, object>();
            hint.Add(EncodeHintType.CHARACTER_SET, cbx_code.Text);
            hint.Add(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);

            //生成二维码 
            BitMatrix bm = writer.encode(text, BarcodeFormat.QR_CODE, int.Parse(tbx_width.Text), int.Parse(tbx_height.Text), hint);
            BarcodeWriter barcodeWriter = new BarcodeWriter();
            Bitmap map = barcodeWriter.Write(bm);
            //计算尺寸
            int[] rectangle = bm.getEnclosingRectangle();

            //计算插入Logo的大小位置
            int middleW = Math.Min((int)(rectangle[2] / 3.5), logo.Width);
            int middleH = Math.Min((int)(rectangle[3] / 3.5), logo.Height);
            int middleL = (map.Width - middleW) / 2;
            int middleT = (map.Height - middleH) / 2;

            //将img转换成bmp格式，否则后面无法创建Graphics对象
            Bitmap bmpimg = new Bitmap(map.Width, map.Height, PixelFormat.Format32bppArgb);
            using (Graphics g = Graphics.FromImage(bmpimg))
            {
                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
                g.DrawImage(map, 0, 0);
            }
            //将二维码插入图片
            Graphics myGraphic = Graphics.FromImage(bmpimg);
            //白底
            myGraphic.FillRectangle(Brushes.White, middleL, middleT, middleW, middleH);
            myGraphic.DrawImage(logo, middleL, middleT, middleW, middleH);

            //保存成图片
            bmpimg.Save(saveFileDialog.FileName, System.Drawing.Imaging.ImageFormat.Png);
            pictureBox.ImageLocation = saveFileDialog.FileName;
        }

相比于生成，识别二维码则要简单很多。

 public void LoadQRC(string filename)
        {
            BarcodeReader reader = new BarcodeReader();
            //设置读取的格式（一般为UTF-8）
            reader.Options.CharacterSet = cbx_loadcode.Text;
            Bitmap p = new Bitmap(filename);
            Result result = reader.Decode(p);            
            rtbx.Text = result.ToString();
        }

部分代码参考：

http://www.cnblogs.com/tianma3798/p/5426869.html