asp.net 生成二维码,带logo，带下方文字

目标可以生成带网址的信息的二维码，可以是带logo 或者不带logo，或者下方带一行说明文字

nuget 下载二维码管理包

	    public static Bitmap GenerateQrCode(string text, int w, int h,string desc = "")
        {
            BarcodeWriter writer = new BarcodeWriter();
            writer.Format = BarcodeFormat.QR_CODE;
            QrCodeEncodingOptions options = new QrCodeEncodingOptions()
            {
                DisableECI = true,//设置内容编码
                CharacterSet = "UTF-8",  //设置二维码的宽度和高度
                Width = w,
                Height = h,
                Margin = 1//设置二维码的边距,单位不是固定像素
            };

            writer.Options = options;
            Bitmap map = writer.Write(text);
            if (!string.IsNullOrWhiteSpace(desc))
            {
                return AddText(desc, map, w, h);
            }
            return map;
        }

        public static Bitmap GenerateQrCodeWithLogo(string text, int w, int h, string logoUrl,string desc = "")
        {
            Bitmap logo = new Bitmap(logoUrl);
            //构造二维码写码器
            MultiFormatWriter writer = new MultiFormatWriter();
            Dictionary<EncodeHintType, object> hint = new Dictionary<EncodeHintType, object>();
            hint.Add(EncodeHintType.CHARACTER_SET, "UTF-8");
            hint.Add(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
            hint.Add(EncodeHintType.MARGIN, 1);

            //生成二维码 
            BitMatrix bm = writer.encode(text, BarcodeFormat.QR_CODE, w, h, hint);
            BarcodeWriter barcodeWriter = new BarcodeWriter();
            Bitmap map = barcodeWriter.Write(bm);

            //获取二维码实际尺寸（去掉二维码两边空白后的实际尺寸）
            int[] rectangle = bm.getEnclosingRectangle();

            //计算插入图片的大小和位置
            int middleW = Math.Min((int)(rectangle[2] / 3), logo.Width);
            int middleH = Math.Min((int)(rectangle[3] / 3), logo.Height);
            int middleL = (map.Width - middleW) / 2;
            int middleT = (map.Height - middleH) / 2;

            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, w, h);
                //白底将二维码插入图片
                g.FillRectangle(Brushes.White, middleL, middleT, middleW, middleH);
                g.DrawImage(logo, middleL, middleT, middleW, middleH);
            }

            if (!string.IsNullOrWhiteSpace(desc))
            {
                return AddText(desc, map, w, h);
            }
           
            return bmpimg;
        }
        
        private static Bitmap AddText(string desc ,Bitmap qrBitMap,int width,int height)
        {
            var txtHeight = 30;  // 默认一行文字
            Font font = new Font("GB2312", 11, FontStyle.Regular);//设置字体，大小
            SolidBrush sbrush = new SolidBrush(Color.Black); // 设置颜色
            var newMap = new Bitmap(width, height + txtHeight);
            Graphics g = Graphics.FromImage(newMap);
            g.Clear(Color.White);
            var format = StringFormat.GenericDefault;
            format.LineAlignment = StringAlignment.Center;
            format.Alignment = StringAlignment.Center;
            g.DrawString(desc, font, sbrush, new RectangleF(0,height,width, txtHeight), format);

            // 合并位图
            g.DrawImage(qrBitMap, new Rectangle(0, 0, width, height));
            g.Dispose();
            return newMap;
        }
        
		/// 

        /// 解码二维码
        /// 
        /// 待解码的二维码图片
        /// 扫码结果
        public static string DecodeQrCode(Bitmap barcodeBitmap)
        {
            BarcodeReader reader = new BarcodeReader();
            reader.Options.CharacterSet = "UTF-8";
            var result = reader.Decode(barcodeBitmap);
            return (result == null) ? null : result.Text;
        }