# C# 使用ZXing產出QRCode

using ZXing;
using ZXing.QrCode;
using System.Drawing;

/// <summary>
/// QRCode中間放Icon
/// </summary>
public static Bitmap overlay_o { get; set; }

/// <summary>
/// 產生QrCode上面後製添加文字
/// </summary>
/// <param name="content"></param>
/// <param name="height"></param>
/// <param name="width"></param>
/// <returns></returns>
public static Bitmap QREncodeAndAddText(string content, string qrCodeText, int height = 500, int width = 500)
{
    var writer = new BarcodeWriter //dll裡面可以看到屬性
    {
        Format = BarcodeFormat.QR_CODE,
        Options = new QrCodeEncodingOptions //設定大小
        {
            Height = height,
            Width = width,
        }
    };
    var result = writer.Write(content);
    overlay_o = (Bitmap)Image.FromFile(HttpContext.Current.Server.MapPath("~/images/Icon2.png"));
    Bitmap overlay = new Bitmap(overlay_o, new Size(50,50));
    int deltaHeigth = result.Height - overlay.Height;
    int deltaWidth = result.Width - overlay.Width;
    Graphics g = Graphics.FromImage(result);
    g.DrawImage(overlay, new Point((deltaWidth / 2), (deltaHeigth / 2)));

    //控制QrCode原始圖片大小
    var img = new Bitmap(result.Width, result.Height + 50);
    using (g = Graphics.FromImage(img))
    using (var font = new Font("Microsoft JhengHei", 28))//文字字型大小
    using (var brush = new SolidBrush(Color.Black))
    using (var bgBrush = new SolidBrush(Color.White))
    using (var format = new StringFormat() { Alignment = StringAlignment.Center })
    {
        //填滿白色
        g.FillRectangle(bgBrush, 0, 0, img.Width, img.Height);
        //QRCode原始圖片座標位移(留白)
        g.DrawImage(result, new Point(0, 25));
        //填入文字、座標位移
        g.DrawString(qrCodeText, font, brush, result.Width / 2, 10, format);
    }


    return img;
}