protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
var content = WebUtility.GetRequestStr("s", "");
if (!content.StartsWith("http"))
content = string.Format("http://{0}:{1}{2}", Request.Url.Host, Request.Url.Port, HttpUtility.UrlDecode(content));
QrEncoder qrEncoder = new QrEncoder(ErrorCorrectionLevel.H);
QrCode qrCode = new QrCode();
if (qrEncoder.TryEncode(content, out qrCode))
{
var fCodeSize = new FixedCodeSize(500, QuietZoneModules.Two);
fCodeSize.QuietZoneModules = QuietZoneModules.Four;
GraphicsRenderer renderer = new GraphicsRenderer(fCodeSize, Brushes.Black, Brushes.White);
MemoryStream ms = new MemoryStream();
renderer.WriteToStream(qrCode.Matrix, ImageFormat.Png, ms);
Response.Cache.SetNoStore();
Response.ClearContent();
Response.ContentType = "image/Png";
Response.BinaryWrite(ms.ToArray());
}
}
}
private int CalculateSuitableWidth(int width, int bitMatrixWidth)
{
FixedCodeSize isize = new FixedCodeSize(width, QuietZoneModule);
DrawingSize dSize = isize.GetSize(bitMatrixWidth);
int gap = dSize.CodeWidth - dSize.ModuleSize * (bitMatrixWidth + 2 * (int)QuietZoneModule);
if (gap == 0)
return width;
else if (dSize.CodeWidth / gap < 4)
return (dSize.ModuleSize + 1) * (bitMatrixWidth + 2 * (int)QuietZoneModule);
else
return dSize.ModuleSize * (bitMatrixWidth + 2 * (int)QuietZoneModule);
}
/// <summary>
/// Renders a Quick Reponse code, that can be used with Google Authenticator or compatiple software.
/// </summary>
/// <param name="ident">ident of device as shown to user</param>
/// <param name="key">private key</param>
/// <param name="type">type of QR code, HOTP or TOTP</param>
/// <param name="size">pixels height/width of png image</param>
/// <returns>png image as byte array</returns>
public static byte[] RenderQrCode(string ident, byte[] key, QrCodeType type, int size=200)
{
string url = "otpauth://" + type.ToString().ToLower() + "/" + ident + "?secret=" + Base32.Convert(key);
QrEncoder encoder = new QrEncoder(ErrorCorrectionLevel.M);
QrCode qrCode;
encoder.TryEncode(url, out qrCode);
ISizeCalculation isize = new FixedCodeSize(size, QuietZoneModules.Zero);
GraphicsRenderer gRenderer = new GraphicsRenderer(isize);
using (MemoryStream ms = new MemoryStream())
{
gRenderer.WriteToStream(qrCode.Matrix, ImageFormat.Png, ms);
return ms.GetBuffer();
}
}
