I am making my own captcha image and I have it pretty much working, but I can't figure out how to align the text in the image. I tried using a stringformat, but I can't quite get it lined up right. If someone could tell me where I am going wrong, it would help me out a lot.

Here is the code I am working with.

Code:
    Private Sub CreateImage()

        Dim equation As String = GetEquation()
        Dim bitMap As New Bitmap(150, 30, Imaging.PixelFormat.Format32bppArgb)
        Dim font As New Font("Arial", 22, FontStyle.Bold, GraphicsUnit.Pixel)
        Dim rect As New Rectangle(0, 0, 150, 30)
        Dim sf As New StringFormat(StringFormatFlags.NoWrap)

        sf.Alignment = StringAlignment.Center
        sf.LineAlignment = StringAlignment.Center

        Dim g As Graphics = Graphics.FromImage(bitMap)

        Dim b As New SolidBrush(Color.LightBlue)
        Dim pen As New Pen(Color.Black)

        g.SmoothingMode = Drawing2D.SmoothingMode.AntiAlias
        g.FillRectangle(Brushes.Beige, rect)
        g.DrawRectangle(pen, rect)

        g.DrawString(equation, font, Brushes.Blue, 0, 0, sf)

        Response.ContentType = "image/jpeg"
        bitMap.Save(Response.OutputStream, Imaging.ImageFormat.Jpeg)

        g.Dispose()
        bitMap.Dispose()

    End Sub
Thank you.