How to rotate text to rectangular shape C #

I have created an application that generates a QR code in a PNG image and prints text from the QR image, but now I need to rotate that text 90 degrees and I cannot find a way to do this ... I think the rectangle should be rotated because the text is inside this rectangle.

Example:

code:

namespace QR_Code_with_WFA
{
    public void CreateQRImage(string inputData)
    {
        if (inputData.Trim() == String.Empty)
        {
            System.Windows.Forms.MessageBox.Show("Data must not be empty.");
        }

        BarcodeWriter qrcoder = new ZXing.BarcodeWriter
        {
            Format = BarcodeFormat.QR_CODE,
            Options = new ZXing.QrCode.QrCodeEncodingOptions
            {
                ErrorCorrection = ZXing.QrCode.Internal.ErrorCorrectionLevel.H,
                Height = 250,
                Width = 250
            }
        };

        string tempFileName = System.IO.Path.GetTempPath() + inputData + ".png";

        Image image;
        String data = inputData;
        var result = qrcoder.Write(inputData);
        image = new Bitmap(result);
        image.Save(tempFileName);

        System.Diagnostics.Process.Start(tempFileName);

    var result2 = qrcoder.Write(inputData);

    int textWidth = 200, textHeight = 20;
    // creating new bitmap having imcreased width
    var img = new Bitmap(result2.Width + textWidth, result2.Height);

    using (var g = Graphics.FromImage(img))
    using (var font = new Font(FontFamily.GenericMonospace, 12))
    using (var brush = new SolidBrush(Color.Black))
    using (var bgBrush = new SolidBrush(Color.White))
    using (var format = new StringFormat() { Alignment = StringAlignment.Near })
    {
            // filling background with white color
            g.FillRectangle(bgBrush, 0, 0, img.Width, img.Height);
            // drawing your generated image over new one
            g.DrawImage(result, new Point(0,0));
            // drawing text
            g.DrawString(inputData, font, brush,  result2.Width, (result2.Height - textHeight) / 2, format);
    }

    img.Save(tempFileName);
    }
}