在图片特定位置显示特定字符方法

        protected Bitmap SetImageNumber(Bitmap targetImage, string targetString)
        {
            Bitmap bmpImage = targetImage;
            RectangleF rectTitle = new RectangleF(116, 0, 56, 56);
            Font displayFont = new Font("Tahoma", 9, FontStyle.Regular);
            SolidBrush brush = new SolidBrush(Color.White);
            StringFormat strFormat = new StringFormat();
            strFormat.Alignment = StringAlignment.Center;
            strFormat.LineAlignment = StringAlignment.Center;

            if (null == targetImage)
            {
                return null;
            }
            using(Graphics g = Graphics.FromImage(bmpImage))
            {
                g.DrawString(targetString, displayFont, brush, rectTitle, strFormat);
            }

            brush.Dispose();

            return bmpImage;
        }