字符串長度計算:
Graphics g = Graphics.FromImage(Image.FromFile("d:\\forcal.png"));
Size size = g.MeasureString("jinghe zhang", new Font(new FontFamily("Times New Roman"), 12, FontStyle.Regular)).ToSize();
//g.MeasureString(string str,Font font);
int stringWidth = size.Width;
int stringHeight = size.Height;
Console.WriteLine(stringWidth);
Console.WriteLine(stringHeight);
Console.Read();