业务需要动态给图片增加文字（书本的封面图片），修改字体大小、字体、颜色、控制位置
测试代码：
1 string path = @"E:\cover.png"; 2 3 Bitmap bmp = new Bitmap(path); 4 Graphics g = Graphics.FromImage(bmp); 5 String str = "贤愚经"; 6 Font font = new Font("仿宋_GB2312", 14, FontStyle.Bold);//设置字体，大小，粗细 7 SolidBrush sbrush = new SolidBrush(Color.White);//设置颜色 8 int base_left = 10; 9 int left_space = 30;10 11 int base_top = 27;12 int top_space = 27;13 for (int i = 0; i < str.Length; i++)14 {15 if (i > 13)16 {17 continue;18 g.DrawString(str[i] + "", font, sbrush, new PointF(base_left + (left_space * 2), base_top + (top_space * (i - 14))));19 }20 else if (i > 6)21 {22 g.DrawString(str[i] + "", font, sbrush, new PointF(base_left + (left_space * 1), base_top + (top_space * (i - 7))));23 }24 else25 {26 g.DrawString(str[i] + "", font, sbrush, new PointF(base_left, base_top + (top_space * i)));27 }28 29 }30 31 //MemoryStream ms = new MemoryStream();32 //bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);33 bmp.Save(@"E:\cover1.png");字体选择：
黑体：SimHei
宋体：SimSun
新宋体：NSimSun
仿宋：FangSong
楷体：KaiTi
仿宋_GB2312：FangSong_GB2312
楷体_GB2312：KaiTi_GB2312
微软雅黑体：Microsoft YaHei
完结。
