原图旋转/缩放 然后画布画图 ImageProcessor

            //旋转
            byte[] photoBytes = File.ReadAllBytes(HttpContext.Current.Server.MapPath(diyInfo.ImageUrl));
            ImageFactory imageFactory = new ImageFactory();
            imageFactory.Load(photoBytes);
            imageFactory.Rotate(diyInfo.RotationAngle);
            var ss = imageFactory.Image;
            //缩放
            Bitmap bm1 = new Bitmap(ss, Convert.ToInt32(ss.Width * diyInfo.TemplateZoom * diyInfo.PictureZoom), Convert.ToInt32(ss.Height * diyInfo.TemplateZoom * diyInfo.PictureZoom));
            //画布做图
            Bitmap huabu = new Bitmap(Convert.ToInt32(diyInfo.EditWidth), Convert.ToInt32(diyInfo.EditHeight));
            Graphics huabug = Graphics.FromImage(huabu);
            var neww = bm1.Width;
            var newh = bm1.Height;
            var x = Convert.ToInt32(diyInfo.CenterMarginLeft * diyInfo.TemplateZoom - neww / 2);
            var y = Convert.ToInt32(diyInfo.CenterMarginTop * diyInfo.TemplateZoom - newh / 2);
            Point ulCorner = new Point(x, y);
            huabug.DrawImage(bm1, ulCorner);
            huabu.Save(@"newbm.jpg");

  //创建一块指定大小的画布
            var bitmap = new Bitmap(200, 200);
            var huabug = Graphics.FromImage(bitmap);
            //在画布指定位置添加一张图片
            var ulCorner = new Point(50, 50);
            var newImage = Image.FromFile(@"C:\\Users\\wei.chen\\Desktop\\ConsoleApplication1\\ConsoleApplication1\\images\\chrome.png");
            huabug.DrawImage(newImage, ulCorner);
            //在画布指定位置写文字
            //定义字体
            var frm = new PrivateFontCollection();
            frm.AddFontFile(@"C:\\Users\\wei.chen\\Desktop\\ConsoleApplication1\\ConsoleApplication1\\fonts\\华康娃娃体.TTF");
            Font font = new Font(frm.Families[0], 11);
            //定义颜色
            SolidBrush sbrush = new SolidBrush(System.Drawing.ColorTranslator.FromHtml("#ff0000"));
            // 绘制围绕点旋转的文本
            PointF point = new PointF(50, 50);
            StringFormat format = new StringFormat();
            format.Alignment = StringAlignment.Center;
            format.LineAlignment = StringAlignment.Center;
            Matrix mtxRotate = huabug.Transform;
            mtxRotate.RotateAt(90f, point); // 旋转角度和平移
            huabug.Transform = mtxRotate;
            huabug.DrawString("从前有座山", font, sbrush, point, format);
            bitmap.Save(@"newbm.jpg");