C#图像处理

前段时间在写一个公司层级动态呈现的图形处理功能，对C#的图形处理有了大致的了解，现整理如下:
一、生成图片并实现颜色渐变效果
    Response.Clear(); 
   Bitmap imgOutput = new Bitmap(100, 50); 
   Graphics gic = Graphics.FromImage(imgOutput);

   gic.Clear(Color.BlueViolet);
   gic.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
   gic.DrawString("渐变图形", new Font("黑体",16,FontStyle.Italic),new SolidBrush(Color.White),new PointF(2,2)); 
   gic.FillRectangle(new System.Drawing.Drawing2D.LinearGradientBrush(new Point(0,0), new Point(100,50), Color.FromArgb(0,0,0,0),Color.FromArgb(255,255,255,255)),0,0,100,50); 

   imgOutput.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
   gic.Dispose(); 
   imgOutput.Dispose(); 
   Response.End(); 

二、对图片进行反转
    System.Drawing.Image drawimage = System.Drawing.Image.FromFile(photopath);//photopath表示图片的物理地址
   drawimage.RotateFlip(RotateFlipType.Rotate270FlipNone);
    if(File.Exists(photopath))
   {
        File.SetAttributes(photopath,FileAttributes.Normal);
        File.Delete(photopath);
   }
   drawimage.Save(photopath,System.Drawing.Imaging.ImageFormat.Jpeg);
   drawimage.Dispose();

三、对图片进行缩放
    System.Drawing.Image drawimage = System.Drawing.Image.FromFile(photopath);
   Bitmap imgOutput = new Bitmap(drawimage,60,30);
   imgOutput.Save(newphotppath, System.Drawing.Imaging.ImageFormat.Jpeg); 
   imgOutput.Dispose();  
   Response.End();

其他还有一些画线、画矩形、画圆等的函数和方法都可以在System.Drawing中找到；