代码分享：
//绘制单色画笔
Bitmap l = new Bitmap(800, 600);
Graphics g = Graphics.FromImage(l);
g.Clear(Color.White);
SolidBrush b = new SolidBrush(Color.Yellow);
g.FillEllipse(b, 70, 20, 100, 50);
System.IO.MemoryStream ms = new System.IO.MemoryStream();
l.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
//绘制阴影图案
//Bitmap l = new Bitmap(200, 100);
//Graphics g = Graphics.FromImage(l);
//g.Clear(Color.White);
//HatchBrush b = new HatchBrush( HatchStyle.BackwardDiagonal,Color.Pink,Color.Orange);
//g.FillEllipse(b, 70, 20, 100, 50);
//System.IO.MemoryStream ms = new System.IO.MemoryStream();
//l.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
//Response.ClearContent();
//Response.ContentType = "image/Jpeg";
//Response.BinaryWrite(ms.ToArray());
//绘制图像
//Bitmap l = new Bitmap(200, 100);
//Graphics g = Graphics.FromImage(l);
//g.Clear(Color.White);
//TextureBrush b = new TextureBrush(System.Drawing.Image.FromFile(Server.MapPath("~/地泵.jpg")));
//b.WrapMode = WrapMode.Clamp;
//g.FillEllipse(b, 70, 20, 100, 50);
//System.IO.MemoryStream ms = new System.IO.MemoryStream();
//l.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
//Response.ClearContent();
//Response.ContentType = "image/Jpeg";
//Response.BinaryWrite(ms.ToArray());
//实现渐变
//Bitmap l = new Bitmap(200, 100);
//Graphics g = Graphics.FromImage(l);
//g.Clear(Color.White);
//Rectangle b = new Rectangle(0,0,200,100);
//LinearGradientBrush bru = new LinearGradientBrush(b, Color.Pink, Color.Green, LinearGradientMode.BackwardDiagonal);
//g.FillRectangle(bru, 70, 20, 100, 50);
//System.IO.MemoryStream ms = new System.IO.MemoryStream();
//l.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
//Response.ClearContent();
//Response.ContentType = "image/Jpeg";
//Response.BinaryWrite(ms.ToArray());
//实现彩色渐变
//Bitmap l = new Bitmap(400, 200);
//Graphics g = Graphics.FromImage(l);
//g.Clear(Color.White);
//Point p = new Point(100, 100);
//int R = 100;
//GraphicsPath path = new GraphicsPath();
//path.AddEllipse(p.X - R, p.Y - R, 2 * R, 2 * R);
//PathGradientBrush bru = new PathGradientBrush(path);
//bru.CenterPoint = p;
//bru.CenterColor = Color.Green;
//bru.SurroundColors = new Color[] {Color.Gold};
//g.FillEllipse(bru, p.X - R, p.Y - R, 2 * R, 2 * R);
//System.IO.MemoryStream ms = new System.IO.MemoryStream();
//l.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
//Response.ClearContent();
//Response.ContentType = "image/Jpeg";
//Response.BinaryWrite(ms.ToArray());
//绘制曲线
//Bitmap b = new Bitmap(300,200);
//Graphics g = Graphics.FromImage(b);
//g.Clear(Color.White);
//Point[] ps = {new Point(10,10),new Point(10,100),new Point(200,50),new Point(260,120) };
//g.DrawLines(new Pen(Color.Pink, 3), ps);
//System.IO.MemoryStream ms = new System.IO.MemoryStream();
//b.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
//Response.ClearContent();
//Response.ContentType = "image/Jpeg";
//Response.BinaryWrite(ms.ToArray());
//绘制矩形
//Bitmap b = new Bitmap(500,500);
//Graphics g = Graphics.FromImage(b);
//g.Clear(Color.White);
//g.DrawRectangles(new Pen(Color.Black, 2), new Rectangle[] { new Rectangle(10,10,100,200), new Rectangle(100, 200, 250, 50) });
//System.IO.MemoryStream m = new System.IO.MemoryStream();
//b.Save(m, System.Drawing.Imaging.ImageFormat.Jpeg);
//Response.ClearContent();
//Response.ContentType = "image/Jpeg";
//Response.BinaryWrite(m.ToArray());
//绘制椭圆
//Bitmap b = new Bitmap(200,200);
//Graphics g = Graphics.FromImage(b);
//g.Clear(Color.White);
//g.DrawEllipse(new Pen(Color.Pink, 3), new Rectangle(10, 10, 50, 100));
//System.IO.MemoryStream m = new System.IO.MemoryStream();
//b.Save(m, System.Drawing.Imaging.ImageFormat.Jpeg);
//Response.ClearContent();
//Response.ContentType = "image/Jpeg";
//Response.BinaryWrite(m.ToArray());
//绘制弧形
//Bitmap b = new Bitmap(200, 200);
//Graphics g = Graphics.FromImage(b);
//g.Clear(Color.White);
//g.DrawArc(new Pen(Color.Pink, 3), new Rectangle(10, 10, 50, 100),-60,180);
//System.IO.MemoryStream m = new System.IO.MemoryStream();
//b.Save(m, System.Drawing.Imaging.ImageFormat.Jpeg);
//Response.ClearContent();
//Response.ContentType = "image/Jpeg";
//Response.BinaryWrite(m.ToArray());
//绘制扇形
//Bitmap b = new Bitmap(200, 200);
//Graphics g = Graphics.FromImage(b);
//g.Clear(Color.White);
//g.DrawPie(new Pen(Color.Pink, 3), new Rectangle(10, 10, 150, 100), 50, 200);
//System.IO.MemoryStream m = new System.IO.MemoryStream();
//b.Save(m, System.Drawing.Imaging.ImageFormat.Jpeg);
//Response.ClearContent();
//Response.ContentType = "image/Jpeg";
//Response.BinaryWrite(m.ToArray());
图片展示：
