===============GDI+======================

  public static Bitmap writeImage(Bitmap image,double[] dubleY1, double[] DubleY2, int[] xLine1,int[] xLine2, double yStart, double yUnit, int xUnit, string yName,int tt,int xStart)

        {

            Pen p1 = Pens.Blue;   //写图例的画笔

            Pen p2 = Pens.Red;

            Brush bs1 = Brushes.Blue;  //画线用的

            Brush bs2 = Brushes.Red;

            int[] y1 = getYpoint1(dubleY1, yStart, yUnit);  //Y轴的坐标点

            int[] y2 = getYpoint1(DubleY2, yStart, yUnit);  //Y轴的坐标点

            

            //Bitmap image = Resource2.KT3;//线图底稿  



            Bitmap newimage = new Bitmap(image.Width, image.Height);

            Graphics oGraphic = Graphics.FromImage(newimage);

            Point p00 = new Point(0, 0);

            oGraphic.DrawImage(image, p00);

            image.Dispose();

            image = newimage;





            Point[] py1 = new Point[y1.Length];

            Point[] py2 = new Point[y2.Length];

            

            ……这里有一段得到Y 点数组的代码,取得每个Y点的位置



            using (Graphics g = Graphics.FromImage(image))  //在背景图上画 折线图

            {

                if (py1.Length > 1)

                {

                    g.DrawLines(p1, py1);//标准值 曲线

                }

                if (py2.Length > 1)

                {

                    g.DrawLines(p2, py2);//检测值    曲线

                }

                

                //画y轴坐标

                for (int i = 0; i <7; i++)

                {

                    double iYvalue = yStart + yUnit * 20 * i;

                    g.DrawString(iYvalue.ToString("0.00"), ft, bs2, theYs[i]);

                    

                }

                //画x轴坐标

                for (int i = 0; i <5; i++)

                {

                    string xValue = "0";



                    int theXvalue = (i * xUnit + 1) * 50;

                    xValue = Convert.ToInt32(i * 5 * xUnit+xStart).ToString();





                    g.DrawString(xValue, ft, Brushes.White, theXs[i]);

                }

                //画出图例

                int leng = yName.Length;

                Point pA;

                Point pB;

                        switch (tt)

                        {

                            case 0:

                                pA = new Point(700, 20);

                                pB = new Point(700, 35);

                            ^                            default:

                                pA = new Point(1820, 1160);

                                pB = new Point(1820, 1175);

                                break;

                        }

               

                g.DrawString("[" + yName + ":标准值]", ft2, bs1, pA);

                g.DrawString("[" + yName + ":检测值]", ft2, bs2, pB);





            }

            return image;





        }