asp.net实现折线图的绘制

用到.Net中绘图类，实现折线图的绘制，生成图片，在页面的显示，代码如下：

  1  /// <summary>  2     /// 获取数据   3     /// strChartName：图名称；  4     /// yName：纵坐标名称；  5     /// xName：横坐标名称；  6     /// iyMaxValue:纵坐标最大值；  7     /// dyAveValue:纵坐标单位值=（纵坐标最大值/标量30）  8     /// ----100   30    :3  9     /// ----200   30    :1.5； 10     /// xdbColumnName:横坐标绑定显示数据表值的列名； 11     /// ydbColumnName:纵坐标绑定显示数据表值得列名； 12     /// </summary> 13     public void Get_CurveData(string strSql,string strChartName,string yName,string xName,int iyMaxValue, double dyAveValue,string xdbColumnName,string ydbColumnName) 14     { 15         try 16         { 17             DataSet ds = sqlaccess.ReadFromDB(strSql); 18             draw(ds.Tables[0], strChartName, yName, xName, iyMaxValue, dyAveValue, xdbColumnName, ydbColumnName); 19         } 20         catch (Exception exp) 21         { 22             Response.Write(sqlAccess.ExceptionMessage); 23         } 24     } 25  26     public void draw(DataTable dt, string strChartName, string yName, string xName, int iyMaxValue, double dyAveValue, string xdbColumnName, string ydbColumnName) 27     { 28         //取得记录数量  29         int count = dt.Rows.Count; 30         //记算图表宽度  31         int wd = 80 + 20 * (count - 1); 32         //设置最小宽度为800  33         if (wd < 600) wd = 600; 34         //生成Bitmap对像  35         Bitmap img = new Bitmap(wd, 400); 36         //生成绘图对像  37         Graphics g = Graphics.FromImage(img); 38         //定义黑色画笔  39         Pen Bp = new Pen(Color.Black); 40         //定义红色画笔  41         Pen Rp = new Pen(Color.Red); 42         //定义银灰色画笔  43         Pen Sp = new Pen(Color.Silver); 44         //定义蓝色画笔 45         Pen Blp = new Pen(Color.Blue); 46         //定义大标题字体  47         Font Bfont = new Font("Arial", 12, FontStyle.Bold); 48         //定义一般字体  49         Font font = new Font("Arial", 9); 50         //定义大点的字体  51         Font Tfont = new Font("Arial", 9); 52         //定义横坐标间隔，(最佳值是总宽度-留空宽度[左右侧都需要])/(记录数量-1)  53         int xSpace = (wd - 100) / (count - 1); 54         //定义纵坐标间隔,不能随便修改，跟高度和横坐标线的条数有关，最佳值=(绘图的高度-上面留空-下面留空)  55         int ySpace = 30; 56         //纵坐标最大值和间隔值  57         int yMaxValue = iyMaxValue; 58         //绘制底色  59         g.DrawRectangle(new Pen(Color.White, 400), 0, 0, img.Width, img.Height); 60         //定义黑色过渡型笔刷  61         LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, img.Width, img.Height), Color.Black, Color.Black, 1.2F, true); 62         //定义蓝色过渡型笔刷  63         LinearGradientBrush Bluebrush = new LinearGradientBrush(new Rectangle(0, 0, img.Width, img.Height), Color.Blue, Color.Blue, 1.2F, true); 64         //绘制大标题  65         g.DrawString(strChartName, Bfont, brush, 40, 5); 66         //绘制信息简报  67         //string info = " 曲线图生成时间：" + DateTime.Now.ToString(); 68         //g.DrawString(info, Tfont, Bluebrush, 40, 25); 69         //绘制图片边框  70         g.DrawRectangle(Bp, 0, 0, img.Width - 1, img.Height - 1); 71         //绘制竖坐标轴  72         g.DrawLine(Bp, 40, 55, 40, 360); 73         //绘制横坐标轴 x2的60是右侧空出部分  74         g.DrawLine(Bp, 40, 360, 60 + xSpace * (count - 1), 360); 75         //绘制竖坐标标题  76         g.DrawString(yName, Tfont, brush, 5, 40); 77         //绘制横坐标标题  78         g.DrawString(xName, Tfont, brush, 40, 385); 79         //绘制竖坐标线  80         for (int i = 0; i < count; i++) 81         { 82             g.DrawLine(Sp, 40 + xSpace * i, 60, 40 + xSpace * i, 360); 83         } 84         //绘制时间轴坐标标签  85         for (int i = 0; i < count; i++) 86         { 87             //string st = Convert.ToDateTime(dt.Rows[i]["testdate"]).ToString("MM:dd"); 88             //string st = "第" + dt.Rows[i]["testdate"].ToString() + "周"; 89             string st = dt.Rows[i][xdbColumnName].ToString(); 90             g.DrawString(st, font, brush, 30 + xSpace * i, 370); 91         } 92         //绘制横坐标线  93         for (int i = 0; i < 10; i++) 94         { 95             g.DrawLine(Sp, 40, 60 + ySpace * i, 40 + xSpace * (count - 1), 60 + ySpace * i); 96             //横坐标轴的值间隔是最大值除以间隔数  97             int s = yMaxValue - i * (yMaxValue / 10); 98             //绘制发送量轴坐标标签  99             g.DrawString(s.ToString(), font, brush, 10, 60 + ySpace * i);100         }101 102         //处理39.6%形式的数据103         string[] strArr = new string[dt.Rows.Count];104         for (int i = 0; i < count; i++)105         {106             string strValue = dt.Rows[i][ydbColumnName].ToString();107             if (strValue.Contains("%"))108             {109                 strArr[i] = strValue.Split('%')[0];110             }111             else112             {113                 strArr[i] = strValue;114             }115         }116         //200/30117         //定义纵坐标单位数值=纵坐标最大值/标量最大值118         double yAveValue = dyAveValue;119         //定义曲线转折点 120         Point[] p = new Point[count];121         for (int i = 0; i < count; i++)122         {123             p[i].X = 40 + xSpace * i;124             p[i].Y = 360 - Convert.ToInt32(Convert.ToDouble(strArr[i]) * yAveValue);125         }126 127         //绘制折线图 128         //g.DrawLines(Rp, p); 129         //绘制曲线图 130         //g.DrawCurve(Rp, p); 131         //绘制自定义张力的曲线图（0.5F是张力值，默认就是这个值） 132         g.DrawCurve(Rp, p, 0.5F);133         //g.DrawLines(Rp, p); 134         //当需要在一个图里绘制多条曲线的时候，就多定义个point数组，然后画出来就可以了。 135         for (int i = 0; i < count; i++)136         {137             //绘制发送记录点的发送量 138             g.DrawString(strArr[i], font, Bluebrush, p[i].X, p[i].Y - 10);139             //绘制发送记录点 140             g.DrawRectangle(Rp, p[i].X - 1, p[i].Y - 1, 2, 2);141         }142 143         ///*******************画中值线///144         //for (int i = 0; i < count; i++)145         //{146         //    p[i].X = 40 + xSpace * i;147         //    p[i].Y = 360 - Convert.ToInt32("50") * yAveValue;148         //}149         //for (int i = 0; i < count; i++)150         //{151         //    //绘制发送记录点的发送量 152         //    g.DrawString("", font, Bluebrush, p[i].X, p[i].Y - 10);153         //    //绘制发送记录点 154         //    g.DrawRectangle(Rp, p[i].X - 1, p[i].Y - 1, 2, 2);155         //}156         //g.DrawLine(Blp, 40, 360 - Convert.ToInt32("50") * yAveValue, 60 + xSpace * (count - 1), 360 - Convert.ToInt32("50") * yAveValue);157         ///**************************///158 159         //保存绘制的图片 160         MemoryStream stream = new MemoryStream();161         img.Save(stream, ImageFormat.Jpeg);162         //图片输出 163         Response.Clear();164         Response.ContentType = "image/jpeg";165         Response.BinaryWrite(stream.ToArray());166     } 167 }