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 else 112 { 113 strArr[i] = strValue; 114 } 115 } 116 //200/30 117 //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 }
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