【IT168技术文档】
这是我写的一个生成简单曲线图的程序，效果还是不错的，不过其中也有一些问题，比如如果数据中出现负数，特别是很大的负数就会使得一部分曲线不能够显示出来，还有就是如何才能保证曲线处于坐标轴的中间部位？请知道的朋友帮忙看一下，谢谢。
public static string draw(IList<TargerAnalyse.AggregativeDataSet> ds, string Field, string Title) { if (ds == null) return null; if (Field == "" || Field == string.Empty || Field == null) return null; //取得记录数量 int count = ds.Count; if (count < 2) return null; //图表高度 int height = 600; //记算图表宽度 int wd = 80 + 12 * (count - 1); //设置最小宽度为800 if (wd < 800) wd = 800; //生成Bitmap对像 Bitmap img = new Bitmap(wd, height); //生成绘图对像 Graphics g = Graphics.FromImage(img); //定义黑色画笔 Pen Bp = new Pen(Color.Black); //定义红色画笔 Pen Rp = new Pen(Color.Red); //定义银灰色画笔 Pen Sp = new Pen(Color.Silver); //定义大标题字体 Font Bfont = new Font("Arial", 12, FontStyle.Bold); //定义一般字体 Font font = new Font("Arial", 8); //定义大点的字体 Font Tfont = new Font("Arial", 10); //绘制底色 g.DrawRectangle(new Pen(Color.White, height), 0, 0, img.Width, img.Height); //定义黑色过渡型笔刷 LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, img.Width, img.Height), Color.Black, Color.Black, 1.2F, true); //定义蓝色过渡型笔刷 LinearGradientBrush Bluebrush = new LinearGradientBrush(new Rectangle(0, 0, img.Width, img.Height), Color.Blue, Color.Blue, 1.2F, true); //绘制大标题 g.DrawString(Title, Bfont, brush, 300, 5); //左边距 int zuobian = 40; //右边距 int youbian = 40; //上边距 int shangbian = 60; //下边距 int xiabian = 40; //间隔 int xjiange = (wd - zuobian - youbian) / count; // 60; int yjiange = (height - shangbian - xiabian) / count; //60; //图示位置 int ts = zuobian + xjiange * (count - 1) + 20; //取得合计数 double nums = 0; //取得最小值 double min = 0; //取得最大值 double max = 0; bool IsHasNegative = false; for (int i = 0; i < count; i++) { nums += Math.Abs(Convert.ToDouble(ds[i][Field])); if (Convert.ToDouble(ds[i][Field]) < min) { min = Convert.ToDouble(ds[i][Field]); } if (Convert.ToDouble(ds[i][Field]) > max) { max = Math.Abs(Convert.ToDouble(ds[i][Field])); } if (Convert.ToDouble(ds[i][Field]) < 0) IsHasNegative = true; } //绘制图片边框 g.DrawRectangle(Bp, 0, 0, img.Width - 1, img.Height - 1); //绘制竖坐标线 for (int i = 0; i < count; i++) { g.DrawLine(Sp, zuobian + xjiange * i, shangbian, zuobian + xjiange * i, height - xiabian); if (i % 2 == 1) { string st = Convert.ToString(ds[i]["bbny"]); g.DrawString(st, font, brush, zuobian + xjiange * i - 20, height - xiabian + 5); } } //绘制时间轴坐标标签 //for (int i = 0; i < count; i += 2) //{ // string st = Convert.ToString(ds.Tables[0].Rows[i]["bbny"]); // g.DrawString(st, font, brush, zuobian + xjiange * i - 20, height - xiabian+5); //} //绘制横坐标线 for (int i = 0; i < count; i++) { if (height - xiabian - yjiange * i > shangbian) g.DrawLine(Sp, zuobian, height - xiabian - yjiange * i, zuobian + xjiange * (count - 1), height - xiabian - yjiange * i); } //绘制竖坐标轴 g.DrawLine(Bp, zuobian, shangbian - 15, zuobian, height - xiabian); //绘制横坐标轴 if (!IsHasNegative) g.DrawLine(Bp, zuobian, height - xiabian, zuobian + xjiange * (count - 1) + 15, height - xiabian); else g.DrawLine(Bp, zuobian, 300, zuobian + xjiange * (count - 1) + 15, 300); //均值所对应得Y坐标 int zhy = (int)(((double)(height - shangbian - xiabian)) * nums / count / max) - (height - shangbian - xiabian) / 2; //定义曲线转折点 Point[] p = new Point[count]; for (int i = 0; i < count; i++) { p[i].X = zuobian + xjiange * i; //p[i].Y = 360 - Convert.ToInt32(ds.Tables[0].Rows[i][Field]) / 5 * 3 / 5; //p[i].Y =Convert.ToInt32( System.Math.Round(Convert.ToDouble(height-shangbian-xiabian)*(Convert.ToDouble(ds.Tables[0].Rows[i][Field])) / nums))+shangbian ; if (!IsHasNegative) p[i].Y = height - (int)((double)(height - shangbian - xiabian) * (Convert.ToDouble(ds[i][Field])) / max) + shangbian + zhy - xiabian; else { if (Convert.ToDouble(ds[i][Field]) > 0) p[i].Y = height / 2 - (int)((double)(height / 2 - shangbian) * (Convert.ToDouble(ds[i][Field])) / max) + shangbian; else p[i].Y = height / 2 + (int)((double)(height / 2 - xiabian) * (Math.Abs(Convert.ToDouble(ds[i][Field]))) / max); } } //绘制曲线 g.DrawCurve(Rp, p); for (int i = 0; i < count; i++) { //绘制数据 g.DrawString(ds[i][Field].ToString(), font, Bluebrush, p[i].X - 5, p[i].Y - 10); //绘制数据点 g.DrawRectangle(Rp, p[i].X - 1, p[i].Y - 1, 2, 2); } //绘制竖坐标标题 g.DrawString("指标", Tfont, brush, 5, shangbian - 20); //绘制横坐标标题 g.DrawString("月度", Tfont, brush, zuobian + xjiange * (count - 1) + 20, height - xiabian + 5); //保存绘制的图片 //MemoryStream stream = new MemoryStream(); //img.Save(stream, ImageFormat.Jpeg); Random r = new Random(1); string filepath = System.Web.Hosting.HostingEnvironment.MapPath("~\\chart\\") + r.Next().ToString() + ".jpg"; img.Save(filepath, ImageFormat.Jpeg); g.Dispose(); img.Dispose(); //return stream; return filepath; }
