制作曲线图

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
//添加画图类 
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Drawing;
using System.IO;
using System.Data.SqlClient; 
using Com.LingHu.Db;

public partial class quxiantu : System.Web.UI.Page
{
    SqlHelper sqlhelper = new SqlHelper();
    protected void Page_Load(object sender, EventArgs e)
    {
        string sql = "";
        string sql1 = "";
        string sql2 = "";
        if (Request.QueryString["type"].ToString() == "体重")
        {
            sql = "select Weight as testValue,Date as testDate from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql1 = "select min(Weight) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql2 = "select max(Weight) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
        }
        else if (Request.QueryString["type"].ToString() == "体重指数")
        {
            sql = "select BMI as testValue,Date as testDate from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql1 = "select min(BMI) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql2 = "select max(BMI) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
        }
        else if (Request.QueryString["type"].ToString() == "收缩压")
        {
            sql = "select BPss as testValue,Date as testDate from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql1 = "select min(BPss) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql2 = "select max(BPss) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
        }
        else if (Request.QueryString["type"].ToString() == "舒张压")
        {
            sql = "select BPsz as testValue,Date as testDate from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql1 = "select min(BPsz) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql2 = "select max(BPsz) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
        }
        else if (Request.QueryString["type"].ToString() == "体温")
        {
            sql = "select Temperature as testValue,Date as testDate from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql1 = "select min(Temperature) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql2 = "select max(Temperature) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
        }
        else if (Request.QueryString["type"].ToString() == "空腹血糖")
        {
            sql = "select FPG as testValue,Date as testDate from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql1 = "select min(FPG) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
            sql2 = "select max(FPG) as testValue from PhysicalExam where userid = '" + Session["userid"].ToString() + "'";
        }
        string min = sqlhelper.GetDataSet(sql1).Tables[0].Rows[0]["testValue"].ToString().Trim();
        string max = sqlhelper.GetDataSet(sql2).Tables[0].Rows[0]["testValue"].ToString().Trim();
        Get_CurveData(sqlhelper.GetDataSet(sql).Tables[0], min, max);
    }
    //获取数据 
    public void Get_CurveData(DataTable dt,string minvalue,string maxvalue)
    {
        draw(dt,minvalue,maxvalue);
    }
    public void draw(DataTable dt, string minvalue, string maxvalue)
    {
        //取得记录数量 
        int count = dt.Rows.Count;
        //记算图表宽度 
        int wd = 80 + 20 * (count - 1);
        //设置最小宽度为800 
        if (wd < 600) wd = 600;
        //生成Bitmap对像 
        Bitmap img = new Bitmap(wd, 400);
        //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", 6);
        //定义大点的字体 
        Font Tfont = new Font("Arial", 9);
        //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) 
        int xSpace = (wd - 100) / (count - 1);
        //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) 
        int ySpace = 30;
        //纵坐标最大值和间隔值 
        int yMaxValue = Convert.ToInt32(maxvalue);
        //绘制底色 
        g.DrawRectangle(new Pen(Color.White, 400), 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(Request.QueryString["type"].ToString()+"曲线图", Bfont, brush, 40, 5);
        //绘制信息简报 
        string info = " 曲线图生成时间：" + DateTime.Now.ToString();
        g.DrawString(info, Tfont, Bluebrush, 40, 25);
        //绘制图片边框 
        g.DrawRectangle(Bp, 0, 0, img.Width - 1, img.Height - 1);
        //绘制竖坐标轴 
        g.DrawLine(Bp, 40, 55, 40, 360);
        //绘制横坐标轴 x2的60是右侧空出部分 
        g.DrawLine(Bp, 40, 360, 60 + xSpace * (count - 1), 360);
        //绘制竖坐标标题 
        g.DrawString(Request.QueryString["type"].ToString(), Tfont, brush, 5, 40);
        //绘制横坐标标题 
        g.DrawString("体检时间", Tfont, brush, 40, 385);
        //绘制竖坐标线 
        for (int i = 0; i < count; i++)
        {
            g.DrawLine(Sp, 40 + xSpace * i, 60, 40 + xSpace * i, 360);
        }
        //绘制时间轴坐标标签 
        for (int i = 0; i < count; i++)
        {
            string st = dt.Rows[i]["testdate"].ToString().Substring(0,10);
            g.DrawString(st, font, brush, 30 + xSpace * i, 370);
        }
        //绘制横坐标线 
        for (int i = 0; i < 10; i++)
        {
            g.DrawLine(Sp, 40, 60 + ySpace * i, 40 + xSpace * (count - 1), 60 + ySpace * i);
            if (yMaxValue % 10 == 0)
            {
                //横坐标轴的值间隔是最大值除以间隔数 
                int s = yMaxValue - i * (yMaxValue / 10);
                //绘制发送量轴坐标标签 
                g.DrawString(s.ToString(), font, brush, 10, 60 + ySpace * i);
            }
            else
            {
                //横坐标轴的值间隔是最大值除以间隔数 
                double s = Convert.ToDouble(yMaxValue) - Convert.ToDouble(i) * (Convert.ToDouble(yMaxValue) / Convert.ToDouble(10));
                //绘制发送量轴坐标标签 
                g.DrawString(s.ToString(), font, brush, 10, 60 + ySpace * i);
            }
        }
        //定义纵坐标单位数值=纵坐标最大值/标量最大值（360/yMaxValue*1.2） 
        double yAveValue = Convert.ToDouble(360) / Convert.ToDouble(yMaxValue*1.2);
        //定义曲线转折点 
        Point[] p = new Point[count];
        for (int i = 0; i < count; i++)
        {
            p[i].X = 40 + xSpace * i;
            p[i].Y = Convert.ToInt32(Convert.ToDouble(360) - Convert.ToDouble(dt.Rows[i]["testvalue"]) * Convert.ToDouble(yAveValue));
        }
        //绘制折线图 
        //g.DrawLines(Rp, p); 
        //绘制曲线图 
        //g.DrawCurve(Rp, p); 
        //绘制自定义张力的曲线图（0.5F是张力值，默认就是这个值） 
        g.DrawCurve(Rp, p, 0.5F);
        //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。 
        for (int i = 0; i < count; i++)
        {
            //绘制发送记录点的发送量 
            g.DrawString(dt.Rows[i]["testvalue"].ToString(), font, Bluebrush, p[i].X, p[i].Y - 10);
            //绘制发送记录点 
            g.DrawRectangle(Rp, p[i].X - 1, p[i].Y - 1, 2, 2);
        }
        //保存绘制的图片 
        MemoryStream stream = new MemoryStream();
        img.Save(stream, ImageFormat.Jpeg);
        //图片输出 
        System.Web.HttpContext.Current.Response.Clear();
        System.Web.HttpContext.Current.Response.ContentType = "image/jpeg";
        System.Web.HttpContext.Current.Response.BinaryWrite(stream.ToArray());
    }
}