三月份发电量折线走势图（纯笔绘）

实现效果图：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

using System.Drawing.Imaging;
using System.Drawing;


public partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

        //string[] month = new string[12] { "一月", "二月", "三月", "四月", "五月", "六月", "七月", "八月", "九月", "十月", "十一月", "十二月" };
        //float[] d = new float[12] { 20.5f, 60, 10.8f, 15.6f, 30, 70.9f, 50.3f, 30.7f, 70, 50.4f, 30.8f, 20 }; //图中的点的数据

        string[] month = new string[15] { "2", "4", "6", "8", "10", "12", "14", "16", "18", "20", "22", "24", "26", "28", "30" };
       
        float[] d = new float[15] { 0.03f, 0.025f, 0.04f, 0.02f, 0.045f, 0.04f, 0.04f, 0.05f, 0.06f, 0.03f, 0.04f, 0.03f, 0.01f, 0.02f, 0.04f };
        //画图初始化
        Bitmap bmap = new Bitmap(800, 800);
        Graphics gph = Graphics.FromImage(bmap);
        gph.Clear(Color.White);

        PointF cpt = new PointF(40, 420);//中心点
        //x轴端点三角形
        PointF[] xpt = new PointF[3] { new PointF(cpt.Y + 105, cpt.Y), new PointF(cpt.Y+90, cpt.Y - 8), new PointF(cpt.Y+90, cpt.Y + 8) };
        //y轴端点三角形
        PointF[] ypt = new PointF[3] { new PointF(cpt.X, cpt.X - 15), new PointF(cpt.X - 8, cpt.X), new PointF(cpt.X + 8, cpt.X) };
        //图表标题
        gph.DrawString("三月份发电量走势图", new Font("宋体", 14), Brushes.Black, new PointF(cpt.X + 60, cpt.X));
        

        //画x轴
        gph.DrawLine(Pens.Black, cpt.X, cpt.Y, cpt.Y+90, cpt.Y);
        gph.DrawPolygon(Pens.Black, xpt);
        gph.FillPolygon(new SolidBrush(Color.Black), xpt);
        //画x轴标题
        gph.DrawString("日期(三月份)", new Font("宋体", 12), Brushes.Black, new PointF(cpt.Y + 100, cpt.Y + 10));
       
        //画y轴
        gph.DrawLine(Pens.Black, cpt.X, cpt.Y, cpt.X, cpt.X);
        gph.DrawPolygon(Pens.Black, ypt);
        gph.FillPolygon(new SolidBrush(Color.Black), ypt);
        //画y轴标题
        gph.DrawString("发电量(单位:千瓦时)", new Font("宋体", 12), Brushes.Black, new PointF(0, 7));
       
       
       
        for ( int i = 1; i <=15; i++)
        { 
            //画y轴刻度
            if (i < 7)
            {
                gph.DrawString((i * 0.01).ToString(), new Font("宋体", 11), Brushes.Black, new PointF(cpt.X - 30, cpt.Y - i * 30 - 6));
                gph.DrawLine(Pens.Black, cpt.X - 3, cpt.Y - i * 30, cpt.X, cpt.Y - i * 30);
            }

            //画x轴项目
            gph.DrawString(month[i - 1], new Font("宋体", 11), Brushes.Black, new PointF(cpt.X + i * 30 - 5, cpt.Y + 5));
            
            //gph.DrawString(month[i - 1].Substring(0, 1), new Font("宋体", 11), Brushes.Black, new PointF(cpt.X + i * 30 - 5, cpt.Y + 5));
           // gph.DrawString(month[i - 1].Substring(1, 1), new Font("宋体", 11), Brushes.Black, new PointF(cpt.X + i * 30 - 5, cpt.Y + 20));
           
           // if (month[i - 1].Length > 2) gph.DrawString(month[i - 1].Substring(2, 1), new Font("宋体", 11), Brushes.Black, new PointF(cpt.X + i * 30 - 5, cpt.Y + 35));
            
            //画点
            gph.DrawEllipse(Pens.Black, cpt.X + i * 30 - 1.5f, cpt.Y - d[i - 1] * 3000 - 1.5f, 3, 3);
            gph.FillEllipse(new SolidBrush(Color.Black), cpt.X + i * 30 - 1.5f, cpt.Y - d[i - 1] * 3000 - 1.5f, 3, 3);
            //画数值
            gph.DrawString(d[i - 1].ToString(), new Font("宋体", 11), Brushes.Black, new PointF(cpt.X + i * 30, cpt.Y - d[i - 1] * 3000));
            //画折线
            if (i > 1) gph.DrawLine(Pens.Red, cpt.X + (i - 1) * 30, cpt.Y - d[i - 2] * 3000, cpt.X + i * 30, cpt.Y - d[i - 1] *3000);
        }
        //保存输出图片
        //bmap.Save(Response.OutputStream, ImageFormat.Gif);
      //  PictureBox1.Image = bmap;

         System.IO.MemoryStream ms = new System.IO.MemoryStream();
        bmap.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
        Response.ClearContent();
        Response.ContentType = "image/Gif";
        Response.BinaryWrite(ms.ToArray());
        gph.Dispose();
        bmap.Dispose();


    }
}

本文主要参考： http://blog.csdn.net/yiyiwyy326/article/details/1702979