GDI绘图

 public   void   draw(Page page,DataTable dt,int   Tnum)   
    {   
    //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   <   800)   wd   =   800;   
    //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);   
    //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(dt.Rows[0]["Num"].ToString() + "本年慢病随访情况曲线图", Bfont, brush, 40, 5);   
    //取得当前发送量   
    int   nums=0;   
    for   (int   i   =   0;   i   <   count;   i++)   
    {
        nums += Convert.ToInt32(dt.Rows[i]["Num"]);   
    }   
    //绘制信息简报   
    string   info="首次随访时间："+dt.Rows[0]["dc"].ToString()+"   曲线图生成时间："+DateTime.Now.ToString()+"   随访次数："+dt.Rows.Count.ToString()+"   当前发送总量："+nums.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);   

    //绘制竖坐标线   
    for   (int   i   =   0;   i   <   count;   i++)   
    {   
    g.DrawLine(Sp,   40+20   *   i,   60,   40+20   *   i,   360);   
    }   

    //绘制时间轴坐标标签   
    for   (int   i   =   0;   i   <   count;   i+=2)   
    {   
    string   st   =   Convert.ToDateTime(dt.Rows[i]["dc"]).ToString("yyyy-MM-dd");   
    g.DrawString(st,   font,   brush,   30   +   20   *   i,   370);   } 
    //绘制横坐标线   
    for   (int   i   =   0;   i   <   10;   i++)   
    {   
    g.DrawLine(Sp,   40,   60+30*i,   40+20*(count-1),   60+30*i);   
    int   s   =   2500   -   50   *   i   *   5;   
    //绘制发送量轴坐标标签   
    g.DrawString(s.ToString(),   font,   brush,   10,   60   +   30   *   i);   
    }   

    //绘制竖坐标轴   
    g.DrawLine(Bp,   40,   55,   40,   360);   
    //绘制横坐标轴   
    g.DrawLine(Bp,   40,   360,   45   +   20   *   (count   -   1),   360);   

    //定义曲线转折点   
    Point[]   p   =   new   Point[count];   
    for   (int   i   =   0;   i   <   count;   i++)   
    {   
    p[i].X   =   40   +   20   *   i;
    p[i].Y = 360 - Convert.ToInt32(dt.Rows[i]["Num"]) / 5 * 3 / 5;   
    }   
    //绘制发送曲线   
    g.DrawLines(Rp,   p);   

    for   (int   i   =   0;   i   <   count;   i++)   
    {   
    //绘制发送记录点的发送量   
        g.DrawString(dt.Rows[i]["Num"].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);   
    }   
    //绘制竖坐标标题   
    g.DrawString("血压值",   Tfont,   brush,   5,   40);   
    //绘制横坐标标题   
    g.DrawString("随访时间",   Tfont,   brush,   40,   385);   


    //保存绘制的图片   
    MemoryStream   stream   =   new   MemoryStream();   
    img.Save(stream,   ImageFormat.Jpeg);   
    //图片输出   
    page.Response.Clear();   
    page.Response.ContentType = "image/jpeg";   
    page.Response.BinaryWrite(stream.ToArray());   
}