ASP.NET畫曲線圖

類LineChart
public class LineChart
{
public Bitmap b;
public string Title = "在ASP.NET中實現資料圖表";
public ArrayList chartValues = new ArrayList();
public float Xorigin = 0, Yorigin = 0;
public float ScaleX, ScaleY;
public float Xdivs = 2, Ydivs = 2;

private int Width, Height;
private Graphics g;
private Page p;

struct datapoint
{
public float x;
public float y;
public bool valid;
}
public LineChart(int myWidth, int myHeight, Page myPage)
{
Width = myWidth;
Height = myHeight;
ScaleX = myWidth;
ScaleY = myHeight;
b = new Bitmap(myWidth, myHeight);
g = Graphics.FromImage(b);
p = myPage;
}

public void AddValue(int x, int y)
{
datapoint myPoint;
myPoint.x = x;
myPoint.y = y;
myPoint.valid = true;
chartValues.Add(myPoint);
}

public void Draw()
{
int i;
float x, y, x0, y0;
string myLabel;
Pen blackPen = new Pen(Color.Blue, 2);//定義畫筆
Brush blackBrush = new SolidBrush(Color.Black);//定義畫刷
Font axesFont = new Font("arial", 10);//定義字型

//首先要建立圖片的大小
p.Response.ContentType = "image/jpeg";
g.FillRectangle(new SolidBrush(Color.LightGreen), 0, 0, Width, Height);
int ChartInset = 50;
int ChartWidth = Width - (2 * ChartInset);
int ChartHeight = Height - (2 * ChartInset);
g.DrawRectangle(new Pen(Color.Black, 1), ChartInset, ChartInset, ChartWidth, ChartHeight);
//寫出圖片上面的圖片內容文字
g.DrawString(Title, new Font("arial", 14), blackBrush, Width / 3, 10);
//沿X座標寫入X標籤
for (i = 0; i <= Xdivs; i++)
{
x = ChartInset + (i * ChartWidth) / Xdivs;
y = ChartHeight + ChartInset;
myLabel = (Xorigin + (ScaleX * i / Xdivs)).ToString();
g.DrawString(myLabel, axesFont, blackBrush, x - 4, y + 10);
g.DrawLine(blackPen, x, y + 2, x, y - 2);
}
//沿Y座標寫入Y標籤
for (i = 0; i <= Ydivs; i++)
{
x = ChartInset;
y = ChartHeight + ChartInset - (i * ChartHeight / Ydivs);
myLabel = (Yorigin + (ScaleY * i / Ydivs)).ToString();
g.DrawString(myLabel, axesFont, blackBrush, 5, y - 6);
g.DrawLine(blackPen, x + 2, y, x - 2, y);
}
g.RotateTransform(180);
g.TranslateTransform(0, -Height);
g.TranslateTransform(-ChartInset, ChartInset);
g.ScaleTransform(-1, 1);

//畫出圖表中的資料
datapoint prevPoint = new datapoint();
prevPoint.valid = false;
foreach (datapoint myPoint in chartValues)
{
if (prevPoint.valid == true)
{
x0 = ChartWidth * (prevPoint.x - Xorigin) / ScaleX;
y0 = ChartHeight * (prevPoint.y - Yorigin) / ScaleY;
x = ChartWidth * (myPoint.x - Xorigin) / ScaleX;
y = ChartHeight * (myPoint.y - Yorigin) / ScaleY;
g.DrawLine(blackPen, x0, y0, x, y);
g.FillEllipse(blackBrush, x0 - 2, y0 - 2, 4, 4);
g.FillEllipse(blackBrush, x - 2, y - 2, 4, 4);
}
prevPoint = myPoint;
}

//最後以圖片形式來瀏覽
b.Save(p.Response.OutputStream, ImageFormat.Jpeg);

}

public void Dispose()
{
g.Dispose();
b.Dispose();
}
}

aspx.cs頁面調用：
private void Page_Load(object sender, System.EventArgs e)
{
// 在此處放置使用者代碼以初始化頁面
LineChart c = new LineChart(640, 480, this.Page);
c.Title = " 在ASP.NET中實現資料圖表";
c.Xorigin = 0; c.ScaleX = 500; c.Xdivs = 5;
c.Yorigin = 0; c.ScaleY = 1000; c.Ydivs = 5;
c.AddValue(0, 150);
c.AddValue(50, 50);
c.AddValue(100, 700);
c.AddValue(200, 150);
c.AddValue(300, 450);
c.AddValue(400, 75);
c.AddValue(450, 450);
c.AddValue(500, 250);
c.Draw();
c.Dispose();
}