C#Graphics画图

public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
Graphics g = this.CreateGraphics();//创建GDI对像

//创建画笔(颜色)
Pen npen = new Pen(Brushes.Red);

//创建两个点
Point n1 = new Point(20, 20);
Point n2 = new Point(255, 255);

g.DrawLine(npen, n1, n2);

}

private void Form1_Paint(object sender, PaintEventArgs e)
{
Graphics g = this.CreateGraphics();//创建GDI对像

//创建画笔(颜色)
Pen npen = new Pen(Brushes.Red);

//创建两个点
Point n1 = new Point(20, 20);
Point n2 = new Point(255, 255);

g.DrawLine(npen, n1, n2);

}

private void button2_Click(object sender, EventArgs e)
{
Graphics ng = this.CreateGraphics();

//创建画笔
Pen npen = new Pen(Brushes.Red);

Size sz=new System.Drawing.Size(100,100);
Rectangle res = new Rectangle(new Point(50, 50), sz);

ng.DrawRectangle(npen, res);
}

private void button3_Click(object sender, EventArgs e)
{
Graphics g = this.CreateGraphics();

Pen npen = new Pen(Brushes.Blue);

Size sz = new System.Drawing.Size(180, 180);

Rectangle rec = new Rectangle(new Point(150, 150), sz);

g.DrawPie(npen, rec, -50, -50);
}

private void button4_Click(object sender, EventArgs e)
{
Graphics g = this.CreateGraphics();

Pen npen = new Pen(Brushes.Blue);

g.DrawString("我是中国人", new Font("宋体", 20, FontStyle.Bold), Brushes.Blue, new PointF(29, 29));
}