二、使用GDI+画线(补充)

DrawLines(Pen pen,PointF[] points)

绘制多个直线

private void Form1_Paint(object sender, PaintEventArgs e)
{
    //创建画板从Paint事件中的直接引用Graphics对象
    Graphics graphics = e.Graphics;
    //定义画笔
    Pen pen = new Pen(Color.Red, 3.0f);
    //定义坐标数组
    PointF[] points = { 
                        new PointF(10.0f,10.0f),
                        new PointF(10.0f,100.0f),
                        new PointF(200.0f,50.0f),
                        new PointF(300.0f,100.0f),
                        new PointF(300.0f,150.0f)
                    };

    //画线(线条粗线为3.0f,长度400，垂直于屏幕的一条直线)
    graphics.DrawLines(pen,points);
}

利用画线函数绘制坐标(复习画线函数，用到了DrawString函数，后面学习)

效果图：

private void Form1_Paint(object sender, PaintEventArgs e)
{    
    //创建画板从Paint事件中的直接引用Graphics对象
    Graphics graphics = e.Graphics;

    graphics.Clear(Color.Black);

    //定义画笔
    Pen pen = new Pen(Color.White, 3.0f);
    Pen thickPen = new Pen(Color.White,2.0f);
    Pen thick = new Pen(Color.Red, 2.0f);

    //画横坐标
    Point pointFirstX = new Point(0, this.ClientRectangle.Height / 2);
    Point pointFirstY = new Point(this.ClientRectangle.Width, this.ClientRectangle.Height / 2);
    Point pointSecondX = new Point(this.ClientRectangle.Width / 2, 0);
    Point pointSecondY = new Point(this.ClientRectangle.Width / 2, this.ClientRectangle.Height);
    graphics.DrawLine(pen, pointFirstX, pointFirstY);
    graphics.DrawLine(pen, pointSecondX, pointSecondY);

    //画箭头
    Point PointUpLeftX = new Point(this.ClientRectangle.Width / 2, 0);
    Point PointUpLeftY = new Point(this.ClientRectangle.Width / 2 - 10, 10);
    Point PointUpRightY = new Point(this.ClientRectangle.Width / 2 + 10, 10);
    Point PointRightUpX = new Point(this.ClientRectangle.Width, this.ClientRectangle.Height / 2);
    Point PointRightUpY = new Point(this.ClientRectangle.Width - 10, this.ClientRectangle.Height / 2 - 10);
    Point PointRightDownY = new Point(this.ClientRectangle.Width - 10, this.ClientRectangle.Height / 2 + 10);
    graphics.DrawLine(pen, PointUpLeftX, PointUpLeftY);
    graphics.DrawLine(pen, PointUpLeftX, PointUpRightY);
    graphics.DrawLine(pen, PointRightUpX, PointRightUpY);
    graphics.DrawLine(pen, PointRightUpX, PointRightDownY);

    //画原点
    PointF centre = new PointF(this.ClientRectangle.Width / 2, this.ClientRectangle.Height / 2);
    Font font = new Font("黑体", 14.0f);
    Brush brush = Brushes.White;
    graphics.DrawString("0",font,brush,centre);

    //画坐标点    
    int iWidht = this.ClientRectangle.Width/2;
    int iHeight = this.ClientRectangle.Height/2;
    int j=0;
    for (int i=iWidht;i<this.ClientRectangle.Width;i=i+50)
    {
        Point tmpStart = new Point(i, iHeight);
        Point tmpEnd = new Point(i, iHeight - 8);
        graphics.DrawLine(thickPen, tmpStart, tmpEnd);
        if (j != 0)
        {
            graphics.DrawString(j.ToString(), font, brush, new Point(tmpEnd.X-7,tmpEnd.Y+10));
        }
        j++;
    }

    int k = 0;
    for (int i = iWidht; i > 0;i=i-50 )
    {
        Point tmpStart = new Point(i, iHeight);
        Point tmpEnd = new Point(i, iHeight - 8);
        graphics.DrawLine(thickPen, tmpStart, tmpEnd);
        if (k != 0)
        {
            graphics.DrawString("-"+k.ToString(), font, brush, new Point(tmpEnd.X - 7, tmpEnd.Y + 10));
        }
        k++;
    }
    int l = 0;
    for (int i = iHeight; i >0; i = i - 50)
    {
        Point tmpStart = new Point(iWidht, i);
        Point tmpEnd = new Point(iWidht+8, i);
        graphics.DrawLine(thickPen, tmpStart, tmpEnd);
        if (l != 0)
        {
            graphics.DrawString(l.ToString(), font, brush, new Point(tmpEnd.X, tmpEnd.Y - 9));
        }
        l++;
    }

    int m = 0;
    for (int i = iHeight; i < this.ClientRectangle.Height; i = i + 50)
    {
        Point tmpStart = new Point(iWidht, i);
        Point tmpEnd = new Point(iWidht + 8, i);
        graphics.DrawLine(thickPen, tmpStart, tmpEnd);
        if (m != 0)
        {
            graphics.DrawString("-"+m.ToString(), font, brush, new Point(tmpEnd.X, tmpEnd.Y-9));
        }
        m++;
    }
    

    //定义坐标数组
    PointF[] points = { 
                        new PointF(105.0f,102.0f),
                        new PointF(106.0f,105.0f),
                        new PointF(200.0f,121.0f),
                        new PointF(220.0f,126.0f),
                        new PointF(230.0f,110.0f),
                        new PointF(300.0f,200.0f),
                        new PointF(320.0f,95.0f),
                        new PointF(343.0f,158.0f),
                        new PointF(360.0f,100.0f),
                        new PointF(450.0f,184.3f)
                    };

    //画折线
    graphics.DrawLines(thick,points);
}