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5.1       画笔

Pen类对象指定绘制的图形外轮廓线宽度和颜色。Pen类有4个构造函数,分别是:

l publicPen(Color color);//建立颜色为color的笔,宽度默认为1

l publicPen(Color color,float width);//建立颜色为color的笔,宽度为width

l publicPen(Brush brush);//使用刷子为笔

l publicPen(Brush,float width);//使用刷子为笔,宽度为width

Pen类常用的属性:Color为笔的颜色,Width为笔的宽度,DashStyle为笔的样式,EndCap和StartCap为线段终点和起点的外观。下例显示各种笔的DashStyle、EndCap和StartCap不同选项的样式(见下图)。主窗体Paint事件处理函数如下:

private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)

{  Graphics g=e.Graphics;

Pen pen1=new Pen(Color.Red,6);//默认为实线笔

g.DrawLine(pen1,10,10,100,10);//画实线,图中左边第1条线

pen1.DashStyle=System.Drawing.Drawing2D.DashStyle.Dash;//虚线笔

g.DrawLine(pen1,10,20,100,20);//画虚线,图中左边第2条线

pen1.DashStyle=System.Drawing.Drawing2D.DashStyle.DashDot;//点,短线风格的线

g.DrawLine(pen1,10,30,100,30);//图中左边第3条线

//双点,短线风格的线

pen1.DashStyle=System.Drawing.Drawing2D.DashStyle.DashDotDot;

g.DrawLine(pen1,10,40,100,40);//图中左边第4条线

pen1.DashStyle=System.Drawing.Drawing2D.DashStyle.Dot;//由点组成的线

g.DrawLine(pen1,10,50,100,50);//图中左边第5条线

pen1.DashStyle=System.Drawing.Drawing2D.DashStyle.Solid;//实线笔

pen1.EndCap=System.Drawing.Drawing2D.LineCap.ArrowAnchor;//后箭头

g.DrawLine(pen1,150,10,250,10);//图中右边第1条线

pen1.StartCap=System.Drawing.Drawing2D.LineCap.ArrowAnchor;//前箭头

g.DrawLine(pen1,150,22,250,22);//图中右边第2条线

pen1.EndCap=System.Drawing.Drawing2D.LineCap.RoundAnchor;

g.DrawLine(pen1,150,34,250,34);//图中右边第3条线

pen1.EndCap=System.Drawing.Drawing2D.LineCap.SquareAnchor;

g.DrawLine(pen1,150,46,250,46);//图中右边第4条线

pen1.EndCap=System.Drawing.Drawing2D.LineCap.Triangle;

g.DrawLine(pen1,150,58,250,58);//图中右边第5条线

pen1.EndCap=System.Drawing.Drawing2D.LineCap.DiamondAnchor;

//图中右边第6条线

g.DrawLine(pen1,150,70,250,70);

}

运行效果如右图: