基本图形绘制举例

1.画一个矩形

引用命名空间using System.Drawing.Drawing2D;

        protected override void OnPaint(PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            Rectangle rect = new Rectangle(50, 30, 100, 100);
            LinearGradientBrush lBrush = new LinearGradientBrush(rect, Color.Red, Color.Yellow, LinearGradientMode.BackwardDiagonal);
            g.FillRectangle(lBrush, rect); 
            //base.OnPaint(e);
        }

2.画一个圆弧

        protected override void OnPaint(PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            Pen pn = new Pen(Color.Blue);
            Rectangle rect = new Rectangle(50, 50, 200, 100);
            g.DrawArc(pn, rect, 12, 84);
        }

3.画一条直线

        protected override void OnPaint(PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            Pen pn = new Pen(Color.Blue);
            Point pt1 = new Point(30, 30);
            Point pt2 = new Point(110, 100);
            g.DrawLine(pn, pt1, pt2); 
        }

4.画椭圆

  protected override void OnPaint(PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            Pen pn = new Pen(Color.Blue, 100);
            Rectangle rect = new Rectangle(50, 50, 200, 100);
            g.DrawEllipse(pn, rect); 
        }

5.输出文本

protected override void OnPaint(PaintEventArgs e)
        {
            Font fnt = new Font("黑体", 26);
            Graphics g = e.Graphics;
            g.DrawString("GDI+ World", fnt, new SolidBrush(Color.Red), 14, 10);
        }

6.填充路径

Graphics g = e.Graphics;
  g.FillRectangle(new SolidBrush(Color.White), ClientRectangle);
  GraphicsPath path = new GraphicsPath(new Point[] {
  new Point(40, 140), new Point(275, 200),
  new Point(105, 225), new Point(190, 300),
  new Point(50, 350), new Point(20, 180), },
  new byte[] {
  (byte)PathPointType.Start,
  (byte)PathPointType.Bezier,
  (byte)PathPointType.Bezier,
  (byte)PathPointType.Bezier,
  (byte)PathPointType.Line,
  (byte)PathPointType.Line,
  });
  PathGradientBrush pgb = new PathGradientBrush(path);
  pgb.SurroundColors = new Color[]       
{ 
Color.Green,Color.Yellow,Color.Red, Color.Blue,
Color.Orange, Color.White, 
};
g.FillPath(pgb, path);