Create an irregular Region add a circle to the region : Region « 2D « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. 2D
3. Region

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Text;
using System.Windows.Forms;

public class Form1 : Form {
    protected override void OnPaint(PaintEventArgs e) {
        Graphics g = e.Graphics;
        g.FillRectangle(Brushes.White, this.ClientRectangle);
        Region reg = new Region();
        reg.MakeEmpty();

        GraphicsPath gp = new GraphicsPath();
        gp.AddEllipse(10, 10, 50, 50);
        reg.Union(gp);
        gp.Reset();
        gp.AddLine(40, 40, 70, 10);
        gp.AddLine(70, 10, 100, 40);
        gp.CloseFigure();
        reg.Union(gp);
        reg.Union(new Rectangle(40, 50, 60, 60));
        g.SetClip(reg, CombineMode.Replace);
        g.FillRectangle(Brushes.Green, this.ClientRectangle);
        gp.Dispose();
        reg.Dispose();
    }
    public static void Main() {
        Application.Run(new Form1());
    }
}