Draw an ellipse in C#

To draw an ellipse in C#, you use the DrawEllipse() method from the Graphics class. This method requires a Pen object to define the ellipse's outline and either a Rectangle or coordinate parameters to specify the ellipse's position and size.

Drawing ellipses is commonly done in Windows Forms applications using the Paint event handler or by overriding the OnPaint method.

Syntax

The DrawEllipse() method has several overloads −

graphics.DrawEllipse(pen, rectangle);
graphics.DrawEllipse(pen, x, y, width, height);

Parameters

• pen − Defines the color, width, and style of the ellipse outline

• rectangle − Specifies the bounding rectangle that contains the ellipse

• x, y − Upper-left corner coordinates of the bounding rectangle

• width, height − Dimensions of the bounding rectangle

Using DrawEllipse() with Rectangle

Example

using System;
using System.Drawing;
using System.Windows.Forms;

public partial class Form1 : Form {
   public Form1() {
      InitializeComponent();
      this.Paint += Form1_Paint;
      this.Text = "Draw Ellipse Example";
      this.Size = new Size(400, 300);
   }

   private void Form1_Paint(object sender, PaintEventArgs e) {
      Graphics g = e.Graphics;
      Pen p = new Pen(Color.Red, 3);
      Rectangle r = new Rectangle(50, 50, 200, 100);
      g.DrawEllipse(p, r);
      p.Dispose();
   }

   public static void Main() {
      Application.EnableVisualStyles();
      Application.Run(new Form1());
   }
}

Using DrawEllipse() with Coordinates

Example

using System;
using System.Drawing;
using System.Windows.Forms;

public partial class Form2 : Form {
   public Form2() {
      InitializeComponent();
      this.Paint += Form2_Paint;
      this.Text = "Multiple Ellipses";
      this.Size = new Size(450, 350);
   }

   private void Form2_Paint(object sender, PaintEventArgs e) {
      Graphics g = e.Graphics;
      
      // Red ellipse
      Pen redPen = new Pen(Color.Red, 2);
      g.DrawEllipse(redPen, 20, 20, 150, 80);
      
      // Blue ellipse
      Pen bluePen = new Pen(Color.Blue, 4);
      g.DrawEllipse(bluePen, 200, 50, 180, 180);
      
      // Green ellipse with dashed style
      Pen greenPen = new Pen(Color.Green, 3);
      greenPen.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;
      g.DrawEllipse(greenPen, 100, 180, 220, 100);
      
      redPen.Dispose();
      bluePen.Dispose();
      greenPen.Dispose();
   }

   public static void Main() {
      Application.EnableVisualStyles();
      Application.Run(new Form2());
   }
}

Drawing Filled Ellipses

To create a filled ellipse, use the FillEllipse() method with a Brush object instead of a Pen −

Example

using System;
using System.Drawing;
using System.Windows.Forms;

public partial class Form3 : Form {
   public Form3() {
      InitializeComponent();
      this.Paint += Form3_Paint;
      this.Text = "Filled Ellipses";
      this.Size = new Size(400, 300);
   }

   private void Form3_Paint(object sender, PaintEventArgs e) {
      Graphics g = e.Graphics;
      
      // Solid brush for filled ellipse
      SolidBrush solidBrush = new SolidBrush(Color.Orange);
      g.FillEllipse(solidBrush, 50, 50, 120, 80);
      
      // Gradient brush for filled ellipse
      System.Drawing.Drawing2D.LinearGradientBrush gradientBrush = 
         new System.Drawing.Drawing2D.LinearGradientBrush(
            new Point(200, 100), new Point(320, 180), 
            Color.Purple, Color.Pink);
      g.FillEllipse(gradientBrush, 200, 100, 120, 80);
      
      solidBrush.Dispose();
      gradientBrush.Dispose();
   }

   public static void Main() {
      Application.EnableVisualStyles();
      Application.Run(new Form3());
   }
}

Conclusion

The DrawEllipse() method in C# provides a straightforward way to draw ellipses using a Graphics object, Pen for styling, and either a Rectangle or coordinate parameters for positioning. Always dispose of Pen and Brush objects to free system resources.