Java AWT and Canvas (Canvas) - Example

CustomCanvas canvas = new CustomCanvas();

package com.java.myapp;

import java.awt.BorderLayout;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.event.WindowEvent;

public class MyForm extends Frame {

	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				MyForm form = new MyForm();
				form.setVisible(true);
			}
		});
	}

	public MyForm() {

		// Create Form Frame
		super("ThaiCreate.Com Java GUI Tutorial");
		setSize(434, 285);
		setLocation(500, 280);
		setLayout(null);

		//Canvas
		CustomCanvas canvas = new CustomCanvas();
		canvas.setBounds(135, 90, 160, 80);
		add(canvas, BorderLayout.CENTER);

		// Close
		addWindowListener(new java.awt.event.WindowAdapter() {
			public void windowClosing(WindowEvent evt) {
				System.exit(0);
			}
		});
	}

	class CustomCanvas extends Canvas {

		public CustomCanvas() {
			setBackground(Color.yellow);
		}

		public void paint(Graphics g) {
			Rectangle r = getBounds();

			g.setColor(Color.black);
			g.fillRect(0, 0, r.width, r.height);

			g.setColor(Color.yellow);
			g.drawLine(0, 0, r.width, r.height);

			g.setColor(Color.white);
			g.drawLine(0, r.height, r.width, 0);
		}
	}

}

package com.java.myapp;

import java.awt.Adjustable;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.ScrollPane;
import java.awt.event.WindowEvent;

public class MyForm extends Frame {

	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				MyForm form = new MyForm();
				form.setVisible(true);
			}
		});
	}

	public MyForm() {

		// Create Form Frame
		super("ThaiCreate.Com Java GUI Tutorial");
		setSize(434, 285);
		setLocation(500, 280);
		setLayout(null);

		ScrollPane scroller = new ScrollPane(ScrollPane.SCROLLBARS_AS_NEEDED);
		scroller.add(new DrawCanvas());

		Adjustable vadjust = scroller.getVAdjustable();
		Adjustable hadjust = scroller.getHAdjustable();
		hadjust.setUnitIncrement(10);
		vadjust.setUnitIncrement(10);
		scroller.setBounds(120, 50, 130, 70);
		scroller.setSize(200, 200);

		add("Center", scroller);

		// Close
		addWindowListener(new java.awt.event.WindowAdapter() {
			public void windowClosing(WindowEvent evt) {
				System.exit(0);
			}
		});
	}

	class DrawCanvas extends Canvas {

		public Dimension getPreferredSize() {
			return new Dimension(300, 300);
		}

		public void paint(Graphics g) {
			// Note: For most efficient repainting, we should check the
			// clip rectangle in the Graphics object to determine the
			// damaged region and only paint that; we don't do that here
			// for simplicity in this example
			//
			Rectangle r = getBounds();

			g.setColor(Color.black);
			g.fillRect(0, 0, r.width, r.height);

			g.setColor(Color.yellow);
			g.drawLine(0, 0, r.width, r.height);

			g.setColor(Color.white);
			g.drawLine(0, r.height, r.width, 0);
		}
	}

}