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AWT Canvas Class
Introduction
Canvas control represents a rectangular area where application can draw something or can receive inputs created by user.
Class declaration
Following is the declaration for java.awt.Canvas class:
public class Canvas extends Component implements Accessible
Class constructors
S.N. | Constructor & Description |
---|---|
1 | Canvas() Constructs a new Canvas. |
2 | Canvas(GraphicsConfiguration config) Constructs a new Canvas given a GraphicsConfiguration object. |
Class methods
S.N. | Method & Description |
---|---|
1 | void addNotify() Creates the peer of the canvas. |
2 | void createBufferStrategy(int numBuffers) Creates a new strategy for multi-buffering on this component. |
3 | void createBufferStrategy(int numBuffers, BufferCapabilities caps) Creates a new strategy for multi-buffering on this component with the required buffer capabilities. |
4 | AccessibleContext getAccessibleContext() Gets the AccessibleContext associated with this Canvas. |
5 | BufferStrategy getBufferStrategy() Returns the BufferStrategy used by this component. |
6 | void paint(Graphics g) Paints this canvas. |
7 | void pdate(Graphics g) Updates this canvas. |
Methods inherited
This class inherits methods from the following classes:
java.awt.Component
java.lang.Object
Canvas Example
Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtControlDemo.javapackage com.tutorialspoint.gui; import java.awt.*; import java.awt.event.*; public class AwtControlDemo { private Frame mainFrame; private Label headerLabel; private Label statusLabel; private Panel controlPanel; public AwtControlDemo(){ prepareGUI(); } public static void main(String[] args){ AwtControlDemo awtControlDemo = new AwtControlDemo(); awtControlDemo.showCanvasDemo(); } private void prepareGUI(){ mainFrame = new Frame("Java AWT Examples"); mainFrame.setSize(400,400); mainFrame.setLayout(new GridLayout(3, 1)); mainFrame.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent windowEvent){ System.exit(0); } }); headerLabel = new Label(); headerLabel.setAlignment(Label.CENTER); statusLabel = new Label(); statusLabel.setAlignment(Label.CENTER); statusLabel.setSize(350,100); controlPanel = new Panel(); controlPanel.setLayout(new FlowLayout()); mainFrame.add(headerLabel); mainFrame.add(controlPanel); mainFrame.add(statusLabel); mainFrame.setVisible(true); } private void showCanvasDemo(){ headerLabel.setText("Control in action: Canvas"); controlPanel.add(new MyCanvas()); mainFrame.setVisible(true); } class MyCanvas extends Canvas { public MyCanvas () { setBackground (Color.GRAY); setSize(300, 300); } public void paint (Graphics g) { Graphics2D g2; g2 = (Graphics2D) g; g2.drawString ("It is a custom canvas area", 70, 70); } } }
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtControlDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtControlDemo
Verify the following output