gcc/libjava/java/awt/Canvas.java

/* Copyright (C) 1999, 2000, 2002  Free Software Foundation

This file is part of GNU Classpath.

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package java.awt;

import java.awt.peer.ComponentPeer;

public class Canvas extends Component implements java.io.Serializable
{
  transient GraphicsConfiguration graphicsConfiguration;

  /**
   * Initializes a new instance of <code>Canvas</code>.
   */
  public Canvas() { }

  public Canvas(GraphicsConfiguration graphicsConfiguration)
  {
    this.graphicsConfiguration = graphicsConfiguration;
  }

  GraphicsConfiguration getGraphicsConfigurationImpl()
  {
    if (graphicsConfiguration != null)
      return graphicsConfiguration;
    return super.getGraphicsConfigurationImpl();
  }

  /**
   * Creates the native peer for this object.
   */
  public void addNotify()
  {
    if (peer == null)
      peer = (ComponentPeer) getToolkit().createCanvas(this);
    super.addNotify();
  }

  /**
   * Repaints the canvas window.  This method should be overriden by 
   * a subclass to do something useful, as this method simply paints
   * the window with the background color.
   */
  public void paint(Graphics gfx)
  {
    /* This implementation doesn't make much sense since the filling
      of background color is guaranteed for heavyweight components
      such as this.  But there's no need to worry, since paint() is
      usually overridden anyway.  */
    gfx.setColor(getBackground());
    Dimension size = getSize();
    gfx.fillRect(0, 0, size.width, size.height);
  }

  // Serialization constant
  private static final long serialVersionUID = -2284879212465893870L;
}