import java.awt.BorderLayout;

import java.awt.Graphics;

import javax.swing.JComponent;

/**

* A wrapper Container for holding components that use a background Color

* containing an alpha value with some transparency.

*

* A Component that uses a transparent background should really have its

* opaque property set to false so that the area it occupies is first painted

* by its opaque ancestor (to make sure no painting artifacts exist). However,

* if the property is set to false, then most Swing components will not paint

* the background at all, so you lose the transparent background Color.

*

* This components attempts to get around this problem by doing the

* background painting on behalf of its contained Component, using the

* background Color of the Component.

*/

public class AlphaContainer extends JComponent

{

private JComponent component;

public AlphaContainer(JComponent component)

{

this.component = component;

setLayout( new BorderLayout() );

setOpaque( false );

component.setOpaque( false );

add( component );

}

/**

* Paint the background using the background Color of the

* contained component

*/

@Override

public void paintComponent(Graphics g)

{

g.setColor( component.getBackground() );

g.fillRect(0, 0, getWidth(), getHeight());

}

}