CaRMtl/eric/jobs/AlphaContainer.java
2018-09-04 22:51:42 -04:00

45 lines
1.3 KiB
Java

package eric.jobs;
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());
super.paintComponent(g);
}
}