In this tutorial I will explain how to create transparent swing UI components.
Let’s start with simple example of how to make a transparent button:
java
class TransparentButton extends JButton {
public TransparentButton(String text) {
super(text);
setOpaque(false);
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g.create();
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f));
super.paint(g2);
g2.dispose();
}
}To use
TransparentButton instead of
JButton all what you want to modify is transparency level (I will show you how in next paragraph) and overwrite constructors you want as the above code.
All what you want to change transparency level is to change the
0.5f value in line
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f)); To make it clearer
0.0f means 100% transparent (you will not see it)0.5f means 50% transparent1.0f means 0% transparent (Not transparent at all)Let’s try this way now with popup menu:
java
class TransparentPopupMenu extends JPopupMenu {
public TransparentPopupMenu() {
super();
setOpaque(false);
}
}
class TransparentMenuItem extends JMenuItem{
public TransparentMenuItem(String text) {
super(text);
setOpaque(false);
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g.create();
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f));
super.paint(g2);
g2.dispose();
}
}: You can get rid of
TransparentPopupMenu class but in this case you have to remember to call
setOpaque(false); after initialize
JPopupMenu object
And you can try this way with other components.
Make a transparent swing UI components
9 Jul, 2008 - 10:39 AM
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