Add Translucent Image to JLayeredPane

Question

So I'm making a stopmotion application - the live feed from my webcam is inside a JPanel (with setOpaque(false)) that is inside the top (10th) layer in a JLayeredPane - and basically, when I take a picture, I want to add it to one of the lower layers so that a trace of the previous pictures you've taken shows up on screen. Here's how I'm trying to do that now:

EDIT: this is my new code based off the answer below - this now does nothing, as opposed to just adding the opaque image as before - if I add this to a JPanel, though, and add the JPanel to the JLayeredPane, then all I get is gray

BufferedImage img2 = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D g = img2.createGraphics();
g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, .5f));              

g.drawImage(img2, 0, 0, null);
g.dispose(); 

ImageIcon imgIcon = new ImageIcon(new ImageIcon(img2).getImage().getScaledInstance(img2.getWidth(), img2.getHeight(), Image.SCALE_SMOOTH));
JLabel showPic = new JLabel(imgIcon);
showPic.setSize(layers.getSize());
showPic.setBounds(layers.getX() + 18, layers.getY(), img2.getWidth(), img2.getHeight());

layers.add(showPic, new Integer(1)); //layers is my JLayeredPane
layers.repaint();
layers.revalidate();

img is the picture I've just captured from my webcam, and I'm trying to make it semi transparent, then add it to a JLabel. How can I make this work? Or is there a better way to do this?

Answer 1

I don't know if this will solve the problem but the image you are looking for is

BufferedImage img2 = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_INT_ARGB);

java.awt.Transparency.TRANSLUCENT has the value of 3 and corresponds to BufferedImage.TYPE_INT_ARGB_PRE which only god knows what it's doing.

With BufferedImage.TYPE_INT_ARGB you can create a transparent image and apply Composite etc

You also need to correct this

g.drawImage(img2, null, 0, 0);

to

g.drawImage(img2, 0, 0, null);

--

Heres how transparency works for me:

I have two images bim and bim2 and I draw one on top of the other:

BufferedImage bim=null, bim2=null;
try {
  bim=ImageIO.read(new File("...."));
  bim2=ImageIO.read(new File("...."));
}
catch (Exception ex) { System.err.println("error in bim "+ex); }
int wc=bim.getWidth(), hc=bim.getHeight();

BufferedImage img2 = new BufferedImage(bim.getWidth(), bim.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D g = img2.createGraphics();
g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, .5f));              

g.drawImage(bim, 0, 0, null);
g.drawImage(bim2, 0, 0, wc, hc, null);

Then I can display it on a JPanel Jframe or whatever.

I can even create the Label:

JLabel showPic = new JLabel(new ImageIcon(img2));
JFrame f=new JFrame();
f.setSize(500, 500);
f.add(showPic);
f.setVisible(true);