Implementing drag and drop across components with drag image...

Question

Hey all,
Finally got the hang of drag and drop. Not too hard, but a little time consuming. I found an article showing how to capture and drag a BufferedImage within a JTree. When you click and drag a node, it creates a BufferedImage of the node on screen and "ghosts" it a bit, which has a very appealing effect.
However, when I try to drag this image to a JList component, it disappears. So I created the same affect in the JList component. Now you can drag the image from the tree to the list and vice versa. However, the problem is, the image does not "fly over" the borders of the two components (butted up against each other) with the mouse. The image seems to go under the borders, while the mouse floats above everything.
What I would like to do is be able to drag the image all over the application, perhaps even the desktop in the case of a SDI application. I want to be able to see this image drag from my Java app over the Windows Explorer folder, just like how you can do that with Windows Explorer, dragging an image of the selected node into any app that supports the drop. I know we can handle the "transfer" data from explorer and vice versa, but how to be able to keep an image with the mouse?
My best guess is somehow using the Glass pane, grabbing a ref to its BufferedImage (if that is even what is there), and drawing the dragged item in that pane. But, then, how will the image move over the desktop outside of the app, where a glass pane is not?
Is there a way to draw on top of anything, anywhere, but still be able to redraw the background as the image moves with the mouse? There are times where the image may be big, so I don't want to have to capture the underlying screen as an image covering the size of the drag image to restore it as the drag image moves around.
Thank you.

Answer 1

We know cursors support some degree of transparence because they have shapes other than blocks.
I've done some playing around with
Toolkit.getDefaultToolkit().createCustomCursor(....);The sad news is, it seems that as soon as a pixel's alpha value is greater than 0, it automatically becomes 100% opaque.
The best you can do, is to take your image, and divide it into a pixel-checkerboard, and set the alpha value of alternating pixels to 0.
e.g.
BufferedImage i = new BufferedImage(32, 32, BufferedImage.TYPE_INT_ARGB);
        int[] data = ((DataBufferInt)i.getRaster().getDataBuffer()).getData();
        boolean on = true;
        for (int z=0; z<data.length; z++)
            if (on)
                data[z] = 0xffffffff;
            else
                data[z] = 0x00000000;
            on = !on;
            if (z%32==0) on = !on;
        Cursor hazyWhite = Toolkit.getDefaultToolkit().createCustomCursor(i, new Point(0,0), "hw");