Find format of clipboard image in Java

Question

I'm getting images from clipboard using this:

if(Toolkit.getDefaultToolkit().getSystemClipboard().isDataFlavorAvailable(DataFlavor.imageFlavor)){
       ImageIcon IMG = new ImageIcon((BufferedImage) Toolkit.getDefaultToolkit().getSystemClipboard().getData(DataFlavor.imageFlavor));
}

Now I want to save this image in disk using ImageIO.write;
How can I find image format (JPG,PNG,GIF,...) to use in ImageIO.write as formatName ?

Thanks

Answer 1

The mime type of the content of the clipboard when checked via

.isDataFlavorAvailable(DataFlavor.imageFlavor)

is image/x-java-image (but OS vendors do not need to follow MIME types for clipboards).

I found two ways to supposedly get an image from a clipboard and write it to a file:

1. Using a helper method found in this blog post: The nightmares of getting images from the Mac OS X clipboard using Java.

   Clipboard clip = Toolkit.getDefaultToolkit().getSystemClipboard()
   
   ImageIcon IMG = new ImageIcon((BufferedImage)    
   clip.getData(DataFlavor.imageFlavor));
   BufferedImage bImage = getBufferedImage(IMG.getImage());
   ImageIO.write(bImage, "png", new File("/tmp/test.png"));
   

   The getBufferedImage method looks like this:

   public static BufferedImage getBufferedImage(Image img) {
       if (img == null) {
           return null;
       }
       int w = img.getWidth(null);
       int h = img.getHeight(null);
       // draw original image to thumbnail image object and 
       // scale it to the new size on-the-fly 
       BufferedImage bufimg = new BufferedImage(w, h, 
           BufferedImage.TYPE_INT_RGB);
       Graphics2D g2 = bufimg.createGraphics();
       g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
           RenderingHints.VALUE_INTERPOLATION_BILINEAR);
       g2.drawImage(img, 0, 0, w, h, null);
       g2.dispose();
       return bufimg;
   }
   

2. Via Transferable. Note that this runs on OS X but produces an empty image of the correct size:

   Clipboard clip = Toolkit.getDefaultToolkit().getSystemClipboard()
   Transferable content =
       clip.getContents(null);
   BufferedImage img = (BufferedImage) content.getTransferData(
       DataFlavor.imageFlavor);
   ImageIO.write(img, "png", new File("/tmp/test.png"));