// get required Java libraries
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.datatransfer.*;
import java.io.IOException;


public void setup() {
    size(500, 500);
}

public void draw() {
  
  if (mousePressed) {
     ellipse(mouseX, mouseY, 20, 20);
  }
  
}

    public void keyReleased() {
        // CTRL+C: Copy to Clipboard
        if (key == 3) {
            BufferedImage clipBoardImage = new BufferedImage(width, height,
                    (g.format == ARGB)
                    ? BufferedImage.TYPE_INT_ARGB : BufferedImage.TYPE_INT_RGB);
            g.loadPixels();
            clipBoardImage.setRGB(0, 0, width, height, g.pixels, 0, width);
            copyImageToClipboard(clipBoardImage);
        }

        // CTRL+V: Paste Clipboard
        if (key == 22) {
            PImage img = getClipboardImage(this);
            if (img == null) {
                return; // not an image on clipboard
            }
            int w = img.width;
            int h = img.height;
            int dx = (width - w) / 2;
            int dy = (height - h) / 2;
            image(img, dx, dy);
        }
    }
         
    /**
     * Clipboard copy and paste: references
     * http://www.devx.com/Java/Article/22326/0/page/1
     * http://processing.org/hacks/hacks:clipboard  ----- this link is now dead
     *
     * make everything here static so it could be implemented in a separate class
     * 
     * Author: Martin Humby 2009
     *
     */
    public static void copyImageToClipboard(Image image) {
        TransferableImage imageSelection = new TransferableImage(image);
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        toolkit.getSystemClipboard().setContents(imageSelection, null);
    }

    public static PImage getClipboardImage(PApplet p) {
        Transferable t =
                Toolkit.getDefaultToolkit().getSystemClipboard().getContents(null);
        try {
            if (t != null && t.isDataFlavorSupported(DataFlavor.imageFlavor)) {
                BufferedImage bimg = (BufferedImage) t.getTransferData(DataFlavor.imageFlavor);
                int w = bimg.getWidth();
                int h = bimg.getHeight();
                // make it ARGB to be on the safe side - makes no difference unless
                // clipboard image has some tranparency maybe?
                PImage pImg = p.createImage(w, h, PApplet.ARGB);
                pImg.loadPixels();
                bimg.getRGB(0, 0, w, h, pImg.pixels, 0, w);
                pImg.updatePixels();
                return pImg;
            }
        } catch (ClassCastException e) {
          println(e);
        } catch (UnsupportedFlavorException e) {
          println(e);
        } catch (IOException e) {
          println(e);
        }
        return null;
    }

    static class TransferableImage implements Transferable {

        private Image image;

        public TransferableImage(Image image) {
            this.image = image;
        }

        public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException {
            if (!flavor.equals(DataFlavor.imageFlavor)) {
                throw new UnsupportedFlavorException(flavor);
            }
            return image;
        }

        public boolean isDataFlavorSupported(DataFlavor flavor) {
            return flavor.equals(DataFlavor.imageFlavor);
        }

        public DataFlavor[] getTransferDataFlavors() {
            // in some cases there may be more than one flavour?
            return new DataFlavor[]{DataFlavor.imageFlavor};
        }
    }