transparentbackground.java

JGraph扩展应用。自定义Renderer,自定义视图View实现自定义工作流控件

package flow.graph.test;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;

public class TransparentBackground extends JComponent
                implements ComponentListener, WindowFocusListener, Runnable {

        // constants ---------------------------------------------------------------

        // instance ----------------------------------------------------------------

        private JFrame _frame;
        private BufferedImage _background;
        private long _lastUpdate = 0;
        private boolean _refreshRequested = true;

        private Robot _robot;
        private Rectangle _screenRect;

        private ConvolveOp _blurOp;

        // constructor -------------------------------------------------------------

        public TransparentBackground(JFrame frame) {
                _frame = frame;

                try {
                        _robot = new Robot();
                } catch (AWTException e) {
                        e.printStackTrace();
                        return;
                }

                Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
                _screenRect = new Rectangle(dim.width, dim.height);

                float[] my_kernel = {
                                0.10f, 0.10f, 0.10f,
                                0.10f, 0.20f, 0.10f,
                                0.10f, 0.10f, 0.10f};
                _blurOp = new ConvolveOp(new Kernel(3, 3, my_kernel));

                updateBackground();
                _frame.addComponentListener(this);
                _frame.addWindowFocusListener(this);
                new Thread(this).start();
        }

        // protected ---------------------------------------------------------------

        protected void updateBackground() {
                _background = _robot.createScreenCapture(_screenRect);
        }

        protected void refresh() {
                if (_frame.isVisible() && this.isVisible()) {
                        repaint();
                        _refreshRequested = true;
                        _lastUpdate = System.currentTimeMillis();
                }
        }

        // JComponent --------------------------------------------------------------

        protected void paintComponent(Graphics g) {
                Graphics2D g2 = (Graphics2D) g;

                Point pos = this.getLocationOnScreen();

                BufferedImage buf = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_RGB);
                buf.getGraphics().drawImage(_background, -pos.x, -pos.y, null);

                Image img = _blurOp.filter(buf, null);
                g2.drawImage(img, 0, 0, null);

                g2.setColor(new Color(255, 255, 255, 0));
                g2.fillRect(0, 0, getWidth(), getHeight());
        }

        // ComponentListener -------------------------------------------------------

        public void componentHidden(ComponentEvent e) {
        }

        public void componentMoved(ComponentEvent e) {
                repaint();
        }

        public void componentResized(ComponentEvent e) {
                repaint();
        }

        public void componentShown(ComponentEvent e) {
                repaint();
        }

        // WindowFocusListener -----------------------------------------------------

        public void windowGainedFocus(WindowEvent e) {
                refresh();
        }

        public void windowLostFocus(WindowEvent e) {
                refresh();
        }

        // Runnable ----------------------------------------------------------------

        public void run() {
                try {
                        while (true) {
                                Thread.sleep(100);
                                long now = System.currentTimeMillis();
                                if (_refreshRequested && ((now - _lastUpdate) > 1000)) {
                                        if (_frame.isVisible()) {
                                                Point location = _frame.getLocation();
                                                _frame.setLocation(-_frame.getWidth(), -_frame.getHeight());
                                                updateBackground();
                                                _frame.setLocation(location);
                                                refresh();
                                        }
                                        _lastUpdate = now;
                                        _refreshRequested = false;
                                }
                        }
                } catch (InterruptedException e) {
                        e.printStackTrace();
                }
        }

        public static void main(String[] args) {
                JFrame frame = new JFrame("Transparent Window");
                TransparentBackground bg = new TransparentBackground(frame);
                bg.setLayout(new BorderLayout());
                frame.getContentPane( ).add("Center",bg);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setSize(200, 200);
                frame.setLocation(500, 500);
                frame.setVisible(true);
        }
}