/*
* Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in the
*     documentation and/or other materials provided with the distribution.
*
*   - Neither the name of Oracle or the names of its
*     contributors may be used to endorse or promote products derived
*     from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
import java.awt.*;
import java.awt.image.*;

import javax.swing.*;
import javax.swing.plaf.LayerUI;

public class Myopia {
  public static void main(String[] args) {
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        createUI();
      }
    });
  }

  public static void createUI() {
    JFrame f = new JFrame ("Myopia");
    
    LayerUI<JComponent> layerUI = new BlurLayerUI();
    JPanel panel = createPanel();
    JLayer<JComponent> jlayer = new JLayer<JComponent>(panel, layerUI);
    
    f.add (jlayer);
    
    f.setSize(300, 200);
    f.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
    f.setLocationRelativeTo (null);
    f.setVisible (true);
  }

  private static JPanel createPanel() {
    JPanel p = new JPanel();

    ButtonGroup entreeGroup = new ButtonGroup();
    JRadioButton radioButton;
    p.add(radioButton = new JRadioButton("Beef", true));
    entreeGroup.add(radioButton);
    p.add(radioButton = new JRadioButton("Chicken"));
    entreeGroup.add(radioButton);
    p.add(radioButton = new JRadioButton("Vegetable"));
    entreeGroup.add(radioButton);

    p.add(new JCheckBox("Ketchup"));
    p.add(new JCheckBox("Mustard"));
    p.add(new JCheckBox("Pickles"));

    p.add(new JLabel("Special requests:"));
    p.add(new JTextField(20));

    JButton orderButton = new JButton("Place Order");
    p.add(orderButton);

    return p;
  }
}

class BlurLayerUI extends LayerUI<JComponent> {
  private BufferedImage mOffscreenImage;
  private BufferedImageOp mOperation;

  public BlurLayerUI() {
    float ninth = 1.0f / 9.0f;
    float[] blurKernel = {
      ninth, ninth, ninth,
      ninth, ninth, ninth,
      ninth, ninth, ninth
    };
    mOperation = new ConvolveOp(
            new Kernel(3, 3, blurKernel),
            ConvolveOp.EDGE_NO_OP, null);
  }

  @Override
  public void paint (Graphics g, JComponent c) {
    int w = c.getWidth();
    int h = c.getHeight();

    if (w == 0 || h == 0) {
      return;
    }

    // Only create the offscreen image if the one we have
    // is the wrong size.
    if (mOffscreenImage == null ||
            mOffscreenImage.getWidth() != w ||
            mOffscreenImage.getHeight() != h) {
      mOffscreenImage = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
    }

    Graphics2D ig2 = mOffscreenImage.createGraphics();
    ig2.setClip(g.getClip());
    super.paint(ig2, c);
    ig2.dispose();

    Graphics2D g2 = (Graphics2D)g;
    g2.drawImage(mOffscreenImage, mOperation, 0, 0);
  }
}