AffineTransform demo

[Java Tip]

Code:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;

import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class AffineTransformApp extends JFrame {
  DisplayPanel displayPanel;

  JComboBox scaleXval, scaleYval, shearXval, shearYval;

  String[] scaleValues = { "0.10", "0.25", "0.50", "0.75", "1.00", "1.25",
      "1.50", "1.75", "2.00" };

  String[] shearValues = { "0.00", "0.25", "0.50", "0.75", "1.00" };

  public AffineTransformApp() {
    super();
    Container container = getContentPane();

    displayPanel = new DisplayPanel();
    container.add(displayPanel);

    JPanel panel = new JPanel();
    panel.setLayout(new GridLayout(2, 4, 5, 5));
    scaleXval = new JComboBox(scaleValues);
    scaleXval.setSelectedItem("1.00");
    scaleXval.addActionListener(new ComboBoxListener());
    scaleYval = new JComboBox(scaleValues);
    scaleYval.setSelectedItem("1.00");
    scaleYval.addActionListener(new ComboBoxListener());

    shearXval = new JComboBox(shearValues);
    shearXval.setSelectedItem("0.00");
    shearXval.addActionListener(new ComboBoxListener());
    shearYval = new JComboBox(shearValues);
    shearYval.setSelectedItem("0.00");
    shearYval.addActionListener(new ComboBoxListener());

    panel.add(new JLabel("Scale X value:"));
    panel.add(scaleXval);
    panel.add(new JLabel("Scale Y value:"));
    panel.add(scaleYval);
    panel.add(new JLabel("Shear X value:"));
    panel.add(shearXval);
    panel.add(new JLabel("Shear Y value:"));
    panel.add(shearYval);

    container.add(BorderLayout.SOUTH, panel);

    addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });
    setSize(displayPanel.getWidth(), displayPanel.getHeight() + 10);
    setVisible(true);
  }

  public static void main(String arg[]) {
    new AffineTransformApp();
  }

  class ComboBoxListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      JComboBox temp = (JComboBox) e.getSource();

      if (temp == scaleXval) {
        displayPanel.scalex = Double.parseDouble((String) temp
            .getSelectedItem());
        displayPanel.applyValue(true, false);
        displayPanel.applyFilter();
        displayPanel.repaint();
      } else if (temp == scaleYval) {
        displayPanel.scaley = Double.parseDouble((String) temp
            .getSelectedItem());
        displayPanel.applyValue(true, false);
        displayPanel.applyFilter();
        displayPanel.repaint();
      } else if (temp == shearXval) {
        displayPanel.shearx = Double.parseDouble((String) temp
            .getSelectedItem());
        displayPanel.applyValue(false, true);
        displayPanel.applyFilter();
        displayPanel.repaint();
      } else if (temp == shearYval) {
        displayPanel.sheary = Double.parseDouble((String) temp
            .getSelectedItem());
        displayPanel.applyValue(false, true);
        displayPanel.applyFilter();
        displayPanel.repaint();
      }
    }
  }
}

class DisplayPanel extends JLabel {
  Image displayImage;

  BufferedImage biSrc, biDest;

  BufferedImage bi;

  Graphics2D big;

  AffineTransform transform;

  double scalex = 1.0;

  double scaley = 1.0;

  double shearx = 1.0;

  double sheary = 1.0;

  DisplayPanel() {
    setBackground(Color.black);
    loadImage();
    setSize(displayImage.getWidth(this), displayImage.getWidth(this)); // panel
    createBufferedImages();

    transform = new AffineTransform();
  }

  public void loadImage() {
    displayImage = Toolkit.getDefaultToolkit().getImage(
        "largeJavaLogo.jpg");
    MediaTracker mt = new MediaTracker(this);
    mt.addImage(displayImage, 1);
    try {
      mt.waitForAll();
    } catch (Exception e) {
      System.out.println("Exception while loading.");
    }

    if (displayImage.getWidth(this) == -1) {
      System.out.println(" Missing .jpg file");
      System.exit(0);
    }
  }

  public void createBufferedImages() {
    biSrc = new BufferedImage(displayImage.getWidth(this), displayImage
        .getHeight(this), BufferedImage.TYPE_INT_RGB);

    big = biSrc.createGraphics();
    big.drawImage(displayImage, 0, 0, this);

    bi = biSrc;

    biDest = new BufferedImage(displayImage.getWidth(this), displayImage
        .getHeight(this), BufferedImage.TYPE_INT_RGB);
  }

  public void applyValue(boolean scale, boolean shear) {
    if (scale) {
      transform.setToScale(scalex, scaley);
      scale = false;
    } else if (shear) {
      transform.setToShear(shearx, sheary);
      shear = false;
    }
  }

  public void applyFilter() {
    AffineTransformOp op = new AffineTransformOp(transform, null);
    Graphics2D biDestG2D = biDest.createGraphics();
    biDestG2D
        .clearRect(0, 0, biDest.getWidth(this), biDest.getHeight(this));
    op.filter(biSrc, biDest);
    bi = biDest;
  }

  public void reset() {
    big.setColor(Color.black);
    big.clearRect(0, 0, bi.getWidth(this), bi.getHeight(this));
    big.drawImage(displayImage, 0, 0, this);
  }

  public void update(Graphics g) {
    g.clearRect(0, 0, getWidth(), getHeight());
    paintComponent(g);
  }

  public void paintComponent(Graphics g) {
    super.paintComponent(g);
    Graphics2D g2D = (Graphics2D) g;
    g2D.drawImage(bi, 0, 0, this);
  }
}