Java Tutorial/2D Graphics/Tranformation

Calculate Rotation Transform with Math.PI

import java.awt.Canvas;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.geom.AffineTransform;
import java.awt.geom.Line2D;
import javax.swing.JFrame;
public class Draw2DRotate extends JFrame {
  public static void main(String args[]) {
    Draw2DRotate app = new Draw2DRotate();
  }
  public Draw2DRotate() {
    add("Center", new MyCanvas());
    setSize(400, 400);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
  }
}
class MyCanvas extends Canvas {
  public void paint(Graphics graphics) {
    Graphics2D g = (Graphics2D) graphics;
    AffineTransform transform = AffineTransform.getRotateInstance(Math.PI / 16.0d);
    g.setTransform(transform);
    Line2D.Double shape = new Line2D.Double(0.0, 0.0, 300.0, 300.0);
    g.draw(shape);
    g.setFont(new Font("Helvetica", Font.BOLD, 24));
    String text = ("jexp");
    g.drawString(text, 300, 50);
    Toolkit toolkit = Toolkit.getDefaultToolkit();
    Image image = toolkit.getImage("image1.gif");
    g.drawImage(image, 100, 150, this);
  }
}

Coordinate Translation.

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Translation extends JPanel {
  public void paint(Graphics g) {
    super.paint(g);
    Graphics2D g2d = (Graphics2D) g;
    g2d.setColor(new Color(150, 150, 150));
    g2d.fillRect(20, 20, 80, 50);
    g2d.translate(150, 50);
    g2d.fillRect(20, 20, 80, 50);
  }
  public static void main(String[] args) {
    JFrame frame = new JFrame("Translation");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(new Translation());
    frame.setSize(300, 200);
    frame.setVisible(true);
  }
}

Move and scale graphical objects with a mouse on the panel

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import java.awt.geom.Rectangle2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class MouseMoveScale extends JPanel {
  private Rectangle2D.Float myRect = new Rectangle2D.Float(50, 50, 50, 50);
  MovingAdapter ma = new MovingAdapter();
  public MouseMoveScale() {
    addMouseMotionListener(ma);
    addMouseListener(ma);
    addMouseWheelListener(new ScaleHandler());
  }
  public void paint(Graphics g) {
    super.paint(g);
    Graphics2D g2d = (Graphics2D) g;
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
        RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
    g2d.setColor(new Color(0, 0, 200));
    g2d.fill(myRect);
  }
  class MovingAdapter extends MouseAdapter {
    private int x;
    private int y;
    public void mousePressed(MouseEvent e) {
      x = e.getX();
      y = e.getY();
    }
    public void mouseDragged(MouseEvent e) {
      int dx = e.getX() - x;
      int dy = e.getY() - y;
      if (myRect.getBounds2D().contains(x, y)) {
        myRect.x += dx;
        myRect.y += dy;
        repaint();
      }
      x += dx;
      y += dy;
    }
  }
  class ScaleHandler implements MouseWheelListener {
    public void mouseWheelMoved(MouseWheelEvent e) {
      int x = e.getX();
      int y = e.getY();
      if (e.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL) {
        if (myRect.getBounds2D().contains(x, y)) {
          float amount = e.getWheelRotation() * 5f;
          myRect.width += amount;
          myRect.height += amount;
          repaint();
        }
      }
    }
  }
  public static void main(String[] args) {
    JFrame frame = new JFrame("Moving and Scaling");
    MouseMoveScale m = new MouseMoveScale();
    m.setDoubleBuffered(true);
    frame.add(m);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(300, 300);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}

Rotate a line of character (String)

import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.font.FontRenderContext;
import java.awt.font.GlyphVector;
import java.awt.geom.AffineTransform;
import java.awt.geom.Point2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class RotatedText extends JPanel {
  public void paint(Graphics g) {
    Graphics2D g2d = (Graphics2D) g;
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    String s = "111111111111111111111111111111";
    Font font = new Font("Courier", Font.PLAIN, 12);
    g2d.translate(20, 20);
    FontRenderContext frc = g2d.getFontRenderContext();
    GlyphVector gv = font.createGlyphVector(frc, s);
    int length = gv.getNumGlyphs();
    for (int i = 0; i < length; i++) {
      Point2D p = gv.getGlyphPosition(i);
      AffineTransform at = AffineTransform.getTranslateInstance(p.getX(), p.getY());
      at.rotate((double) i / (double) (length - 1) * Math.PI / 3);
      Shape glyph = gv.getGlyphOutline(i);
      Shape transformedGlyph = at.createTransformedShape(glyph);
      g2d.fill(transformedGlyph);
    }
  }
  public static void main(String[] args) {
    JFrame frame = new JFrame("Rotated text");
    frame.add(new RotatedText());
    frame.setSize(400, 300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}

Rotates a shape about the specified coordinates.

/* 
 * JCommon : a free general purpose class library for the Java(tm) platform
 * 
 *
 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jcommon/index.html
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * -------------------
 * ShapeUtilities.java
 * -------------------
 * (C)opyright 2003-2008, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: ShapeUtilities.java,v 1.18 2008/06/02 06:58:28 mungady Exp $
 *
 * Changes
 * -------
 * 13-Aug-2003 : Version 1 (DG);
 * 16-Mar-2004 : Moved rotateShape() from RefineryUtilities.java to here (DG);
 * 13-May-2004 : Added new shape creation methods (DG);
 * 30-Sep-2004 : Added createLineRegion() method (DG);
 *               Moved drawRotatedShape() method from RefineryUtilities class
 *               to this class (DG);
 * 04-Oct-2004 : Renamed ShapeUtils --> ShapeUtilities (DG);
 * 26-Oct-2004 : Added a method to test the equality of two Line2D
 *               instances (DG);
 * 10-Nov-2004 : Added new translateShape() and equal(Ellipse2D, Ellipse2D)
 *               methods (DG);
 * 11-Nov-2004 : Renamed translateShape() --> createTranslatedShape() (DG);
 * 07-Jan-2005 : Minor Javadoc fix (DG);
 * 11-Jan-2005 : Removed deprecated code in preparation for 1.0.0 release (DG);
 * 21-Jan-2005 : Modified return type of RectangleAnchor.coordinates()
 *               method (DG);
 * 22-Feb-2005 : Added equality tests for Arc2D and GeneralPath (DG);
 * 16-Mar-2005 : Fixed bug where equal(Shape, Shape) fails for two Polygon
 *               instances (DG);
 * 01-Jun-2008 : Fixed bug in equal(GeneralPath, GeneralPath) method (DG);
 *
 */
import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.awt.geom.Point2D;
/**
 * Utility methods for {@link Shape} objects.
 *
 * @author David Gilbert
 */
public class Main {
  /**
   * Rotates a shape about the specified coordinates.
   *
   * @param base  the shape (<code>null</code> permitted, returns
   *              <code>null</code>).
   * @param angle  the angle (in radians).
   * @param x  the x coordinate for the rotation point (in Java2D space).
   * @param y  the y coordinate for the rotation point (in Java2D space).
   *
   * @return the rotated shape.
   */
  public static Shape rotateShape(final Shape base, final double angle,
                                  final float x, final float y) {
      if (base == null) {
          return null;
      }
      final AffineTransform rotate = AffineTransform.getRotateInstance(
              angle, x, y);
      final Shape result = rotate.createTransformedShape(base);
      return result;
  }
}

Rotating image using Java 2D AffineTransform class

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.geom.AffineTransform;
import javax.swing.JPanel;
class ImagePanel extends JPanel {
  int offset = 5;
  private Image image;
  private int angle;
  private int w, h;
  private AffineTransform transform;
  public ImagePanel(Image i) {
    image = i;
    w = image.getWidth(this);
    h = image.getHeight(this);
    transform = new AffineTransform();
  }
  public void paintComponent(Graphics grp) {
    Rectangle rect = this.getBounds();
    Graphics2D g2d = (Graphics2D) grp;
    transform.setToTranslation((rect.width - w) / 2,
        (rect.height - h) / 2);
    transform.rotate(Math.toRadians(angle), w / 2,
        h / 2);
    g2d.drawImage(image, transform, this);
  }
  public void rotate() {
    angle -= offset;
    if (angle <= 0) {
      angle = 360;
    }
    repaint();
  }
}

Rotation and coordinate translation

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Rotate extends JPanel {
  public void paint(Graphics g) {
    super.paint(g);
    Graphics2D g2d = (Graphics2D) g;
    g2d.setColor(new Color(150, 150, 150));
    g2d.fillRect(20, 20, 80, 50);
    g2d.translate(180, -150);
    g2d.rotate(Math.PI / 4);
    g2d.fillRect(20, 20, 80, 50);
  }
  public static void main(String[] args) {
    JFrame frame = new JFrame("Rotation");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(new Rotate());
    frame.setSize(300, 200);
    frame.setVisible(true);
  }
}

Scaling an object

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Scale extends JPanel {
  public void paint(Graphics g) {
    super.paint(g);
    Graphics2D g2d = (Graphics2D) g;
    g2d.setColor(new Color(150, 150, 150));
    g2d.fillRect(0, 0, 80, 50);
    AffineTransform tx1 = new AffineTransform();
    tx1.translate(110, 20);
    tx1.scale(0.5, 0.5);
    g2d.setTransform(tx1);
    g2d.fillRect(0, 0, 80, 50);
    AffineTransform tx2 = new AffineTransform();
    tx2.translate(200, 20);
    tx2.scale(1.5, 1.5);
    g2d.setTransform(tx2);
    g2d.fillRect(0, 0, 80, 50);
  }
  public static void main(String[] args) {
    JFrame frame = new JFrame("Scaling");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(new Scale());
    frame.setSize(330, 160);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}

Tranformation with AffineTransform.getScaleInstance

import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
public class AffineTransformGetScaleInstance extends Frame {
  public static void main(String[] args) {
    (new AffineTransformGetScaleInstance()).setVisible(true);
  }
  public AffineTransformGetScaleInstance() {
    setSize(350, 300);
  }
  public void paint(Graphics g) {
    AffineTransform atrans = null;
    Graphics2D g2d = (Graphics2D) g;
    atrans = AffineTransform.getScaleInstance(2, 3);
    if (atrans != null)
      g2d.setTransform(atrans);
    g2d.fillRect(50, 50, 100, 50);
  }
}

Tranformation with AffineTransform.getShearInstance

import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
public class AffineTransformGetShearInstance extends Frame {
  public static void main(String[] args) {
    (new AffineTransformGetShearInstance()).setVisible(true);
  }
  public AffineTransformGetShearInstance() {
    setSize(350, 300);
  }
  public void paint(Graphics g) {
    AffineTransform atrans = null;
    Graphics2D g2d = (Graphics2D) g;
    atrans = AffineTransform.getShearInstance(.1, .5);
    if (atrans != null)
      g2d.setTransform(atrans);
    g2d.fillRect(50, 50, 100, 50);
  }
}

Tranformation with AffineTransform.getTranslateInstance

import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
public class AffineTransformGetTranslateInstance extends Frame {
  public static void main(String[] args) {
    (new AffineTransformGetTranslateInstance()).setVisible(true);
  }
  public AffineTransformGetTranslateInstance() {
    setSize(350, 300);
  }
  public void paint(Graphics g) {
    AffineTransform atrans = null;
    Graphics2D g2d = (Graphics2D) g;
    atrans = AffineTransform.getTranslateInstance(50, 100);
    if (atrans != null)
      g2d.setTransform(atrans);
    g2d.fillRect(50, 50, 100, 50);
  }
}

Transform Lab

import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
public class AffineTransformGetRotateInstance extends Frame {
  public static void main(String[] args) {
    (new AffineTransformGetRotateInstance()).setVisible(true);
  }
  public AffineTransformGetRotateInstance() {
    setSize(350, 300);
  }
  public void paint(Graphics g) {
    AffineTransform atrans = null;
    Graphics2D g2d = (Graphics2D) g;
    atrans = AffineTransform.getRotateInstance(Math.PI / 4, 50, 50);
    if (atrans != null)
      g2d.setTransform(atrans);
    g2d.fillRect(50, 50, 100, 50);
  }
}

Translate and rotate all objects

import java.awt.AlphaComposite;
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.Toolkit;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Ellipse2D;
import java.awt.geom.RoundRectangle2D;
import javax.swing.JComponent;
import javax.swing.JFrame;
public class Main extends JComponent {
  private Image image;
  private int theta;
  public Main() {
    image = Toolkit.getDefaultToolkit().getImage("A.jpg");
    theta = 0;
    addMouseListener(new MouseAdapter() {
      public void mousePressed(MouseEvent me) {
        theta = (theta + 15) % 360;
        repaint();
      }
    });
  }
  public void paint(Graphics g) {
    Graphics2D g2 = (Graphics2D) g;
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    int cx = getSize().width / 2;
    int cy = getSize().height / 2;
    g2.translate(cx, cy);
    g2.rotate(theta * Math.PI / 180);
    Shape oldClip = g2.getClip();
    Shape e = new Ellipse2D.Float(-cx, -cy, cx * 2, cy * 2);
    g2.clip(e);
    Shape c = new Ellipse2D.Float(-cx, -cy, cx * 3 / 4, cy * 2);
    g2.setPaint(new GradientPaint(40, 40, Color.blue, 60, 50, Color.white, true));
    g2.fill(c);
    g2.setPaint(Color.yellow);
    g2.fillOval(cx / 4, 0, cx, cy);
    g2.setClip(oldClip);
    g2.setFont(new Font("Times New Roman", Font.PLAIN, 64));
    g2.setPaint(new GradientPaint(-cx, 0, Color.red, cx, 0, Color.black, false));
    g2.drawString("Hello, 2D!", -cx * 3 / 4, cy / 4);
    AlphaComposite ac = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, (float) .75);
    g2.setComposite(ac);
    Shape r = new RoundRectangle2D.Float(0, -cy * 3 / 4, cx * 3 / 4, cy * 3 / 4, 20, 20);
    g2.setStroke(new BasicStroke(4));
    g2.setPaint(Color.magenta);
    g2.fill(r);
    g2.setPaint(Color.green);
    g2.draw(r);
    g2.drawImage(image, -cx / 2, -cy / 2, this);
  }
  public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.add(new Main(), BorderLayout.CENTER);
    frame.setSize(300, 300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}