Rotating image using Java 2D AffineTransform class : Tranformation « 2D Graphics « Java Tutorial

1. Java Tutorial
2. 2D Graphics
3. Tranformation

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();
  }
}

16.3.Tranformation
	16.3.1.	Transform Lab
	16.3.2.	Coordinate Translation.
	16.3.3.	Rotation and coordinate translation
	16.3.4.	Rotate a line of character (String)
	16.3.5.	Scaling an object
	16.3.6.	Tranformation with AffineTransform.getScaleInstance
	16.3.7.	Tranformation with AffineTransform.getTranslateInstance
	16.3.8.	Tranformation with AffineTransform.getShearInstance
	16.3.9.	Calculate Rotation Transform with Math.PI
	16.3.10.	Rotating image using Java 2D AffineTransform class
	16.3.11.	Translate and rotate all objects
	16.3.12.	Move and scale graphical objects with a mouse on the panel
	16.3.13.	Rotates a shape about the specified coordinates.