Move and scale graphical objects with a mouse on the panel : Tranformation « 2D Graphics « Java Tutorial

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

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);
  }
}

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.