如何改变affinetransform的原点

Question

使用affinetransform进行图像的拖动时，鼠标的位置总是处于图像的左上角。
如何改变鼠标的位置，使得鼠标可以点中图像中的任意位置而进行拖动？

Answer 1

下面的程序也体现了这个问题，不管当鼠标点中正方形的哪个部分，当拖动时，正方形自动跳到鼠标的右下角。import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.geom.AffineTransform;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.awt.geom.Point2D.Double;import javax.swing.JFrame;
import javax.swing.JPanel;public class AffineTest extends JFrame {   
    /**
     *
     */
    private static final long serialVersionUID = 1L;    public Rectangle2D.Double rect = new Rectangle2D.Double(30,50,60,60);
    public double movex = 0 ,movey = 0;
    Point2D clickPoint = new Point2D.Double(0,0);
    public AffineTest()
    {
        this.setSize(600,600);
        this.setLocationRelativeTo(null);
        this.add(new DrawingPanel());
        this.setVisible(true);
       
    }
   
   
    private class DrawingPanel extends JPanel
    {
        public DrawingPanel()
        {
            this.addMouseListener(new panelListener());
            this.addMouseMotionListener(new panelListener());
        }
       
        public void paintComponent(Graphics g)
        {
            super.paintComponent(g);
            AffineTransform tx = new AffineTransform();
            if( rect.contains((Point2D.Double)clickPoint))
            {
            tx.translate(movex, movey);
            }
            Graphics2D g2d = (Graphics2D)g;
            g2d.setTransform(tx);
           
           
            g2d.draw(rect);
            repaint();
        }
    }
   
   
    private class panelListener implements MouseListener,MouseMotionListener
    {        @Override
        public void mouseClicked(MouseEvent e) {
            clickPoint.setLocation(e.getX(), e.getY());
            repaint();
           
        }        @Override
        public void mouseEntered(MouseEvent arg0) {
            // TODO Auto-generated method stub
           
        }        @Override
        public void mouseExited(MouseEvent arg0) {
            // TODO Auto-generated method stub
           
        }        @Override
        public void mousePressed(MouseEvent arg0) {
            // TODO Auto-generated method stub
           
        }        @Override
        public void mouseReleased(MouseEvent arg0) {
            // TODO Auto-generated method stub
           
        }        @Override
        public void mouseDragged(MouseEvent arg0) {
            movex = arg0.getX();
            movey = arg0.getY();
        }        @Override
        public void mouseMoved(MouseEvent arg0) {
            // TODO Auto-generated method stub
           
        }
       
    }
   
   
   
    public static void main(String [] args)
    {
        new AffineTest();
    }
   
   
   
}