Resizing et moving Components with aspect ratio constraint

Question

hi all
i m creating a GUI application and i need to manipulate components in an internal fram .
thoose components must be moved and resized with the mousse with the constraint of aspect ratio keep
thx for your help

Answer 1

real thxno problem morfus
Don't know whether you've come up with anything, but I got bored and implemented it. Resizeable has been changed so now you can set an aspect ratio on it, either an angle or x and y lengths
package tjacobs.ui;
import java.awt.Component;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
//For testing
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
* tjacobs.ui.Resizeable<p>
* Makes a component resizeable. Does not work if there's a layout manager
* messing with things<p>
* <code>
*  usage:
*                 Component c = ...
*                 new Resizeable(c);
*                 parent.add(c);
*  </code>
public class Resizeable extends MouseAdapter implements MouseMotionListener {
     int fix_pt_x = -1;
     int fix_pt_y = -1;
    Component mResizeable;
     Cursor mOldcursor;
     private Double mAspectRatio;
     public Resizeable(Component c) {
          mResizeable = c;
          c.addMouseListener(this);
          c.addMouseMotionListener(this);
     public void setMaintainAspect(double x, double y) {
          setMaintainAspect(new Double(Math.atan2(y, x)));
     public void setMaintainAspect(Double angle) {
          mAspectRatio = angle;
     public void mouseEntered(MouseEvent me) {
          setCursorType(me.getPoint());
     private void setCursorType(Point p) {
          boolean n = p.y <= WindowUtilities.RESIZE_MARGIN_SIZE;
          boolean s = p.y + WindowUtilities.RESIZE_MARGIN_SIZE >= mResizeable.getHeight();
          boolean w = p.x <= WindowUtilities.RESIZE_MARGIN_SIZE;
          boolean e = p.x + WindowUtilities.RESIZE_MARGIN_SIZE >= mResizeable.getWidth();
          if (e) {
               if (s) {
                    mResizeable.setCursor(Cursor.getPredefinedCursor(Cursor.SE_RESIZE_CURSOR));
                    return;
               mResizeable.setCursor(Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR));
               return;
          if(s) {
               mResizeable.setCursor(Cursor.getPredefinedCursor(Cursor.S_RESIZE_CURSOR));
               return;
     public void mouseExited(MouseEvent me) {
          if (mOldcursor != null)
               ((Component)me.getSource()).setCursor(mOldcursor);
          mOldcursor = null;
    public void mousePressed(MouseEvent me) {
          Cursor c = mResizeable.getCursor();
          Point loc = mResizeable.getLocation();
          if (c.equals(Cursor.getPredefinedCursor(Cursor.SE_RESIZE_CURSOR))) {
               fix_pt_x = loc.x;
               fix_pt_y = loc.y;
               return;
          if (c.equals(Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR))) {
               fix_pt_x = loc.x;
               fix_pt_y = -1;
               return;
          if (c.equals(Cursor.getPredefinedCursor(Cursor.S_RESIZE_CURSOR))) {
               fix_pt_x = -1;
               fix_pt_y = loc.y;
               return;
     public void mouseReleased(MouseEvent me) {
          fix_pt_x = -1;
          fix_pt_y = -1;
     public void mouseMoved(MouseEvent me) {
          setCursorType(me.getPoint());
     public void mouseDragged(MouseEvent me) {
          Point p = me.getPoint();
          int width = fix_pt_x == -1 ? mResizeable.getWidth() : p.x;
          int height = fix_pt_y == -1 ? mResizeable.getHeight() : p.y;
          if (mAspectRatio == null) {
               mResizeable.setSize(new Dimension(width > 1 ? width : 1, height > 1 ? height : 1));
          else {
               //do something
               double distance = Math.sqrt(width * width + height * height);
               width = (int) (distance * Math.cos(mAspectRatio));
               height = (int) (distance * Math.sin(mAspectRatio));
               mResizeable.setSize(new Dimension(width > 1 ? width : 1, height > 1 ? height : 1));
     //For Testing
     public static void main(String args[]) {
          JPanel jp = new JPanel();
          JButton jb = new JButton("hello");
          JButton jb2 = new JButton("hello2");
          jp.setPreferredSize(new Dimension(300,300));
          jp.setSize(300,300);
          jp.setLayout(null);
          jp.add(jb);
          jp.add(jb2);
          jb.setSize(20,20);
          jb.setLocation(2,2);
          jb2.setSize(30,20);
          jb2.setLocation(30,10);
          new Resizeable(jb);
          Resizeable r = new Resizeable(jb2);
          r.setMaintainAspect(30, 20);
          JFrame jf = new JFrame();
          jf.add(jp);
          jf.setDefaultCloseOperation(jf.EXIT_ON_CLOSE);
          jf.setLocation(100,100);
          jf.pack();
          jf.setVisible(true);
}