How to Rotate with AffineTransform and keep the orignal coordinates system?

Question

I'am a command pattern to rotate and translate shapes on Java Swing The translation and the rotation work well separatly, but when I do a 60 deg. rotation and then the translation, the translation follow the new rotated coordinate. Which means if I drag the mouse, the shape moves with a 60 deg gap from the mouse mouvement vector is there any easy solution ? please help, I'am hitting a wall here

My execute method for the rotation

public void execute() {  
    System.out.println("command: rotate " + thetaDegrees );       
    Iterator iter = objects.iterator();  
    Shape shape;  
    while(iter.hasNext()){  
        shape = (Shape)iter.next();           
        mt.addMememto(shape);             
        AffineTransform t =  shape.getAffineTransform();      
        t.rotate(Math.toRadians(thetaDegrees), shape.getCenter().x, shape.getCenter().y);  
        shape.setAffineTransform(t);              
    }  
}  

My execute method for the translation

public void execute() {  
    Iterator iter = objects.iterator();  
    Shape shape;  
    while(iter.hasNext()){  
        shape = (Shape)iter.next();  
        mt.addMememto(shape);  
        AffineTransform t = shape.getAffineTransform();  
        System.out.println("Translation x :"+x + ", Translation y :"+y);  
        t.translate(x,y);  
        shape.setAffineTransform(t);  
    }  
} 

Any help can be really appreciated

Answer 1

To accomplish an "in-place" rotation (where the object rotates about its own axis), you must:

1. translate the object to the origin
2. apply the rotation
3. translate back to the original position
4. apply the desired translation

Note that steps 3 and 4 could be applied at once.

If rotation is attempted at position other than the origin, a "revolving" effect is achieved - one where the object appears to be revolving about the origin.