import javax.swing.*;
import java.awt.*;

/** Square frames */
public class MyFrame extends JFrame {
    
    private int previousMinDim= -1;  //Min dim before frame gets squared
                                     //Initialize to -1 to indicate no prev dim
    
    /** Make this frame a square */
    public void makeSquare() {
        this.previousMinDim= Math.min(this.getWidth(),
                                      this.getHeight());
        int dim= Math.max(this.getHeight(), this.getWidth());
        this.setSize(dim,dim);
    }
    
    /** get the minimum dimension of the frame before it got squared */
    public int getPreviousMinDim() {
        return this.previousMinDim;
    }
    
    /** Draw a square in the frame */
    public void paint(Graphics g) {
        g.setColor(Color.blue);
        //Move the origin to left-top cell below title bar
          g.translate(this.getInsets().left, this.getInsets().top);
        //Draw square in center of this frame
          g.drawRect((this.getWidth()-100)/2, (this.getHeight()-100)/2, 100, 100);
        //What happens if you specify a negative coordinate?
          g.drawRect(-10, (this.getHeight()-100)/2, 100, 100);
    }
    
}