import java.awt.*;       // potrebujemo za Dimension
import java.awt.event.*; // potrebujemo za ActionListener
import javax.swing.*;    // potrebujemo za Swing

public class GlavnoOkno extends JFrame implements ActionListener {
  private JTextField besedilo;
  private JLabel naslov;
  private JButton narisiGumb;
  private Slika slika; 
  private Dimension preferredSize = new Dimension(500, 300);
  
  public GlavnoOkno() {
    getContentPane().setLayout(new BorderLayout());
    
    slika = new Slika();
    getContentPane().add(slika, BorderLayout.CENTER);
    
    naslov = new JLabel("Krog");
    getContentPane().add(naslov, BorderLayout.NORTH);
    
    JPanel p = new JPanel();
    getContentPane().add(p, BorderLayout.SOUTH);
    
    p.add(new JLabel("r = "));
    
    besedilo = new JTextField(20);
    p.add(besedilo);
    
    narisiGumb = new JButton("Narisi");
    p.add(narisiGumb);
    narisiGumb.addActionListener(this);
    
    // ce uporabnik zapre okno, se program zakljuci
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
    // nastavimo naslov okna
    setTitle("Elipsa in krog");
  }
  
  public Dimension getPreferredSize() {
    return preferredSize;
  }
  
  public void actionPerformed(ActionEvent e) {
    Object m = e.getSource();;
    
    if (m == narisiGumb) {
      try {
        double r = Double.parseDouble(besedilo.getText());
        slika.nastaviPolmer(r);
        naslov.setText("Krog (r = " + r + ")");
      } catch (NumberFormatException ex) {
        naslov.setText("Krog (neveljaven r)");
      }
    }
  }
}