import javax.swing.JButton;
import javax.swing.JFrame;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;

import java.awt.Graphics;

import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Zad2 extends JFrame{

    boolean selected;
    Canvas canvas;
    JFrame frame;

    public Zad2() {
    frame = this;
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setLayout(new FlowLayout());
    setPreferredSize(new Dimension(400,400));
    canvas = getCanvas(75, 50);
    canvas.setPreferredSize(new Dimension(390, 300));
    add(canvas);
    add(getButton());
    pack();
    setLocationRelativeTo(null);
    }
    /**
    * Metoda obslugująca rysowanie
    * x - pozycja x
    * y - pozycja y
    *
    */
    public Canvas getCanvas(final int x, final int y)
    {
    Canvas canvas = new Canvas()
    {
    private static final long serialVersionUID = 1L;
    public void paint(Graphics g)
    {
    //rysowanie lini
    Dimension d = getSize();
    g.drawLine(0, 0, d.width, d.height);
    g.drawLine(d.width, 0, 0, d.height);
    //dodatki
    if(selected)
    {
    setBackground(new Color(50, 100, 150));
    g.drawString("Test Środowiska GUI", x, y); //75, 50
    g.setColor(Color.blue);
    g.fillOval(x+35, y+20, 50, 50);
    g.setColor(Color.red);
    g.drawRoundRect(x-10, y-20, 140, 30, 20, 20);
    }
    else
    setBackground(new Color(255, 255, 255));
    }
    };
    return canvas;
    }
    /**
    * Przycisk rysowania/czyszczenia
    *
    */
    public JButton getButton()
    {
    final JButton button = new JButton("Rysuj");
    button.addActionListener(new ActionListener()
    {
    @Override
    public void actionPerformed(ActionEvent e) {
    if(selected==false)
    {
    selected=true;
    button.setText("Czyść");
    }
    else
    {
    selected = false;
    button.setText(" Rysuj ");
    }
    //odswiezenie
    Rectangle rect = frame.getBounds();
    canvas.repaint(rect.x, rect.y, rect.width, rect.height);
    }
    });
    return button;
    }
    public static void main(String args[]){
        new Zad2().setVisible(true);
    }
}