Java?? ?? ??? ???? JPanel? ? ???

???? JPanel? ? ?? ?? ?? ??? ???? ????. . JPanel?? ?? ???? Paint() ???? ???? ???. ??? ?? ????? ?? ???? ?? ????.

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import java.awt.*;
import java.awt.event.*;

public class circuit extends JFrame {

    private JPanel contentPane;
    private JPanel drawPane;
    private Point p1, p2;
    private boolean drawing;

    public circuit() {
        // Code...

        // Create the draw panel
        drawPane = new JPanel() {
            @Override
            protected void paintComponent(Graphics g) {
                super.paintComponent(g);
                Graphics2D g2 = (Graphics2D) g;
                g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                if (p1 != null && p2 != null && drawing) {
                    g2.drawLine(p1.x, p1.y, p2.x, p2.y);
                }
            }
        };
        drawPane.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                drawing = true;
                p1 = e.getPoint();
                p2 = p1;
                drawPane.repaint();
            }

            @Override
            public void mouseReleased(MouseEvent e) {
                drawing = false;
                p2 = e.getPoint();
                drawPane.repaint();
            }
        });
        drawPane.addMouseMotionListener(new MouseAdapter() {
            @Override
            public void mouseDragged(MouseEvent e) {
                if (drawing) {
                    p2 = e.getPoint();
                    drawPane.repaint();
                }
            }
        });

        // Add the draw panel to the content pane
        contentPane.add(drawPane, BorderLayout.CENTER);

        // Code...
    }

    public static void main(String[] args) {
        new circuit().setVisible(true);
    }
}

? ????? ??? ??? PaintComponent() ???? ???? ? ?? ??? ?? ????. ??? p1? p2. ?? ???? ??? p1? ?? ? ??? ?????. ???? ???? p2? ?????? ?? ???? ?????. ???? ??? p2? ?? ? ??? ???? ?? ??? ?????.

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?? ?? ??? ???? JPanel?? ?? ?? ? ????. ??? ??? ???. ??? ??? ????? ?? ??? ???? ?? ?? ????? ??? ?? ??? ??? ?? ? ????.

? ??? ??? ??? ???? ???? Java JPanel?? ?? ??? ??? ??????? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!