Question

I have an applet where I am drawing stuff by overriding the paint() method, and have added a Canvas to the applet, which will take up the whole screen. This canvas seems to be being drawn after my paint()ing, and so my applet’s paint()ed stuff is invisible. Any ideas on how to force the canvas to be drawn before my paint method on my applet?

Edit:

public void paint(Graphics g) {
    super.paint(g);
    if (DEBUG) {
        g.setColor(Color.red);
        g.drawString("Memory free: " + ((Runtime.getRuntime().freeMemory()
            / 1024) / 1024) + "MB", 5, 20);
        g.drawString("Memory total: " + ((Runtime.getRuntime().totalMemory()
            / 1024) / 1024) + "MB", 5, 35);
        g.drawString("Memory used: " + (((Runtime.getRuntime().totalMemory()
            - Runtime.getRuntime().freeMemory()) / 1024) / 1024) + "MB", 5, 50);
    }
}

Answer 1

Even if you must use AWT, you should be able to use a separate Panel for the GL content and the memory status:

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

public class AWTPaintTest {

    public static void main(String[] args) {
        Frame frame = new Frame();
        // frame.add(new AWTGLCanvas(), BorderLayout.CENTER);
        frame.add(new MemoryPanel(), BorderLayout.SOUTH);
        frame.addWindowListener(new WindowAdapter() {

            @Override
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        frame.pack();
        frame.setVisible(true);
    }

    private static class MemoryPanel extends Panel {

        private final Runtime r = Runtime.getRuntime();

        public MemoryPanel() {
            this.setPreferredSize(new Dimension(240, 120));
            this.setForeground(Color.blue);
            this.setFont(new Font("Monospaced", Font.BOLD, 16));
            this.addMouseListener(new MouseAdapter() {

                @Override
                public void mousePressed(MouseEvent e) {
                    r.gc();
                    MemoryPanel.this.repaint();
                }
            });
        }

        @Override
        public void paint(Graphics g) {
            super.paint(g);
            long m = r.maxMemory();
            long t = r.totalMemory();
            long f = r.freeMemory();
            int y = g.getFontMetrics().getHeight() + 4;
            g.drawString("Memory max:   " + toMB(m), 5, 1 * y);
            g.drawString("Memory total: " + toMB(t), 5, 2 * y);
            g.drawString("Memory free:  " + toMB(f), 5, 3 * y);
            g.drawString("Memory used:  " + toMB(t - f), 5, 4 * y);
            g.drawString("Click to update.", 5, 5 * y);
        }

        private String toMB(long bytes) {
            return (bytes / 1024) / 1024 + " MB";
        }
    }
}