Filling Large Rectangle Causes Choppy Animation

Question

<Font Size = 2>Hello everyone,
I hope you guys can help me with this.
I am working on an application that needs to fade in a large rectangle matching the size of its container. What I have noticed is I can easily achieve smooth animations at sizes up to 1000x1000 however when reaching sizes such as 1500x1500 the animations begin to appear choppy. It gets even worse if I make the window the size of my screen resolution which is 2560x1440. I have created a SSCCE to demonstrate the problem. I have the paint method painting several large rectangles just to amplify the problem I am experiencing. So I was wondering is there anyway to get rid of these choppy animations so that the rectangle(s) appear to fade in smooth.
Thank you for your help :)
import java.awt.*;
import javax.swing.*;
import java.util.concurrent.*;
public class Lag {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new Lag();
    Toolkit kit = Toolkit.getDefaultToolkit();
    Dimension screenSize = kit.getScreenSize();
    float opacity = 0f;
    PaintSurface canvas = new PaintSurface();
    JFrame frame = new JFrame();
    public Lag() {
        ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(3);
        executor.scheduleAtFixedRate(new AnimationThread(), 0L, 20L, TimeUnit.MILLISECONDS);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(screenSize);
        frame.setLocation(0,0);
        frame.add(canvas);
        frame.setVisible(true);
    public class AnimationThread implements Runnable {
        public void run() {
            canvas.repaint();
    public class PaintSurface extends JComponent {
        public void paintComponent(Graphics g) {
            Graphics2D g2 = (Graphics2D)g;
            if(opacity < 0.6f) {
                opacity+=0.05f;
            } else {
                opacity = 0f;
            g2.setColor(Color.black);
            g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, opacity));
            g2.fillRect(0, 0, getWidth(), getHeight());
            g2.fillRect(0, 0, getWidth(), getHeight());
            g2.fillRect(0, 0, getWidth(), getHeight());
}

Answer 1

Maxideon wrote:
Fill in a smaller rectangle, and copyArea() it to the other regions.<Font Size = 2>Thank you both that helps a lot but i've ran into a problem with the copyArea() method. It works like a charm and speeds up the animation a lot however this transparent rectangle is meant to be an overlay on top of other graphics to make it appear as though those other graphics are faded out. When I copyArea() as expected it copies everything in the region I specify and places it in the destination area that I specify. However this becomes undesirable when I have other graphics painted underneath the rectangle and it gets even trickier to solve knowing that I have to paint the transparent rectangle last so that it appears on top of the other graphics. Now the only thing I can think of that might fix this problem is if there were a way to copyArea() from another graphics and paste that copied area to the current graphics. Here an example of the problem below:
Thank you for your help. I'm not sure if I should post this as another question but I think its still relevant to my first.
import java.awt.*;
import java.awt.event.*;
import java.util.concurrent.*;
import javax.swing.*;
public class Lag {
  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
      @Override
      public void run() {
        new Lag();
  float opacity = 0f;
  PaintSurface canvas = new PaintSurface();
  JFrame frame = new JFrame();
  int repaintCount, paintCount;
  Rectangle paintRect = new Rectangle();
  public Lag() {
    ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(3);
    executor.scheduleAtFixedRate(new AnimationThread(), 0L, 20L, TimeUnit.MILLISECONDS);
    //frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.addWindowListener(new WindowAdapter() {
      @Override
      public void windowClosing(WindowEvent e) {
        System.out.println("Repaint count: " + repaintCount);
        System.out.println("Paint count: " + paintCount);
        System.exit(0);
    canvas.addComponentListener(new ComponentAdapter() {
      @Override
      public void componentResized(ComponentEvent e) {
        paintRect.width = canvas.getWidth();
        paintRect.height = canvas.getHeight();
    frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
    frame.add(canvas);
    frame.setVisible(true);
  public class AnimationThread implements Runnable {
    @Override
    public void run() {
      if (opacity < 0.6f) {
        opacity += 0.05f;
      } else {
        opacity = 0f;
      repaintCount++;
      canvas.paintImmediately(paintRect);
  public class PaintSurface extends JComponent {
    @Override
    public void paintComponent(Graphics g) {
      paintCount++;
      Graphics2D g2 = (Graphics2D) g;
      //background graphics get copied to. (as expected)
      g2.setColor(Color.red);
      g2.fillRect(100, 100, 300, 300);
      g2.setColor(Color.black);
      g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, opacity));
      g2.fillRect(0, 0, 200, 200);
      for(int i = 0; i<getHeight(); i+=200) {
          for(int x = 0; x < getWidth(); x+=200) {
              g2.copyArea(0, 0, 200, 200, x, i);
}