How to Efficiently Draw Constantly Changing Graphics in Java?

How to Draw Constantly Changing Graphics in Java

Introduction

Creating dynamic graphics that update constantly can be a challenging task in Java. In this article, we will demonstrate how to tackle this using efficient techniques and thread synchronization.

Problem Statement

The initial code provided in the question had several performance issues, resulting in slow graphic updates. The goal is to optimize the code to achieve constant updates with improved speed.

Optimized Code

Here's an optimized version of the code:

import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.geom.Ellipse2D;
import java.awt.image.BufferedImage;

public class ZoomPanel extends JPanel {

    private static final int STEP = 40;
    private int iter = 0;
    private long cumulativeTimeTaken = 0;

    // Model to hold pixel colors
    private final Color[][] model = new Color[8][8];

    // Flag to prevent concurrent painting
    private boolean isDrawing = false;

    public static void main(String[] args) {
        final JFrame frame = new JFrame("Image zoom");

        final ZoomPanel zoomPanel = new ZoomPanel();
        frame.getContentPane().add(zoomPanel);
        final Ticker t = new Ticker(zoomPanel);

        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent we) {
                t.done();
                frame.dispose();
            }
        });
        t.start();

        frame.setLocation(new Point(640, 0));
        frame.pack();
        frame.setVisible(true);
    }

    // Sets the pixel color at the given position
    private void setColorAt(int x, int y, Color pixelColor) {
        model[x][y] = pixelColor;
        repaint(40 + x * STEP, 45 + y * STEP, 40 + (x * STEP) - 3, 45 + (y * STEP) - 3);
    }

    // Gets the pixel color at the given position
    private Color getColorAt(int x, int y) {
        return model[x][y];
    }

    // Draws the graphics
    public void paintComponent(Graphics g) {
        long start = System.currentTimeMillis();

        if (!SwingUtilities.isEventDispatchThread()) {
            throw new RuntimeException("Repaint attempt is not on event dispatch thread");
        }

        // Prevent concurrent painting
        isDrawing = true;

        final Graphics2D g2 = (Graphics2D) g;
        g2.setColor(getBackground());

        try {

            for (int x = 0; x <p><strong>Improvements</strong></p>

• Robot Optimization: The getPixelColor method in the original code was inefficient. By using createScreenCapture to fetch all 64 pixels at once, we significantly improve performance.
• Smart Clipping: Only the modified region is repainted, reducing unnecessary updates.
• Improved Threading: The model and view are updated on the Event Dispatch Thread, ensuring proper thread synchronization and avoiding potential concurrency issues.
• FPS Monitoring: An FPS counter prints the number of frames updated within a second.
• Synchronization: A lock prevents concurrent painting, further improving stability.

These optimizations result in a vast improvement in performance, with the screen updates appearing virtually instantaneous. The FPS counter provides a measure of the improved speed.

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