Java Fullscreen Image resizing?

Question

Hello I am kind of new to java. I am working on a game. when the game starts a loading screen appears and the fades away that's it so far. My question is simple. Is there a way to change the image size to fit the size of the computer screen. I want it to fit all types of screen sizes and be a larger scale of the original image. Here is my Main class so far(there are other classes like player and title and play but they are irrelevant to the question:

package Main;

import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferStrategy;

import javax.swing.ImageIcon;
import javax.swing.JFrame;

public class Comp extends Canvas implements Runnable, KeyListener {

    private static final long serialVersionUID = 1L;    
    public boolean run = true;
    public Image screen, img;    
    public static double dir = 5;
    public static int pixelSize = 1;    
    public static Dimension size = new Dimension(680, 500);
    public static Dimension pixel = new Dimension(size.width / pixelSize,
            size.height / pixelSize);    
    public static int mx;    
    public static manager m;
    public static int my;
    public static int fps;    
    public static boolean mr;    
    public static boolean ml;

    JFrame frame = new JFrame();    
    public Thread t;    
    public boolean splashscreen = true;
    public int time = 0;
    public int timer = 140;    
    public int btime = 0;
    public int btimer = 1;     
    private int FPS = 5;
    private long targetTime = 1000 / FPS;

    public Comp() {
        setPreferredSize(size);
        setFocusable(true);
        addKeyListener(this);    
        addKeyListener(new listen());
        addMouseListener(new listen());
        addMouseMotionListener(new listen());
        addMouseWheelListener(new listen());    
        m = new manager();
        requestFocus();    
        // h = new InputHandler(this);
    }

    public void start() {
        run = true;    
        frame.add(this);    
        frame.pack();
        frame.requestFocus();    
        frame.setTitle("In The Maze");
        frame.setResizable(false);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);    
        frame.setIconImage(new ImageIcon("res/traps/beartrap1.png").getImage());    
        t = new Thread(this);
        t.start();
    }

    public void stop() {
        run = false;    
    }

    public static void main(String[] args) {
        Comp c = new Comp();    
        c.start();
    }

    public void render() {
        BufferStrategy bs = this.getBufferStrategy();
        if (bs == null) {
            createBufferStrategy(2);
            return;
        }
        Graphics g = bs.getDrawGraphics();
        g.setColor(Color.white);
        g.fillRect(0, 0, 1000, 1000);    
        if (!splashscreen) {    
            m.render(g);
        }           
        if(splashscreen){
            ImageIcon i62 = new ImageIcon("res/splashscreen.png");
            img = i62.getImage();
            g.drawImage(img,(int)0 ,(int)0,Comp.size.width+10,Comp.size.height + 10,null);            
            time++;
        }    
        g.dispose();    
        bs.show();
    }

    public void tick() {
        if(time >= timer){
            time = 0;
            splashscreen = false;
        }

        if(!splashscreen){
            m.tick();
        }
        Keys.update();
        Esentials.tick();    
    }

    public void run() {
        screen = createVolatileImage(pixel.width, pixel.height);                
        long start;
        long elapsed;
        long wait;          
        long currentTime = System.currentTimeMillis();          
        while (run) {
            start = System.nanoTime();
            fps++;
            if(System.currentTimeMillis()  - currentTime >= 1000){
            //  System.out.println("fps:" + fps);    
                currentTime = System.currentTimeMillis();
                fps = 0;
            }
            tick();
            render();
            elapsed = System.nanoTime() -start;    
            wait = targetTime = elapsed / 1000000;              
            try {
                Thread.sleep(wait);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    public void keyTyped(KeyEvent i) {
    }

    public void keyPressed(KeyEvent i) {
        Keys.keySet(i.getKeyCode(), true);    
    }

    public void keyReleased(KeyEvent i) {
        Keys.keySet(i.getKeyCode(), false);
    }    
}

Answer 1

Determining the screen size...

• How to set present screensize in Java Swing?
• Full-Screen Exclusive Mode API

Scaling the image...

• Java: maintaining aspect ratio of JPanel background image
• Quality of Image after resize very low -- Java
• The Perils of Image.getScaledInstance()

I'd also discourage the use KeyListener and encourage the use of the Key Bindings API. See How to use key bindings for more details

Answer 2

Using the default Graphics object from the java.awt package, you can use the drawImage method with 10 parameters:

int destinationWidth = ...;
int destinationHeight = ...;
g.drawImage(originalImage, 0, 0, destinationWidth, destinationHeight, 0, 0, originalImage.getWidth(null), originalImage.getHeight(null), null);

That way your image will be scaled and painted to g. Note that simply by using as in the example provided will stretch and deform your image if the aspect ratio of your window is different from the aspect ratio of the image.

Answer 3

Try to use Toolkit.getScreenSize()

Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
double width = screenSize.getWidth();
double height = screenSize.getHeight();

For resizing the image you can use simple imgscalr library

BufferedImage scaledImage = Scalr.resize(myImage, 100);