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Creating endless number of objects in JPanel and draw them through PaintComponent in Java

I have one dilemma , how to realize application. I have JPanel with width 288 and height 512, then I created two objects ( images ) and drew them through paintComponent using coordinates
drawImage (Image1,288,128,this) ;
drawImage (Image2, 288, 384, this);
. They are decrementing simultaneously in the X axis and when it reaches x = 144 , new (same) images should be drawn at the coordinates ‘( x = 288 , y = (int)Math.random()* 512 )’ and begin decrement as well as first ones should still decrements. And this process should be endless. Every new objects reaching x = 144 should build new ones . I tried to create ArrayList with adding coordinates in it
ArrayList arrayX = new ArrayList();
arrayX.add(288)
arrayY.add((int) Math.random()* 512 )
and then extract values through
array.get()
But that was unsuccessfully.
I saw video where man did it using JavaScript through the array
var position = []
position = ({
X : 288
Y : 256
})
And then implemented through the loop like this
function draw() {
for (int i = 0; i < position.length; i++ ){
cvs.drawImage(Image1,position[i].x , position[i].y)
cvs.drawImage(Image2,position[i].x , position[i].y + 50)
position [i] .x - -;
if(position[i].x == 128)
position.push({
X : 288
Y : Math.floor(Math.random()*512 })
})
}
}
I don’t know how to do this in Java.
May be I should use array too to keep variables with coordinates , or arraylist but in different way. Help me please .
Thanks in advance

Conceptually the idea is simple enough, the problem is, Swing is signal thread and NOT thread safe.
See Concurrency in Swing for more details.
This means you can run a long running or blocking operation (like a never ending loop) inside the Event Dispatching Thread, but also, you shouldn't update the UI (or properties the UI depends on) from outside the context of the EDT.
While there are a number of possible solutions to the problem, the simplest is probably to use a Swing Timer, which provides a means to schedule a delay safely (that won't block the EDT) and which will trigger it's updates within the context of the EDT, allowing you to update the UI from within it.
See How to Use Swing Timers for more details.
Now, because you're in a OO language, you should leverage the power it provides, to me, this means encapsulation.
You have a image, you want drawn at a specific location, but whose location change be changed based on some rules, this just screams Plain Old Java Old (POJO)
Normally, I'd start with a interface to describe the basic properties and operations, but for brevity, I've jumped straight for a class...
public class Drawable {
private int x, y;
private Color color;
public Drawable(int x, int y, Color color) {
this.x = x;
this.y = y;
this.color = color;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public Color getColor() {
return color;
}
public void update() {
x--;
if (x <= 144) {
reset();
}
}
protected void reset() {
x = 288;
y = (int) (Math.random() * (512 - 20));
}
public void paint(Graphics2D g2d) {
Graphics2D copy = (Graphics2D) g2d.create();
copy.translate(getX(), getY());
copy.setColor(getColor());
copy.drawOval(0, 0, 20, 20);
copy.dispose();
}
}
But wait, you say, it's using Color instead of image!? Yes, I didn't have any small images at hand, besides, I need to leave you something to do ;)
Now, the animation is a sequence of updating and painting repeatedly until a desired state is reached.
In this case, you don't care about the end state so much, so you can just keep it running.
The "update" cycle is handled by a Swing Timer, which loops over a List of Drawable objects, calls their update methods and then schedules a repaint, which triggers the JPanels paintComponent where by the Drawable objects are painted, simple 😝...
public class TestPane extends JPanel {
private List<Drawable> drawables;
public TestPane() {
drawables = new ArrayList<>(2);
drawables.add(new Drawable(288, 128, Color.RED));
drawables.add(new Drawable(288, 384, Color.RED));
Timer timer = new Timer(5, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
for (Drawable drawable : drawables) {
drawable.update();
}
repaint();
}
});
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(288, 512);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Drawable drawable : drawables) {
Graphics2D g2d = (Graphics2D) g.create();
drawable.paint(g2d);
g2d.dispose();
}
}
}
Putting it altogether - runnable example...
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class Drawable {
private int x, y;
private Color color;
public Drawable(int x, int y, Color color) {
this.x = x;
this.y = y;
this.color = color;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public Color getColor() {
return color;
}
public void update() {
x--;
if (x <= 144) {
reset();
}
}
protected void reset() {
x = 288;
y = (int) (Math.random() * (512 - 20));
}
public void paint(Graphics2D g2d) {
Graphics2D copy = (Graphics2D) g2d.create();
copy.translate(getX(), getY());
copy.setColor(getColor());
copy.drawOval(0, 0, 20, 20);
copy.dispose();
}
}
public class TestPane extends JPanel {
private List<Drawable> drawables;
public TestPane() {
drawables = new ArrayList<>(2);
drawables.add(new Drawable(288, 128, Color.RED));
drawables.add(new Drawable(288, 384, Color.RED));
Timer timer = new Timer(5, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
for (Drawable drawable : drawables) {
drawable.update();
}
repaint();
}
});
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(288, 512);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Drawable drawable : drawables) {
Graphics2D g2d = (Graphics2D) g.create();
drawable.paint(g2d);
g2d.dispose();
}
}
}
}
"Is there a simpler solution"? Yes, of course, I always go to the hardest possible way to solve a problem first 🤪. First, good animation is hard. Seriously. I've been playing around with this sought of thing more nearly 20 years, making a good animation engine which is flexible to meet all the possible needs it might be put to is near impossible mission, especially in a framework which isn't really designed for it.
If you don't belief me, you could have a look at
How do I change Swing Timer Delay inside actionPerformed()
How can I fade out or fade in by command JPanel, its components and its color
which are just a couple of examples how complicated animation can be
Sorry, you'd be amazed how often I get asked "can it be simpler" when it comes to animation ;)
"Every new objects reaching x = 144 should build new ones
So, apparently I may be confused about this particular point. If this means "adding new objects after reaching 144" then this raises some new issues. The primary issue is one over GC overhead, which cause slow downs in the animation. Sure, we're only dealing with about 4-6 objects, but it's one of those things which can come back to byte you if you're not careful.
So I took the above example and made some modifications to the update cycle. This adds a reusePool where old objects are placed and can be re-used, reducing the GC overhead of repeatedly creating and destroying short lived objects.
The decaying List simply ensures that once an object passes the swanPoint, it won't be consider for re-spawning new objects. Sure you could put a flag on the POJO itself, but I don't think this is part of the POJOs responsibility
public TestPane() {
drawables = new ArrayList<>(2);
reusePool = new ArrayList<>(2);
decaying = new ArrayList<>(2);
timer = new Timer(5, new ActionListener() {
private List<Drawable> spawned = new ArrayList<>(5);
#Override
public void actionPerformed(ActionEvent e) {
spawned.clear();
Iterator<Drawable> it = drawables.iterator();
int swapnPoint = getWidth() / 2;
while (it.hasNext()) {
Drawable drawable = it.next();
drawable.update();
if (drawable.getX() > 0 && drawable.getX() < swapnPoint) {
if (!decaying.contains(drawable)) {
decaying.add(drawable);
Drawable newDrawable = null;
if (reusePool.isEmpty()) {
newDrawable = new Drawable(
getWidth() - 20,
randomVerticalPosition(),
randomColor());
} else {
newDrawable = reusePool.remove(0);
newDrawable.reset(getWidth() - 20,
randomVerticalPosition(),
randomColor());
}
spawned.add(newDrawable);
}
} else if (drawable.getX() <= -20) {
System.out.println("Pop");
it.remove();
decaying.remove(drawable);
reusePool.add(drawable);
}
}
drawables.addAll(spawned);
repaint();
}
});
}
This will now allow objects to travel the whole width of the width, spawning new objects as they pass the half way point. Once they pass beyond the visual range of the view, they will be placed into the reuse List so they can be reused again when new objects are required.
Runnable example...
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
TestPane testPane = new TestPane();
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(testPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
testPane.start();
}
});
}
});
}
public class Drawable {
private int x, y;
private Color color;
public Drawable(int x, int y, Color color) {
this.x = x;
this.y = y;
this.color = color;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public Color getColor() {
return color;
}
public void update() {
x--;
}
protected void reset(int x, int y, Color color) {
this.x = x;
this.y = y;
this.color = color;
}
public void paint(Graphics2D g2d) {
Graphics2D copy = (Graphics2D) g2d.create();
copy.translate(getX(), getY());
copy.setColor(getColor());
copy.fillOval(0, 0, 20, 20);
copy.setColor(Color.BLACK);
copy.drawOval(0, 0, 20, 20);
copy.dispose();
}
}
public class TestPane extends JPanel {
private List<Drawable> drawables;
private List<Drawable> decaying;
private List<Drawable> reusePool;
private Color[] colors = new Color[]{Color.BLUE, Color.CYAN, Color.DARK_GRAY, Color.GREEN, Color.MAGENTA, Color.ORANGE, Color.PINK, Color.RED, Color.YELLOW};
private Random rnd = new Random();
private Timer timer;
public TestPane() {
drawables = new ArrayList<>(2);
reusePool = new ArrayList<>(2);
decaying = new ArrayList<>(2);
timer = new Timer(40, new ActionListener() {
private List<Drawable> spawned = new ArrayList<>(5);
#Override
public void actionPerformed(ActionEvent e) {
spawned.clear();
Iterator<Drawable> it = drawables.iterator();
int swapnPoint = getWidth() / 2;
while (it.hasNext()) {
Drawable drawable = it.next();
drawable.update();
if (drawable.getX() > 0 && drawable.getX() < swapnPoint) {
if (!decaying.contains(drawable)) {
decaying.add(drawable);
Drawable newDrawable = null;
if (reusePool.isEmpty()) {
System.out.println("New");
newDrawable = new Drawable(
getWidth() - 20,
randomVerticalPosition(),
randomColor());
} else {
System.out.println("Reuse");
newDrawable = reusePool.remove(0);
newDrawable.reset(getWidth() - 20,
randomVerticalPosition(),
randomColor());
}
spawned.add(newDrawable);
}
} else if (drawable.getX() <= -20) {
System.out.println("Pop");
it.remove();
decaying.remove(drawable);
reusePool.add(drawable);
}
}
drawables.addAll(spawned);
repaint();
}
});
}
public void start() {
drawables.add(new Drawable(getWidth(), 128, randomColor()));
drawables.add(new Drawable(getWidth(), 384, randomColor()));
timer.start();
}
protected int randomVerticalPosition() {
return rnd.nextInt(getHeight() - 20);
}
protected Color randomColor() {
return colors[rnd.nextInt(colors.length - 1)];
}
#Override
public Dimension getPreferredSize() {
return new Dimension(288, 512);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Drawable drawable : drawables) {
Graphics2D g2d = (Graphics2D) g.create();
drawable.paint(g2d);
g2d.dispose();
}
}
}
}

My answer is completely based on MadProgrammer's answer (A comprehensive tutorial actually).
From what I read in the post : "Every new objects reaching x = 144 should build new ones", I think the desired implementation is slightly different:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class ImageAnimator {
public ImageAnimator() {
SwingUtilities.invokeLater(() -> {
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new AnimationPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
public static class Drawable {
private int x;
private final int y;
private static final Image image = image();
//construct with a random y value
public Drawable(int x) {
this(x, -1);
}
public Drawable(int x, int y) {
this.x = x;
this.y = y < 0 ? (int) (Math.random() * (512 - 20)) : y;
}
public int getX() { return x; }
public int getY() { return y; }
public void update() { x--; }
public Image getImage(){ return image; }
public static Image image() {
URL url = null;
try {
//5.SEP.2021 replaced dead link
//url = new URL("https://dl1.cbsistatic.com/i/r/2017/09/24/b2320b25-27f3-4059-938c-9ee4d4e5cadf/thumbnail/32x32/707de8365496c85e90c975cec8278ff5/iconimg241979.png");
url = new URL("https://cdn3.iconfinder.com/data/icons/softwaredemo/PNG/32x32/Circle_Green.png");
return ImageIO.read(url);
} catch ( IOException ex) {
ex.printStackTrace();
return null;
}
}
}
public class AnimationPane extends JPanel {
private final List<Drawable> drawables;
private static final int W = 288, H = 512, CYCLE_TIME = 5;
public AnimationPane() {
drawables = new ArrayList<>(2);
drawables.add(new Drawable(W, H/4));
drawables.add(new Drawable(W, 3*H/4));
Timer timer = new Timer(CYCLE_TIME, e -> animate());
timer.start();
}
private void animate() {
for (Drawable drawable : new ArrayList<>(drawables)) {
drawable.update();
if(drawable.getX() == W/2) {
drawables.add(new Drawable(W)); //random Y
}
if(drawable.getX() <= 0) {
drawables.remove(drawable);
}
}
repaint();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(W, H);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Drawable drawable : drawables ) {
g.drawImage(drawable.getImage(),drawable.getX(), drawable.getY(), null);
}
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(()->new ImageAnimator());
}
}

The following solution is based on my previous answer.
I add it in response to MadProgrammer's comment: "A better solution is to pool the objects for re-use".
DrawAblesProducer produces drawable objects on-demand. It also stores surplus object, to prevent producing too many such objects.
I post it as a separate answer because the additional functionality comes with somewhat higher complexity:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class ImageAnimator {
private static final int W = 288, H = 512;
public ImageAnimator() {
SwingUtilities.invokeLater(() -> {
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new AnimationPane(new DrawAblesProducer()));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
public class AnimationPane extends JPanel {
private final List<Drawable> drawables;
private static final int CYCLE_TIME = 5;
private final DrawAblesProducer producer;
public AnimationPane(DrawAblesProducer producer) {
this.producer = producer;
drawables = new ArrayList<>(2);
drawables.add(producer.issue(W, H/4));
drawables.add(producer.issue(W, 3*H/4));
Timer timer = new Timer(CYCLE_TIME, e -> animate());
timer.start();
}
private void animate() {
for (Drawable drawable : new ArrayList<>(drawables)) {
drawable.update();
if(drawable.getX() == W/2) {
drawables.add(producer.issue(W)); //random Y
}else if(drawable.getX() <= 0) {
drawables.remove(drawable);
producer.retrn(drawable);
}
}
repaint();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(W, H);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Drawable drawable : drawables ) {
g.drawImage(drawable.getImage(),drawable.getX(), drawable.getY(), null);
}
}
}
//produces `drawable` objects on-demand. stores surplus object, to prevent producing
//too many such objects
public class DrawAblesProducer {
private final Queue<Drawable> warehouse = new LinkedList<>();
public Drawable issue(int x){
return issue(x, -1);
}
public Drawable issue(int x, int y){
Drawable drawable = warehouse.poll();
if(drawable != null ) {
drawable.setX(x); drawable.setY(y);
return drawable;
}
return new Drawable(x, y);
}
public void retrn(Drawable drawable){
warehouse.add(drawable);
}
}
public static class Drawable {
//made static so image is reused for all instances
private static final Image image = image();
private int x, y;
//construct with a random y value
public Drawable(int x) {
this(x, -1);
}
public Drawable(int x, int y) {
setX(x);
setY(y);
}
public int getX() { return x; }
public void setX(int x) { this.x = x;}
public int getY() { return y; }
public void setY(int y) {
this.y = y < 0 ? randomY() : y ;
}
private int randomY() {
int iHeight = image.getHeight(null);
return iHeight + (int) (Math.random() * (H - iHeight));
}
public void update() { x--; }
public Image getImage(){ return image; }
public static Image image() {
URL url = null;
try {
//5.SEP.2021 replaced dead link
//url = new URL("https://dl1.cbsistatic.com/i/r/2017/09/24/b2320b25-27f3-4059-938c-9ee4d4e5cadf/thumbnail/32x32/707de8365496c85e90c975cec8278ff5/iconimg241979.png");
url = new URL("https://cdn3.iconfinder.com/data/icons/softwaredemo/PNG/32x32/Circle_Green.png");
return ImageIO.read(url);
} catch ( IOException ex) { ex.printStackTrace(); }
return null;
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(()->new ImageAnimator());
}
}

Why is my Mario clone game sprite getting cut off when I try to change it? [closed]

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
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BIG EDIT: I have now a MCVE for this
In my Super Mario 3 clone, my sprite draws correctly upon instantiating the JFrame, but when I press one of the buttons I've set to jump, it gets partially cut off. Everything on the screen is a JLabel.
Here is the code:
//for all
import java.nio.file.*;
import javax.imageio.ImageIO;
import java.io.IOException;
import java.awt.image.*;
import java.net.*;
import java.awt.*;
import javax.swing.*;
import static java.lang.invoke.MethodHandles.*;
import java.awt.event.*;
//my Mario class (cut down a lot)
class Mario {
// all numbers multiplied by 2 from OG game
protected Direction dir;
protected int x, y;
protected BufferedImage sprite;
public Mario() {
this.x = 54;
this.y = 808;
dir = Direction.RIGHT;
setSprite(MVCE.SMALLSTANDFACERIGHT);
}
public void moveRight() {
if (this.dir == Direction.LEFT) {
this.dir = Direction.RIGHT;
} else if (this.dir == Direction.RIGHT) {
this.x += 2;
}
}
public void jump() {
this.y -= 46;
}
public void setSprite(String spriteName) {
URL spriteAtLoc = MVCE.urlGenerator(spriteName);
this.sprite = MVCE.generateAndFilter(sprite, spriteAtLoc);
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.drawImage(sprite, 0, 0, null); // DO NOT SET x and y TO ANYTHING,
// this sets 0,0 to top left!!
}
}
// my MarioRender class:
class MarioRender extends JLabel {
protected Mario marioSprite;
public MarioRender() {
marioSprite = new Mario();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
marioSprite.paint(g2);
}
public void moveMarioRight() {
marioSprite.moveRight();
setLocation(this.marioSprite.x, this.marioSprite.y);
repaint();
}
public void jumpMario() {
marioSprite.jump();
setLocation(this.marioSprite.x, this.marioSprite.y);
repaint();
}
}
// direction class, solely for moving
enum Direction {
LEFT, RIGHT
}
// my calling class, which I called MVCE where I make the frame
public class MVCE extends JFrame {
MarioRender m = new MarioRender();
JLabel bg;
public MVCE() {
bg = new JLabel();
this.setSize(868, 915);
this.setVisible(true);
this.add(bg, BorderLayout.CENTER);
bg.setLayout(null);
bg.add(m);
m.setBounds(m.marioSprite.x, m.marioSprite.y, m.marioSprite.sprite.getWidth(),
m.marioSprite.sprite.getHeight());
KeyListener kl = new MoveListener();
this.addKeyListener(kl);
this.setFocusable(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static final String SMALLSTANDFACERIGHT = "SmallStandFaceRight.bmp"; // 30
// x
// 32
public static final String SMALLJUMPFACERIGHT = "SmallJumpFaceRight.bmp"; // 32
// x
// 32
// generate URL
public static URL urlGenerator(String name) {
URL u = lookup().lookupClass().getResource(name);
return u;
}
// return image with filtered color
public static BufferedImage generateAndFilter(BufferedImage b, URL u) {
try {
b = ImageIO.read(u);
int width = b.getWidth();
int height = b.getHeight();
int[] pixels = new int[width * height];
b.getRGB(0, 0, width, height, pixels, 0, width);
for (int i = 0; i < pixels.length; i++) {
// System.out.println(pixels[i]);
if (pixels[i] == 0xFFff00fe) {
pixels[i] = 0x00ff00fe;
}
}
BufferedImage newSprite = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
newSprite.setRGB(0, 0, width, height, pixels, 0, width);
b = newSprite;
} catch (IOException e) {
System.out.println("sprite not found");
e.printStackTrace();
}
return b;
}
// key listener
class MoveListener implements KeyListener {
public void keyPressed(KeyEvent k) {
if ((k.getKeyCode() == 39)) {
m.marioSprite.setSprite(SMALLSTANDFACERIGHT);
m.moveMarioRight();
}
if (k.getKeyCode() == 83) { // S key
m.marioSprite.setSprite(SMALLJUMPFACERIGHT);
m.jumpMario();
}
}
public void keyReleased(KeyEvent k) {
}
public void keyTyped(KeyEvent k) {
}
}
public static void main(String[] args) {
MVCE m = new MVCE();
}
}
sprites can be found here and here tho the downloads are in .jpg, whereas in my code, they're .bmp but you can just download, open in another app, save as bmp, or change the code

This is most likely a result of the horizontal and vertical constraints on your JLabel objects. From the look of the picture, the Mario that is jumping is slightly wider horizontally than the Mario standing on the ground.

How do I draw the same moving image multiple times?

Hello I'm making a platformer game and when you press space the character shoots a fireball that moves across the screen but when you press space again the fireball's coordinates are set back to the player's coordinates rather than drawing another fireball which is what I want.
import java.awt.*;
import javax.swing.*;
public class Fire extends JPanel{
Image fireball;
private int x=155000,y=155000;
Player player = new Player();
public void paint(Graphics g){
g.drawImage(fireball, x, y, null);
}
public Fire(){
}
public void update(){
fireball = new ImageIcon("C:\\Users\\steven.greens10\\Desktop\\Programs\\Raw Java\\Platform\\res\\fireball.png").getImage();
x+=5;
if(x > 640){
x=155000;
}
}
public void shoot(Player p){
x = p.getX();
y = p.getY();
repaint();
}
}

#KevinWorkman is right. You need some kind of data structure to hold the fireballs. In the example below I used a List of Fireball.
List<Fireball> fireBalls;
...
private class Fireball {
Image fireball;
int x = 150;
int y = 125;
public Fireball(Image image) {
fireball = image;
}
public void drawFireball(Graphics g) {
g.drawImage(fireball, x, y, 50, 50, null);
}
}
To paint them, I just iterate through them. To make them move forward I just increas the x value in the timer and call repaint
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
...
for (Fireball ball : fireBalls) {
ball.drawFireball(g);
}
}
Here's the complete code
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import java.util.*;
import java.util.List;
import java.util.logging.*;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.Timer;
public class WannaBeStreetFighter extends JPanel {
private static final int D_W = 700;
private static final int D_H = 250;
private static final int X_INC = 10;
List<Fireball> fireBalls;
BufferedImage ryu;
BufferedImage fireball;
BufferedImage background;
public WannaBeStreetFighter() {
try {
ryu = ImageIO.read(new URL("http://www.sirlin.net/storage/street_fighter/ryu_hadoken_pose.png?__SQUARESPACE_CACHEVERSION=1226531909576"));
background = ImageIO.read(new URL("http://fightingstreet.com/folders/variousinfofolder/ehondasbath/hondasfz3stage.gif"));
fireball = ImageIO.read(new URL("http://farm6.staticflickr.com/5480/12297371495_ec19ded155_o.png"));
} catch (IOException ex) {
Logger.getLogger(WannaBeStreetFighter.class.getName()).log(Level.SEVERE, null, ex);
}
fireBalls = new LinkedList<>();
Timer timer = new Timer(40, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
Iterator<Fireball> it = fireBalls.iterator();
while (it.hasNext()) {
Fireball ball = it.next();
if (ball.x > D_W) {
it.remove();
System.out.println(fireBalls.size());
} else {
ball.x += X_INC;
repaint();
}
}
}
});
timer.start();
InputMap inputMap = getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
inputMap.put(KeyStroke.getKeyStroke("SPACE"), "hadouken");
getActionMap().put("hadouken", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
fireBalls.add(new Fireball(fireball));
}
});
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(background, 0, 0, D_W, D_H, this);
g.drawImage(ryu, 50, 125, 150, 115, this);
for (Fireball ball : fireBalls) {
ball.drawFireball(g);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(D_W, D_H);
}
private class Fireball {
Image fireball;
int x = 150;
int y = 125;
public Fireball(Image image) {
fireball = image;
}
public void drawFireball(Graphics g) {
g.drawImage(fireball, x, y, 75, 50, null);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame("Best Street Fighter ever");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new WannaBeStreetFighter());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}

Did you try creating another instance of Image? For example:
Image fireball, firball2;
Now you have two Image objects. So when you call g.dawImage(...):
public void paint(Graphics g){
g.drawImage(fireball, x, y, null);
g.drawImage(fireball2, x+10, y+10, null);//just draw this other Image
}
You can just keep drawing multiple images. Also, I changed the x and y positions, so the two Image objects don't overlap.
Now if you want a bunch of Image objects, then use an ArrayList of Image objects:
ArrayList<Image> fireballs = new ArrayList<Image>();
Read more about ArrayList here.

Image won't draw onto screen but no errors occur

I've started creating a simple java game and at the moment I have the Game Window created with a screen and a basic Player class. The player image however won't draw onto the screen despite the program not giving me any errors so I'm not sure where to start debugging for the problem maybe someone could help me out?
Here are the classes:
import java.awt.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class GameWindow extends JFrame {
public static int windowWidth = 600;
public static int windowHeight = 600;
public static void main(String[] args) {
new GameWindow();
}
public GameWindow() {
this.setSize(windowWidth, windowHeight);
this.setTitle("Berzerk Clone");
this.setVisible(true);
// Defaults the window to be set in the middle of the screen
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GameDrawing drawGame = new GameDrawing();
this.add(drawGame, BorderLayout.CENTER);
}
}
Drawing Class:
import java.awt.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class GameDrawing extends JComponent {
PlayerHuman p;
public GameDrawing() {
p = new PlayerHuman(300, 300);
}
public void paint(Graphics g) {
super.paint(g);
Graphics2D graphics = (Graphics2D)g;
graphics.setColor(Color.BLACK);
graphics.fillRect(0, 0, GameWindow.windowWidth,GameWindow.windowHeight);
graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
graphics.drawImage(p.getPlayerImage(), 300, 300, null);
}
}
Player class:
import java.awt.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;
public class PlayerHuman extends GlobalPosition {
BufferedImage basicPlayer;
public PlayerHuman(int x, int y) {
super(x, y);
try {
basicPlayer = ImageIO.read(new File("Images/Player.png"));
} catch (IOException e) {
e.printStackTrace();
}
}
public void draw(Graphics2D g2d) {
g2d.drawImage(getPlayerImage(), x, y, null);
}
public BufferedImage getPlayerImage() {
return basicPlayer;
}
}
All help is appreciated.
EDIT:
My Apologies
GlobalPosition Class to give the player a starting point:
public class GlobalPosition {
public int x;
public int y;
public GlobalPosition() {
x = y = 0;
}
public GlobalPosition(int _x, int _y) {
x = _x;
y = _y;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public void setX(int newX) {
x = newX;
}
public void setY(int newY) {
y = newY;
}
}
I have a Game Loop class that repaints:
public class GameLoop implements Runnable {
GameWindow gWindow;
public GameLoop(GameWindow newGWindow) {
this.gWindow = newGWindow;
}
#Override
public void run() {
gWindow.repaint();
}
}

Suggestions:
Start small: test a very small program that does nothing but loads an image, puts it into an ImageIcon and displays the ImageIcon in a JOptionPane. Solve that first, and only then work on using it in the larger application.
You're better off reading the image in as a URL via getClass().getResource("....") than as a File.
don't call setVisible(true) on the top-level window until after adding all components.
Override the JComponent's paintComponent(Graphics g) method, not its paint method.
e.g.,
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
public class ShowImage {
// ******* add the path to the image resource below *****
private static final String IMAGE_RESOURCE_PATH = "";
public static void main(String[] args) {
URL imgUrl = ShowImage.class.getResource(IMAGE_RESOURCE_PATH);
BufferedImage img;
try {
img = ImageIO.read(imgUrl);
if (img == null) {
String message = "Image cannot be found at \""
+ IMAGE_RESOURCE_PATH + "\"";
JOptionPane.showMessageDialog(null, message);
System.exit(-1);
}
Icon icon = new ImageIcon(img);
JOptionPane.showMessageDialog(null, icon);
} catch (IOException e) {
e.printStackTrace();
}
}
}

Turns out that it was the
setVisible(true)
call that was causing the problem. I pushed it below all the other calls in the method and the screen and image appeared. Thanks for the help.
EDIT:
#Sage this is the location so the location is correct, however I will begin to use the
getClass().getResource(..)
method from now on.

Images do not appear correctly on MouseEvent in swing

I have a 3x3 check board-like image rendered on a JPanel which is added onto a JFrame. Then I have 9 more JPanels (1 on top of each square) and on click something needs to be drawn on the corresponding square. My problem is that it only works for the top-left square. The rest of the drawings seem to be drawn below the checkboard image. So if I comment out the part that loads the checkboard image,and click as if they were there then the drawings appear correctly. I get the same result with a layered pane. Absolute positioning is used and the coordinates seem to be correct since if I remove the checkboard image then the drawings appear where they should and the drawings do not occupy more than a square.
My code is structured as follows:
'main' class creates the frame and adds an instance of another class which extends JPanel and which also draws the checkboard image using paintComponent(Graphics g).
'main' class has also 9 instances added of a class that extends JPanel and draws something on a mouse click using paintComponent(Graphics g). Each instance is placed on top of a square
Please note that because I was going to do it with just Rectangles I named the second class Rectangles but it is rectangualar JPanels not java Rectangle instances
Code:
public class Main3
{
private JFrame frame=new JFrame("");
private Rectangles rect00=new Rectangles(0,0,129,129);
private Rectangles rect01=new Rectangles(136,0,129,129);
private Rectangles rect02=new Rectangles(268,0,129,129);
private Rectangles rect10=new Rectangles(0,136,129,129);
private Rectangles rect11=new Rectangles(134,136,129,129);
private Rectangles rect12=new Rectangles(269,137,129,129);
private Rectangles rect20=new Rectangles(0,270,129,129);
private Rectangles rect21=new Rectangles(136,269,129,129);
private Rectangles rect22=new Rectangles(269,270,129,129);
public void Display()
{
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setLayout(null);
frame.setSize(600,400);
sub inter=new sub();
inter.setLayout(null);
inter.setBounds(0,0,600,400);
inter.setSize(600,400);
rect00.setBounds(rect00.getX(),rect00.getY(),rect00.getWidth(),rect00.getHeight());
rect01.setBounds(rect01.getX(),rect01.getY(),rect01.getWidth(),rect01.getHeight());
rect02.setBounds(rect02.getX(),rect02.getY(),rect02.getWidth(),rect02.getHeight());
rect10.setBounds(rect10.getX(),rect10.getY(),rect10.getWidth(),rect10.getHeight());
rect11.setBounds(rect11.getX(),rect11.getY(),rect11.getWidth(),rect11.getHeight());
rect12.setBounds(rect12.getX(),rect12.getY(),rect12.getWidth(),rect12.getHeight());
rect20.setBounds(rect20.getX(),rect20.getY(),rect20.getWidth(),rect20.getHeight());
rect21.setBounds(rect21.getX(),rect21.getY(),rect21.getWidth(),rect21.getHeight());
rect22.setBounds(rect22.getX(),rect22.getY(),rect22.getWidth(),rect22.getHeight());
rect00.setOpaque(false);
rect01.setOpaque(false);
rect02.setOpaque(false);
rect10.setOpaque(false);
rect11.setOpaque(false);
rect12.setOpaque(false);
rect20.setOpaque(false);
rect21.setOpaque(false);
rect22.setOpaque(false);
inter.add(rect00);
inter.add(rect01);
inter.add(rect02);
inter.add(rect10);
inter.add(rect11);
inter.add(rect12);
inter.add(rect20);
inter.add(rect21);
inter.add(rect22);
frame.add(inter);
frame.setResizable(false);
frame.setVisible(true);
}
public static void main(String args[])
{
new main().Display();
}
private class sub extends JPanel
{
private BufferedImage image;
public sub ()
{
try
{
image=ImageIO.read(new File("image.jpg"));
}
catch (IOException e)
{
e.printStackTrace();
}
}
#Override
public Dimension getPreferredSize()
{
return (new Dimension(600,400));
}
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawImage(image, 0, 0, null);
}
}
}
This is the other class
public class Rectangles extends JPanel implements MouseListener
{
private int Posx;
private int Posy;
private int width;
private int height;
private boolean selected=false;
public Rectangles(int Posx,int Posy,int width,int height)
{
this.Posx=Posx;
this.Posy=Posy;
this.width=width;
this.height=height;
this.addMouseListener(this);
}
#Override
protected void paintComponent(Graphics g)
{
if(selected==true)
{
Graphics2D g2 = (Graphics2D) g;
super.paintComponent(g2);
g2.setColor(new Color(250, 235, 215));
g2.drawRect(Posx,Posy,width,height);
Graphics2D g3=(Graphics2D)g;
g2.setColor(new Color(0,0,0));
g3.setStroke(new BasicStroke(20));
g3.drawLine(Posx,Posy,Posx+width,Posy+height);
g3.drawLine(Posx+width,Posy,Posx,Posy+height);
}
}
public int getX()
{
return Posx;
}
public int getY()
{
return Posy;
}
public int getWidth()
{
return width;
}
public int getHeight()
{
return height;
}
public void setSelected()
{
selected=true;
}
#Override
public void mouseClicked(MouseEvent arg0)
{
}
#Override
public void mouseEntered(MouseEvent arg0)
{
}
public void mouseExited(MouseEvent arg0)
{
}
#Override
public void mousePressed(MouseEvent arg0)
{
}
#Override
public void mouseReleased(MouseEvent arg0)
{
selected=true;
repaint();
}
}

1) You dont honor the components paint chain.
As per java docs for paintComponent(Graphics g):
 Further, if you do not invoker super's implementation you must honour
the opaque property, that is if this component is opaque, you must
completely fill in the background in a non-opaque color. If you do not
honor the opaque property you will likely see visual artifacts.
2) super.paintComponent would in most cases be the first call in the method.
3) But there is more, your cast to Graphics2D twice, that should not be done:
Graphics2D g2 = (Graphics2D) g;
...
Graphics2D g3=(Graphics2D)g;
omit the g3 its not needed you already have casted to a Graphics2D object
4) Another problem lies here in sub class. You do this in your main code:
inter.add(rect00);
inter.add(rect01);
...
but in inter which is your variable name for the instance of sub class you only have:
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawImage(image, 0, 0, null);
}
Thus it will only draw a single image no matter how many rectangles you add!
Also dont do
g2.drawLine(Posx, Posy, Posx + width, Posy + height); rather
g2.drawLine(0, 0, Posx + width, Posy + height); as the JPanel has been added at co-ordinates x and y on its container, when you draw on the JPanel we want to start at the top left i.e 0,0, changing the value would move the image further down on its conatiner
See fixed code here:
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Test {
private JFrame frame = new JFrame("");
private Rectangles rect00 = new Rectangles(0, 0, 129, 129);
private Rectangles rect01 = new Rectangles(136, 0, 129, 129);
private Rectangles rect02 = new Rectangles(268, 0, 129, 129);
private Rectangles rect10 = new Rectangles(0, 136, 129, 129);
private Rectangles rect11 = new Rectangles(134, 136, 129, 129);
private Rectangles rect12 = new Rectangles(269, 137, 129, 129);
private Rectangles rect20 = new Rectangles(0, 270, 129, 129);
private Rectangles rect21 = new Rectangles(136, 269, 129, 129);
private Rectangles rect22 = new Rectangles(269, 270, 129, 129);
public void Display() {
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setLayout(null);
frame.setSize(600, 400);
sub inter = new sub();
inter.setLayout(null);
inter.setBounds(0, 0, 600, 400);
inter.setSize(600, 400);
rect00.setBounds(rect00.getX(), rect00.getY(), rect00.getWidth(), rect00.getHeight());
rect01.setBounds(rect01.getX(), rect01.getY(), rect01.getWidth(), rect01.getHeight());
rect02.setBounds(rect02.getX(), rect02.getY(), rect02.getWidth(), rect02.getHeight());
rect10.setBounds(rect10.getX(), rect10.getY(), rect10.getWidth(), rect10.getHeight());
rect11.setBounds(rect11.getX(), rect11.getY(), rect11.getWidth(), rect11.getHeight());
rect12.setBounds(rect12.getX(), rect12.getY(), rect12.getWidth(), rect12.getHeight());
rect20.setBounds(rect20.getX(), rect20.getY(), rect20.getWidth(), rect20.getHeight());
rect21.setBounds(rect21.getX(), rect21.getY(), rect21.getWidth(), rect21.getHeight());
rect22.setBounds(rect22.getX(), rect22.getY(), rect22.getWidth(), rect22.getHeight());
rect00.setOpaque(false);
rect01.setOpaque(false);
rect02.setOpaque(false);
rect10.setOpaque(false);
rect11.setOpaque(false);
rect12.setOpaque(false);
rect20.setOpaque(false);
rect21.setOpaque(false);
rect22.setOpaque(false);
inter.addPanel(rect00);
inter.addPanel(rect01);
inter.addPanel(rect02);
inter.addPanel(rect10);
inter.addPanel(rect11);
inter.addPanel(rect12);
inter.addPanel(rect20);
inter.addPanel(rect21);
inter.addPanel(rect22);
frame.add(inter);
frame.setResizable(false);
frame.setVisible(true);
}
public static void main(String args[]) {
new Test().Display();
}
private class sub extends JPanel {
private BufferedImage image;
private ArrayList<Rectangles> rects = new ArrayList<>();
public sub() {
try {
image = ImageIO.read(new File("c:/image.png"));
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
public Dimension getPreferredSize() {
return (new Dimension(600, 400));
}
void addPanel(Rectangles r) {
rects.add(r);
add(r);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Rectangles r : rects) {
g.drawImage(image, r.getX(), r.getY(), null);
}
}
}
}
class Rectangles extends JPanel implements MouseListener {
private int Posx;
private int Posy;
private int width;
private int height;
private boolean selected = false;
public Rectangles(int Posx, int Posy, int width, int height) {
this.Posx = Posx;
this.Posy = Posy;
this.width = width;
this.height = height;
this.addMouseListener(this);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (selected == true) {
Graphics2D g2 = (Graphics2D) g;
g2.setColor(new Color(250, 235, 215));
g2.drawRect(0,0, width, height);
g2.setColor(new Color(0, 0, 0));
g2.setStroke(new BasicStroke(20));
g2.drawLine(0,0, width,height);
g2.drawLine(getWidth(),0, 0, height);
}
}
public int getX() {
return Posx;
}
public int getY() {
return Posy;
}
public int getWidth() {
return width;
}
public int getHeight() {
return height;
}
public void setSelected() {
selected = true;
}
#Override
public void mouseClicked(MouseEvent arg0) {
}
#Override
public void mouseEntered(MouseEvent arg0) {
}
public void mouseExited(MouseEvent arg0) {
}
#Override
public void mousePressed(MouseEvent arg0) {
}
#Override
public void mouseReleased(MouseEvent arg0) {
selected = true;
repaint();
}
}
A few other pointers:
Dont use Absolute/Null layout. A GridLayout or GridBagLayout would suit your needs fine. (see here for more.)
Dont do JFrame#setSize(...); rather use Correct LayoutManager and call pack() on JFrame before setting it visible.
Dont call setSize on your Rectangles instances, simply override getPreferredSize like you did with sub panel??
No need for implementing MouseListener, just use MouseAdapter thus giving you the freedom to choose which methods to override and not just override all.
Have a read on Concurrency in Swing especailly Event-Dispatch-Thread