As you already know everything I started writing little game about space.
"Not a bad start" - https://stackoverflow.com/questions/19818655/simulation-of-spaceplanets-and-stars :D
I wrote a little plan of the work, and the first point in that it is' Random generation of stars.
You could say, easier use the random.
Random random = new Random();
int x = random.nextInt(getWidth()*2);
int y = random.nextInt(getHeight()*2);
g.drawImage(Image,x,y,4,4,this);
But it does not work (
And it is not working because the pictures "jump" on the screen.
As to the video: https://www.youtube.com/watch?v=EELo_-eh3fA
So how do you randomly bring the stars? (Star is a small picture or a white square)
That's all the code:
import java.awt.Graphics;
import javax.imageio.ImageIO;
import javax.swing.JComponent;
import javax.swing.JFrame;
import java.io.IOException;
public class Game extends JComponent {
public Game() {
try {
image = ImageIO.read(getClass().getResource("star.png"));
} catch (IOException e) {
e.printStackTrace();
}
}
public void paint(Graphics g) {
super.paint(g);
repaint();
Random random = new Random();
int x = random.nextInt(getWidth()*2);
int y = random.nextInt(getHeight()*2);
g.drawImage(Image,x,y,4,4,this);
}
public static void main(String[] args) {
JFrame frame = new JFrame(NAME);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.add(new Game());
frame.setVisible(true);
frame.setLocationRelativeTo(null);
frame.setResizable(true);
frame.addMouseListener(mos);
frame.addMouseMotionListener(mos);
}
}
Here's a code does not work (
Pictures jump again.
public void paintComponent(Graphics g) {
super.paintComponent(g);
repaint();
Random random = new Random();
int x = random.nextInt(getWidth()*2);
int y = random.nextInt(getHeight()*2);
g.drawImage(kor,x,y,10,10,this);
}
#camickr, You said to remove repaint(); but without it I do not get a picture
Custom painting is done by overriding the paintComponent() method not the paint() method.
Never invoke repaint() in a painting method. This will cause an infinite loop.
How to fix the picture? that they did not jump.
Basically the location needs to be determined outside of the painting method.
Maybe you can start with Custom Painting Approaches to get the idea of painting multiple objects on a panel. I would suggest the first approach of adding objects to a List. So you would add multiple objects to the list, but each object would be given a random location.
You said to remove repaint(); but without it I do not get a picture
Did you take the time to look at the link I gave you? The examples show you when to do a repaint().
Related
I have a class called CharMove,in it are the paint(Graphics g) method, and some custom methods. The class should create a square,then move that square randomly around the screen. However,when I create two instances of this class in my World Class,only one square appears. First the square doesn't move but the new coord.'s are displayed,then after 5 runs the square begins to move randomly. I think the program is getting caught on the Graphics method because only one square is being created,when the CharMove class should be creating another instance of Graphics.I have searched online but can't find a way to create different instances of Graphics.Thanks in advance.
CharMove Class
import java.awt.*;
import java.util.concurrent.TimeUnit;
import javax.swing.*;
import java.util.Random;
public class CharMove extends JPanel {
int x = 250;
int y = 250;
public void paint(Graphics g) {
Graphics pane = (Graphics2D) g;
pane.setColor(Color.blue);
pane.fillRect(x, y, 10, 10);
}
public void movement(JFrame frame) {
for (int i=0;i<5;i++) {
try {
TimeUnit.SECONDS.sleep(1);
this.x = Getx(this.x,frame);
this.y = Gety(this.y,frame);
frame.repaint();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public int Getx(int a, JFrame frame) {
Random rn = new Random();
int xnum = rn.nextInt(10)-5;
a += xnum;
System.out.println("x:" + a);
return a;
}
public int Gety(int b, JFrame frame){
Random rn = new Random();
int ynum = rn.nextInt(10)-5;
b += ynum;
System.out.println("y:" + b);
return b;
}
}
World Class
import java.awt.*;
import java.util.concurrent.TimeUnit;
import javax.swing.*;
import java.util.Random;
public class World {
public static void main(String[] args) {
JFrame game = new JFrame();
game.setTitle("Matrix");
game.setSize(500, 500);;
game.getContentPane().setBackground(Color.white);
game.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
game.setVisible(true);
CharMove char1 = new CharMove();
CharMove char2 = new CharMove();
game.add(char1);
game.add(char2);
char1.movement(game);
char2.movement(game);
}
}
In swing, all of your painting should be down in paintComponent(Graphics g) (rename your method)
To do animation, you should use a Swing Timer (w/ an ActionListener) to update the positions of your animated items. Once that's done, the timer should call repaint();
public void actionPerformed(ActionEvent ae) {
this.x = Getx(this.x,frame);
this.y = Gety(this.y,frame);
frame.repaint();
}
However,when I create two instances of this class in my World Class,only one square appears.
The default layout manager for a JFrame is a BorderLayout.
game.add(char1);
game.add(char2);
When you add components without specifying a constraint then both components are added to the CENTER. However, only one component can be added to the CENTER so only the last one added is displayed.
Try:
game.add(char1, BorderLayout.PAGE_START);
game.add(char2, BorderLayout.PAGE_END);
However when you do this the componens won't be displayed because they have a (0, 0) preferredSize. So you will also need to override the getPreferredSize() method of your CharMove class.
#Override
public Dimension getPreferredSize()
{
return new Dimension(300, 200);
}
Also, custom painting should be done in the paintComponent(...) method and you need to invoke super.paintComponent(...) at the start to clear the background.
The repaint() method in your movement() method should be on the panel, not the frame, since you are changing properties of the panel.
Each CharMove is essentially a JPanel which draws a single square of size 10 somewhere on itself when it is painted. You are adding two CharMove panels to the game JFrame (which in fact adds them to the default content pane, which has a subclassed BorderLayout). As you are not providing a layout constraints object, in fact both panels are being added to the BorderLayout.CENTER of the content pane, and the second is completely covering the first.
To correct this you should modify CharMove so that it paints all of the squares (eg by maintaining an array or some sort of collection of squares, and painting all of them in the paint method) and just add that one panel to the JFrame.
Apart from this issue, while you are animating the squares in the movement method you are blocking the Event Dispatch Thread, meaning that during the animation you won't be able to move any other windows or respond to any mouse clicks or other inputs. Take ControlAltDel's advice about using the Swing Timer for animation to correct this problem.
I am trying to write a simple 2d animation engine in Java for visualizing later programming projects. However, I am having problems with the window refresh. On running, the frame will sometimes display a blank panel instead of the desired image. This begins with a few frames at a time at apparently random intervals, worsening as the program continues to run until the actual image only occasionally blinks into view. The code for processing each frame is run, but nothing in the frame is actually displayed. I believe the problem may come from my computer more than my code (certainly not from bad specs though), but am not sure. Help much appreciated.
Three classes. Code here:
package animator;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.applet.AudioClip;
public class APanel extends JPanel
{
public APanel(int l, int h){
setPreferredSize(new Dimension(l,h));
setLocation(80, 80);
setVisible(true);
setFocusable(true);
}
public Graphics renderFrame(Graphics g){
return g;
}
public void paintComponent(Graphics g) {
requestFocusInWindow();
renderFrame(g);
}
}
package animator;
import java.awt.*;
public class Animator extends APanel
//extending the APanel class allows you to code for different animations
//while leaving the basic functional animator untouched
{
public static final int SCREEN_X = 700;
public static final int SCREEN_Y = 700;
int frameNum;
public Animator() {
super(SCREEN_X, SCREEN_Y);
frameNum = 0;
}
public Graphics renderFrame(Graphics g) {
frameNum++;
g.drawString(""+frameNum,5,12);
return g;
}
}
package animator;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.Timer;
public class Runner {
int framerate = 30;
Animator a = new Animator();
JFrame j = new JFrame();
public Runner(){
j.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
j.add(a);
start();
j.setSize(a.getPreferredSize());
j.setVisible(true);
}
public void start() {
Timer t = new Timer(1000/framerate, new ActionListener() {
public void actionPerformed(ActionEvent e){
j.getComponent(0).paint(j.getComponent(0).getGraphics());
//The following line of code keeps the window locked to a preferred size
// j.setSize(j.getComponent(0).getPreferredSize());
}
});
t.start();
}
public static void main(String[] args){
Runner r = new Runner();
}
}
There are some serious mistakes in your code which could be the cause or a factor of your problem...
j.setSize(a.getPreferredSize()); is irrelevant, simply use JFrame#pack, you get better results as it takes into account the frame decorations
j.setSize(j.getComponent(0).getPreferredSize()); use JFrame#setResizable and pass it false instead...
NEVER do j.getComponent(0).paint(j.getComponent(0).getGraphics()); this! You are not responsible for the painting of components within Swing, that's the decision of the RepaintManager. Just call j.repaint()
super(SCREEN_X, SCREEN_Y);...just override the getPreferredSize method and return the size you want.
setLocation(80, 80); irrelevant, as the component is under the control of a layout manager
setVisible(true); (inside APanel)...Swing components are already visible by default, with the exception of windows and JInternalFrames
And finally...
public void paintComponent(Graphics g) {
requestFocusInWindow();
renderFrame(g);
}
There is never any need for this method to be made public, you NEVER want someone to be able to call it, this will break the paint chain and could have serious ramifications in the ability for the component to paint itself properly.
You MUST call super.paintComponent before performing any custom painting, otherwise you could end up with all sorts of wonderful paint artifacts and issues
Never modify the state of a component from within a paint method...while it "might" not be an immediate issue calling requestFocusInWindow(); within your paintComponent could have side effects you don't know about...
Instead, it should look more like...
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
renderFrame(g);
}
I am trying to draw an image on a JPanel that requires thousands of calculations, and I want to animate the progression of the drawing. I.e., instead of doing all 100K iterations of drawing in one go, and then repainting the JPanel, I want to repaint after each iteration, then pause for a fraction of a second, so the user sees the image gradually appearing. However, each refresh of the JPanel erases previous drawings, so my method doesn't work. How can I do this without replicating all (1..N-1) calculations on the Nth iteration?
Consider this example: I want "snow" to gradually appear on the screen. However, this code will only show the 100,000th "snowflake" as all previous ones get erased each time repaint() is called.
import javax.swing.*;
import java.awt.*;
import java.util.Random;
class spanel extends JPanel{
public void paintComponent(Graphics g){
super.paintComponent(g);
g.drawLine(snow.x, snow.y, snow.x, snow.y);
}
}
class snow extends Thread {
static int x,y;
Random r = new Random();
public void run(){
JFrame sboard = new JFrame();
sboard.setSize(600,600);
sboard.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
spanel mypanel = new spanel();
sboard.add(mypanel);
sboard.setVisible(true);
for (int i=0;i<100000;i++){
x=r.nextInt(600);
y=r.nextInt(600);
sboard.repaint();
try {
snow.sleep((long)10);
} catch (InterruptedException e) {};
}
}
}
public class SnowAnim {
public static void main(String[] args) {
(new snow()).start();
}
}
Custom Painting Approaches shows how to draw on a BufferedImage. There are also plenty of other examples in the forum.
Also, when doing animation you should use a Swing Timer to schedule the animation.
How can I do this without replicating all (1..N-1) calculations on the Nth iteration?
Add them to a BufferedImage as seen in this example.
You should probably do your painting on a buffer, then draw the current state of the buffer in paintComponent();
You could also skip the call to super.paintComponent(g);, but then you would have to worry about other elements getting visually "stuck" in your panel.
Thanks all! I figured it out. BufferedImage solves it. For the record, here is my updated code. It also implements camickr's suggestion to use a Swing timer instead of a thread to schedule the animation. I also made some aesthetic changes to make the output look more like snow :-) Thanks again!
import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
import java.util.Random;
import java.awt.event.*;
class spanel extends JPanel{
int x,y,rad,i;
static Random r = new Random();
BufferedImage image;
Graphics2D g2d;
Timer timer;
spanel(){
image = new BufferedImage(600, 600, BufferedImage.TYPE_INT_ARGB);
g2d = (Graphics2D)image.getGraphics();
setBackground(Color.black);
g2d.setColor(Color.white);
i=0;
ActionListener listener = new ActionListener() {
public void actionPerformed(ActionEvent ae) {
iterate();
}
};
timer = new Timer(10, listener);
timer.start();
}
public void iterate(){
x=r.nextInt(600);
y=r.nextInt(600);
rad=r.nextInt(5)+5;
g2d.fillOval(x, y, rad, rad);
repaint();
i++;
if (i==1000){timer.stop();}
}
public void paintComponent(Graphics g){
super.paintComponent(g);
g.drawImage(image,0,0,null);
}
}
public class SnowAnim {
public static void main(String[] args) {
JFrame sboard = new JFrame();
sboard.setSize(600,600);
sboard.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
spanel mypanel = new spanel();
sboard.add(mypanel);
sboard.setVisible(true);
}
}
I am making a simple Java Swing GUI chessboard where the player can drag and drop pieces. The problem is that, because of the border around the frame (with the title on top, maximize/minimize/close buttons, etc), the coordinates are skewed off - (0, 0) is the upper-left-hand corner of the frame, that is, a little above the X button, but the GUI starts building itself right below the title bar, so the GUI doesn't align with the coordinates, and things do not end up working the way they should. Additionally, when I set the size of the frame to, for instance, 100 x 100, the lower part and some of the right-hand part of my GUI is cut off because the frame doesn't compensate for its border. When I run it as an applet, I don't have this problem, but I don't want to do that. How can I either get rid of that border around my frame window so I can just have the plain GUI, or have the coordinates set themselves up properly?
sscce:
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
public class class1 extends JFrame{
public class1(){
addMouseListener(new MouseAdapter(){
public void mousePressed(MouseEvent evt){
System.out.print(evt.getPoint());
}
});
}
public static void main(String[] args){
class1 c = new class1();
c.setTitle("Test");
c.setSize(320, 320);
c.setLocationRelativeTo(null);
c.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
c.setVisible(true);
}
}
It's hard to know what is wrong with your code without the code, but I do know that if you go the easy way by using various layout managers, and let these managers do the laying out of components for you and the sizing of things as well, including calling pack() on the JFrame, usually things fall easily and well into place. So again, don't set the size of anything, but rather let the components' preferred sizes and the layout managers do this for you.
If this advice doesn't help, please give us more information and code, preferably an sscce, a small compilable and runnable program that doesn't do anything other than demonstrate your problem.
Edit: I am assuming that this is a Swing GUI. Please verify if this is so.
Edit 2: One problem you're having is that you're setting the size of a JFrame not taking into account its "decorations" including the menu bar, the resize/maximize/close icon. Again, you shouldn't be setting sizes directly, but if you must better override the getPreferredSize() method of the JPanel that holds your grid.
Edit 3: For example:
import java.awt.*;
import javax.swing.*;
public class Grid extends JPanel {
public static final Color DARK_COLOR = Color.red.darker().darker().darker();
public static final Color LIGHT_COLOR = Color.lightGray.brighter();
public static final int SQUARE_SIDE = 60;
private static final int ROW_COUNT = 8;
#Override
public Dimension getPreferredSize() {
return new Dimension(ROW_COUNT * SQUARE_SIDE, ROW_COUNT * SQUARE_SIDE);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (int i = 0; i < ROW_COUNT; i++) {
for (int j = 0; j < ROW_COUNT; j++) {
Color c = (i % 2 == j % 2) ? LIGHT_COLOR : DARK_COLOR;
g.setColor(c);
int x = i * SQUARE_SIDE;
int y = j * SQUARE_SIDE;
g.fillRect(x, y, SQUARE_SIDE, SQUARE_SIDE);
}
}
}
public Grid() {
// TODO Auto-generated constructor stub
}
private static void createAndShowGui() {
Grid mainPanel = new Grid();
JFrame frame = new JFrame("Grid");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Before I start know this: I am extremely new to Java and programming. How would I properly draw the "grass.jpg" to the screen?
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.ImageIcon;
import java.util.Random;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class Game extends Canvas {
private static int Height = 300, Width = 600; //25x50
private Random generator = new Random();
private String[][] TerrainList = new String[12][12];
public void GameSetup() {
JFrame container = new JFrame("CARSSémon");
// get hold the content of the frame and set up the resolution of the game
JPanel panel = (JPanel) container.getContentPane();
panel.setPreferredSize(new Dimension(Width,Height));
//panel.setLayout(null);
//setBounds(0,0,800,600);
//panel.add(this);
// finally make the window visible
container.pack();
container.setResizable(false);
container.setVisible(true);
container.setLocationRelativeTo(null); //Centers screen
container.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
PrepareTerrain();
PreparePlayer();
}
public void PrepareTerrain() {
for (int a=0; a<=11; a++){
for (int b=0; b<=11; b++){
TerrainList[a][b]="grass"; //Sets defult terrain of grass
}
}
int BushLocationx = generator.nextInt(12);
int BushLocationy = generator.nextInt(12);
BushCheck(BushLocationx,BushLocationy); //Checks to see if it can make bushs at the location
}
#Override
public void paint(Graphics g) {
super.paint(g);
// Draw an Image object
Image grass = new ImageIcon("grass.jpg").getImage();
Image bushes = Toolkit.getDefaultToolkit().getImage("bushes.jpg");
g.setColor(Color.BLACK);
g.drawImage(grass, 0, 0, null);
g.drawImage(grass, 0, 50, null);
g.drawImage(grass, 50, 0, null);
g.drawImage(grass, 200, 200, null);
}
public void DrawTerrain() {
for (int r=0; r<=11; r++){
for (int c=0; c<=11; c++){
}
}
}
private void BushCheck(int x, int y){
}
public void PreparePlayer() {
}
public static void main(String[] args) {
Game G =new Game();
G.GameSetup();
}
}
Now I obviously realize that this program has basically nothing implemented but I figured what's the point of starting to implement things if I could never even display any pictures?
My problem is that I can not figure out why the .jpgs aren't being displayed. Shouldn't the paint(); method be called when the JFrame and JPanel are created? The code is pretty messy, but I figured it would be best to include all of it.
In case this matters, this is eventually going to be a Pokemon like game, where the the run window is made up of many 16x16 pixel squares, that a player could move around on. Before starting any of that I wanted to experiment with outputting some images at random places. I've been reading similar questions and looking at examples, I just read a section of Java text on graphics but could only find information on loading images, not displaying through paint. If anyone could help by even pointing me in the right way, it would be greatly appreciated.
(I realize that I will most likely completely need to restart, and are going about things completely wrong but anything you could do would help.)
I just read a huge section of Java text on graphics but could only find information on loading images, not displaying through paint.
For a Pokemon style game, I don't think using JLabel for each icon/image would provide any benefit. Instead:
Create a BufferedImage of the desired size of the game area.
Get Image instances for each of the smaller icons that you might need to paint (characters, elements in the terrain etc.) & paint them to the Graphics instance of the main BufferedImage1.
To display the main 'game' image there are two good options:
Add the main image to a JLabel and add it to a JPanel, call label.repaint().
Paint the game image directly to the Graphics instance supplied to the paintComponent() method of a JComponent.
For the last part, I would recommend option 1.
1. E.G.
public void gameRenderLoop() {
Graphics2D g2 = gameImage.createGraphics();
g2.drawImage(playerImage, 22, 35, this);
...
g2.dispose();
}
Examples of dealing with BufferedImage & Graphics
Very simple example of painting an image.
More complicated example dealing with text & clips.
A slightly different tack (extending a JLabel) showing image painting with transparency.
Don't reinvent the wheel. Use a JLabel with an ImageIcon to paint your image for you. Just add it to a JPanel and you're all set.