I am creating a retro arcade game in Java. The screen resolution for the game is 304 x 256, which I want to keep to preserve the retro characteristics of the game (visuals, animations, font blockiness, etc.).
But when I render this on a large desktop display, it is too small, as one would expect.
I'd like to be able to scale the window up say by a constant factor, without having to code the various paint(Graphics) methods to be knowledgeable about the fact that there's a scale-up. That is, I'd like the rendering code believe that the screen is 304 x 256. I also don't want to have to change my desktop resolution or go into full screen exclusive mode. Just want a big window with scaled up pixels, essentially.
I'd be looking for something along the following lines:
scale(myJFrame, 4);
and have all the contents automatically scale up.
UPDATE: Regarding input, my game happens to use keyboard input, so I don't myself need the inverse transform that trashgod describes. Still I can imagine that others would need that, so I think it's an appropriate suggestion.
One approach, suggested here, is to rely on drawImage() to scale an image of the content. Your game would render itself in the graphics context of a BufferedImage, rather than your implementation of paintComponent(). If the game includes mouse interaction, you'll have to scale the mouse coordinates as shown. In the variation below, I've given the CENTER panel a preferred size that is a multiple of SCALE = 8 and added the original as an icon in the WEST of a BorderLayout. As the default, CENTER, ignores a component's preferred size, you may want to add it to a (possibly nested) panel having FlowLayout. Resize the frame to see the effect.
f.setLayout(new FlowLayout());
f.add(new Grid(NAME));
//f.add(new JLabel(ICON), BorderLayout.WEST);
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.image.BufferedImage;
import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
/**
* #see https://stackoverflow.com/a/44373975/230513
* #see http://stackoverflow.com/questions/2900801
*/
public class Grid extends JPanel implements MouseMotionListener {
private static final String NAME = "OptionPane.informationIcon";
private static final Icon ICON = UIManager.getIcon(NAME);
private static final int SCALE = 8;
private final BufferedImage image;
private int imgW, imgH, paneW, paneH;
public Grid(String name) {
super(true);
imgW = ICON.getIconWidth();
imgH = ICON.getIconHeight();
image = new BufferedImage(imgW, imgH, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = (Graphics2D) image.getGraphics();
ICON.paintIcon(null, g2d, 0, 0);
g2d.dispose();
this.addMouseMotionListener(this);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(imgW * SCALE, imgH * SCALE);
}
#Override
protected void paintComponent(Graphics g) {
paneW = this.getWidth();
paneH = this.getHeight();
g.drawImage(image, 0, 0, paneW, paneH, null);
}
#Override
public void mouseMoved(MouseEvent e) {
Point p = e.getPoint();
int x = p.x * imgW / paneW;
int y = p.y * imgH / paneH;
int c = image.getRGB(x, y);
this.setToolTipText(x + "," + y + ": "
+ String.format("%08X", c));
}
#Override
public void mouseDragged(MouseEvent e) {
}
private static void create() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new Grid(NAME));
f.add(new JLabel(ICON), BorderLayout.WEST);
f.pack();
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
create();
}
});
}
}
One approach, suggested here, is to rely on the graphics context's scale() method and construct to an inverse transform to convert between mouse coordinates and image coordinates. In the example below, note how the original image is 256 x 256, while the displayed image is scaled by SCALE = 2.0. The mouse is hovering over the center the image; the tooltip shows an arbitrary point in the display and the center point (127, 127) in the original.
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.geom.AffineTransform;
import java.awt.geom.NoninvertibleTransformException;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JPanel;
/** #see https://stackoverflow.com/a/2244285/230513 */
public class InverseTransform {
private static final double SCALE = 2.0;
public static void main(String[] args) {
JFrame frame = new JFrame("Inverse Test");
BufferedImage image = getImage(256, 'F');
AffineTransform at = new AffineTransform();
at.scale(SCALE, SCALE);
frame.add(new ImageView(image, at));
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
private static BufferedImage getImage(int size, char c) {
final Font font = new Font("Serif", Font.BOLD, size);
BufferedImage bi = new BufferedImage(
size, size, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = bi.createGraphics();
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setPaint(Color.white);
g2d.fillRect(0, 0, size, size);
g2d.setPaint(Color.blue);
g2d.setFont(font);
FontMetrics fm = g2d.getFontMetrics();
int x = (size - fm.charWidth(c)) / 2;
int y = fm.getAscent() + fm.getDescent() / 4;
g2d.drawString(String.valueOf(c), x, y);
g2d.setPaint(Color.black);
g2d.drawLine(0, y, size, y);
g2d.drawLine(x, 0, x, size);
g2d.fillOval(x - 3, y - 3, 6, 6);
g2d.drawRect(0, 0, size - 1, size - 1);
g2d.dispose();
return bi;
}
private static class ImageView extends JPanel {
private BufferedImage image;
private AffineTransform at;
private AffineTransform inverse;
private Graphics2D canvas;
private Point oldPt = new Point();
private Point newPt;
#Override
public Dimension getPreferredSize() {
return new Dimension( // arbitrary multiple of SCALE
(int)(image.getWidth() * SCALE * 1.25),
(int)(image.getHeight() * SCALE * 1.25));
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
try {
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
inverse = g2d.getTransform();
inverse.invert();
g2d.translate(this.getWidth() / 2, this.getHeight() / 2);
g2d.transform(at);
g2d.translate(-image.getWidth() / 2, -image.getHeight() / 2);
inverse.concatenate(g2d.getTransform());
g2d.drawImage(image, 0, 0, this);
} catch (NoninvertibleTransformException ex) {
ex.printStackTrace(System.err);
}
}
ImageView(final BufferedImage image, final AffineTransform at) {
this.setBackground(Color.lightGray);
this.image = image;
this.at = at;
this.canvas = image.createGraphics();
this.canvas.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
this.canvas.setColor(Color.BLACK);
this.addMouseMotionListener(new MouseMotionAdapter() {
#Override
public void mouseMoved(MouseEvent e) {
Point m = e.getPoint();
Point i = e.getPoint();
try {
inverse.inverseTransform(m, i);
setToolTipText("<html>Mouse: " + m.x + "," + m.y
+ "<br>Inverse: " + i.x + "," + i.y + "</html>");
} catch (NoninvertibleTransformException ex) {
ex.printStackTrace();
}
}
});
}
}
}
Thanks to trashgod for pointing me in the right direction with his two answers. I was able to combine elements of both answers to arrive at something that works for what I need to do.
So first, my goal was to scale up an entire UI rather than scaling up a single icon or other simple component. By "an entire UI" I specifically mean a JPanel containing multiple custom child components laid out using a BorderLayout. There are no JButtons or any other interactive Swing components, and no mouse input (it's all keyboard-based input), so really I just need to scale a 304 x 256 JPanel up by a factor of 3 or 4.
Here's what I did:
package bb.view;
import javax.swing.JComponent;
import javax.swing.JPanel;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import static bb.BBConfig.SCREEN_WIDTH_PX; // 304
import static bb.BBConfig.SCREEN_HEIGHT_PX; // 256
public class Resizer extends JPanel {
private static final int K = 3;
private static final Dimension PREF_SIZE =
new Dimension(K * SCREEN_WIDTH_PX, K * SCREEN_HEIGHT_PX);
private static final AffineTransform SCALE_XFORM =
AffineTransform.getScaleInstance(K, K);
public Resizer(JComponent component) {
setLayout(new FlowLayout(FlowLayout.LEFT, 0, 0));
add(component);
}
#Override
public Dimension getPreferredSize() {
return PREF_SIZE;
}
#Override
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.setTransform(SCALE_XFORM);
super.paint(g2);
}
}
Some important elements of the solution:
Using a FlowLayout here shrinkwraps the child component, which is what I want. (Thanks trashgod for that.) That is, I don't want the child to expand to fill the Resizer preferred size, because that wrecks the child component's layout. Specifically it was creating this huge gap between the child component's CENTER and SOUTH regions.
I configured the FlowLayout with left alignment and hgap, vgap = 0. That way my scale transform would have the scaled up version anchored in the upper left corner too.
I used an AffineTransform to accomplish the scaling. (Again thanks trashgod.)
I used paint() instead of paintComponent() because the Resizer is simply a wrapper. I don't want to paint a border. I basically want to intercept the paint() call, inserting the scale transform and then letting the JPanel.paint() do whatever it would normally do.
I didn't end up needing to render anything in a separate BufferedImage.
The end result is that the UI is large, but the all the code other than this Resizer thinks the UI is 304 x 256.
I am learning how to work with Gui's in java. Currently I'm trying to make a simple program that opens a Gui and draws an image to the background. The problem is that the background is completely white instead of the image.
Code:
Main.java:
package com.flaghacker.buckygame;
public class Main
{
public static void main(String[] args)
{
GuiFrame guiFrame = new GuiFrame();
}
}
GuiFrame.java:
package com.flaghacker.buckygame;
import javax.swing.JFrame;
public class GuiFrame extends JFrame
{
private GuiPanel guiPanel;
public GuiFrame()
{
//General
super("Title");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Size
this.setSize(1100, 650);
this.setResizable(true);
//Components
guiPanel = new GuiPanel();
this.add(guiPanel);
//Final
this.setVisible(true);
}
}
GuiPane.java:
package com.flaghacker.buckygame;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import java.awt.Graphics;
import java.awt.Image;
public class GuiPanel extends JPanel
{
private Image backGround;
public GuiPanel()
{
backGround = new ImageIcon("D:\\Install\\Java Projects\\Testing\\Bucky\\Back.jpg").getImage();
}
#Override
public void paint(Graphics g)
{
super.paint(g);
g.drawImage(backGround, 0, 0, null);
}
}
I test your code and it works ... the possible problem are two
first) your image isn't in
"D:\\Install\\Java Projects\\Testing\\Bucky\\Back.jpg"
i suggested you to use
"D:/Install/Java Projects/Testing/Bucky/Back.jpg"
and verify
Case insensitive.
second) the image Back.jpg have width and height more high of 1100 650 so you display only a top left angle of image
i used a class Imagepanel to show a background image to my panel in netbeans .It successfully works when running it from the IDE netbeans 6.8 ,but when i run it from the jar file it doesn't show the image .Please help me to solve this problem .Thanks for your remarks .
Here is my code ImagePanel.java
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
class ImagePanel extends JPanel {
private Image img;
public ImagePanel(String img ) {
this(new ImageIcon(img).getImage());
}
public ImagePanel(Image img) {
this.img = img;
Dimension size = new Dimension(img.getWidth(null), img.getHeight(null));
setPreferredSize(this.getMaximumSize());
setMinimumSize(size);
setMaximumSize(size);
setSize(this.getMaximumSize());
setLayout(null);
}
#Override
public void paintComponent(Graphics g) {
g.drawImage(img, 0, 0, null);
}
}
I have created my panel which is in another class like this where my image is in the directory images under src. Thanks in advance .
ImagePanel pan2 = new ImagePanel("src/images/tarif.png");
import java.awt.*;
import javax.swing.*;
class BackgroundPanel extends JPanel
{
Image image;
public BackgroundPanel(String path)
{
try
{
image = (new ImageIcon(getClass().getResource(path))).getImage();
}
catch(Exception e){/*handled in paintComponent()*/}
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
}
}
this code worked and i call the class like this
String path ="/images/tarif.png";
JPanel pan2=new BackgroundPanel(path);
I've been trying for a while to load an image into this JFrame for it to display it without success. Here is the code:
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JOptionPane;
public class Main extends JPanel{
Bird bird = new Bird(this);
public void paint(Graphics g){
super.paint(g);
Graphics2D g2D = (Graphics2D) g;
g2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
bird.paint(g2D);
}
public static void main(String[] args)throws InterruptedException{
JFrame frame = new JFrame("Java Birds");
Main game = new Main();
frame.add(game);
frame.setSize(500, 300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
while(true){
game.repaint();
Thread.sleep(10);
}
}
}
This is my Bird Class:
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.Toolkit;
public class Bird {
private static final Image sprite = Toolkit.getDefaultToolkit().getImage("bird.jpeg");
private static final int DIAMETER = 30;
double g = 0.12, vy = 0, xo = 100, yo = 10;
private Main game;
public Bird(Main game){
this.game = game;
}
public void paint(Graphics2D g){
g.setColor(Color.BLACK);
g.drawImage(sprite, 30, 30, game);
}
}
When I run this nothing shows up onscreen, but if I place a g.fillOval instruction I do get a circle in the panel. Help much appreciated, please.
There are a cascade of issues, first...
public void paint(Graphics g){
super.paint(g);
Graphics2D g2D = (Graphics2D) g;
g2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
bird.paint(g2D);
}
You're overriding paint, it is highly unrecommended to do so, instead, it is recommended that you override paintComponent instead.
Another problem is...
Toolkit.getDefaultToolkit().getImage("bird.jpeg");
The problem with this is getImage(String) expects that the value you pass it refers to a file on the file system. In most cases, this is not true and the image is stored as an embedded resource, in which use you would need to use something more like...
Toolkit.getDefaultToolkit().getImage(Bird.class.getResource("bird.jpeg"));
or
Toolkit.getDefaultToolkit().getImage(Bird.class.getResource("/bird.jpeg"));
There is still no guarantee that the image is loaded and none of these approaches actually tells you when it has failed.
A better solution would be to use ImageIO to read the image, apart from supporting more formats, it will throw an IOException when it fails...
public class Bird {
private Image sprite;
//...
public Bird(Main game) throws IOException {
image = ImageIO.read(getClass().getResource("/bird.jpeg"));
This...
while(true){
game.repaint();
Thread.sleep(10);
}
Is also very dangerous, you've started this in the main method, but you've take no consideration into what thread main might be called in. While in "normal" operations, main is called by the JVM from what is known as the "main thread", there is no guarantee that this is how your main method is called. It might called by another class from the context of the EDT which would cause the program to freeze.
Generally you should either use a javax.swing.Timer or a separate thread all together.
To display an image which fills the entire panel, you should have the following. You can use ImageIO.read(File) to read in an image from a file (you can adjust the position and size of the image inside the paintComponent method). You may want to also see Graphics.drawImage`.
import javax.swing.*;
import java.awt.image.*;
import java.awt.*;
public class PictureFrame extends JComponent{
private final Image img;
public PictureFrame(final String file) throws IOException {
this(new File(file));
}
public PictureFrame(final File file) throws IOException {
this(ImageIO.read(file));
}
public PictureFrame(BufferedImage img){
this.img = img;
this.setPreferredSize(new Dimension(img.getWidth(), img.getHeight()));
}
public void paintComponent(Graphics g){
super.paintComponent(g);
g.drawImage(img, 0, 0, getWidth(), getHeight(), null);
}
}
Tester main:
public static final String TEST_FILE = "file path here";
public static void main(String... args) throws IOException {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
}
final JFrame frame = new JFrame();
final JComponent picture = new PictureFrame(TEST_FILE);
frame.setContentPane(picture);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 300);
frame.setVisible(true);
}
Currently in my code I have a BufferedImage drawn like:
Graphics2D g2d = (Graphics2D) g;
g2d.transform(at); //at is an AffineTransform that just rotates the .gif
g2d.drawImage(sharkie, xCenter-5*radius, yCenter-3*radius, 10*radius, 6*radius, null);
I already have it fully functioning as a BufferedImage, but as expected it shows only the first frame. I was wondering if anyone knew of a way that is analogous to BufferedImage that works for animated gifs. I can't seem to get swing to work with the technique of adding it to a JButton. I also cannot figure out if there is a viable ImageObserver that would animate the .gif in the drawImage() call.
I am willing to try anything, but I am most interested in the possibility of making the draw call work with an ImageObserver as that would be only a small change.
Thanks all!
"I already have it fully functioning as a BufferedImage, but as expected it shows only the first frame"
This will happen when trying to read the image with ImageIO.read(...). If you read it with new ImageIcon(...).getImage(), you'll get the gif animation. See here.
"I also cannot figure out if there is a viable ImageObserver that would animate the .gif in the drawImage() call."
The ImageObserver is the component you are painting on. So instead of using drawImage(..., null), you should be using drawImage(..., this)
"I am willing to try anything, but I am most interested in the possibility of making the draw call work with an ImageObserver as that would be only a small change."
Combine the two points above and you got your answer.
Give this code a test run. gif image taken from this answer
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestGif {
public TestGif() {
JFrame frame = new JFrame();
frame.add(new GifPanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public class GifPanel extends JPanel {
Image image;
{
try {
image = new ImageIcon(new URL("http://i.stack.imgur.com/lKfdp.gif")).getImage();
} catch (MalformedURLException ex) {
Logger.getLogger(TestGif.class.getName()).log(Level.SEVERE, null, ex);
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
}
#Override
public Dimension getPreferredSize() {
return image == null ? new Dimension(200, 200)
: new Dimension(image.getWidth(this), image.getHeight(this));
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TestGif();
}
});
}
}