Consider this small runnable example:
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import java.util.ArrayList;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Test2 extends JFrame implements MouseWheelListener{
ArrayList<JLabel> lista = new ArrayList<JLabel>();
JPanel p;
double d = 0.1;
Test2(){
p=new JPanel();
_JLabel j = new _JLabel("Hello");
j.setOpaque(true);
j.setBackground(Color.yellow);
p.add(j);
p.setBackground(Color.blue);
add(p);
this.setVisible(true);
this.setSize(400,400);
addMouseWheelListener(this);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String args[]){
new Test2();
}
private class _JLabel extends JLabel{
_JLabel(String s){
super(s);
}
protected void paintComponent(Graphics g) {
d+=0.01;
Graphics2D g2d = (Graphics2D) g;
g2d.scale(d, d);
setMaximumSize(null);
setPreferredSize(null);
setMinimumSize(null);
super.paintComponent(g2d);
System.out.println("d= " +d);
}
}
public void mouseWheelMoved(MouseWheelEvent e) {
this.repaint();
}
}
When I scroll the mousewheel the JLabel increases in size and the variable d is printed out. However, when it reaches the actual size (d=1) only the text continues zooming. How can I make the background continue to zoom?
You shouldn't be modifying the preferred/min/max sizes in the paint method, this coud have unexpected results (cause another repaint).
The problem is that the parent layout has no reference from which to determine size of the component. That is, the preferred/in/max size is actually calculated based on the font information & this information is not been changed.
So, while it "appears" that the component is being resized, it's actual size has not changed.
Try instead to scale against the original font size.
AffineTransformation af = AffineTranfrmation.getScaleInstance(scale, scale);
Font font = originalFont.deriveFont(af);
setFont(font);
invalidate();
repaint();
Of course you run into the problem of what happens if the user changes the font, but with a little bit of flagging, you should be able to over come that
Related
The program works fine, but when I add the setUndecorated code, the panel does not appear. Problem is solving when I minimize and reopen the program. I tried repaint() , but It's not working.
package testing;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class test extends JFrame{
static int width = 900;
static int height = 520;
JFrame frame;
JPanel panel;
JButton selectKey = new JButton("Select KeyIMG");
static BufferedImage bg;
class MyCanvas extends JComponent{
public void paint(Graphics g) {
try {
bg = ImageIO.read(new File("BGFILE"));
} catch (IOException e) {
e.printStackTrace();
}
g.setClip(0, 0, width, height);
g.drawImage(bg,0,0,width,height, this);
g.dispose();panel.repaint();
}
}
public test(){
super("Test");
setBounds(250, 100, width, height);
selectKey.setBounds(width/9,height/2,width/45*8,height/13);
getContentPane().add(new MyCanvas());setUndecorated(true);setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel = new JPanel();
panel.setBackground( new Color(0, 0, 0, 0));
panel.setLayout(null);
panel.add(selectKey);
add(panel);
}
public static void main(String...Args){
new test();
}
}
What's wrong ?
Issues
Overriding paint. It's highly discouraged to override paint, painting is a complex series of compounding methods which work together to produce a the final result. It's highly recommended that you override paintComponent instead
Not calling super.paint, see the previous comment. Unless you know exactly what you're doing and are prepared to take over the responsibility of the paint method, call it's super method, there only a very few use cases I'd consider it safe not to do this.
Using a alpha based color on an opaque component; panel.setBackground(new Color(0, 0, 0, 0));. This is bad idea. Swing only knows how to deal with opaque and transparent components, it doesn't know how it should paint components with alpha based colors. The API will simply ignore any components beneath it, which is likely one of the major causes of your problem
g.dispose(); don't ever dispose of a Graphics context you did not create or copy. Doing so can prevent other components from been painted
Don't call panel.repaint(); from within any paint method, painting paints the current state, it should never do anything to change it, doing so well put you into a spiral of CPU death as it begins to chew up all the CPU cycles, in fact, MyCanvas has no right to be modifying panel anyway and the way your code is set up, it could generate a NullPointerException
"Other" concerns
static BufferedImage bg; is worrisome. No body else has any need to deal with this variable, the only class which should be dealing with it is the MyCanvas class
g.setClip(0, 0, width, height); is pointless (and potentially dangerous), this has already been done before the paint method was called. This is made worse by the fact that you are not relying on the components actual size, which could cause the painting to overrun the visible bounds of the component
Extending from JFrame. You should avoid extending from top level containers, they are complex components to which you rarely add any new/reusable functionality to and they lock you into a single use case, much better to start with a JPanel and add that to whatever container you need
An example...
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Test {
class Background extends JComponent {
private BufferedImage bg;
public Background() {
try {
bg = ImageIO.read(new File("/path/to/your/image"));
} catch (IOException e) {
e.printStackTrace();
}
setLayout(new BorderLayout());
}
#Override
public Dimension getPreferredSize() {
return bg == null ? super.getPreferredSize() : new Dimension(bg.getWidth(), bg.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (bg != null) {
Graphics2D g2d = (Graphics2D) g.create();
g2d.drawImage(bg, 0, 0, getWidth(), getHeight(), this);
g2d.dispose();
}
}
}
public Test() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.setContentPane(new Background());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setUndecorated(true);
JPanel panel = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
panel.add(new JLabel("This is a label, don't I look pretty"), gbc);
JButton selectKey = new JButton("Select KeyIMG");
panel.add(selectKey, gbc);
panel.setOpaque(false);
frame.add(panel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static void main(String... Args) {
new Test();
}
}
I want to have an image fade in onto a panel that is part of a card layout. When i'm at a certain place in the program, this panel will show on top and I then want the image to be loaded in with a fade-in effect.
This is a big project so I will only paste the relevant code.
I have a GUI class which contains the jFrame, all the jPanels etc. When a certain event is triggered, this code runs:
cardMain.show(pMain, "cLeprechaun");
FadeIn.run(pLeprechaun);
It loads up the correct panel and then runs a static method in the FadeIn class, that is supposed to add the image onto the panel pLeprechaun.
Here is the FadeIn class:
import java.awt.AlphaComposite;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class FadeIn extends JPanel implements ActionListener {
Image imagem;
Timer timer;
private float alpha = 0f;
public FadeIn() {
imagem = new ImageIcon("darkforest.jpg").getImage();
timer = new Timer(100, this);
timer.start();
}
// here you define alpha 0f to 1f
public FadeIn(float alpha) {
imagem = new ImageIcon("darkforest.jpg").getImage();
this.alpha = alpha;
}
#Override
public void paintComponent(Graphics g) {
System.out.println("paint");
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER,
alpha));
g2d.drawImage(imagem, 0, 0, null);
}
public static void run(JPanel jPanel) {
jPanel.add(new FadeIn());
}
public void actionPerformed(ActionEvent e) {
alpha += 0.05f;
if (alpha >1) {
alpha = 1;
timer.stop();
}
repaint();
}
}
Nothing happens, no image is show on the panel. Just to try it out, instead of jPanel.add(new FadeIn()); I have also tried to create a new jFrame and adding a new FadeIn onto that, and it works then. Of course, instead of an image being painted on the jPanel, a new jFrame pops up ontop of the main one, with the image nicely fading in. But that's not what I want happening.
Is there a way to solve this?
Er go:
assuming you have the following sequence of calls:
JFrame f=new JFrame();
f.setSize(500, 500);
JPanel j=new JPanel();
f.add(j);
f.setVisible(true);
FadeIn.run(j);
you need to change the size as follows:
public FadeIn(Dimension d) {
setSize(d);
.... // the rest of set up
}
then in run:
run(Jpanel jPanel) {
jPanel.add(new FadeIn(jPanel.getSize()));
}
Hi I'm new to java GUI Programming. I created Jframe(MainFrame) and add JPanel(OutPanel) Which has another Jpanel(InnerPanel). I try to achieve drawing Image in InnerPanel, not drawing OutPanel. I want OutPanel used to be just Container. So as you see TestA. I get Graphics from InnerPanel in OutPanel's paintComponent() which is overided method.
So finally I can draw using InnerPanel's Graphics in OutPanel's paintComponent() method. but It couldn't work well. It couldn't draw Image one time when program starts. when I hided window and shown again, the program shows image. Even though that is part of Image, not all Image.
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class TestA{
private static Image image = GUI.loadImage("PlayerBoard.jpg");
public static void main(String[] args) {
TestA testA = new TestA();
}
public TestA() {
JFrame mainFrame = new JFrame("Main Frame");
mainFrame.setLayout(null);
mainFrame.setSize(500, 500);
mainFrame.setVisible(true);
mainFrame.setBackground(Color.black);
mainFrame.setLocation(800, 400);
OutPanel outPanel = new OutPanel();
mainFrame.getContentPane().add(outPanel);
mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
outPanel.repaint();
}
private class OutPanel extends JPanel {
JPanel innerPanel;
public OutPanel() {
this.setLayout(null);
this.setLocation(0, 0);
this.setSize(500, 50);
this.setBackground(Color.red);
innerPanel = new JPanel();
this.innerPanel.setSize(400, 50);
this.innerPanel.setVisible(true);
this.add(innerPanel);
}
#Override
protected void paintComponent(Graphics g) {
// TODO Auto-generated method stub
super.paintComponent(g);
int width = 500;
int height = 50;
BufferedImage resized = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB_PRE);
Graphics gBuffer = resized.createGraphics();
gBuffer.drawImage(TestA.image, 0, 0, width, height, this);
Graphics gPanel = innerPanel.getGraphics();
gPanel.drawImage(resized, 0, 0, width, height, this);
}
}
}
So I try diffrerent way(TestB). Only different thing is I just moved drawImage() method and getGraphics() thing to InnerPanel's paintComponent() from OutPanel's paintComponent(). Here's another Code TestB. and It works well.
Why this happens. Is it relates to context?. What is Context. and could I draw InnerPanel's Image in OutPanel?
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class TestB {
private static Image image = GUI.loadImage("PlayerBoard.jpg");
public static void main(String[] args) {
TestB testB = new TestB();
}
public TestB() {
JFrame mainFrame = new JFrame("Main Frame");
mainFrame.setLayout(null);
mainFrame.setSize(500, 500);
mainFrame.setVisible(true);
mainFrame.setBackground(Color.black);
mainFrame.setLocation(800, 400);
OutPanel outPanel = new OutPanel();
mainFrame.add(outPanel);
outPanel.repaint();
}
private class OutPanel extends JPanel {
JPanel innerPanel;
public OutPanel() {
this.setLayout(null);
this.setLocation(0, 0);
this.setSize(500, 50);
this.setBackground(Color.red);
innerPanel = new InnerPanel(this);
this.innerPanel.setSize(500, 50);
this.innerPanel.setVisible(true);
this.add(innerPanel);
this.repaint();
}
}
private class InnerPanel extends JPanel {
OutPanel outPanel;
public InnerPanel(OutPanel outPanel) {
this.outPanel = outPanel;
}
#Override
protected void paintComponent(Graphics g) {
// TODO Auto-generated method stub
super.paintComponent(g);
int width = 500;
int height = 50;
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g.drawImage(TestB.image, 0, 0, width, height, this);
}
}
}
The paintComponent() method of a component is responsible for painting itself only. It should never know or care about any other component.
I want OutPanel used to be just Container.
Then do just that. Create the panel and set the layout manager for the outer panel and then add the outer panel to the JFrame.
Then create your inner panel and add it to the outer panel. Make sure you override the getPreferredSize() method of the inner panel so the layout manager of the outer panel can do its job.
Read the section from the Swing tutorial on Custom Painting for more information and working examples to start with.
I discovered the Robot class yesterday, and thought it was pretty cool. Today I wanted to experiment with it and see what was possible; so I decided I wanted to make a program that took a screenshot of the entire screen, and rendered out an image pixel by pixel on a JPanel. I have the program finished (two classes), but it isn't working and I can't find out why (I HAVE looked over the code a few times). Here's the code:
(FIRST CLASS)
import java.awt.AWTException;
import java.awt.FlowLayout;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
public class One {
public static void main(String[] args) {
BufferedImage screenCap = null;
Rectangle screenRect = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());
try {
screenCap = new Robot().createScreenCapture(screenRect);
Two imageRenderer = new Two(screenCap, screenRect);
imageRenderer.doRender();
JFrame frame = new JFrame();
frame.setVisible(true);
frame.setResizable(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new FlowLayout());
frame.add(imageRenderer);
frame.pack();
} catch (AWTException e) {
e.printStackTrace();
}
}
}
(SECOND CLASS)
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import javax.swing.JPanel;
public class Two extends JPanel {
private BufferedImage screenCap;
private Rectangle screenRect;
private Color pixelRGB;
//c1 and c2 are the x and y co-ordinates of the selected pixel.
private int c1, c2;
public Two(BufferedImage sC, Rectangle rect) {
screenCap = sC;
screenRect = rect;
setPreferredSize(new Dimension(rect.width, rect.height));
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
setBackground(Color.WHITE);
g.setColor(pixelRGB);
g.drawRect(c1, c2, 1, 1);
}
public void doRender() {
for(int i=0; i<screenRect.width; i++) {
for(int j=0; j<screenRect.height; j++) {
pixelRGB = new Color(screenCap.getRGB(i, j));
c1 = i;
c2 = j;
repaint();
}
}
}
}
I have googled around this problem to no avail.
Can anyone tell me what I'm doing wrong?
In order to make it work, just replace your paintComponent() method in your class Two with the following:
public void paintComponent(Graphics g) {
super.paintComponent(g);
setBackground(Color.WHITE);
g.drawImage(screenCap, 0, 0, getWidth(), getHeight(), null);
}
You can also get rid of the doRender() method.
Two should probably be an instance of a JLabel that is displaying screenCap. E.G.
import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class Screenshot {
public static void main(String[] args) throws Exception {
Rectangle screenRect = new Rectangle(
Toolkit.getDefaultToolkit().getScreenSize());
final BufferedImage screenCap =
new Robot().createScreenCapture(screenRect);
Runnable r = new Runnable() {
#Override
public void run() {
JOptionPane.showMessageDialog(null, new ImageIcon(screenCap));
}
};
SwingUtilities.invokeLater(r);
}
}
Drop it in a scroll pane if you wish to be really neat about it. Batteries not included.
In case it is not obvious: A JOptionPane uses a JLabel to render an ImageIcon.
Each time you repaint, you paint white over the whole panel, then do only a single pixel. So after each one, you'll only get one pixel. It also shouldn't be necessary to call repaint many times. In fact, when you call repaint, it does not immediately actually call paintComponent. It simply submits a request to repaint, which swing will eventually do. And it might not be one-to-one. E.g., many calls to repaint might result in only one call to paintComponent. You should try to write code so that a single call to paintComponent will completely display the component.
To do this, you can use g.drawImage to display a BufferedImage. See this post for more information on displaying an image in a JPanel.
This is my first non-school related program. I have a few questions that you guys can hopefully answer with ease. I have 3 questions. How can I add my button to my JFrame even though it's in a different class than the button?
Also, how would I go about making my shape and ten others like it about a quarter second after each other so I had a line of them.
Then, how would I force them to follow a predetermined path that scales to somebody dragging the box around?
Thanks a lot for reading and helping me out guys. Here are my three classes:
gameRunner.java
import javax.swing.JFrame;
public class gameRunner {
public static void main(String args []){
Enemy e = new Enemy();
Buttons b = new Buttons();
JFrame f = new JFrame();
f.add(b);
f.add(e);
f.setVisible(true);
f.setSize(1300, 700);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setTitle("Tower Defense");
}
}
Enemy.java
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Rectangle2D;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Enemy extends JPanel implements ActionListener {
Timer t = new Timer(5, this);
double x = 0;
double y = 0;
double velX = 3;
double velY = .5;
int health = 10;
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
Rectangle2D square = new Rectangle2D.Double(x, y, 10, 10);
g2.fill(square);
t.start();
}
public double adjustHorizontalSpeed() {
y += velY;
return y;
}
public double adjustVerticalSpeed() {
x += velX;
return x;
}
public void actionPerformed(ActionEvent e) {
adjustHorizontalSpeed();
adjustVerticalSpeed();
repaint();
}
}
Buttons.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.JButton;
import javax.swing.JFrame;
public class Buttons extends JFrame implements ActionListener{
private JButton shoot;
public Buttons(){
shoot = new JButton("Shoot!");
shoot.setBounds(50,60,50,100);
shoot.addActionListener(this);
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
}
Buttons shouldn't extend JFrame if all you want to do is use it to create a JButton that you wish to add to another GUI. Instead perhaps give it a public method called getShoot() that returns the button created:
public JButton getShoot() {
return shoot;
}
Next, to do things in a timed fashion, you should use a Swing Timer. The tutorials will tell you how to do this: How to use Swing Timers
Next, you'll want to read the Swing tutorial section on how to use layout managers so you can add a complex mix of components to the GUI and have them all fit well together: Laying out Components in a Container
Finally, as for this:
Then, how would I force them to follow a predetermined path that scales to somebody dragging the box around?
You'll have to describe this better for me to understand what you're trying to do.
For the predetermined path, you should probably have them move/size themselves proportional to the containing pane. With a layout manager, assuming they are inside their own JPanel, the pane should scale automatically, so when the window is resized, the shapes will resize and move properly.