This is a very simple problem to some people I'm assuming and I just can't see it. (I'm very amateur at Java).
This is some test code I wrote to try and troubleshoot why it's not working in my other project. For some reason my rocketshipStationary.png just won't show up when I load the Java Applet.
This is my code:
public class Test extends Applet {
public Image offScreen;
public Graphics d;
public BufferedImage rocketship;
public void init() {
setSize(854, 480);
offScreen = createImage(854,480);
d = offScreen.getGraphics();
try {
rocketship = ImageIO.read(new File("rocketshipStationary.png"));
} catch (IOException e) {
e.printStackTrace();
}
}
public void paint(Graphics g) {
d.clearRect(0, 0, 854, 480);
d.drawImage(rocketship, 100, 100, this);
d.drawImage(offScreen, 0, 0, this);
}
}
You should be getting a nice big stack trace that describes what happens. The bottom line is that 'applets and files do not play well together'.
Instead, either establish an URL to the image and use that for ImageIO, or alternately use the URL in the Applet.getImage(URL) method.
Related
jWindow opened for 2 seconds but image doesn't paint... any thoughts?
image file is in the same folder as class file...
public class CreateSplashScreen extends JWindow {
JWindow jw = new JWindow();
Image scImage = Toolkit.getDefaultToolkit().getImage("testImage.png");
ImageIcon imageIcon = new ImageIcon(scImage);
public CreateSplashScreen() {
try {
jw.setSize(700, 500);
jw.setLocationRelativeTo(null);
jw.setVisible(true);
} catch (Exception e) {
}
}
public void paint(Graphics g) {
super.paint(g);
g.drawImage(scImage, 0, 0, jw);
}
public void CloseSplashScreen() {
jw.setVisible(false);
}
public static void main(String[] args) {
CreateSplashScreen sp = new CreateSplashScreen();
try {
Thread.sleep(2000);
} catch (InterruptedException ex) {
Logger.getLogger(CreateSplashScreen.class.getName()).log(Level.SEVERE, null, ex);
}
sp.CloseSplashScreen();
}
}
jWindow opened for 2 seconds but image doesn't paint... any thoughts?
image file is in the same folder as class file...
Why are you creating an internal JWindow when your class CreateSplashScreen already extends JWindow?
There is no need of it. You are messing with your program.
How?
You are actually viewing the inner JWindow by jw.setVisible(true); but you are painting the image in the CreateSplashScreen's `JWindow.
Try this code :
public class CreateSplashScreen extends JWindow
{
ImageIcon i = new ImageIcon(getClass().getResource("/createsplashscreen/testImage.png"));
public CreateSplashScreen() {
setSize(700, 500);
setLocationRelativeTo(null);
setVisible(true);
}
#Override
public void paint(Graphics g) {
super.paint(g);
g.drawImage(i.getImage(), 0, 0, null);
}
public void CloseSplashScreen() {
setVisible(false);
}
public static void main(String[] args) {
CreateSplashScreen sp = new CreateSplashScreen();
try {
Thread.sleep(2000);
} catch (InterruptedException ex) {
}
sp.CloseSplashScreen();
}
}
Note: I do not know about your method to fetch image resource from the source folder.
Edit: Assuming that the name of the package containing your class CreateSplashScreen is createsplashscreen, make sure that the image testImage.png is present in the createsplashscreen package of your project.
#Peter
For error code, I deleted one line that I added in mamifest.mf file and build a program...
This time, didn't give me an error, weird...
I was following error code when I got it and it led me to something like "CLASSPATH" section of application generated code... sorry I can't remember exactly
Really appreciate Peter for your help.
Wish you luck...
I'm new to programming. I'm trying to write a simple drawing program using java with processing. I need help with making it take a screenshot and save the image.
Here's what I have so far.
void setup(){
size(displayWidth, displayHeight);
background(255,255,255);
}
void keyPressed(KeyEvent SPACE){
background(255,255,255);
}
void draw(){
}
void mouseDragged()
{
strokeWeight(3);
stroke(0,0,0);
line(pmouseX, pmouseY, mouseX, mouseY);
}
I have no idea what you are trying to do with the code you provided with your question although here is how to make a screenshot and save it using Java.
try
{
Rectangle screenResolution = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());
BufferedImage screenshot = new Robot().createScreenCapture(screenResolution);
ImageIO.write(screenshot, "PNG", new File("yourimageoutput.png"));
}
catch(IOException | AWTException error)
{
error.printStackTrace();
}
Here you can see the result:
If you want to change it to for example a 'jpeg' or 'bmp' image you have to change the second parameter of ImageIO.write() and the file extension.
I need some help with painting an Image object upon/inside/on a BufferedImage and then painting that BufferedImage on a JPanel.
I've prepared a small program to illustrate my problem. Just a frame with a panel accompanied by an ImageLoader.
The image is placed in the same folder as the code. The sten Image is painted successfully when just painted, but not when I try painting it with the BufferedImage, which you'll notice if you try to run the program. just create the Test object and the constructor does the rest.
Thanks in advance!
My code:
public class Test extends JFrame{
static class ImageLoader {
public static Image loadImage(String name){
Image img = null;
img = Toolkit.getDefaultToolkit().getImage(ImageLoader.class.getResource(name));
return img;
}
}
class Panel extends JPanel{
Image sten;
BufferedImage bf = new BufferedImage(500,500,BufferedImage.TYPE_INT_RGB);
public Panel(Image sten){
super();
this.sten = sten;
initBF();
}
private void initBF(){
Graphics2D g = (Graphics2D) bf.createGraphics();
g.drawImage(sten, 0,0,this);
}
public void paintComponent (Graphics g)
{
g.drawImage(bf, 100,100,null);
g.drawImage(sten, 0,0,null);
repaint();
}
}
public Test(){
setSize(new Dimension(500, 500));
setEnabled(true);
this.setBounds(50, 150, 500, 500);
setVisible(true);
Image sten = ImageLoader.loadImage("sten.png");;
Panel panel = new Panel(sten);
panel.setBackground(Color.GREEN);
panel.setSize(500, 500);
this.add(panel);
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel.paintComponent(this.getGraphics());
}
}
The problem is that Toolkit.getDefaultToolkit().getImage loads images asychronously so will not be loaded when paintComponent is invoked. Use a MediaTracker to block until the image has been loaded:
public Image loadImage(String name) {
Image img = null;
MediaTracker tracker = new MediaTracker(myPanel); // pass the panel from ctor
img = Toolkit.getDefaultToolkit().getImage(ImageLoader.class.getResource(name));
tracker.addImage(img, 0);
try {
tracker.waitForID(0);
} catch (InterruptedException e) {
e.printStackTrace();
}
return img;
}
or far simpler:
img = ImageIO.read(ImageLoader.class.getResource(name)));
This will eliminate the need to use MediaTracker.
Some notes:
Don't call paintComponent directly, request repaints by invoking repaint.
Don't use getGraphics for custom painting - this uses a transient Graphics reference.
When using a custom Graphics reference, make sure to call Graphics#dispose when finished using the reference.
In addition of Reimeus' aswer, notice that Toolkit.getDefaultToolkit().getImage() is non-blocking, it loads images asynchronously, so at the point when you call g.drawImage(sten, 0,0,this); sten will probably not still actually be loaded (see the doc of the method). See also this (false) bug report.
I am using Jtree for listing various images of a directory, I want to display image on applet when the user click on the image name displayed in the Tree, the code i'm using is as below, ta is an object of the applet because i'm using it in another class.
private void displayImage(URL furl, String fname) {
ta.Picture = ta.getImage(furl, fname);
prepareImage(ta.Picture, this);
Graphics g = ta.imageCanvas.getGraphics();
g.clearRect(10, 10, 800, 800);
g.drawImage(ta.Picture, 10, 10, this);
} // displayImage
public void valueChanged(TreeSelectionEvent e)
{
// TODO Auto-generated method stub
FileTreeNode node = (FileTreeNode) tree.getLastSelectedPathComponent();
System.out.println("slecte asldf " + node.isLeaf());
if (node.isLeaf())
{
currentFile = node.file;
System.out.println("File name " + currentFile.getName());
try
{
URL furl = new URL("file:/F:/photos");
displayImage(furl, currentFile.getName());
}
catch (MalformedURLException mle)
{
System.out.println("Exception::::::" + mle);
}
}
else
currentFile = null;
}
But its not working.
As you are showing files from the local filesystem, working with URLs is not required. Use
displayImage(currentFile);
and rewrite that method as following:
private void displayImage(File file) {
BufferedImage image = ImageIO.read(file);
ta.image = image;
ta.repaint();
}
where the paint method of the (I an assuming) component ta must be like
BufferedImage image;
public void paint(Graphics g) {
g.clearRect(10, 10, 800, 800);
g.drawImage(ta.Picture, 10, 10, this);
}
Because of security reasons, the applet will only be able to access the file system if signed or running without security manager (most often on the same computer).
But its not working.
This is in no way helpful, do you get exceptions? What happens? Please post an SSCCE for better help sooner
I want to display image on applet when the user click on the image
name displayed in the Tree, the code i'm using is as below, ta is an
object of the applet because i'm using it in another class.
IMO you are going about it wrong using the JPanel object and Component#getGraphics.
Dont use Component#getGraphics() as its not good practice and not persistent thus on next call to repaint() the screen will be cleared.
Dont use Applet with Swing components rather use JApplet.
Add a custom JPanel with getters and setters for BufferedImage variable to the container and than override paintComponnet and draw the BufferedImage there.
Now to change the BufferedImage simply call the setter i.e setBackgroundImage(BufferedImage img) and than call repaint() on JPanel to show the changes. Like so:
public class MyPanel extends JPanel {
private BufferedImage bg;
public MyPanel(BufferedImage bi) {
bg=bi;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d=(Graphics2D)g;
g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
g2d.drawImage(bg,0,0,this);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(bg.getWidth(),bg.getHeight());
}
public BufferedImage setBackgroundImage(BufferedImage bi) {
bg=bi;
}
}
Now we use it like so:
MyPanel mp=new MyPanel(...);//create the panel with an image
...
add(mp);//add to container
...
mp.setBackgroundImage(..);//change the image being displayed
mp.repaint();//so the new image may be painted
How do I make an Image show up in a Java Swing Applet?
The simplest way is to add it as an Icon to a JLabel that you put on your GUI.
http://download.oracle.com/javase/6/docs/api/javax/swing/JLabel.html#JLabel(javax.swing.Icon)
Here's an outline of what you need
class myApplet extends JApplet {
private BufferedImage image;
myApplet() {
try {
image = ImageIO.read(new File("insert image path here"));
} catch (IOException ex) {
// handle exception...
}
}
#Override
public void paint(Graphics g) {
g.drawImage(image, 0, 0, null);
}
}