Why is the following bit of code returns Height: -1 which means that the height is yet not known. How to get height of the image?
try {
// Create a URL for the image's location
URL url = new URL("http://bmw-2006.auto-one.co.uk/wp-content/uploads/bmw-m3-2006-3.jpg");
// Get the image
java.awt.Image image = Toolkit.getDefaultToolkit().createImage(url);
System.out.println("Height: " + image.getHeight(null));
} catch (MalformedURLException e) {
} catch (IOException e) {
}
Use ImageIO.read(URL) or ImageIO.read(File) instead. It will block while loading, and the image width & height will be known after it returns.
E.G.
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.imageio.ImageIO;
import java.net.URL;
class SizeOfImage {
public static void main(String[] args) throws Exception {
URL url = new URL("https://i.stack.imgur.com/7bI1Y.jpg");
final BufferedImage bi = ImageIO.read(url);
final String size = bi.getWidth() + "x" + bi.getHeight();
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JLabel l = new JLabel(
size,
new ImageIcon(bi),
SwingConstants.RIGHT );
JOptionPane.showMessageDialog(null, l);
}
});
}
}
Alternately, add a MediaTracker to the image being loaded asynchronously by the Toolkit and wait until it is completely loaded.
You want something like this:
try {
// Create a URL for the image's location
URL url = new URL("http://bmw-2006.auto-one.co.uk/wp-content/uploads/bmw-m3-2006-3.jpg");
// Get the image
Image image = ImageIO.read(url);
System.out.println("Height: " + image.getHeight(null));
}
catch(MalformedURLException e) {
e.printStackTrace();
}
catch(IOException e) {
e.printStackTrace();
}
The java.awt.Toolkit approach won't block, so will return -1 and notify the observer (or not in your case because it's null) when it is loaded. If you do want it asynchronously then you'll need to provide a callback in the form of an image observer.
Oh, and don't just ignore exceptions, at least print the stack trace!
Because the image is loaded asynchronously, in the background.
As the getHeight() javadoc says, you need to provide an ImageObserver (instead of null), which is called when the image has been loaded.
Toolkit#createImage(...) is non-blocking. Generally I would rather use javax.imageio.ImageIOto read images.
To wait for the Toolkit#createImage(...), use:
MediaTracker mediaTracker = new MediaTracker(component);
mediaTracker.addImage(image);
try {
mediaTracker.waitForAll();
} catch (InterruptedException e) {
e.printStackTrace();
}
After that, you can call image.getHeight()
createImage runs in background to load the Image.
use a MediaTracker to wait for the loading and then use getHeight (and use a valid ImageObserver to prevent errors)
Related
JPanel with 3 JButton and I need only two of them to be captured...
public static void grabScreenShot(JPanel panel) {
BufferedImage image = (BufferedImage) panel.createImage(
panel.getSize().width, panel.getSize().height);
panel.paint(image.getGraphics());
File file = null;
file = new File("Customers");
if (!file.exists()) {
file.mkdir();
}
try {
file = new File("Customers" + File.separator
+ String.valueOf(System.currentTimeMillis()));
ImageIO.write(image, "png", file);
System.out.println("Image was created");
} catch (IOException e) {
System.out.println("Had trouble writing the image.");
e.printStackTrace();
}
}
How to avoid unnecessary components to be captured.?
You can try to override paintComponent() of the buttons and introduce a flag needPaint. The flag is true by default.
if (needPaint) {
super.paintComponent(g);
}
In your grabScreenShot() set the flag to false for the button to be hidden and reset it back after panel.paint(image.getGraphics()); call
I want to display different images in a same frame within a loop. String pathName[] contains the different paths of the images. When running this code, only last image i.e image at path pathname[last] is getting displayed on frame instead I want all images to be displayed in a continuous way (have given delay of 1sec ). Help is appreciated.
public void actionPerformed(ActionEvent event) {
int i=0;
while(i<5){
if(i>0){
Container labelParent = receiverImageLabel.getParent();
labelParent.remove(receiverImageLabel);
labelParent.validate();
labelParent.repaint();
}
try {
imageR = ImageIO.read(new File(pathName[i++])).getScaledInstance(512,512 , BufferedImage.SCALE_SMOOTH);
receivedImage = new ImageIcon(imageR);
}catch (IOException e) {
e.printStackTrace();
}
receiverImageLabel = new JLabel(receivedImage);
receiverFrame.getContentPane().add(BorderLayout.EAST,receiverImageLabel);
receiverFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
receiverFrame.setSize(800,700);
receiverFrame.setVisible(true);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
Your problem is a common one: you're calling Thread.sleep(...) in a Swing GUI on the event thread and are essentially thus putting the entire GUI to sleep.
Solution: Google the Swing Timer and use this in place of your while loop/Thread.sleep(...)
Also, if the images aren't too big, then consider reading them all in at once (in a background thread), putting them into ImageIcons, and then swapping out a JLabel's ImageIconsand in your Swing Timer.
For example, you could do something like:
ImageIcon[] icons = new ImageIcon[IMAGE_COUNT];
for (int i = 0; i < IMAGE_COUNT; i++) {
BufferedImage img = ImageIO.read(...); // read in the appropriate image
// ...... here manipulate the image if desired such as re-size it
icons[i] = new ImageIcon(img); // put it into an icon
}
elsewhere:
int timerDelay = 1000;
new Timer(timerDelay, new ActionListener(){
int count = 0;
#Override
public void actionPerformed(ActionEvent e) {
if (count < IMAGE_COUNT) {
someLabel.setIcon(icons[count]);
count++;
} else {
// stop the timer
((Timer)e.getSource()).stop();
}
}
}).start();
Note: code not compiled nor tested and is posted only as a general example of steps to consider.
i am trying to load image from specified path, and list of files are stored inside List<>.
at first time when i initialize image it display but when i am trying to display next image from List instance which contain list of files, it doesn't repaint the image.
what's wrong going is i am initializing image in constructor first time that overwrite
the new image, now where to initialize image first time outside constructor i don't know.
my code :
public void nextImage(int cnt)
{
System.out.println(cnt);
if (cnt < imageFiles.size())
{
System.out.println(imageFiles.size());
try
{
bg = ImageIO.read(new File((imageFiles.get(cnt)).toString()));
scaled = getScaledInstanceToFit(bg, new Dimension(600, 600));
setBackground(Color.BLACK);
}
catch(Exception e)
{
e.printStackTrace();
}
}
MouseHandler handler = new MouseHandler();
addMouseListener(handler);
addMouseMotionListener(handler);
System.out.println(cnt);
System.out.println(imageFiles.get(cnt).toString());
}
menu item click code :
JMenuItem mntmRestoreImage = new JMenuItem("Next Image");
final ImagePane st = new ImagePane();
mntmRestoreImage.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent arg0)
{
st.nextImage(k);
k++;
}
});
mnEdit.add(mntmRestoreImage);
class code & constructor :
private BufferedImage bg;
private BufferedImage scaled;
java.util.List<Path> imageFiles= getFilesFromDirectory(FileSystems.getDefault().getPath("D:\\New folder"));
public ImagePane()
{
try
{
bg = ImageIO.read(getClass().getResource("/images/src11.jpg"));
scaled = getScaledInstanceToFit(bg, new Dimension(600, 600));
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
counter also increments, now the code inside ImagePane() constructor
overwrites the image of nextImage() function, so idea what happen out
in this code ??
any suggestion ?
I think I have the perfect solution for you! I wrote a little program for you so it is easier to understand.
First I have a method for you to check if the file is a picture:
public Stack<File> getFilesInFolder(String startPath) {
File startFolder = new File(startPath);
Stack<File> picturestack = new Stack<File>();
String extension;
int dotindex;
// Go through the folder
for (File file : startFolder.listFiles()) {
extension = "";
dotindex = file.getName().lastIndexOf('.'); // Get the index of the dot in the filename
if (dotindex > 0) {
extension = file.getName().substring(dotindex + 1);
// Iterate all valid file types and check it
for (String filetype : validpicturetypes) {
if (extension.equals(filetype)) {
picturestack.add(file);
}
}
}
}
return picturestack;
}
Very easy! Take the folder and iterate his files. Take the extension of the file and check if it is a valid file type. Define the file types in a array at the begining of your code.
String[] validpicturetypes = {"png", "jpg", "jpeg", "gif"};
At the end I push every file into a stack. Remember to fill the stack into a variable, do not read the files more than once because than you get the same problem as before:
Stack<File> pictures = getFilesInFolder("C:\\Users\\Admin\\Desktop");
After that use a Action for your JMenuItem! In my example I do not have much, you have to put your methods in!
Action nextpictureaction = new AbstractAction("Next Picture") {
private static final long serialVersionUID = 2421742449531785343L;
#Override
public void actionPerformed(ActionEvent e) {
if (!pictures.isEmpty()) {
System.out.println(pictures.pop().getName());
}
}
};
Add the Action at your JMenu and set the properties of your Frame.
/*
* Add Components to Frame
*/
setJMenuBar(menubar);
menubar.add(toolsmenu);
toolsmenu.add(nextpictureaction);
/*
* Frame Properties
*/
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationByPlatform(true);
setSize(1000, 700);
setTitle("PictureEditor");
setVisible(true);
At the end execute your program with the invokeLater method!
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
new PictureEditor();
}
});
}
Summary
Basically you need a somthing to iterate through because values like integer are not saved the way you like. In my example I used a Stack and save at the beginning all pictures in it. Important is that, if you used or finished with the picture, you have to remove it (use stack.pop() for a Stack). I do not found a method where you check if the file is a picture (if it is the ImageIO catch it is bad). I wrote a method for that if you want you could use it.
This is not an answer, but I cannot paste that much code into a comment.
I would change your code to something along the lines of this piece of code. This seperates the image loading from the gui updating logic (like adding mousehandlers and the like, I pasted only image loading code).
import java.awt.Dimension;
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.Arrays;
import java.util.Iterator;
import javax.imageio.ImageIO;
public class ImageLoader
{
public static class ImageContainer
{
BufferedImage bg = null;
BufferedImage scaled;
}
Iterator<File> imageFiles = Arrays.asList(
new File("D:\\New folder").listFiles()).iterator();
public ImageContainer nextImage(Dimension dimensionToFit) throws Exception
{
ImageContainer c = new ImageContainer();
if (imageFiles.hasNext())
{
File file = imageFiles.next();
//you might not need this, if only images are in this directory
if(file.isDirectory())
return null;
c.bg = ImageIO.read(file);
c.scaled = getScaledInstanceToFit(c.bg, dimensionToFit);
return c;
}
else
return null;
}
private BufferedImage getScaledInstanceToFit(BufferedImage bg,
Dimension dimensionToFit)
{
//do the risizing
}
}
This is not yet optimized though.
I have a program that uses OpenCV to take a picture using your webcam. It works like a charm on windows, yet, it doesn't work on OSx. The Frame where the Webcam view should appear stays empty. And when I take a picture, it just shows a black void, as if it couldnt find the webcam
public void run(){
try {
grabber = new VideoInputFrameGrabber(0);
grabber.start();
while (active) {
IplImage originalImage = grabber.grab();
Label.setIcon(new ImageIcon( originalImage.getBufferedImage() ));
}
grabber.stop();
grabber.flush();
} catch (Exception ex) {
//Logger.getLogger(ChPanel.class.getName()).log(Leve l.SEVERE, null, ex);
}
}
public BufferedImage saveImage(){
IplImage img;
try {
//capture image
img = grabber.grab();
// save to file
File outputfile = new File(Project.getInstance().getFileURLStr() + " capture" + fotoCount++ + ".jpg");
ImageIO.write(img.getBufferedImage(), "jpg", outputfile);
//get file and set it in the project library
BufferedImage ImportFile = ImageIO.read(outputfile);
Project p = Project.getInstance();
MainScreen ms = MainScreen.getInstance();
ImageIcon takenPhoto = new ImageIcon(ImportFile);
p.setNextImage(takenPhoto);
ms.setPanels();
return ImportFile;
} catch (com.googlecode.javacv.FrameGrabber.Exception e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
Does anyone know how to solve this? I suspect something about rights to use the webcam or something like that
grabber = new VideoInputFrameGrabber(0);
Here 0 is specified for Capture device number 0
May be the number 0th device is not available for video capture
Use this code to get the list of devices and number respectively.
import com.googlecode.javacv.cpp.videoInputLib.videoInput;
class Main {
public static void main(String[] args) {
int n=videoInput.listDevices();
for(int i=0;i<n;i++)
{
System.out.println(i+" = "+videoInput.getDeviceName(i));
}
}
}
And then specify the number for that device
grabber = new VideoInputFrameGrabber(1); // 0 or 1 or 2
To interact with webcam I use this library webcam-capture you can easely add openCV dependency with maven. This is a great library
I am working on a JFrame/panel that will contain a button. When the user clicks the button, I want an image (which will be stored in the computer hard disk beforehand) to open on the front screen.
button.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
//here i want a code that will somehow open the image from a given directory
}});
Any suggestions on how to go about this ? I have to tell where the image is stored and trigger a virtual 'double click' for the image to pop up on the front screen. Is that even possible using java to synchronize such computer functions?
I don't know a very short way, but I would use something like this (as qick hack to get an impression):
try {
// this is a new frame, where the picture should be shown
final JFrame showPictureFrame = new JFrame("Title");
// we will put the picture into this label
JLabel pictureLabel = new JLabel();
/* The following will read the image */
// you should get your picture-path in another way. e.g. with a JFileChooser
String path = "C:\\Users\\Public\\Pictures\\Sample Pictures\\Koala.jpg";
URL url = new File(path).toURI().toURL();
BufferedImage img = ImageIO.read(url);
/* until here */
// add the image as ImageIcon to the label
pictureLabel.setIcon(new ImageIcon(img));
// add the label to the frame
showPictureFrame.add(pictureLabel);
// pack everything (does many stuff. e.g. resizes the frame to fit the image)
showPictureFrame.pack();
//this is how you should open a new Frame or Dialog, but only using showPictureFrame.setVisible(true); would also work.
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
showPictureFrame.setVisible(true);
}
});
} catch (IOException ex) {
System.err.println("Some IOException accured (did you set the right path?): ");
System.err.println(ex.getMessage());
}
I think this will work ...
Code:
process = new ProcessBuilder("mspaint","yourFileName.jpeg").start();
This will open your image file with mspaint.....
and also use *Java Advanced Imaging (JAI)*
Try this code
try
{
// the line that reads the image file
BufferedImage image;
// work with the image here ...
image = ImageIO.read(new File("C://Users//Neo//Desktop//arduino.jpg"));
jLabel1.setIcon(new ImageIcon(image));
}
catch (IOException e)
{
// log the exception
// re-throw if desired
}
I'm not sure but try this...
try
{
JLabel picture=new JLabel();
ImageIcon ic=new ImageIcon(Toolkit.getDefaultToolkit().getImage(getClass().getResource("C:\\Users\\Desktop\\xyz.jpg")));
picture.setIcon(ic);
}
catch(Exception)
{
}