Develop Reference

How to resize image in JAVA to fit a jLabel?

Apparently, this is my code I have been using to get image from my disks to my program.
public void getVehicleImage(){
FileDialog fd = new FileDialog(this);
fd.setFile("*.jpg; *.jpg; *.png; *.gif");
fd.show();
vehicle_path = fd.getDirectory()+fd.getFile();
vehicleFileName.setText(vehicle_path = fd.getFile());
vehicleImagePath.setText(vehicle_path = fd.getDirectory()+fd.getFile());
image.setIcon(new ImageIcon(vehicle_path));
}
How do I fit the image to the size of my jLabel? I have tried using the
getScaledInstance()
but still no good. And also I want to ask if I am using the right code on how to get Image from my disk? I kinda feel it is wrong.

I faced similar problem and did below workaround:
Step1: Read the picture as a BufferedImage from your file system.
BufferedImage image = null;
try {
image = ImageIO.read(new File("fileName.jpg"));
} catch (IOException e) {
e.printStackTrace();
}
Step2: Create a new BufferedImage that is the size of the JLabel
BufferedImage img= image.getScaledInstance(label.width, label.height,
Image.SCALE_SMOOTH);
Step3: Create new ImageIcon from the resized BufferedImage (Step 2)
ImageIcon imageIcon = new ImageIcon(img);
In your case, create a helper method and call it while creating ImageIcon as below:
public void getVehicleImage(){
...................
image.setIcon(new ImageIcon(getScaledImage(vehicle_path)));//call helper here
}
This can be helper function:
public BufferedImage getScaledImage(String imagePath){
BufferedImage image = null;
try {
image = ImageIO.read(new File("fileName.jpg"));
} catch (IOException e) {
e.printStackTrace();
}
BufferedImage img= image.getScaledInstance(label.width, label.height,
Image.SCALE_SMOOTH);
return img;
}

How to grab only selected components image while capturing the JPanel?

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

OpenCV not working correctly on mac

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

How can I get height and width of an image?

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)

How to read OS X *.icns file with Java

I want to read *.icns files in OS X into a BufferedImage. Help

Try this: http://code.google.com/p/appengine-awt/source/browse/trunk/apache-sanselan/src/main/java/org/apache/sanselan/formats/icns/IcnsDecoder.java?spec=svn8&r=8
Which is actually from: http://incubator.apache.org/sanselan/site/index.html

You need to convert ICNS to another image type first, and after load this image you can delete it. This is how to convert PNG to ICNS, so you just need to do in the opposite way:
public static void Png(File png, File icns) throws IOException{
ImageIcon image = new ImageIcon(ImageIO.read(png));
ImageIconAs(image, icns);
}
public static void ImageIconAs(ImageIcon ii, File icns) throws IOException{IconAs((Icon)ii,icns);}
public static void IconAs(Icon icon, File icns) throws IOException{
if (icon != null) {
BufferedImage bi = new BufferedImage(icon.getIconWidth(), icon.getIconHeight(), BufferedImage.TYPE_INT_ARGB );
Graphics2D g = bi.createGraphics();
icon.paintIcon(new Canvas(), g, 0, 0 );
g.dispose();
File outputfile = new File("temp000.png");
ImageIO.write(bi, "png", outputfile);
execTerminal(new String[]{ "sips", "-s", "format", "tiff",
"temp000.png","--out", "temp000.tiff" });
File apaga2 = new File("temp000.png");
apaga2.delete();
execTerminal(new String[]{ "tiff2icns", "-noLarge",
"temp000.tiff", icns.getAbsolutePath()});
File apaga = new File("temp000.tiff");
apaga.delete();
}
}
static void execTerminal(String[] cmd){
int exitCode = 0;
try {
exitCode = Runtime.getRuntime().exec(cmd).waitFor();
}
catch (InterruptedException e) {e.printStackTrace();}
catch (IOException e) {
if (exitCode != 0) System.out.println("ln signaled an error with exit code " + exitCode);
}
}
You just need to use this to call the action:
Png(png_file,icns_file);

You can youse IconManager. It works with following icons formats:
*.ico - Windows Icon
*.icl - Windows Icon Library
*.icns - Macintosh Icon