Develop Reference

Image.getScaledInstance() doesn't work

I would like scale image. I am trying use getScaledInstance() method by doesn't work for me. Image which I write is the same size as the funniest...
It is my code:
Image image = ImageIO.read(file.getInputStream());
image.getScaledInstance(100, -1, Image.SCALE_SMOOTH);
BufferedImage bImage = (BufferedImage) image;
ImageIO.write(bImage, "jpg", new File(urlImage));

Image.getScaledInstance() returns an instance of the same image, scaled to the desired size without modifying your existing image. Assuming you are trying to save the scaled instance to file, you merely need to move the call to the line below.
E.g:
Image image = ImageIO.read(file.getInputStream());
BufferedImage bImage = (BufferedImage) image.getScaledInstance(100, -1, Image.SCALE_SMOOTH);
ImageIO.write(bImage, "jpg", new File(urlImage));

How to convert Image into BufferedImage

Right now I have an image and I want to convert it into a BufferedImage...
This is my code -
private BufferedImage toBufferedImage(Image img, int width, int height){
// Create a buffered image with transparency
BufferedImage bimage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
// Draw the image on to the buffered image
Graphics bGr = bimage.getGraphics();
bGr.drawImage(img, 0, 0, null);
bGr.dispose();
// Return the buffered image
return bimage;
}
But it doesn't work. Can someone explain what's wrong?

Try the new JRE that includes JavaFX.
You could use SwingFXUtils. There is a method which does what you ask for:
BufferedImage image = SwingFXUtils.fromFXImage(fxImage, null);
or
BufferedImage image = ImageIO.read(new File(filename));

BufferedImage extends Image, so you can cast it:
BufferedImage buffered = (BufferedImage) image;
But you must check the type of your image object in runtime, because it can contain other kind of Image.
UPDATE
To convert an Image to a BufferedImage you should check this class and try it:
http://www.dzone.com/snippets/converting-images

Convert imagicon to image

I need to convert an ImageIcon into an Image for a program how should I go about doing it? I there a method of casting I can use or a built in method to do it?

Building on the answer from the question I linked. I'm not sure which Image you mean, save it as a file or get a java Image instance, but you can use just the second method if you mean the latter, or use the former (which depends on the latter) if you need that.
// format should be "jpg", "gif", etc.
public void saveIconToFile(ImageIcon icon, String filename, String format) throws IOException {
BufferedImage image = iconToImage(icon);
File output = new File(filename);
ImageIO.write(bufferedImage, format, outputfile);
}
public BufferedImage iconToImage(ImageIcon icon) {
BufferedImage bi = new BufferedImage(
icon.getIconWidth(),
icon.getIconHeight(),
BufferedImage.TYPE_INT_ARGB);
Graphics g = bi.createGraphics();
// paint the Icon to the BufferedImage.
icon.paintIcon(null, g, 0,0);
g.dispose();
return bi;
}

Grab image from clipboard on Mac OSX using applet

I am using an Applet to save image from clipboard. The image is saved but something happened with its format. It is darken and lost colors.
here's how I am doing it:
AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
try {
//create clipboard object
Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
//Get data from clipboard and assign it to an image.
//clipboard.getData() returns an object, so we need to cast it to a BufferdImage.
BufferedImage image = (BufferedImage) clipboard.getData(DataFlavor.imageFlavor);
//file that we'll save to disk.
File file = new File("/tmp/clipboard.jpg");
//class to write image to disk. You specify the image to be saved, its type,
// and then the file in which to write the image data.
ImageIO.write(image, "jpg", file);
//getData throws this.
} catch (UnsupportedFlavorException ufe) {
ufe.printStackTrace();
return "Não tem imagem na área de transferência";
} catch (Exception ioe){
ioe.printStackTrace();
}
return null;
}
}
);
I read that Mac uses a different image format but I did not find how to convert it to a format I could save. I imagined that java should have taken care of that.
So, how can I convert the image from clipboard to jpg?
PS. I tried using png instead of jpg, got a worse result: black image

To solve the issue on Mac, I used the solution proposed on The nightmares of getting images from the Mac OS X clipboard using Java.
I pass the retrieved BufferedImage to method that redraws it to new BufferedImage, returning a valid image. Here follows the code from that page:
public static BufferedImage getBufferedImage(Image img) {
if (img == null) return null;
int w = img.getWidth(null);
int h = img.getHeight(null);
// draw original image to thumbnail image object and
// scale it to the new size on-the-fly
BufferedImage bufimg = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = bufimg.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2.drawImage(img, 0, 0, w, h, null);
g2.dispose();
return bufimg;
}
And how I use it:
Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
//Get data from clipboard and assign it to an image.
//clipboard.getData() returns an object, so we need to cast it to a BufferdImage.
BufferedImage image = (BufferedImage) clipboard.getData(DataFlavor.imageFlavor);
if (isMac()) {
image = getBufferedImage(image);
}

PNG is the preferred image format for Macs. You might want to try saving as that and then converting to a JPG if needed afterwards.

How can I create an image with Java?

I would like to create a gif image of a filled red circle on a green background. What is the easiest way to do it in Java?

If you already have an image file or image URL, then you can use Toolkit to get an Image:
Image img = Toolkit.getDefaultToolkit().createImage(filename);
If you need to construct a new image raster and paint into the image, then you can use BufferedImage. You can paint onto a BufferedImage, by calling its createGraphics function and painting on the graphics object. To save the BufferedImage into a GIF, you can use the ImageIO class to write out the image.

The best way is to generate a BufferedImage:
BufferedImage img = new BufferedImage(int width, int height, int imageType)
// you can find the Types variables in the api
Then, generated the Graphics2D of this image, this object allows you to set a background and to draw shapes:
Graphics2D g = img.createGraphics();
g.setBackground(Color color) ; //Find how to built this object look at the java api
g.draw(Shape s);
g.dispose(); //don't forget it!!!
To built the image:
File file = new File(dir, name);
try{
ImageIO.write(img, "gif", file);
}catch(IOException e){
e.printStackTrace();
}

Create a BufferedImage and then write it to a file with ImageIO.write(image, "gif", fileName).