How to resize images in Java (Tutorial)

In this article, I will show you how to change image size of images in Java.

ImageIO allows the reading and writing of images in Java and processing the image. I will also cover image resizing using our JDeli image library.

How to resize an image in ImageIO

1. Create a File handle, InputStream, or URL pointing to the raw image.
2. ImageIO will now be able to read a BMP file into a BufferedImage.
3. Create a second BufferedImage at the new size
4. Create a transformation
5. Apply the transformation

and the Java code to resize an image in ImageIO…

File imageFile = new File("C:\\path\\to\\pdf\\image.tif");

BufferedImage image = ImageIO.read(imageFile);

final int w = image.getWidth();

final int h = image.getHeight();

BufferedImage scaledImage = new BufferedImage((w * 2), (h * 2), BufferedImage.TYPE_INT_ARGB);

final AffineTransform at = AffineTransform.getScaleInstance(2.0, 2.0);

final AffineTransformOp ato = new AffineTransformOp(at, AffineTransformOp.TYPE_BICUBIC);

scaledImage = ato.filter(image, scaledImage);

How to resize an image in JDeli

1. Add JDeli to your class or module path. (download the trial jar).
2. Create a File, InputStream pointing to the raw image. You can also use a byte[] containing the image data.
3. Read the image into a BufferedImage
4. Create a transformation
5. Apply the transformation

and the Java code to resize an image in JDeli…

File imageFile = new File("C:\\path\\to\\pdf\\exampleImage.tif");

BufferedImage image = JDeli.read(imageFile);

ImageProcessingOperations operations = new ImageProcessingOperations();

operations.scale(scalingFactor);

image = JDeli.process(ImageProcessingOperations operations,

BufferedImage image);

// Read an image
BufferedImage bufferedImage = JDeli.read(dicomImageFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(heicImageFile);

// Write an image
JDeli.write(bufferedImage, "heic", outputStreamOrFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(jpegImageFile);

// Write an image
JDeli.write(bufferedImage, "jpeg", outputStreamOrFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(jpeg2000ImageFile);

// Write an image
JDeli.write(bufferedImage, "jpx", outputStreamOrFile);

// Write an image
JDeli.write(bufferedImage, "pdf", outputStreamOrFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(pngImageFile);

// Write an image
JDeli.write(bufferedImage, "png", outputStreamOrFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(tiffImageFile);

// Write an image
JDeli.write(bufferedImage, "tiff", outputStreamOrFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(webpImageFile);

// Write an image
JDeli.write(bufferedImage, "webp", outputStreamOrFile);