In this article I will show you how to scale an Image in Java.
The simplest way to scale an image in Java is to use the AffineTransformOp class. You can load an image into Java as a BufferedImage and then apply the scaling operation to generate a new BufferedImage. You can use Java’s ImageIO or a third-party image library such as JDeli to load and save the image. We have used JDeli in our example below because it works with all JPEG files and the widest range of filetypes.
Step:1 Load an image file into Java as a BufferedImage
You can load an image file using Java ImageIO (which is built into Java )
BufferedImage image = ImageIO.read(new File("C:\\path\\to\\image.jpg"));
You can also load image files using other open source or commercial libraries. Here is an example using JDeli Image library.
BufferedImage image = JDeli.read(new File("C:\\path\\to\\image.jpg"));
Step:2 Scale the BufferedImage in Java
This code will scale the image by a factor of 2.
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);
final Scale scaler = new Scale(2);
BufferedImage scaledImage= scaler.apply(image);
Step:3 Resave the BufferedImage to a new File
You can save an image file using Java ImageIO (which is built into Java )
ImageIO.write(scaledImage, "JPG", new File("C:\\path\\to\\scaledImage.jpg"));
You can also save image files using other open source or commercial libraries. Here is an example using JDeli Image library.
JDeli.write(scaledImage, "JPG", new File("C:\\path\\to\\scaledImage.jpg"));
And that is all you need to do!!!
More about JDeli
In our examples we show you how to use the built-in Java features with ImageIO. We also include as an alternative code for our own Java Image Library. JDeli is a commercial library which offers a range of advantages over ImageIO and alternatives, including:
- prevents heap related JVM crashes
- implements unsupported image formats
- reduce output file size
- improve read/write performance
- supports threading
- superior image scaling algorithms
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