Basic JPEG image resizing in Java


/* JpegResizerDemo.java */

import java.io.FileInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.awt.image.RescaleOp;
import java.awt.image.AffineTransformOp;
import java.awt.geom.AffineTransform;

import java.util.Map;
import java.util.HashMap;

import com.sun.image.codec.jpeg.JPEGImageDecoder;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.ImageFormatException;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

/**
* @author CyranoVR
*/
public class ImageResizer {

public static void main(String args[]) {

if (args.length != 3) {
System.out.println("Usage: ImageResizer <input> <output>
<scale>");
System.exit(0);
}

String inFile = args[0];
String outFile = args[1];

FileInputStream fs = null;

try {

float scale = Float.parseFloat(args[2]);

fs = new FileInputStream(inFile);
JPEGImageDecoder decoder = JPEGCodec.createJPEGDecoder(fs);
BufferedImage srcImg = decoder.decodeAsBufferedImage();
fs.close();

AffineTransform af =
AffineTransform.getScaleInstance(scale, scale );

Map hints = new HashMap();
hints.put(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
RenderingHints rh = new RenderingHints(hints);

AffineTransformOp transform = new AffineTransformOp(af,rh);

BufferedImage destImg =
transform.createCompatibleDestImage(srcImg, srcImg.getColorModel());
transform.filter(srcImg, destImg);

FileOutputStream out = new FileOutputStream(outFile);

JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out,
JPEGCodec.getDefaultJPEGEncodeParam(destImg));

encoder.encode(destImg);
out.close();
System.out.println("Saved file " + outFile);

} catch (FileNotFoundException fnfe ) {
System.out.println("File " + inFile + " does not exist!");

} catch (NumberFormatException nfe){
System.out.println("You entered " + args[2] + ". Please
enter a decimal expression.");

} catch (IOException ioe) {
System.out.println("IO Exception: " + ioe.getMessage());

} catch (ImageFormatException ife) {
System.out.println("Image Format Excpetion: Could not
decode " + inFile);

} catch (Exception e) {
System.out.println(e.getMessage());

} finally {
try {
if(fs != null)
fs.close();
} catch (Exception e) {
System.err.println(e.getMessage());
}
}
}
}

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