Load an image, scale it to thumbnail size and save it as JPEG in Java


import com.sun.image.codec.jpeg.*;
import java.awt.*;
import java.awt.image.*;
import java.io.*;

/**
* Thumbnail.java (requires Java 1.2+)
* Load an image, scale it down and save it as a JPEG file.
* @author Marco Schmidt
*/
public class Thumbnail {
public static void main(String[] args) throws Exception {
if (args.length != 5) {
System.err.println("Usage: java Thumbnail INFILE " +
"OUTFILE WIDTH HEIGHT QUALITY");
System.exit(1);
}
// load image from INFILE
Image image = Toolkit.getDefaultToolkit().getImage(args[0]);
MediaTracker mediaTracker = new MediaTracker(new Container());
mediaTracker.addImage(image, 0);
mediaTracker.waitForID(0);
// determine thumbnail size from WIDTH and HEIGHT
int thumbWidth = Integer.parseInt(args[2]);
int thumbHeight = Integer.parseInt(args[3]);
double thumbRatio = (double)thumbWidth / (double)thumbHeight;
int imageWidth = image.getWidth(null);
int imageHeight = image.getHeight(null);
double imageRatio = (double)imageWidth / (double)imageHeight;
if (thumbRatio < imageRatio) { thumbHeight = (int)(thumbWidth / imageRatio); } else { thumbWidth = (int)(thumbHeight * imageRatio); } // draw original image to thumbnail image object and // scale it to the new size on-the-fly BufferedImage thumbImage = new BufferedImage(thumbWidth, thumbHeight, BufferedImage.TYPE_INT_RGB); Graphics2D graphics2D = thumbImage.createGraphics(); graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR); graphics2D.drawImage(image, 0, 0, thumbWidth, thumbHeight, null); // save thumbnail image to OUTFILE BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(args[1])); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); JPEGEncodeParam param = encoder. getDefaultJPEGEncodeParam(thumbImage); int quality = Integer.parseInt(args[4]); quality = Math.max(0, Math.min(quality, 100)); param.setQuality((float)quality / 100.0f, false); encoder.setJPEGEncodeParam(param); encoder.encode(thumbImage); out.close(); System.out.println("Done."); System.exit(0); } }

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