Java Tutorial/2D Graphics/JPEG

Encoding an image to a JPEG file

   <source lang="java">

import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.awt.image.PixelGrabber; import java.io.FileOutputStream; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGEncodeParam; import com.sun.image.codec.jpeg.JPEGImageEncoder; public class Main {

 public static void main(String[] args) throws Exception {
   BufferedImage img = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB);
   Graphics g = img.getGraphics();
   g.setColor(Color.red);
   g.setFont(new Font("Arial", Font.BOLD, 14));
   g.drawString("Reference", 10, 80);
   int w = 100;
   int h = 100;
   int x = 1;
   int y = 1;
   
   int[] pixels = new int[w * h];
   PixelGrabber pg = new PixelGrabber(img, x, y, w, h, pixels, 0, w);
   pg.grabPixels();
   BufferedImage bimg = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
   for (int j = 0; j < h; j++) {
     for (int i = 0; i < w; i++) {
       bimg.setRGB(x + i, y + j, pixels[j * w + i]);
     }
   }
   FileOutputStream fout = new FileOutputStream("jpg.jpg");
   JPEGImageEncoder jencoder = JPEGCodec.createJPEGEncoder(fout);
   JPEGEncodeParam enParam = jencoder.getDefaultJPEGEncodeParam(bimg);
   enParam.setQuality(1.0F, true);
   jencoder.setJPEGEncodeParam(enParam);
   jencoder.encode(bimg);
   fout.close();
 }

}</source>

Rescale JPG

   <source lang="java">

import java.awt.Graphics2D; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage; import java.io.File; import javax.imageio.ImageIO; public class Main {

 public static void main(String[] args) throws Exception {
   BufferedImage bsrc = ImageIO.read(new File("a.jpg"));
   BufferedImage bdest = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB);
   Graphics2D g = bdest.createGraphics();
   AffineTransform at = AffineTransform.getScaleInstance(2, 2);
   g.drawRenderedImage(bsrc, at);
   ImageIO.write(bdest, "JPG", new File("b.jpg"));
 }

}</source>