Example of an ImageIO transcoder

A transcoder is responsible for converting one particular image type to another and is designed in such a way that metadata specific to that image type is not lost.

The following example outputs all transcoders that are defined for converting gif to jpg. Currently there are none, but since ImageIO is pluggable, third-party transcoders should become available soon.

Main.java:

import javax.imageio.stream.*;
import javax.imageio.*;
import java.util.*;
  
public class Main
{
   public static void main(String []args) {
      Iterator readers = ImageIO.getImageReadersByFormatName("gif");
      ImageReader reader = (ImageReader) readers.next();
 
      Iterator writers = ImageIO.getImageWritersByFormatName("jpg");
      ImageWriter writer = (ImageWriter) writers.next();
 
      Iterator transcoders = ImageIO.getImageTranscoders(reader, writer);
      while (transcoders.hasNext()) {
         ImageTranscoder tc = (ImageTranscoder) transcoders.next();
         System.out.println(tc);
      }
   }
}