Image transcoding (JPEG to PNG) with Java

Question

In my Java application I would like to download a JPEG, transfer it to a PNG and do something with the resulting bytes.

I am almost certain I remember a library to d

Answer 1

ImageIO can be used to load JPEG files and save PNG files (also into a ByteArrayOutputStream if you don't want to write to a file).

Answer 2

javax.imageio should be enough. Put your JPEG to BufferedImage, then save it with:

File file = new File("newimage.png");
ImageIO.write(myJpegImage, "png", file);

Answer 3

This is what I ended up doing, I was thinking toooo far outside of the box when I asked the question..

// these are the imports needed
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import java.io.ByteArrayOutputStream;

// read a jpeg from a inputFile
BufferedImage bufferedImage = ImageIO.read(new File(inputFile));

// write the bufferedImage back to outputFile
ImageIO.write(bufferedImage, "png", new File(outputFile));

// this writes the bufferedImage into a byte array called resultingBytes
ByteArrayOutputStream byteArrayOut = new ByteArrayOutputStream();
ImageIO.write(bufferedImage, "png", byteArrayOut);
byte[] resultingBytes = byteArrayOut.toByteArray();

Answer 4

BufferedImage bufferGambar;
try {

    bufferGambar = ImageIO.read(new File("ImagePNG.png"));
    // pkai type INT karna bertipe integer RGB bufferimage
    BufferedImage newBufferGambar = new BufferedImage(bufferGambar.getWidth(), bufferGambar.getHeight(), BufferedImage.TYPE_INT_RGB);

    newBufferGambar.createGraphics().drawImage(bufferGambar, 0, 0, Color.white, null);
    ImageIO.write(newBufferGambar, "jpg", new File("Create file JPEG.jpg"));

    JOptionPane.showMessageDialog(null, "Convert to JPG succes YES");

} catch(Exception e) {
    JOptionPane.showMessageDialog(null, e);
}