Converting transparent gif / png to jpeg using java

Question

I\'d like to convert gif images to jpeg using Java. It works great for most images, but I have a simple transparent gif image:

Input gif image http://img292.imagesha

Answer 1

3 months late, but I am having a very similar problem (although not even loading a gif, but simply generating a transparent image - say, no background, a colored shape - where when saving to jpeg, all colors are messed up, not only the background)

Found this bit of code in this rather old thread of the java2d-interest list, thought I'd share, because after a quick test, it is much more performant than your solution:

        final WritableRaster raster = img.getRaster();
        final WritableRaster newRaster = raster.createWritableChild(0, 0, img.getWidth(), img.getHeight(), 0, 0, new int[]{0, 1, 2});

        // create a ColorModel that represents the one of the ARGB except the alpha channel
        final DirectColorModel cm = (DirectColorModel) img.getColorModel();
        final DirectColorModel newCM = new DirectColorModel(cm.getPixelSize(), cm.getRedMask(), cm.getGreenMask(), cm.getBlueMask());

        // now create the new buffer that we'll use to write the image
        return new BufferedImage(newCM, newRaster, false, null);

Unfortunately, I can't say I understand exactly what it does ;)