How to convert an image into a transparent image in java

Question

How to convert a white background of an image into a transparent background? Can anyone tel me how to do this?

Answer 1

The first result from Google is this:

Make a color transparent http://www.rgagnon.com/javadetails/java-0265.html

It makes the Blue part of an image transparent, but I'm sure you can adapt that to use White intstead

(hint: Pass Color.WHITE to the makeColorTransparent function, instead of Color.BLUE)

Found a more complete and modern answer here: http://stackoverflow.com/questions/665406/how-to-make-a-color-transparent-in-a-bufferedimage-and-save-as-png

Answer 2

Here is my solution. This filter will remove the background from any image as long as the background image color is in the top left corner.

private static class BackgroundFilter extends RGBImageFilter{

    boolean setUp = false;
    int bgColor;

    @Override
    public int filterRGB(int x, int y, int rgb) {
        int colorWOAlpha = rgb & 0xFFFFFF;
        if( ! setUp && x == 0 && y == 0 ){
            bgColor = colorWOAlpha;
            setUp = true;
        }
        else if( colorWOAlpha == bgColor )
            return colorWOAlpha;
        return rgb;
    }
}

Elsewhere...

ImageFilter bgFilter = new BackgroundFilter();
ImageProducer ip = new FilteredImageSource(image.getSource(), bgFilter);
image = Toolkit.getDefaultToolkit().createImage(ip);