Change a color in an image

Question

I am using getPixel() and setPixel() to process the whole image to change one of the colors, is there more efficient way to do that with 2D or Jai?
thanks.

Answer 1

Use java.awt.image.ImageFilter. My example code converts a colour image to greyscale, but you can easily change that to check for the colour you're interested in and otherwise return rgb.
Image img, out_img;
// Code to set up img here
// Get an image producer for the image
ImageProducer ip = img.getSource();
// Construct a suitable filter
RGBImageFilter filter = new RGBImageFilter()
    boolean canFilterIndexColorModel = true;
    public int filterRGB(int x, int y, int rgb)
        // Extract the individual fields
        int red = ((rgb & 0x00ff0000) >> 16);
        int green = ((rgb & 0x0000ff00) >> 8);
        int blue = (rgb & 0x000000ff);
        // Get the HSB equivalent values
        float[] hsb;
        hsb = Color.RGBtoHSB(red, green, blue, null);
        // Use the brightness to code up a grey
        int return_value = Color.HSBtoRGB(0.0f,
                                          0.0f,
                                          hsb[2]);
        return return_value;
// Create an image producer for the filtered image
ImageProducer filt_ip = new FilteredImageSource(ip,
                                                filter);
// Produce the output image
out_img = getToolkit().createImage(filt_ip);