从BufferedImage读取像素-颜色值错误

Question

When a spaceship is destroyed I create list containg pixels of spaceship's image. Pixels are objects of my Pixel class. After creating list it's added to main list where various actions are performed on them. This is how my code looks like:

//Code which creates an array
List<Pixel> pixels = new LinkedList<>();
BufferedImage buff = (BufferedImage)image;
for (int px = 0; px < buff.getWidth(); px++) {
    for (int py = 0; py < buff.getHeight(); py++) {
        int rgb = buff.getRGB(px, py);
        int red = (rgb & 0x00ff0000) >> 16;
        int green = (rgb & 0x0000ff00) >> 8;
        int blue = rgb & 0x000000ff;
        int alpha = (rgb >> 24) & 0xff;
        if (alpha == 255) {
            pixels.add(new Pixel(px, py, red, green, blue));
        }
    }
}
//Pixel class constructor
Pixel(float x, float y, int red, int green, int blue) {
    super(x, y);
    BufferedImage buff = new BufferedImage(1, 1, BufferedImage.TYPE_INT_ARGB);
    WritableRaster raster = buff.getRaster();
    //LOOKS EVERYTHING IS OKAY SINCE THIS LINE SO THE ERROR MUST BE SOMEWHERE IN THOSE 2 LINES
    raster.setPixel(0, 0, new int[]{red, blue, green, 255});
    image = buff;
}

Short explanation: image is private field of type Image. It's used in repaint() method which paints pixel using drawImage() method. And about my problem: Eveything works almost okay. Pixels are creating on right position but all are violet-color. They have different tones(brighter and darker) but are all violet instead of having the same colors as image's colors! Why is this happening? Why violet? Could someone help me unserstand this strange behaviour?

Answer 1

It's probably a mixup of green and blue values in your setPixel method. Colors are usually given in RGB order, which is how you unpacked them from your BufferedImage .

Instead of

raster.setPixel(0, 0, new int[]{red, blue, green, 255});

try

raster.setPixel(0, 0, new int[]{red, green, blue, 255});

If that doesn't work you may have to tinker with different variable orders in your array until it looks right.