import java.awt.*;
import java.awt.image.*;
public class GrayscaleImageFilter extends RGBImageFilter {
public GrayscaleImageFilter() {
canFilterIndexColorModel = true;
}
// Convert color pixels to grayscale
// The algorithm matches the NTSC specification
public int filterRGB(int x, int y, int pixel) {
// Get the average RGB intensity
int red = (pixel & 0x00ff0000) >> 16;
int green = (pixel & 0x0000ff00) >> 8;
int blue = pixel & 0x000000ff;
int luma = (int) (0.299 * red + 0.587 * green + 0.114 * blue);
// Return the luma value as the value for each RGB component
// Note: Alpha (transparency) is always set to max (not transparent)
return (0xff << 24) | (luma << 16) | (luma << 8) | luma;
}
}
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