import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
 
public class ColorToGrayImage {
 
    // 轉換彩色圖像為灰度圖像
    public static BufferedImage convertToGray(BufferedImage colorImage) {
        int width = colorImage.getWidth();
        int height = colorImage.getHeight();
        
        // 創(chuàng)建新的灰度圖像
        BufferedImage grayImage = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
 
        // 遍歷每個像素并進行灰度轉換
        for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                // 獲取原圖像的RGB值
                int rgb = colorImage.getRGB(x, y);
                
                // 獲取RGB各個通道的值
                int red = (rgb >> 16) & 0xFF;
                int green = (rgb >> 8) & 0xFF;
                int blue = rgb & 0xFF;
 
                // 使用灰度轉換公式計算灰度值
                int gray = (int) (0.299 * red + 0.587 * green + 0.114 * blue);
 
                // 創(chuàng)建新的灰度像素值
                int grayRGB = (gray << 16) | (gray << 8) | gray;  // 將灰度值填充到RGB的每個通道
 
                // 設置灰度圖像的對應像素值
                grayImage.setRGB(x, y, grayRGB);
            }
        }
 
        return grayImage;
    }
 
    // 保存灰度圖像
    public static void saveImage(BufferedImage image, String outputPath) throws IOException {
        ImageIO.write(image, "PNG", new File(outputPath));
    }
 
    public static void main(String[] args) {
        try {
            // 加載彩色圖像
            File inputFile = new File("color_image.jpg");
            BufferedImage colorImage = ImageIO.read(inputFile);
 
            // 將彩色圖像轉換為灰度圖像
            BufferedImage grayImage = convertToGray(colorImage);
 
            // 保存灰度圖像
            saveImage(grayImage, "gray_image.png");
 
            System.out.println("圖像已成功轉換為灰度圖并保存為 gray_image.png");
 
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}