如何將BufferedImage（RGB）轉換為BufferedImage（ARGB或RGBA）？

Question

我正在嘗試將Robot.createScreenCapture函數產生的RGB圖像轉換為ARGB圖像。 我的目標是在兩個圖像之間的像素沒有變化但我得到黑色的情況下設置透明度。 如下圖所示。

例如，如下創建的BufferedImage：

 BufferedImage currImage = robot.createScreenCapture(new Rectangle(x, y, width,height));

以下功能旨在創建ARGB像素。

private BufferedImage bufferedImagesEqual(BufferedImage prevImage,
        BufferedImage currImage) {
    boolean changed = false;
    BufferedImage imagePart = new BufferedImage(currImage.getWidth(), currImage.getHeight(), BufferedImage.TYPE_INT_ARGB);
    if (prevImage.getWidth() == currImage.getWidth()
            && prevImage.getHeight() == currImage.getHeight()) {

        for (int x = 0; x < currImage.getWidth(); x++) {
            for (int y = 0; y < prevImage.getHeight(); y++) {
                 int argb =  currImage.getRGB(x, y);
                if (prevImage.getRGB(x, y) != currImage.getRGB(x, y)){
                //  return false;
                    //  currImage.setRGB(x, y, 0);
                    if(!changed){
                        changed = true;
                    }
                }
                else {
                    imagePart.setRGB(x, y, 0xff000000);
                }
            }
        }
    } else {
        return imagePart;
    }
    if(changed){
        return imagePart;
    }else {
        return null;
    }
}

Answer 1

從之前和之后的圖像開始...

通過使用new Color(0, 0, 0, 0) 0xff000000 new Color(0, 0, 0, 0)而不是0xff000000 （並在像素相等時繪制SOMETHING），我得到

使用...

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JOptionPane;

public class ConvertBuffer {

    public static void main(String[] args) {
        try {
            BufferedImage before = ImageIO.read(new File("/Before.jpg"));
            BufferedImage after = ImageIO.read(new File("/After.jpg"));

            BufferedImage result = bufferedImagesEqual(before, after);

            JLabel label = new JLabel(new ImageIcon(result));
            label.setOpaque(true);
            label.setBackground(Color.BLUE);
            JOptionPane.showMessageDialog(null, label);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static BufferedImage bufferedImagesEqual(BufferedImage prevImage,
                    BufferedImage currImage) {
        boolean changed = false;
        BufferedImage imagePart = new BufferedImage(currImage.getWidth(), currImage.getHeight(), BufferedImage.TYPE_INT_ARGB);
        if (prevImage.getWidth() == currImage.getWidth()
                        && prevImage.getHeight() == currImage.getHeight()) {

            for (int x = 0; x < currImage.getWidth(); x++) {
                for (int y = 0; y < prevImage.getHeight(); y++) {
                    if (prevImage.getRGB(x, y) != currImage.getRGB(x, y)) {
                //  return false;
                        //  currImage.setRGB(x, y, 0);
                        if (!changed) {
                            changed = true;
                        }
                        imagePart.setRGB(x, y, currImage.getRGB(x, y));
                    } else {
                        imagePart.setRGB(x, y, new Color(0, 0, 0, 0).getRGB());
                    }
                }
            }
        } else {
            return imagePart;
        }
        if (changed) {
            return imagePart;
        } else {
            return null;
        }
    }

}

因此，除非您有示例圖像可玩，否則這是我們能做到的最好的...