【java/image】使用梯度表的方式对图像进行反色处理

【需求】

从通达信截取的K线图是黑底白色，需要进行反色处理，再由打印机打印出来。

【代码】

package test240313;

import java.awt.image.BufferedImage;
import java.awt.image.ByteLookupTable;
import java.awt.image.LookupOp;
import java.io.File;

import javax.imageio.ImageIO;

/**
 * 将单张图像进行反色处理
 *
 */
public class ImageTest2 {
    public static void main(String[] args) throws Exception {
        // 读png文件
        File inFile = new File("C:\\Users\\ufo\\Desktop\\2024-03-13_210728.png");
        BufferedImage img = ImageIO.read(inFile);

        BufferedImage inversedImg = inverseColor(img);

        // 写入新文件
        File outFile = new File("C:\\Users\\ufo\\Desktop\\2.png");
        ImageIO.write(inversedImg, "png", outFile);
    }
    
    /**
     * 返回反色处理后的新图像
     * @param image
     * @return
     */
    public static BufferedImage inverseColor(BufferedImage image) {
        byte reverse[] = new byte[256];
        for (int j = 0; j < 256; j++) {
            reverse[j] = (byte) (255 - j);
        }

        ByteLookupTable blut = new ByteLookupTable(0, reverse);
        BufferedImage bimg = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_RGB);
        LookupOp lop = new LookupOp(blut, null);
        lop.filter(image, bimg);

        return bimg;
    }
}

【参考资料】

https://www.jianshu.com/p/6b2bbf95aee0

END