jpg并未被image.write()覆盖

Question

我已经进行了以下示例，我不知道为什么它不起作用。

• 我的任何支票都没有返回false，
• 我已经阅读并写了权限，
• Imageio回答说它实际上已经覆盖了图像，
• 没有例外...

但是图像在磁盘上仍未更改。

import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.JFileChooser;
import javax.swing.filechooser.FileNameExtensionFilter;
public class example
{
    public static void main(String[] args)
        {
            try
                {
                    // load a jpg file
                    File imageFile = getFile();
                    // Make a Buffered Image from it
                    BufferedImage img = ImageIO.read(imageFile);
                    // for every pixel in the image
                    for (int x = 0; x < img.getWidth(); x++)
                        for (int y = 0; y < img.getHeight(); y++)
                            // check if the RGB integer is an odd number
                            if (img.getRGB(x, y) % 2 != 0)
                                // make it an even number if it is odd (the OCD god demands it!)
                                img.setRGB(x, y, img.getRGB(x, y) - 1);
                    // Write the OCD friendly version to the file
                    System.out.println("Was overwritten: " + ImageIO.write(img, "jpg", imageFile));
                    System.out.println();
                    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                    // Select the same file again
                    imageFile = getFile();
                    // Make the bufferedImage from it
                    img = ImageIO.read(imageFile);
                    // for every pixel in the image
                    for (int x = 0; x < img.getWidth(); x++)
                        for (int y = 0; y < img.getHeight(); y++)
                            // check if the RGB integer is an odd number
                            if (img.getRGB(x, y) % 2 != 0)
                                {
                                    // Report the failing
                                    System.out.println("It didn't work :(");
                                    // Stop the loop
                                    x = img.getWidth();
                                    y = img.getHeight();
                                }
                }
            catch (Exception e)
                {
                    e.printStackTrace();
                }
        }
    public static File getFile()
        {
            // set up a file chooser that only accepts jpgs
            JFileChooser chooser = new JFileChooser();
            chooser.setFileFilter(new FileNameExtensionFilter("JPG Images only", "jpg"));
            // This will represent our loaded file
            File imageFile = null;
            // Select a file
            chooser.showOpenDialog(null);
            imageFile = chooser.getSelectedFile();
            // Check we can do stuff to this file
            System.out.println("Exists: " + imageFile.exists());
            System.out.println("Can Read: " + imageFile.canRead());
            System.out.println("Can Write: " + imageFile.canWrite());
            System.out.println();
            return imageFile;
        }
}

Answer 1

它被覆盖了，您只是不会在视觉上检测到
眼睛。那是因为您将RGB值更改为1。

for (int x = 0; x < img.getWidth(); x++)
    for (int y = 0; y < img.getHeight(); y++)
        // check if the RGB integer is an odd number
        if (img.getRGB(x, y) % 2 != 0)
            // make it an even number if it is odd (the OCD god demands it!)
            img.setRGB(x, y, 0); /// A ///

像我一样更改此行/// A ///，您会看到它被覆盖了。

当然，这也取决于您正在测试的图片。
如果img.getRGB(x, y)永远不会奇怪，则img.setRGB将永远不会执行。