JavaFX ImageIO.write() doesn't save modified BufferedImage

Question

I'm trying to create an application that lets users modify pictures and then save them. I'm having trouble with the saving part.

This is the method that rotates the picture:

public void process(ImageView imageView) {
    if(imageView.getImage() != null){
        BufferedImage img;
        img = Home.img;
        double rads = Math.toRadians(90);
        double sin = Math.abs(Math.sin(rads)), cos = Math.abs(Math.cos(rads));
        int w = img.getWidth();
        int h = img.getHeight();
        int newWidth = (int) Math.floor(w * cos + h * sin);
        int newHeight = (int) Math.floor(h * cos + w * sin);

        BufferedImage rotated = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2d = rotated.createGraphics();
        AffineTransform at = new AffineTransform();
        at.translate((newWidth - w) / 2, (newHeight - h) / 2);

        int x = w / 2;
        int y = h / 2;

        at.rotate(rads, x, y);
        g2d.setTransform(at);
        g2d.drawImage(img, 0, 0,null);
        g2d.dispose();
        imageView.setImage(convertToFxImage(rotated));
        Home.img = rotated;
    }
}

It sets the image in the Home controller class's imageView and also sets a static field to the modified image. Then I try to save it inside the Home class:

savAs.setOnAction(new EventHandler<ActionEvent>() {
        @Override
        public void handle(ActionEvent actionEvent) {
            File dir = fileChooser.showSaveDialog(opButton.getScene().getWindow());
            if (dir != null) {
                try {
                    ImageIO.write(img, dir.getAbsolutePath().substring(dir.getAbsolutePath().length() - 3), dir);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    });

This for some reason doesn't work. No IOException is thrown, but it doesn't create any file. When I try to save without modifying the image it works. Any idea why?

Answer 1

The method in ImageIO you call is specified below and it returns a boolean status code that you ignore:

public static boolean write(RenderedImage im,
                            String formatName,
                            File output) throws IOException

You haven't included details of the File so there is no way of telling if you have passed in a valid formatName which you derive from the last three characters of the output filename. Note that formatName isn't always 3 characters and should be lowercase - so both "FILE.JPG" and "FILE.JPEG" may fail to save.

If you believe the file extension is correct and is supported by the BufferedImage.TYPE_INT_ARGB format you've used, try change to use lowercase format, then check the result:

String format = dir.getAbsolutePath().substring(dir.getAbsolutePath().length() - 3).toLowerCase();
boolean ok = ImageIO.write(img, format, dir);
if (!ok)
    throw new RuntimeException("Failed to write "+format+" to " + dir.getAbsolutePath());

If the BufferedImage format isn't compatible with the file extension, try using new BufferedImage(... , BufferedImage.TYPE_INT_RGB) or a different format type (eg PNG).