Graphics2D rotate before saving file

Question

I create this image with g2d:

Here is the code:

BufferedImage bufferedImage = new BufferedImage(408, 408, BufferedImage.TYPE_INT_RGB);    
Graphics2D g2d = bufferedImage.createGraphics();
List<Pixel> pixels = cacheRepo.findAll();
pixels.stream().forEach(pixel -> {
    g2d.setColor(getColorFromPixel(pixel));
    g2d.fillRect(getPos(pixel.getPosition().x), getPos(pixel.getPosition().y), 20, 20);
});

Now I am trying to rotate it 90° anticlok so that the bleu square appear on the lower left:

So I add this:

g2d.rotate(Math.toRadians(90));
g2d.drawRenderedImage(bufferedImage, null);

But the rotation doesn't occur (I still have the same image).

Here is the complete piece of code, with the part that save image:

 // Constructs a BufferedImage of one of the predefined image types.
    BufferedImage bufferedImage = new BufferedImage(408, 408, BufferedImage.TYPE_INT_RGB);
    // Create a graphics which can be used to draw into the buffered image
    Graphics2D g2d = bufferedImage.createGraphics();
    List<Pixel> pixels = cacheRepo.findAll();
    pixels.stream().forEach(pixel -> {
        g2d.setColor(getColorFromPixel(pixel));
        g2d.fillRect(getPos(pixel.getPosition().x), getPos(pixel.getPosition().y), 20, 20);
    });
    g2d.rotate(Math.toRadians(90));
    g2d.drawRenderedImage(bufferedImage, null);
    g2d.dispose();
    // Save as PNG
    File file = new File("myimage.png");
    try {
        ImageIO.write(bufferedImage, "png", file);
    } catch (IOException e) {
        e.printStackTrace();
    }

MadProgrammer · Accepted Answer · 2019-01-13T22:58:14.657

Transformations should be applied BEFORE any operations you want to be effected by them, transformations won't affect anything that was done before it...

BufferedImage bufferedImage = new BufferedImage(408, 408, BufferedImage.TYPE_INT_RGB);
// Create a graphics which can be used to draw into the buffered image
Graphics2D g2d = bufferedImage.createGraphics();
g2d.rotate(Math.toRadians(90));
List<Pixel> pixels = cacheRepo.findAll();
pixels.stream().forEach(pixel -> {
    g2d.setColor(getColorFromPixel(pixel));
    g2d.fillRect(getPos(pixel.getPosition().x), getPos(pixel.getPosition().y), 20, 20);
});
//g2d.rotate(Math.toRadians(90));
// Not sure what you're hoping to achieve here
//g2d.drawRenderedImage(bufferedImage, null);
g2d.dispose();

If you prefer, use two BufferedImages. Render the "normal" content to the first, then use the second to paint the first, but with a rotation transformation ... because transformations do my head in

using your code draw a black image

You probably need to supply a anchor point around which the image can be rotated, otherwise it will be rated about the top/left corner

And you'll forgive me, but it's not like this kind of think hasn't been asked before

using your code draw a black image :(... I want to give a try with the "two BufferedImage", but I am not sure how to do it. — Tyvain, Jan 13 '19 at 22:35
So, two things. You should specify a anchor point around which the rotation should occur - I prefer the centre as it's the easiest to resolve; second, I don't know why you're manually copying the pixels, I'd just use `Graphcis2D.drawImage` — MadProgrammer, Jan 13 '19 at 22:44

Graphics2D rotate before saving file

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