I can't seem to downscale pixelart to single pixels without antialiasing

Question

I am trying to downscale an pixelart image (of the game stardew valley) consisting of 4x4 pixels per block of the same color to the same image with 1x1 pixel per block.

Photoshop is doing a great job when I just resize it with the NEAREST_NEIGHBOUR interpolation.

But when I use the technique from: How to scale a BufferedImage but with TYPE_NEAREST_NEIGHBOR instead it gets all destorted.

What is going wrong and how should I go about fixing it?

            BufferedImage old = getScreenShot();
            int w = old.getWidth();
            int h = old.getHeight();

            int newWidth = w/4;
            int newHeight = h/4;


            BufferedImage resized = new BufferedImage(newWidth, newHeight, old.getType());
            AffineTransform at = new AffineTransform();
            at.scale(0.25, 0.25);
            AffineTransformOp scaleOp = new AffineTransformOp(at, AffineTransformOp.TYPE_NEAREST_NEIGHBOR);
            resized = scaleOp.filter(old, resized);

            //TODO (remove)  for debugging the screencapture capability
            File outputfile = new File("C:/Users/Kevin/Desktop/imagetestmap/test.jpg");
            try {
                ImageIO.write(resized, "jpg", outputfile);
            } catch (IOException e) {
                e.printStackTrace();
            }


            return resized;

actual screenshot:

what photoshop sees:

what my program sees:

Kind of funny that your program sees a different image altogether. The character is facing a different way. Cool program!!! :) — Cris Luengo, Apr 25 '19 at 17:24
Anyway, I think you are dealing with JPEG compression artifacts. — Cris Luengo, Apr 25 '19 at 17:25
sorry bout that, i lost the original screenshot as i was just experimenting, but shouldnt there be a way to shrink it whitout artifacts? — Kevin Gleijm, Apr 25 '19 at 19:15
This worked like a charm! you are amazing, thank you very much! — Kevin Gleijm, Apr 25 '19 at 19:57

score 0 · Accepted Answer · answered Apr 25 '19 at 20:00

Cris Luengo found the solution, I should have used .png instead of jpg.

This is the working code:

            BufferedImage old = getScreenShot();
            int w = old.getWidth();
            int h = old.getHeight();

            int newWidth = w/4;
            int newHeight = h/4;


            BufferedImage resized = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_ARGB);

             AffineTransform at = new AffineTransform();
            at.scale(0.25, 0.25);
            AffineTransformOp scaleOp = new AffineTransformOp(at, AffineTransformOp.TYPE_NEAREST_NEIGHBOR);
            resized = scaleOp.filter(old, resized);

            //TODO (remove)  for debugging the screencapture capability
            File outputfile = new File("C:/Users/Kevin/Desktop/imagetestmap/test.png");
            try {
                ImageIO.write(resized, "png", outputfile);
            } catch (IOException e) {
                e.printStackTrace();
            }

I can't seem to downscale pixelart to single pixels without antialiasing

1 Answers1