Programmatically generate pixel art from an image

Question

I want to generate a 64x64 pixel art for any image provided by the user. I'm currently lost on how to do it. OpenCV does not seem to provide any such functionality. Any pointers in the right direction would be gladly appreciated.

Edit

Pixel art is a pixelated image of a given image. The screen shot below shows what I've achieved so far.

Basically what I've done is as follows.

1. Scale the image with aspect ratios maintained so that it would fit within a 64x64 grid

   Image sourceImage;
   Rectangle imageBound = sourceImage.getBounds();
   double sx = (double) 64 / (double) imageBound.width;
   double sy = (double) 64 / (double) imageBound.height;
   double s = Math.min(sx, sy);
   int dx = (int) (s * imageBound.width);
   int dy = (int) (s * imageBound.height);
   Image scaledImage = new Image(d, sourceImage.getImageData().scaledTo(dx, dy));
   

2. Read each pixel from the scaled image and output it on the screen.

Following shows how I extract the color from each pixel. I use SWT framework.

    Display d;
    ImageData data = scaledImage.getImageData();
    for(int i=0; i<data.width; i++) {
        for(int j=0; j<data.height; j++) {
            int pixel = data.getPixel(i,j);
            int red = (pixel & 0x00ff0000) >> 16;
            int green = (pixel & 0x0000ff00) >> 8;
            int blue = pixel & 0x000000ff;
            pixelGrid[i][j].setBackground(new Color(d, red, green, blue));
        }
    }

But as you can see, there is a major difference in the colors after resizing the image. What I want to know is whether I'm on the correct path to achieve this and if so, how can I retain the actual colors while scaling.

Answer 1

You probably have an image in RGBA format, and are extracting the wrong values from the image (as if it were ARGB). It looks very blue currently, and I fail to see any reds. That should have put you on the right track:

int red =   (pixel>>24) & 0xff;
int green = (pixel>>16) & 0xff;
int blue =  (pixel>>8)  & 0xff;
int alpha =  pixel & 0xff; // always 0xff for images without transparency