boxblur

	public static void main(String[] args) {
		Img img = new Img(2048,2048);
		img.fill(0xff000000);
		Random r = new Random();
		img.forEach(px->{px.setG(r.nextInt(256));});
		Img copy = img.copy();
		
		int kernelSize = 21;
		int minus = kernelSize/2;
		int plus = kernelSize-minus;
		int[] sums = new int[Math.max(img.getWidth(), img.getHeight())];
		Consumer<Pixel> blurH = px ->
		{
			int x = px.getX();
			int y = px.getY();
			int sum = sums[y];
			if(x == 0){
				// init sum
				for(int i = -minus; i < plus; i++){
					sum += Pixel.g(copy.getValue(x+i, y, Img.boundary_mode_mirror));
				}
			}
			// update sum
			sum -= Pixel.g(copy.getValue(x-minus, y, Img.boundary_mode_mirror));
			sum += Pixel.g(copy.getValue(x+plus-1, y, Img.boundary_mode_mirror));
			sums[y] = sum;
			px.setG(sum/kernelSize);
		};
		
		
//		ImageSaver.saveImage(img.getRemoteBufferedImage(), new File("orig.png"));
		long t = System.currentTimeMillis();
		Img.stream(img.rowSpliterator(), true).forEach(blurH);
		System.out.println(System.currentTimeMillis()-t);
//		ImageSaver.saveImage(img.getRemoteBufferedImage(), new File("blur.png"));
		
	}