performance test for Pixel with cached x,y values using a box blur with large neighbourhood (51x51 ~ 2600 calls to getX,getY per pixel)

Pixel with cached x,y (not beneficial)

	public static void main(String[] args) {
		Img img1 = new Img(4000, 4000);
		
		
		Img img2 = new Img(4000, 4000) {
			@Override
			public Pixel getPixel() {
				return new Pixol(this, 0);
			}
			
			@Override
			public Pixel getPixel(int x, int y) {
				return new Pixol(this, x, y);
			}
		};
		
		img1.forEach(px->{px.setValue(0xff000000|px.getIndex());});
		img2.forEach(px->{px.setValue(0xff000000|px.getIndex());});
		
		BiConsumer<Pixel, Img> filter = (px, copy)->{
			int size = 25;
			int sum = 0;
			for(int y = -size; y <= size; y++)
			for(int x = -size; x <= size; x++){
				sum += Pixel.getLuminance(copy.getValue(px.getX()+x, px.getY()+y, Img.boundary_mode_mirror));
			}
			sum /= (size+size+1)*(size+size+1);
			px.setRGB(sum, sum, sum);
		};
		
		Img cp1 = img1.copy();
		Img cp2 = img2.copy();
		
		img1.setSpliteratorMinimumSplitSize(1024*32);
		img2.setSpliteratorMinimumSplitSize(1024*32);
		
		long t = System.nanoTime();
		img1.forEachParallel(px->{filter.accept(px, cp1);});
		t = System.nanoTime()-t;
		
		System.out.println(t/1000.0);
		
		t = System.nanoTime();
		img2.forEachParallel(px->{filter.accept(px, cp2);});
		t = System.nanoTime()-t;
		
		System.out.println(t/1000.0);
		
		ImageSaver.saveImage(img1.getRemoteBufferedImage(), "img1.png");
		ImageSaver.saveImage(img2.getRemoteBufferedImage(), "img2.png");
		
	}
	
	static class Pixol extends Pixel {
		
		private int xCached = -1;
		private int yCached = -1;

		public Pixol(Img img, int index) {
			super(img, index);
		}

		public Pixol(Img img, int x, int y) {
			super(img, x, y);
		}
		
		@Override
		public int getX() {
			return xCached == -1 ? (xCached = super.getX()):xCached;
		}
		
		@Override
		public int getY() {
			return yCached == -1 ? (yCached = super.getY()):yCached;
		}
		
		@Override
		public void setIndex(int index) {
			xCached = -1;
			yCached = -1;
			super.setIndex(index);
		}
		
	}