Hello everyone, I'm trying to make a radial gradient using pixels[] and I have to use dist() to do it from the center, but I'm not sure how to do it. So far I'm making a linear gradient, here is the code:

1. PImage img;
2. void setup() {
3.   size(800, 600);
4. }
5. void draw() {
6.   background(0);
7.   img = createImage(300, 300, RGB);
8.   for (int i = 0; i < img.pixels.length; i++) {
9.     float c = map(i, 0, img.pixels.length, 0, 255);
10.     img.pixels[i] = color(c);
11.   }
12.   image(img, 250, 150);
13. }

Now, what I need to do is this:

Any help will be much appreciated, thanks.