Dot Matrix Style Grid, changes color

int circX, circY, sizeofgrid;

color circColor;

​

void setup() {

  size(500, 500);

  // where does the grid originate from. The invisible center 

  circX = width/2;

  circY = height/2;

​

  // how big is the grid

  sizeofgrid = 220;

  circColor = color( random(255), random(255), random(255));

}

​

void draw() {

  background(0);

  noStroke();

  fill(circColor);

​

  // drawing the grid

  for (float x = -sizeofgrid; x<=sizeofgrid; x= x+20) {

    for (float y = -sizeofgrid; y<=sizeofgrid; y=y+20) {

      float diameter = dist(circX, circY, x+circX, y+circY) / 20; // changes the soze of circle based on how far away they are from circX and circY

      // float diameter = 5; // basic version, all circles same size.

      ellipse(circX + x, circY + y, diameter, diameter);

    }

  }

}

​

void keyPressed () {

  if (key == 'r') {

    circColor =  color (random (255), random (255), random(255) );

  }

}