int maxDiameter = 170;
int coords[] = {
  0,0};
int winSize[] = {
  400,400};
color fillColor = color(255,255,0);
int alphaNum = 175;
boolean strokeOn = false;
boolean debug = false;

void setup() 
{
  size(winSize[0], winSize[1]);
  background(0,255,255);
  smooth();
  noLoop();
  if (strokeOn) stroke(125);
  else noStroke();
  fill(red(fillColor), green(fillColor), blue(fillColor), alphaNum);
}

void draw(){
  for (int i=0; i<30; i++){
    float currentDiameter = random(maxDiameter)+30;
    coords[0] = (int)random(winSize[0]);
    coords[1] = (int)random(winSize[1]);
    color sample = get(coords[0], coords[1]);
    if (red(sample) != 0) {
      float newBlue = blue(sample) + 40;
      constrain(newBlue, 0, 255);
      fill( red(fillColor), green(fillColor), newBlue, alphaNum);
      if (debug) print(newBlue + " , ");
    }
    ellipse(coords[0],coords[1], currentDiameter, currentDiameter);
    fill(red(fillColor), green(fillColor), blue(fillColor), alphaNum);  //reset fill
  }
}