Growing Rainbow Circles

float hue, br, hoehe, num, totN, loc;

boolean allow;

​

void setup() {

  background(0, 0, 100);

  size(400, 430);

  hue = 360;

  loc = 15;

  noStroke();

  colorMode(HSB, 360, 100, 100);

  ellipseMode(CENTER);

  drawSlider();

}

​

void draw() {

  background(0, 0, 100);

  br = width/num;

  totN = 360/(num*num);

  hoehe = (height-30)/num;

  for (float x = 0; x < num; x++) {

    for (float y = 0; y < num; y++) {

      hue -= totN;

      pushMatrix();

      translate(x*br, y*hoehe);

      fill(hue, 100, 100); 

      ellipse(0.5*br, 0.5*hoehe, br, hoehe);

      popMatrix();

    }

  }

  hue = 360;

  drawSlider();

}

​

void drawSlider() {

  num = map(loc-10.55, 0.0, width, 0.0, 90);

  fill(0, 0, 100);

  rect(0, height-30, width, 30); 

  fill(200, 35, 100);

  rect(10, height-15, width-20, 5); 

  fill(245, 50, 99);

  ellipse(loc, height-13, 15, 15);

} 

​

void mousePressed() {

  if (mouseY > height-30) allowed = true;  

}

​

void mouseReleased() {

  allowed = false;

} 

​

void mouseDragged() {

  if (mousePressed){

    if (allowed) {

      loc = mouseX;

      if (loc < 15) loc = 15;

      if (loc > width-15) loc = width-15;

    }

  } 

  mousPressed = false;

}

​