i meant ellipse NOT Eclipse

to draw random ellipses within another circle radius you can simply use sin and cos to get a random position within this circle...

1. 
   void setup() {
     size(600,400);
     smooth();
     background(255);
   
   }
   
   void draw() {
    
   float r = random(100);
   float r2 = random(TWO_PI);
   float
   x = width/2 + cos( r2  )*r;
   float y = height/2 +sin( r2 )*r;
   ellipse(x,y,5,5);
   
   }
   

if you dont want them to touch though, you have to check their position by either storing it in an array or checking the color by using get() or the pixelsarray... try to search for "circle packing" or "circle Filling" if that is what you are looking for.

ah i just realized the colorblind post was from you as well. so i guess i already answered the question there...