int numCells=50;
int maxCells=100;
ArrayList cells= new ArrayList();
float avgRadius;
PImage img;

void setup(){
  size(450,450);
  background(255);
  smooth();


  avgRadius=0.4f*sqrt(0.66*width*1.2f*height/(PI*numCells));
  cell c = new cell();
  for(int i=0;i<numCells;i++){


    cells.add(new cell(random(width), random(-0.05f*height,1.05f*height), random(0.1f,2.0f)*avgRadius));

  }
  noStroke();


  ellipseMode(CENTER_RADIUS);

}

void draw(){
  background(255);

  stroke(0,20);
  fill(11,22,22);
  cell c = new cell();
  for(int i=0;i<cells.size();i++){
    c=(cell)cells.get(i);
    circle(c.centerX+1,c.centerY+1,c.radius);

  }
  fill(102,204,221);
  for(int i=0;i<cells.size();i++){
    c=(cell)cells.get(i);
    circle(c.centerX,c.centerY,c.radius);

  }


  if(random(1.0f)<0.1f){
    int selected=constrain(int(random(cells.size())),0,cells.size()-1);
    c=(cell)cells.get(selected);
    cells.remove(selected);
    for(int i=0;i<4*c.radius/avgRadius;i++){
      if(cells.size()<maxCells){
        cells.add(new cell(c.centerX+random(-c.radius,c.radius), c.centerY+random(-c.radius,c.radius), 1.0));
      }
    }

  }
  consolidate();


}


void circle(float cx, float cy, float r){

ellipse(cx,cy,r,r); 

}

void consolidate(){
  float x1=pmouseX;
  float x2=mouseX;
  float y1=pmouseY;
  float y2=mouseY;
  cell ci;
  cell cj;
  for(int i=0;i<cells.size();i++){
    ci=(cell)cells.get(i);
    ci.intersect=false;
  }
  for(int i=0;i<cells.size();i++){
    ci=(cell)cells.get(i);
    for(int j=i+1;j<cells.size();j++){
      cj=(cell)cells.get(j);
      float targetDistance=sq(ci.radius+cj.radius);
      float distance=sq(ci.centerX-cj.centerX)+sq(ci.centerY-cj.centerY);
      float ratio=sqrt(distance/targetDistance);
      if (ratio<=1.0f){
        ci.intersect = true;       
        cj.intersect = true;
      }
      float dx,dy;    


      dx=(ratio>1.0f)?0.0f:0.5f*(1.0f-1.0f/ratio)*(cj.centerX-ci.centerX);
      dy=(ratio>1.0f)?0.0f:0.5f*(1.0f-1.0f/ratio)*(cj.centerY-ci.centerY);



      ci.centerX+=dx;
      ci.centerY+=dy;
      cj.centerX-=dx;
      cj.centerY-=dy;

    }
    ci.centerY-=.5f*avgRadius/ci.radius;
    if(!ci.intersect){
      //cells[i].centerX+=(cells[i].centerX<width/2)?.5:-.5;
      //cells[i].centerY+=(cells[i].centerY<height/2)?.5:-.5;
      ci.centerY-=.5f*avgRadius/ci.radius;

      if (ci.radius<3.0f*avgRadius) ci.radius+=0.1;

    }
    if(ci.centerY<-0.1f*height) ci.centerY+=1.2f*height;
    if(ci.centerX<-0.1f*width) ci.centerX+=1.2f*width;
    if(ci.centerX>1.1f*height) ci.centerX-=1.2f*width;
    //if(ci.centerY>height) ci.centerY=height;
    float x3=ci.centerX;
    float y3=ci.centerY;
    float r=ci.radius;
    float a= sq(x2-x1)+sq(y2-y1);
    float b=2*((x2-x1)*(x1-x3)+(y2-y1)*(y1-y3));
    float c=x3*x3+y3*y3+x1*x1+y1*y1-2*(x3*x1+y3*y1)-r*r;
    float u=-0.5f*b/a;


    if (((b*b-4*a*c)>0.0f)&&(u>=0.0f)&&(u<=1.0f)) ci.radius=1.0f;




  }



}