Handle[] handles;
int num=2;
float centrex, centrey;




void setup() {

  size(500, 500);
  centrex = width/2;
  centrey = height/2;
  handles = new Handle[2];
  int hsize = 10;
  for(int i=0; i<2; i++) {
    handles[i] = new Handle(50, height-i*15-30, width-100, 10, handles);
  }
  handles[0].length=100;
  handles[1].length=50;
}

void draw()
{
  background(255);




  float spacing=handles[1].length+10;
  float radius =handles[0].length+4;

  float x,y;
  float vSpace = 0.86602540378*spacing;
  float cornerToCorner = sqrt(width * width + height * height);

  noFill();

  y=centrey;
  float startx;
  int even=9999;

  do {
    y -= vSpace;
    even++;
  } 
  while (y>-radius);


  float starty=y;

  int row=0;	

  do {
    y-=vSpace;
    even++;
  } 
  while (y>starty);

  strokeWeight(1);

  //for (y=starty; y<height + radius; y+=vSpace) {
  
  int by = 0;

  for (int ay=1; abs(by*vSpace)<height; ay++) {
    if (ay%2==1) {by=ay-1; by/=2; by *= -1;}
    else by = ay/2;

    y=by*vSpace+height/2;
    row++;
    even--;
    if (abs(by)%2==1) x=centrex + (spacing / 2)*1;
    else x=centrex - (spacing);
    do {
      x -= spacing;
    } 
    while (x > -radius);

    startx=x;

    for (x=startx; x<width + radius; x+=spacing) {
      if (
      (
      (x>0 && x<width && y>0 && y<height) && // in rect
      (radius < cornerToCorner)
        ) ||
        !(
      !(x>0 && x<width && y>0 && y<height) && // in rect
      !(radius + cornerToCorner / 2 > sqrt(pow(abs(centrex-x),2)+pow(abs(centrey-y),2))) &&
        !(radius > sqrt(pow(abs(centrex-x),2)+pow(abs(centrey-y),2)) + cornerToCorner / 2)
        )
        ) {
        ellipse(x,y,radius,radius);
      }
    }
  }

  // draw background to sliders

  fill(255,255,255,180);
  noStroke();

  rect(50,height-62.5, width-100,12.5);
  rect(50,height-50,   width-100,  25);
  rect(50,height-25,   width-100,12.5);
  rect(37.5,height-50, 12.5,25);
  rect(width-50,height-50, 12.5,25);

  // the 0.5s are necessary to avoid a visible edge by centring the arc on a pixel edge rather than the centre

  arc(49.5,height-50.5,25,25,PI,1.5*PI);
  arc(49.5,height-25.5,25,25,0.5*PI,PI);
  arc(width-50.5,height-50.5,25,25,PI*1.5,2*PI);
  arc(width-50.5,height-25.5,25,25,0,0.5*PI);

  strokeWeight(3);
  stroke(0);
  for(int i=0; i<num; i++) {
    handles[i].update();
    handles[i].display();
  }
}

void mouseReleased() {
  for(int i=0; i<num; i++) {
    handles[i].release();
  }
}

class Handle {
  int x, y;
  int grabx, graby;
  int length;
  int size;
  boolean over;
  boolean press;
  boolean locked = false;
  boolean otherslocked = false;
  Handle[] others;

  Handle(int ix, int iy, int il, int is, Handle[] o)
  {
    x = ix;
    y = iy;
    length = il + 4;
    size = is;
    grabx = x+length - size/2;
    graby = y - size/2;
    others = o;
  }

  void update() 
  {
    grabx = x+length;
    graby = y - size/2;

    for(int i=0; i<others.length; i++) {
      if(others[i].locked == true) {
        otherslocked = true;
        break;
      } 
      else {
        otherslocked = false;
      }  
    }

    if(otherslocked == false) {
      over();
      press();
    }

    if(press) {
      length = lock(mouseX-50, 0, width-100);
    }
  }

  void over()
  {
    if(overRect(grabx-5, graby, size, size)) {
      over = true;
    } 
    else {
      over = false;
    }
  }

  void press()
  {
    if(over && mousePressed || locked) {
      press = true;
      locked = true;
    } 
    else {
      press = false;
    }
  }

  void release()
  {
    locked = false;
  }

  void display() 
  {
    line(x, y, width-50, y);
    fill(255);
    stroke(0);
    smooth();
    strokeWeight(3);
    ellipse(length+50, y, size, size);
    strokeWeight(3);
  }
}

boolean overRect(int x, int y, int width, int height) 
{
  if (mouseX >= x && mouseX <= x+width && 
    mouseY >= y && mouseY <= y+height) {
    return true;
  } 
  else {
    return false;
  }
}

int lock(int val, int minv, int maxv) 
{ 
  return  min(max(val, minv), maxv); 
}