class Scrollbar {
  int x, y;
  float sw, sh;
  float pos;
  float posMin, posMax;
  boolean rollover;
  boolean locked;
  float minVal, maxVal;
  
  Scrollbar(int xp, int yp, int w, int h, float miv, float mav){
    x = xp;
    y = yp;
    sw = w;
    sh = h;
    minVal = miv;
    maxVal = mav;
    pos = x + sw/2 - sh/2;
    posMin = x;
    posMax = x + sw - sh;
  }
  
//Updates over the boolean and the position of the thumb

void update(int mx, int my) {
  if (over(mx, my) == true) {
    rollover = true;
  } else {
    rollover = false;
    }
  if (locked == true) {
    pos = constrain(mx-sh/2, posMin, posMax);
    }
}

//locks the thumb so the mouse can move off and still update

void press(int mx, int my) {
    if (rollover == true) {
      locked = true;
    } else {
      locked = false;
    }
}

//resets the scrollbar to neutral

void release() {
  locked = false;
}

//returns true if the cursor is over the scrollbar

boolean over(int mx, int my) {
  if ((mx > x) && (mx < x+sw) && (my > y) && (my < y+sh)) {
    return true;
  } else {
    return false;
  }
}

//draws the scrollbar to the screen

void display() {
  stroke(155);
  fill(255);
  rect(x, y, sw, sh);
  if ((rollover == true) || (locked == true)) {
    fill(0);
  } else {
    fill(155);
  }
  stroke(155);
  fill(225);
  rect(pos, y, sh, sh);
  line(x, 412, (sw+x), 412);
  //line(x, 319, (sw+x), 319);
}


// Returns the current value of the thumb
float getPos() {
  float scalar = sw/(sw-sh);
  float ratio = (pos - x) * scalar;
  float offset = minVal + (ratio/sw * (maxVal-minVal));
  return offset;
}

}