class Scroll {
  int swidth, sheight;    // width and height of bar
  int xpos, ypos;         // x and y position of bar
  float spos, newspos;    // x position of slider
  int sposMin, sposMax;   // max and min values of slider
  int loose;              // how loose/heavy
  boolean over;           // is the mouse over the slider?
  boolean locked;
  float ratio;

  Scroll (int xp, int yp, int sw, int sh, int l) {
    swidth = sw;
    sheight = sh;
    int widthtoheight = sw - sh;
    ratio = (float)sw / (float)widthtoheight;
    xpos = xp;
    ypos = yp-sheight/2;
    spos = xpos + swidth/2 - sheight/2;
    newspos = spos;
    sposMin = xpos;
    sposMax = xpos + swidth - sheight;
    loose = 1;
  }

  void update() {
    if(over()) {
      over = true;
    } 
    else {
      over = false;
    }
    if(mousePressed && over) {
      locked = true;
    }
    if(!mousePressed) {
      locked = false;
    }
    if(locked) {
      newspos = constrain(mouseX-sheight/2, sposMin, sposMax);
    }
    if(abs(newspos - spos) > 1) {
      spos = spos + (newspos-spos)/loose;
    }
  }

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

  boolean over() {
    if(mouseX > xpos && mouseX < xpos+swidth &&
      mouseY > ypos && mouseY < ypos+sheight) {
      return true;
    } 
    else {
      return false;
    }
  }

  void draw() {  
    if(xpos==s1x && ypos+sheight/2==s1y) {
      s1p = ((spos-sposMin)/(sposMax-sposMin));
    } 
    else if (xpos==s2x && ypos+sheight/2==s2y) {
      s2p = ((spos-sposMin)/(sposMax-sposMin));
    } 
    else if (xpos==s3x && ypos+sheight/2==s3y) {
      s3p = ((spos-sposMin)/(sposMax-sposMin));
    }
    else if (xpos==s4x && ypos+sheight/2==s4y) {
      s4p = ((spos-sposMin)/(sposMax-sposMin));
    }
    else if (xpos==s5x && ypos+sheight/2==s5y) {
      s5p = ((spos-sposMin)/(sposMax-sposMin));
    }
    else if (xpos==s6x && ypos+sheight/2==s6y) {
      s6p = ((spos-sposMin)/(sposMax-sposMin));
    }
    fill(0,0,100);
    stroke(0,0,50);
    rect(xpos, ypos, swidth, sheight);
    rect(spos, ypos, sheight, sheight);
  }

  float getPos() {
    // convert spos to be values between
    // 0 and the total width of the scrollbar
    return spos * ratio;
  }
}