Make slider from vertical scrollbar start from the beginning

HenryProcessing

From a previous processing thread, I can now make a vertical scrollbar. I want to make the slider start from the beginning through instead of the end.

class Scrollbar
{
  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;

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

  void resizeScrollbar(int xp, int yp, int sw, int sh)
  {
    this.xpos = xp - swidth/2;
    this.ypos = yp;
    this.swidth = sw;
    this.sheight = sh;
  }

  void update() {
    if (over()) {
      over = true;
    } else {
      over = false;
    }
    if (mousePressed && over) {
      locked = true;
    }
    if (!mousePressed) {
      locked = false;
    }
    if (locked) {
      newspos = constrain(mouseY-swidth/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 display() {
    fill(220);
    rect(xpos, ypos, swidth, sheight);
    if (over || locked) {
      fill(80);
    } else {
      fill(190);
    }
    rect(xpos, spos, swidth, swidth);
  }

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

HenryProcessing

i figured it out by changin spos to ypos

GoToLoop

http://forum.processing.org/two/discussion/11731/can-anybody-show-me-how-to-create-a-vertical-scrollbar