/*
* NScroller
* Scroll a set of numbers.
* Copyright (c) 2005 Mackley F. Pexton. All rights reserved.
* Send correspondence and feedback to: mack_pexton[at]acmebase[dot]com.
*/
/*******************************************************************************
NScroller v1.2 -- Scroll numbers over a set of elements.
Example:
*******************************************************************************/
// Scroller configuration variables. (change as desired)
NScroller.Rate = null; // Rate of scroll (milliseconds between iterations, null is adjustable rate)
NScroller.Delay = 500; // Initial delay before scrolling (milliseconds)
NScroller.ClassNameNormal = 'scroll-element'; // class name assigned to non-current elements
NScroller.ClassNameCurrent = 'scroll-element-current'; // class name appended to current page element
// Scroller working variables. (do not change)
NScroller.timer = null; // setTimeOut() timer
NScroller.rate = 0; // working variable - milliseconds between scroll
NScroller.count = 0; // working variable - number of times scrolled (for adjustable rate)
NScroller.dir = 1; // working variable - direction of scroll (-1 left, +1 right)
NScroller.scrollers = []; // array of active scrollers being scrolled
// Constructor
function NScroller(min,max,curr,elements,template,action) {
// Scroller parameters
this.min = min; // minimum scroll number (1 based)
this.max = max; // maximum scroll number
this.curr = curr; // the current scroll (page) number
this.elements = elements; // document elements to scroll through
this.template = template; // string with %N where number is to be substituted
this.action = action; // function called when scroll stops with argument this.curr
// Settings
this.Rate = NScroller.Rate;
this.Delay = NScroller.Delay;
this.ClassNameNormal = NScroller.ClassNameNormal;
this.ClassNameCurrent = NScroller.ClassNameCurrent;
// Working variables
this.first = null; // number in first element (computed)
// Initialize display
this._move(0);
this._display();
return this;
}
// Class methods (implements repeated scrolls in required global context)
NScroller.next = function() {
var scroller, done = false;
for (var i = 0; i < NScroller.scrollers.length; i++) {
scroller = NScroller.scrollers[i];
if (scroller.min > 0 && scroller.max > 0) {
scroller._move(NScroller.dir);
scroller._display();
}
if (scroller.curr == scroller.min || scroller.curr == scroller.max) done = true;
}
if (!done) {
var rate = NScroller.rate ? NScroller.rate : NScroller.adjust_rate(++NScroller.count);
NScroller.timer = setTimeout('NScroller.next()',rate);
}
}
NScroller.stop = function(evt) {
// document onmouseup handler
clearTimeout(NScroller.timer);
for (var i = 0; i < NScroller.scrollers.length; i++) {
NScroller.scrollers[i].stop( (evt ? evt : window.event) );
}
}
NScroller.adjust_rate = function(count) {
if (count > 40) return 20;
else if (count > 15) return 50;
else if (count > 8) return 100;
else if (count > 2) return 200;
else return 300;
}
// Object methods (event handlers)
NScroller.prototype.scroll = function(dir) {
// Use as button's onmousedown event handler.
// Scroll left (dir=-1) or right (dir=1)
document.onmouseup = NScroller.stop; // safety
// Save arguments for next scroll in global context.
NScroller.scrollers = [ this ]; // one element array
NScroller.dir = (dir < 0 ? -1 : 1);
NScroller.rate = this.Rate;
NScroller.count = 0;
this._move(NScroller.dir);
this._display();
// Start scrolling.
NScroller.timer = setTimeout('NScroller.next()',this.Delay);
}
NScroller.prototype.stop = function(evt) {
// Use as button's onmouseup event handler.
clearTimeout(NScroller.timer);
evt = evt ? evt : window.event ? window.event : null;
if (evt) {
evt.cancelBubble = true;
if(evt.stopPropagation) evt.stopPropagation();
}
if (document.selection && document.selection.empty) document.selection.empty(); //IE
if (window.getSelection && window.getSelection().removeAllRanges) window.getSelection().removeAllRanges(); // Moz
if (this.action) {
if (navigator.userAgent.match(/MSIE/)) {
// HACK: IE has a timing problem when action function assigns a
// new url to location.href (an initial intended purpose of this).
NScroller.next_action = this.action;
NScroller.next_curr = this.curr;
setTimeout('NScroller.next_action(NScroller.next_curr)',100);
}
else {
this.action(this.curr);
}
}
}
// Private methods
NScroller.prototype._move = function(dir) {
// Assign new values to the scroll elements.
// dir is either 1 or -1
var nelem = this.elements.length;
// Compute middle element (0 based) to display current page number.
var curr_elem = Math.floor((nelem + 1)/2) - 1;
this.curr += dir;
if (this.curr < this.min) this.curr = this.min;
if (this.curr > this.max) this.curr = this.max;
this.first = this.curr - curr_elem;
if (this.first < this.min) {
curr_elem -= this.min - this.first;
this.first = this.min;
}
if ((this.first + nelem) > this.max) {
curr_elem += (this.first + nelem) - this.max - 1;
this.first = this.curr - curr_elem;
}
}
NScroller.prototype._display = function() {
var n = this.first;
for (var i = 0; i < this.elements.length; i++) {
if (n > 0 && n <= this.max) this.elements[i].innerHTML = this.template.replace(/%N/g,n);
else this.elements[i].innerHTML = ' ';
this.elements[i].className = this.elements[i].className.replace(new RegExp(this.ClassNameCurrent),"");
if (n == this.curr) this.elements[i].className += " "+this.ClassNameCurrent;
n++;
}
}