//dw_glidescroll.js   version date: March 2004   */

dw_scrollLayers = {};
dw_scrollLayer.slideDur = 500; // duration of glide
//  constructor arguments: id of layer containing scrolling layers (clipped layer), id of layer to scroll, 
//	id of table or other element that scrolling content is nested in 
//	ns6+/moz need that extra container to get width for horizontal scrolling.
//	(not needed for vertical scrolling)
function dw_scrollLayer(wnId, lyrId, cntId) {
    this.id = wnId; dw_scrollLayers[this.id] = this;
    this.animString = "dw_scrollLayers." + this.id;
    this.loadLayer(lyrId, cntId);
}

dw_scrollLayer.prototype.loadLayer = function(lyrId, cntId) {
    if (!document.getElementById) return;
    var wndo, lyr;
    if (this.lyrId) {
        lyr = document.getElementById(this.lyrId);
        lyr.style.visibility = "hidden";
    }
    lyr = document.getElementById(lyrId);
    wndo = document.getElementById(this.id);
    lyr.style.top = this.y = 0; lyr.style.left = this.x = 0;
    this.maxY = (lyr.offsetHeight - wndo.offsetHeight > 0) ? lyr.offsetHeight - wndo.offsetHeight : 0;
    this.wd = cntId ? document.getElementById(cntId).offsetWidth : lyr.offsetWidth;
    this.maxX = (this.wd - wndo.offsetWidth > 0) ? this.wd - wndo.offsetWidth : 0;
    this.lyrId = lyrId; // hold id of currently visible layer
    //lyr.style.visibility = "";
    this.on_load(); this.ready = true;
}

dw_scrollLayer.prototype.on_load = function() { }
dw_scrollLayer.prototype.on_slide_start = function() { }
dw_scrollLayer.prototype.on_slide = function() { }
dw_scrollLayer.prototype.on_slide_end = function() { }

dw_scrollLayer.prototype.shiftTo = function(lyr, x, y) {
    lyr.style.left = (this.x = x) + "px";
    lyr.style.top = (this.y = y) + "px";
}

// functions for glide-scroll onclick 

// Resources for time-based slide algorithm: 
//  DHTML chaser tutorial at DHTML Lab - www.webreference.com/dhtml	
//  and cbe_slide.js from	www.cross-browser.com by Mike Foster
dw_scrollLayer.prototype.glideScrollBy = function(dx, dy, dur) {
    if (!document.getElementById || this.sliding) return;
    this.slideDur = dur || dw_scrollLayer.slideDur;
    this.destX = this.destY = this.distX = this.distY = 0;
    this.lyr = document.getElementById(this.lyrId);
    this.startX = this.x; this.startY = this.y;
    if (dy < 0) this.distY = (this.startY + dy >= -this.maxY) ? dy : -(this.startY + this.maxY);
    else if (dy > 0) this.distY = (this.startY + dy <= 0) ? dy : -this.startY;
    if (dx < 0) this.distX = (this.startX + dx >= -this.maxX) ? dx : -(this.startX + this.maxX);
    else if (dx > 0) this.distX = (this.startX + dx <= 0) ? dx : -this.startX;
    this.destX = this.startX + this.distX; this.destY = this.startY + this.distY;
    this.slideTo(this.destX, this.destY);

   
}


dw_scrollLayer.prototype.glideScrollTo = function(destX, destY, dur) {
    if (!document.getElementById || this.sliding) return;
    this.slideDur = dur || dw_scrollLayer.slideDur;
    this.lyr = document.getElementById(this.lyrId);
    this.startX = this.x; this.startY = this.y;
    this.destX = -Math.max(Math.min(destX, this.maxX), 0);
    this.destY = -Math.max(Math.min(destY, this.maxY), 0);
    this.distY = this.destY - this.startY;
    this.distX = this.destX - this.startX;
    this.slideTo(this.destX, this.destY);
}

dw_scrollLayer.prototype.slideTo = function(destX, destY) {
    this.per = Math.PI / (2 * this.slideDur); this.sliding = true;
    this.slideStart = (new Date()).getTime();
    this.aniTimer = setInterval(this.animString + ".doSlide()", 10);
    this.on_slide_start(this.startX, this.startY);
}

dw_scrollLayer.prototype.doSlide = function() {
    var elapsed = (new Date()).getTime() - this.slideStart;
    if (elapsed < this.slideDur) {
        var x = this.startX + this.distX * Math.sin(this.per * elapsed);
        var y = this.startY + this.distY * Math.sin(this.per * elapsed);
        this.shiftTo(this.lyr, x, y); this.on_slide(x, y);
    } else {	// if time's up
        clearInterval(this.aniTimer); this.sliding = false;
        this.shiftTo(this.lyr, this.destX, this.destY);
        this.lyr = null; this.on_slide_end(this.destX, this.destY);
    }
}

// remove layers from table for ns6+/mozilla (needed for scrolling inside tables)
function GeckoTableBugFix() {
    var i, wndo, holderId, holder, x, y;
    if (navigator.userAgent.indexOf("Gecko") > -1 && navigator.userAgent.indexOf("Firefox") == -1) {
        dw_scrollLayer.hold = []; // holds id's of wndo and its container
        for (i = 0; arguments[i]; i++) {
            if (dw_scrollLayers[arguments[i]]) {
                wndo = document.getElementById(arguments[i]);
                holderId = wndo.parentNode.id;
                holder = document.getElementById(holderId);
                document.body.appendChild(holder.removeChild(wndo));
                wndo.style.zIndex = 1000;
                x = holder.offsetLeft; y = holder.offsetTop;
                wndo.style.left = x + "px"; wndo.style.top = y + "px";
                dw_scrollLayer.hold[i] = [arguments[i], holderId];
            }
        }
        window.addEventListener("resize", rePositionGecko, true);
    }
}

// ns6+/mozilla need to reposition layers onresize when scrolling inside tables.
function rePositionGecko() {
    var i, wndo, pt, x, y;
    if (dw_scrollLayer.hold) {
        for (i = 0; dw_scrollLayer.hold[i]; i++) {
            wndo = document.getElementById(dw_scrollLayer.hold[i][0]);
            pt = document.getElementById(dw_scrollLayer.hold[i][1]);
            x = pt.offsetLeft; y = pt.offsetTop;
            wndo.style.left = x + "px"; wndo.style.top = y + "px";
        }
    }
}