ÿþ// animation object holds numerous properties related to motion



var anime;



//initialize default anime object

function initAnime() {

    anime = {elemID:"",

        xCurr:0,

        yCurr: 0,

        xCurrtemp: 0,

        yCurrtemp: 0,

        xTarg:0,

        yTarg:0,

        xStep:0,

        yStep:0,

        xDelta:0,

        yDelta:0,

        xTravel:0,

        yTravel:0,

        vel:1,

        pathLen:1,

        interval:null

    };

}



//stuff animation object with necessary explicit and calculated values

function initSLAnime(elemID, startX, startY, endX, endY, speed) {

    initAnime();

    anime.elemID = elemID;

    anime.xCurr = startX;

    anime.yCurr = startY;

    anime.xTarg = endX;

    anime.yTarg = endY;

    anime.xDelta = Math.abs(endX - startX);

    anime.yDelta = Math.abs(endY - startY);

    anime.vel = (speed) ? speed : 1;

    //get width of element

//    var elemwidth = Math.abs(parseInt(document.getElementById(elemID).style.right) - parseInt(document.getElementById(elemID).style.left));

    // set element's start position

    document.getElementById(elemID).style.left = startX + "px";

    document.getElementById(elemID).style.top = startY + "px";

    // the length of the line between the start and end points

    anime.pathLen = Math.sqrt((Math.pow((startX - endX), 2)) + (Math.pow((startY - endY), 2)));

    //how big the pixel steps are along the way

    anime.xStep = parseInt(((anime.xTarg - anime.xCurr) / anime.pathLen) * anime.vel);

    anime.yStep = parseInt(((anime.yTarg - anime.yCurr) / anime.pathLen) * anime.vel);

    //start the repeated invocation of the animation

    anime.interval = setInterval("doSLAnimation()", 10);

}



//calculate next steps and assign to style properties

function doSLAnimation() {

    if ((anime.xTravel + anime.xStep) <= anime.xDelta &&

        (anime.yTravel + anime.yStep) <= anime.yDelta) {

        var x = anime.xCurr + anime.xStep;

        var y = anime.yCurr + anime.yStep;

        document.getElementById(anime.elemID).style.left = x + "px";

        document.getElementById(anime.elemID).style.top = y + "px";

        anime.xTravel += Math.abs(anime.xStep);

        anime.yTravel += Math.abs(anime.yStep);

        anime.xCurr = x;

        anime.yCurr = y;

    } else {

        document.getElementById(anime.elemID).style.left = anime.xTarg + "px";

        document.getElementById(anime.elemID).style.top = anime.yTarg + "px";

        clearInterval(anime.interval);

    }

}

addOnLoadEvent(initAnime);