source: extensions/pAnchor/pAnchor.js @ 11132

// JavaScript Document

//pAnchor plugin for piwigo - ease to anchor javascript functions (uses jquery)
$(document).ready(function() {
        //check for pAnchor anchor - name of anchor can be customized in main.inc.php
        if ($('#pAnchor').attr('name')) {
            //alert('pAnchor exists');
            var url = window.location.href;
            if (url.indexOf('#') == -1) {
                //defaut values a=0.20, t=16 and delay=250
                easeToInit('pAnchor', 0.20, 16, 250);
            }
        }        
});


function easeTo(yDest, yTemp, a, t) {
        //easeTo function to scroll from 0 to yDest.  X will scroll to 0 also.
        //yDest is y value of destination
        //YTemp is temp value as scroll progresses to yDest
        //a = a || 0.2; //about  0.2
        //t = t || 20;  //about 15-20 milliseconds

        var x1 = 0;
        var y1 = 0;
        var x2 = 0;
        var y2 = 0;
        var x3 = 0;
        var y3 = 0;

        if (document.documentElement) {
                x1 = document.documentElement.scrollLeft || 0;
                y1 = document.documentElement.scrollTop || 0;
        }
        if (document.body) {
                x2 = document.body.scrollLeft || 0;
                y2 = document.body.scrollTop || 0;
        }
        x3 = window.scrollX || 0;
        y3 = window.scrollY || 0;

        var x = Math.max(x1, Math.max(x2, x3));
        var y = Math.max(y1, Math.max(y2, y3));

        var speed = 1 + a;
        var yTemp =  Math.floor(yTemp / speed);
        window.scrollTo(Math.floor(x / speed), yDest - yTemp);
        if(x > 0 || yTemp > 1) {
                var f = "easeTo(" + yDest + ", " + yTemp + ", " +  a + ", " + t + ")";
                //alert(f);
                window.setTimeout(f, t);
        } else {
                //alert('done');
        }
}

function easeToInit(elem, a, t, delay){
        //easeToInit initializes and easeTo operation
        //elem is id of document element, a is psuedo-acceleration, t is timer for interative calls
        //delay is just a small time delay before easeTo actually begins.  give the page a chance to be static before
        //easeTo the desired element.  The position can be fined with params in the main.inc.php file.
        //ALSO NOTE:  DIFFERENT BROWSERS WILL YEILDLY SLIGHLY DIFFERENT RESULTS, but typically within a few pixels.
        y = document.getElementById(elem).offsetTop;
        var f = "easeTo(" + y + ", " + y + ", " +  a + ", " + t + ")";
        window.setTimeout(f, delay);
}