source: trunk/prototype/plugins/scrollto/jquery.scrollTo.js @ 5349

/**
 * jQuery.ScrollTo
 * Copyright (c) 2007-2009 Ariel Flesler - aflesler(at)gmail(dot)com | http://flesler.blogspot.com
 * Dual licensed under MIT and GPL.
 * Date: 5/25/2009
 *
 * @projectDescription Easy element scrolling using jQuery.
 * http://flesler.blogspot.com/2007/10/jqueryscrollto.html
 * Works with jQuery +1.2.6. Tested on FF 2/3, IE 6/7/8, Opera 9.5/6, Safari 3, Chrome 1 on WinXP.
 *
 * @author Ariel Flesler
 * @version 1.4.2
 *
 * @id jQuery.scrollTo
 * @id jQuery.fn.scrollTo
 * @param {String, Number, DOMElement, jQuery, Object} target Where to scroll the matched elements.
 *        The different options for target are:
 *              - A number position (will be applied to all axes).
 *              - A string position ('44', '100px', '+=90', etc ) will be applied to all axes
 *              - A jQuery/DOM element ( logically, child of the element to scroll )
 *              - A string selector, that will be relative to the element to scroll ( 'li:eq(2)', etc )
 *              - A hash { top:x, left:y }, x and y can be any kind of number/string like above.
*               - A percentage of the container's dimension/s, for example: 50% to go to the middle.
 *              - The string 'max' for go-to-end. 
 * @param {Number} duration The OVERALL length of the animation, this argument can be the settings object instead.
 * @param {Object,Function} settings Optional set of settings or the onAfter callback.
 *       @option {String} axis Which axis must be scrolled, use 'x', 'y', 'xy' or 'yx'.
 *       @option {Number} duration The OVERALL length of the animation.
 *       @option {String} easing The easing method for the animation.
 *       @option {Boolean} margin If true, the margin of the target element will be deducted from the final position.
 *       @option {Object, Number} offset Add/deduct from the end position. One number for both axes or { top:x, left:y }.
 *       @option {Object, Number} over Add/deduct the height/width multiplied by 'over', can be { top:x, left:y } when using both axes.
 *       @option {Boolean} queue If true, and both axis are given, the 2nd axis will only be animated after the first one ends.
 *       @option {Function} onAfter Function to be called after the scrolling ends. 
 *       @option {Function} onAfterFirst If queuing is activated, this function will be called after the first scrolling ends.
 * @return {jQuery} Returns the same jQuery object, for chaining.
 *
 * @desc Scroll to a fixed position
 * @example $('div').scrollTo( 340 );
 *
 * @desc Scroll relatively to the actual position
 * @example $('div').scrollTo( '+=340px', { axis:'y' } );
 *
 * @dec Scroll using a selector (relative to the scrolled element)
 * @example $('div').scrollTo( 'p.paragraph:eq(2)', 500, { easing:'swing', queue:true, axis:'xy' } );
 *
 * @ Scroll to a DOM element (same for jQuery object)
 * @example var second_child = document.getElementById('container').firstChild.nextSibling;
 *                      $('#container').scrollTo( second_child, { duration:500, axis:'x', onAfter:function(){
 *                              alert('scrolled!!');                                                                                                                               
 *                      }});
 *
 * @desc Scroll on both axes, to different values
 * @example $('div').scrollTo( { top: 300, left:'+=200' }, { axis:'xy', offset:-20 } );
 */
;(function( $ ){
        
        var $scrollTo = $.scrollTo = function( target, duration, settings ){
                $(window).scrollTo( target, duration, settings );
        };

        $scrollTo.defaults = {
                axis:'xy',
                duration: parseFloat($.fn.jquery) >= 1.3 ? 0 : 1
        };

        // Returns the element that needs to be animated to scroll the window.
        // Kept for backwards compatibility (specially for localScroll & serialScroll)
        $scrollTo.window = function( scope ){
                return $(window)._scrollable();
        };

        // Hack, hack, hack :)
        // Returns the real elements to scroll (supports window/iframes, documents and regular nodes)
        $.fn._scrollable = function(){
                return this.map(function(){
                        var elem = this,
                                isWin = !elem.nodeName || $.inArray( elem.nodeName.toLowerCase(), ['iframe','#document','html','body'] ) != -1;

                                if( !isWin )
                                        return elem;

                        var doc = (elem.contentWindow || elem).document || elem.ownerDocument || elem;
                        
                        return $.browser.safari || doc.compatMode == 'BackCompat' ?
                                doc.body : 
                                doc.documentElement;
                });
        };

        $.fn.scrollTo = function( target, duration, settings ){
                if( typeof duration == 'object' ){
                        settings = duration;
                        duration = 0;
                }
                if( typeof settings == 'function' )
                        settings = { onAfter:settings };
                        
                if( target == 'max' )
                        target = 9e9;
                        
                settings = $.extend( {}, $scrollTo.defaults, settings );
                // Speed is still recognized for backwards compatibility
                duration = duration || settings.speed || settings.duration;
                // Make sure the settings are given right
                settings.queue = settings.queue && settings.axis.length > 1;
                
                if( settings.queue )
                        // Let's keep the overall duration
                        duration /= 2;
                settings.offset = both( settings.offset );
                settings.over = both( settings.over );

                return this._scrollable().each(function(){
                        var elem = this,
                                $elem = $(elem),
                                targ = target, toff, attr = {},
                                win = $elem.is('html,body');

                        switch( typeof targ ){
                                // A number will pass the regex
                                case 'number':
                                case 'string':
                                        if( /^([+-]=)?\d+(\.\d+)?(px|%)?$/.test(targ) ){
                                                targ = both( targ );
                                                // We are done
                                                break;
                                        }
                                        // Relative selector, no break!
                                        targ = $(targ,this);
                                case 'object':
                                        // DOMElement / jQuery
                                        if( targ.is || targ.style )
                                                // Get the real position of the target 
                                                toff = (targ = $(targ)).offset();
                        }
                        $.each( settings.axis.split(''), function( i, axis ){
                                var Pos = axis == 'x' ? 'Left' : 'Top',
                                        pos = Pos.toLowerCase(),
                                        key = 'scroll' + Pos,
                                        old = elem[key],
                                        max = $scrollTo.max(elem, axis);

                                if( toff ){// jQuery / DOMElement
                                        attr[key] = toff[pos] + ( win ? 0 : old - $elem.offset()[pos] );

                                        // If it's a dom element, reduce the margin
                                        if( settings.margin ){
                                                attr[key] -= parseInt(targ.css('margin'+Pos)) || 0;
                                                attr[key] -= parseInt(targ.css('border'+Pos+'Width')) || 0;
                                        }
                                        
                                        attr[key] += settings.offset[pos] || 0;
                                        
                                        if( settings.over[pos] )
                                                // Scroll to a fraction of its width/height
                                                attr[key] += targ[axis=='x'?'width':'height']() * settings.over[pos];
                                }else{ 
                                        var val = targ[pos];
                                        // Handle percentage values
                                        attr[key] = val.slice && val.slice(-1) == '%' ? 
                                                parseFloat(val) / 100 * max
                                                : val;
                                }

                                // Number or 'number'
                                if( /^\d+$/.test(attr[key]) )
                                        // Check the limits
                                        attr[key] = attr[key] <= 0 ? 0 : Math.min( attr[key], max );

                                // Queueing axes
                                if( !i && settings.queue ){
                                        // Don't waste time animating, if there's no need.
                                        if( old != attr[key] )
                                                // Intermediate animation
                                                animate( settings.onAfterFirst );
                                        // Don't animate this axis again in the next iteration.
                                        delete attr[key];
                                }
                        });

                        animate( settings.onAfter );                    

                        function animate( callback ){
                                $elem.animate( attr, duration, settings.easing, callback && function(){
                                        callback.call(this, target, settings);
                                });
                        };

                }).end();
        };
        
        // Max scrolling position, works on quirks mode
        // It only fails (not too badly) on IE, quirks mode.
        $scrollTo.max = function( elem, axis ){
                var Dim = axis == 'x' ? 'Width' : 'Height',
                        scroll = 'scroll'+Dim;
                
                if( !$(elem).is('html,body') )
                        return elem[scroll] - $(elem)[Dim.toLowerCase()]();
                
                var size = 'client' + Dim,
                        html = elem.ownerDocument.documentElement,
                        body = elem.ownerDocument.body;

                return Math.max( html[scroll], body[scroll] ) 
                         - Math.min( html[size]  , body[size]   );
                        
        };

        function both( val ){
                return typeof val == 'object' ? val : { top:val, left:val };
        };

})( jQuery );