jQuery touch events

jquery.touch.js

/**
 * touch for jQuery
 * 
 * Copyright (c) 2008 Peter Schmalfeldt (ManifestInteractive.com) <manifestinteractive@gmail.com>
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details. 
 *
 * @license http://www.gnu.org/licenses/gpl.html 
 * @project jquery.touch
 */

// DEFINE DEFAULT VARIABLES
var _target = null,
    _dragx = null,
    _dragy = null,
    _rotate = null,
    _resort = null;
var _dragging = false,
    _sizing = false,
    _animate = false;
var _rotating = 0,
    _width = 0,
    _height = 0,
    _left = 0,
    _top = 0,
    _xspeed = 0,
    _yspeed = 0;
var _zindex = 1000;

jQuery.fn.touch = function(settings) {

    // DEFINE DEFAULT TOUCH SETTINGS
    settings = jQuery.extend({
        animate: true,
        sticky: false,
        dragx: true,
        dragy: true,
        rotate: false,
        resort: true,
        scale: false
    }, settings);

    // BUILD SETTINGS OBJECT
    var opts = [];
    opts = $.extend({}, $.fn.touch.defaults, settings);

    // ADD METHODS TO OBJECT
    this.each(function() {
        this.opts = opts;
        this.ontouchstart = touchstart;
        this.ontouchend = touchend;
        this.ontouchmove = touchmove;
        this.ongesturestart = gesturestart;
        this.ongesturechange = gesturechange;
        this.ongestureend = gestureend;
    });
};

function touchstart(e) {
    _target = this.id;
    _dragx = this.opts.dragx;
    _dragy = this.opts.dragy;
    _resort = this.opts.resort;
    _animate = this.opts.animate;
    _xspeed = 0;
    _yspeed = 0;

    $(e.changedTouches).each(function() {

        var curLeft = ($('#' + _target).css("left") == 'auto') ? this.pageX : parseInt($('#' + _target).css("left"));
        var curTop = ($('#' + _target).css("top") == 'auto') ? this.pageY : parseInt($('#' + _target).css("top"));

        if (!_dragging && !_sizing) {
            _left = (e.pageX - curLeft);
            _top = (e.pageY - curTop);
            _dragging = [_left, _top];
            if (_resort) {
                _zindex = ($('#' + _target).css("z-index") == _zindex) ? _zindex : _zindex + 1;
                $('#' + _target).css({
                    zIndex: _zindex
                });
            }
        }
    });
};

function touchmove(e) {

    if (_dragging && !_sizing && _animate) {

        var _lastleft = (isNaN(parseInt($('#' + _target).css("left")))) ? 0 : parseInt($('#' + _target).css("left"));
        var _lasttop = (isNaN(parseInt($('#' + _target).css("top")))) ? 0 : parseInt($('#' + _target).css("top"));
    }

    $(e.changedTouches).each(function() {

        e.preventDefault();

        _left = (this.pageX - (parseInt($('#' + _target).css("width")) / 2));
        _top = (this.pageY - (parseInt($('#' + _target).css("height")) / 2));

        if (_dragging && !_sizing) {

            if (_animate) {
                _xspeed = Math.round((_xspeed + Math.round(_left - _lastleft)) / 1.5);
                _yspeed = Math.round((_yspeed + Math.round(_top - _lasttop)) / 1.5);
            }

            if (_dragx || _dragy) $('#' + _target).css({
                position: "absolute"
            });
            if (_dragx) $('#' + _target).css({
                left: _left + "px"
            });
            if (_dragy) $('#' + _target).css({
                top: _top + "px"
            });
        }
    });
};

function touchend(e) {
    $(e.changedTouches).each(function() {
        if (!e.targetTouches.length) {
            _dragging = false;
            if (_animate) {
                _left = ($('#' + _target).css("left") == 'auto') ? this.pageX : parseInt($('#' + _target).css("left"));
                _top = ($('#' + _target).css("top") == 'auto') ? this.pageY : parseInt($('#' + _target).css("top"));

                var animx = (_dragx) ? (_left + _xspeed) + "px" : _left + "px";
                var animy = (_dragy) ? (_top + _yspeed) + "px" : _top + "px";

                if (_dragx || _dragy) $('#' + _target).animate({
                    left: animx,
                    top: animy
                }, "fast");
            }
        }
    });
};

function gesturestart(e) {
    _sizing = [$('#' + this.id).css("width"), $('#' + this.id).css("height")];
};

function gesturechange(e) {
    if (_sizing) {
        _width = (this.opts.scale) ? Math.min(parseInt(_sizing[0]) * e.scale, 300) : _sizing[0];
        _height = (this.opts.scale) ? Math.min(parseInt(_sizing[1]) * e.scale, 300) : _sizing[1];
        _rotate = (this.opts.rotate) ? "rotate(" + ((_rotating + e.rotation) % 360) + "deg)" : "0deg";
        $('#' + this.id).css({
            width: _width + "px",
            height: _height + "px",
            webkitTransform: _rotate
        });
    }
};

function gestureend(e) {
    _sizing = false;
    _rotating = (_rotating + e.rotation) % 360;
};