jquery.event.drag.custom.js
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/**
* @license
* jquery.event.drag.js ~ v1.5 ~ Copyright (c) 2008, Three Dub Media (http://threedubmedia.com)
* Licensed under the MIT License ~ http://threedubmedia.googlecode.com/files/MIT-LICENSE.txt
*/
;
(function ($) { // secure $ jQuery alias
/*******************************************************************************************/
// Created: 2008-06-04 | Updated: 2009-03-24
/*******************************************************************************************/
// Events: drag, dragstart, dragend
/*******************************************************************************************/
// jquery method
$.fn.drag = function (fn1, fn2, fn3) {
if (fn2) this.bind('dragstart', fn1); // 2+ args
if (fn3) this.bind('dragend', fn3); // 3 args
return !fn1 ? this.trigger('drag') // 0 args
: this.bind('drag', fn2 ? fn2 : fn1); // 1+ args
};
// local refs
var $event = $.event, $special = $event.special,
// special event configuration
drag = $special.drag = {
not: ':input', // don't begin to drag on event.targets that match this selector
distance: 0, // distance dragged before dragstart
which: 1, // mouse button pressed to start drag sequence
dragging: false, // hold the active target element
setup: function (data) {
data = $.extend({
distance: drag.distance,
which: drag.which,
not: drag.not
}, data || {});
data.distance = squared(data.distance); // xІ + yІ = distanceІ
$event.add(this, "mousedown", handler, data);
if (this.attachEvent) this.attachEvent("ondragstart", dontStart); // prevent image dragging in IE...
},
teardown: function () {
$event.remove(this, "mousedown", handler);
if (this === drag.dragging) drag.dragging = drag.proxy = false; // deactivate element
selectable(this, true); // enable text selection
if (this.detachEvent) this.detachEvent("ondragstart", dontStart); // prevent image dragging in IE...
}
};
// prevent normal event binding...
$special.dragstart = $special.dragend = { setup: function () {
}, teardown: function () {
} };
// handle drag-releatd DOM events
function handler(event) {
var elem = this, returned, data = event.data || {};
// mousemove or mouseup
if (data.elem) {
// update event properties...
elem = event.dragTarget = data.elem; // drag source element
event.dragProxy = drag.proxy || elem; // proxy element or source
event.cursorOffsetX = data.pageX - data.left; // mousedown offset
event.cursorOffsetY = data.pageY - data.top; // mousedown offset
event.offsetX = event.pageX - event.cursorOffsetX; // element offset
event.offsetY = event.pageY - event.cursorOffsetY; // element offset
}
// mousedown, check some initial props to avoid the switch statement
else if (drag.dragging || ( data.which > 0 && event.which != data.which ) ||
$(event.target).is(data.not)) return;
// handle various events
switch (event.type) {
// mousedown, left click, event.target is not restricted, init dragging
case 'mousedown':
returned = hijack(event, "beforedragstart", elem);
if (returned === false)
return true;
$.extend(data, $(elem).offset(), {
elem: elem, target: event.target,
pageX: event.pageX, pageY: event.pageY
}); // store some initial attributes
$event.add(document, "mousemove mouseup", handler, data);
selectable(elem, false); // disable text selection
drag.dragging = null; // pending state
return false; // prevents text selection in safari
// mousemove, check distance, start dragging
case !drag.dragging && 'mousemove':
if (squared(event.pageX - data.pageX)
+ squared(event.pageY - data.pageY) // xІ + yІ = distanceІ
< data.distance) break; // distance tolerance not reached
event.target = data.target; // force target from "mousedown" event (fix distance issue)
returned = hijack(event, "dragstart", elem); // trigger "dragstart", return proxy element
if (returned !== false) { // "dragstart" not rejected
drag.dragging = elem; // activate element
drag.proxy = event.dragProxy = $(returned || elem)[0]; // set proxy
}
// mousemove, dragging
case 'mousemove':
if (drag.dragging) {
returned = hijack(event, "drag", elem); // trigger "drag"
if ($special.drop) { // manage drop events
$special.drop.allowed = ( returned !== false ); // prevent drop
$special.drop.handler(event); // "dropstart", "dropend"
}
if (returned !== false) break; // "drag" not rejected, stop
event.type = "mouseup"; // helps "drop" handler behave
}
// mouseup, stop dragging
case 'mouseup':
if (drag.dragging === false) break;
$event.remove(document, "mousemove mouseup", handler); // remove page events
if (drag.dragging) {
if ($special.drop) $special.drop.handler(event); // "drop"
hijack(event, "dragend", elem); // trigger "dragend"
}
selectable(elem, true); // enable text selection
drag.dragging = drag.proxy = data.elem = false; // deactivate element
break;
}
return true;
};
// set event type to custom value, and handle it
function hijack(event, type, elem) {
event.type = type; // force the event type
var result = $.event.handle.call(elem, event);
return result === false ? false : result || event.result;
};
// return the value squared
function squared(value) {
return Math.pow(value, 2);
};
// suppress default dragstart IE events...
function dontStart() {
return ( drag.dragging === false );
};
// toggles text selection attributes
function selectable(elem, bool) {
if (!elem) return; // maybe element was removed ?
elem.unselectable = bool ? "off" : "on"; // IE
elem.onselectstart = function () {
return bool;
}; // IE
//if ( document.selection && document.selection.empty ) document.selection.empty(); // IE
if (elem.style) elem.style.MozUserSelect = bool ? "" : "none"; // FF
};
/*******************************************************************************************/
})(jQuery); // confine scope