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