/*______________
| ______ | U I Z E J A V A S C R I P T F R A M E W O R K
| / / | ---------------------------------------------------
| / O / | MODULE : Uize.Widget.Drag.Move.Drop Class
| / / / |
| / / / /| | ONLINE : http://uize.com
| /____/ /__/_| | COPYRIGHT : (c)2005-2016 UIZE
| /___ | LICENSE : Available under MIT License or GNU General Public License
|_______________| http://uize.com/license.html
*/
/* Module Meta Data
type: Class
importance: 2
codeCompleteness: 100
docCompleteness: 2
*/
/*?
Introduction
The =Uize.Widget.Drag.Move.Drop= class implements support for adding/removing/wiring widgets as drop targets.
*DEVELOPERS:* `Tim Carter`, original code contributed by `Zazzle Inc.`
*/
Uize.module ({
name:'Uize.Widget.Drag.Move.Drop',
required:'Uize.Dom.Pos',
builder:function (_superclass) {
'use strict';
var
/*** Variables for Scruncher Optimization ***/
_Uize_Dom_Pos = Uize.Dom.Pos,
/*** General Variables ***/
_dropTargets = [] // widgets onto which draggable widgets can be dropped
;
return _superclass.subclass ({
staticProperties:{
dropTargets:_dropTargets
},
staticMethods:{
addDropTarget:function (_widget, _node) {
_dropTargets.push ({_widget:_widget, _node:_node});
/**
Registers the passed-in widget as a potential drop target for any Uize.Widget.Drag.Move.Drop instance. When a drag instance is dragged, the position of the drag instance is checked against the positions of the drop targets and certain events are fired:
'Drag Enter': fired when the drag instance and drop target's physical positions first intersect.
'Drag Over': fired when the drag instance is over the drop target.
'Drag Leave': fired when the drag instance and the drop target's physical positions no longer intersect.
'Drop': fired when a Drag action terminates while the drag instance and drop target's physical positions intersect.
'Drag Cancel': fired when a Drag is cancelled.
Each of these events contains a =dragObject= parameter which points to the drag instance. It is up to each individual drop target to determine whether or not it should respond to the event or dragObject.
If the _node parameter is specified, that will be the node used to calculate to drop target's current coordinates.
*/
},
removeDropTarget:function (_widget) {
for (var _dropTargetIndex = _dropTargets.length; --_dropTargetIndex >= 0;) {
if (_dropTargets [_dropTargetIndex]._widget == _widget) {
_dropTargets.splice (_dropTargetIndex, 1);
return;
}
}
/**
Removes the passed-in widget from the list of potential drop targets for any Uize.Widget.Drag.Move.Drop instance.
*/
}
},
omegastructor:function() {
var
m = this,
_dropTargetsEntered = m._dropTargetsEntered = {},
_dropTargetIndex = 0,
_restTimeout,
_updateTimeout,
_processDropTargets = function () {
/**
* foreach drop target:
* if the drop target and drag instance intersect:
* if they've intersected before: fire 'Drag Over'
* else: fire 'Drag Enter'
* elseif they've intersected before:
* fire: 'Drag Leave'
* else: do nothing
*/
var
_dropTargetsLength = _dropTargets.length,
_coords = _Uize_Dom_Pos.getCoords (m.getNode())
;
for (_dropTargetIndex = _dropTargetsLength; --_dropTargetIndex >= 0;) {
var
_currDropTarget = _dropTargets [_dropTargetIndex],
_currDropTargetWidget = _currDropTarget._widget,
_instanceId = _currDropTargetWidget.instanceId,
_currDropTargetNodeCoords = _Uize_Dom_Pos.getCoords((_currDropTarget._node || (_currDropTarget._node = _currDropTargetWidget.getNode ()))), // these always have to be re-calculated (and not pre-calculated) because the drop target could also be moving
_hadEntered = _dropTargetsEntered [_instanceId]
;
if (_Uize_Dom_Pos.doRectanglesOverlap (_coords.left, _coords.top, _coords.width, _coords.height, _currDropTargetNodeCoords.left, _currDropTargetNodeCoords.top, _currDropTargetNodeCoords.width, _currDropTargetNodeCoords.height)) {
_currDropTargetWidget.fire ({
name:_hadEntered ? 'Drag Over' : 'Drag Enter',
dragObject:m
});
!_hadEntered && (_dropTargetsEntered [_instanceId] = true);
} else if (_hadEntered) {
_currDropTargetWidget.fire ({
name:'Drag Leave',
dragObject:m
});
_dropTargetsEntered [_instanceId] = false;
}
}
}
;
m.wire ({
'Drag Cancel':function (_event) {
for (_dropTargetIndex = _dropTargets.length; --_dropTargetIndex >= 0;)
_dropTargets[_dropTargetIndex].fire ({
name:'Drag Cancel',
dragObject:m,
domEvent:_event.domEvent
})
;
},
'Drag Rest':function () {
// even if the drag instance is at rest, the drop targets might be moving.
// so it's necessary to process them even on Drag Rest.
// NOTE: if the item is no longer being dragged, but the drop targets are still moving,
// no interaction will occur. This could be rationalized as intended, or considered
// a bug that requires significant refactoring of the Uize drag-drop model.
function _checkOnRest () {
_processDropTargets ();
_restTimeout = setTimeout (
_checkOnRest,
200
);
}
_restTimeout = setTimeout (
_checkOnRest,
200
);
},
'Drag Update':function () {
_restTimeout && clearTimeout (_restTimeout);
_updateTimeout && clearTimeout (_updateTimeout);
_updateTimeout = setTimeout (
_processDropTargets,
0
);
},
'Drag Done':function (_event) {
_restTimeout && clearTimeout(_restTimeout);
_updateTimeout && clearTimeout (_updateTimeout);
var
_dropTargetsLength = _dropTargets.length,
_coords = _Uize_Dom_Pos.getCoords (m.getNode()),
_droppedOn = []
;
for (_dropTargetIndex = _dropTargetsLength; --_dropTargetIndex >= 0;) {
var
_currDropTarget = _dropTargets [_dropTargetIndex],
_currDropTargetWidget = _currDropTarget._widget,
_instanceId = _currDropTargetWidget.instanceId,
_currDropTargetNodeCoords = _Uize_Dom_Pos.getCoords((_currDropTarget._node || (_currDropTarget._node = _currDropTargetWidget.getNode ())))
;
if (_Uize_Dom_Pos.doRectanglesOverlap (_coords.left, _coords.top, _coords.width, _coords.height, _currDropTargetNodeCoords.left, _currDropTargetNodeCoords.top, _currDropTargetNodeCoords.width, _currDropTargetNodeCoords.height)) {
_currDropTargetWidget.fire ({
name:'Drop',
dragObject:m,
domEvent:_event.domEvent
});
_droppedOn.push (_currDropTargetWidget);
}
else if (_dropTargetsEntered [_instanceId])
_currDropTargetWidget.fire ({
name:'Drag Leave',
dragObject:m,
domEvent:_event.domEvent
})
;
}
// it might be preferable to fire the 'Dropped' event for each dropTarget,
// but that's probably not necessary right now.
_droppedOn.length &&
m.fire ({
name:'Dropped',
dropTargets:_droppedOn,
domEvent:_event.domEvent
})
;
m._dropTargetsEntered = _dropTargetsEntered = {};
}
});
}
});
}
});