/**
Provides extended/advanced XY positioning support for Widgets, through an
extension.
It builds on top of the `widget-position` module, to provide alignment and
centering support. Future releases aim to add constrained and fixed positioning
support.
@module widget-position-align
**/
var Lang = Y.Lang,
ALIGN = 'align',
ALIGN_ON = 'alignOn',
VISIBLE = 'visible',
BOUNDING_BOX = 'boundingBox',
OFFSET_WIDTH = 'offsetWidth',
OFFSET_HEIGHT = 'offsetHeight',
REGION = 'region',
VIEWPORT_REGION = 'viewportRegion';
/**
Widget extension, which can be used to add extended XY positioning support to
the base Widget class, through the `Base.create` method.
**Note:** This extension requires that the `WidgetPosition` extension be added
to the Widget (before `WidgetPositionAlign`, if part of the same extension list
passed to `Base.build`).
@class WidgetPositionAlign
@param {Object} config User configuration object.
@constructor
**/
function PositionAlign (config) {}
PositionAlign.ATTRS = {
/**
The alignment configuration for this widget.
The `align` attribute is used to align a reference point on the widget, with
the reference point on another `Node`, or the viewport. The object which
`align` expects has the following properties:
* __`node`__: The `Node` to which the widget is to be aligned. If set to
`null`, or not provided, the widget is aligned to the viewport.
* __`points`__: A two element Array, defining the two points on the widget
and `Node`/viewport which are to be aligned. The first element is the
point on the widget, and the second element is the point on the
`Node`/viewport. Supported alignment points are defined as static
properties on `WidgetPositionAlign`.
@example Aligns the top-right corner of the widget with the top-left corner
of the viewport:
myWidget.set('align', {
points: [Y.WidgetPositionAlign.TR, Y.WidgetPositionAlign.TL]
});
@attribute align
@type Object
@default null
**/
align: {
value: null
},
/**
A convenience Attribute, which can be used as a shortcut for the `align`
Attribute.
If set to `true`, the widget is centered in the viewport. If set to a `Node`
reference or valid selector String, the widget will be centered within the
`Node`. If set to `false`, no center positioning is applied.
@attribute centered
@type Boolean|Node
@default false
**/
centered: {
setter : '_setAlignCenter',
lazyAdd:false,
value :false
},
/**
An Array of Objects corresponding to the `Node`s and events that will cause
the alignment of this widget to be synced to the DOM.
The `alignOn` Attribute is expected to be an Array of Objects with the
following properties:
* __`eventName`__: The String event name to listen for.
* __`node`__: The optional `Node` that will fire the event, it can be a
`Node` reference or a selector String. This will default to the widget's
`boundingBox`.
@example Sync this widget's alignment on window resize:
myWidget.set('alignOn', [
{
node : Y.one('win'),
eventName: 'resize'
}
]);
@attribute alignOn
@type Array
@default []
**/
alignOn: {
value : [],
validator: Y.Lang.isArray
}
};
/**
Constant used to specify the top-left corner for alignment
@property TL
@type String
@value 'tl'
@static
**/
PositionAlign.TL = 'tl';
/**
Constant used to specify the top-right corner for alignment
@property TR
@type String
@value 'tr'
@static
**/
PositionAlign.TR = 'tr';
/**
Constant used to specify the bottom-left corner for alignment
@property BL
@type String
@value 'bl'
@static
**/
PositionAlign.BL = 'bl';
/**
Constant used to specify the bottom-right corner for alignment
@property BR
@type String
@value 'br'
@static
**/
PositionAlign.BR = 'br';
/**
Constant used to specify the top edge-center point for alignment
@property TC
@type String
@value 'tc'
@static
**/
PositionAlign.TC = 'tc';
/**
Constant used to specify the right edge, center point for alignment
@property RC
@type String
@value 'rc'
@static
**/
PositionAlign.RC = 'rc';
/**
Constant used to specify the bottom edge, center point for alignment
@property BC
@type String
@value 'bc'
@static
**/
PositionAlign.BC = 'bc';
/**
Constant used to specify the left edge, center point for alignment
@property LC
@type String
@value 'lc'
@static
**/
PositionAlign.LC = 'lc';
/**
Constant used to specify the center of widget/node/viewport for alignment
@property CC
@type String
@value 'cc'
@static
*/
PositionAlign.CC = 'cc';
PositionAlign.prototype = {
// -- Protected Properties -------------------------------------------------
initializer : function() {
if (!this._posNode) {
Y.error('WidgetPosition needs to be added to the Widget, ' +
'before WidgetPositionAlign is added');
}
Y.after(this._bindUIPosAlign, this, 'bindUI');
Y.after(this._syncUIPosAlign, this, 'syncUI');
},
/**
Holds the alignment-syncing event handles.
@property _posAlignUIHandles
@type Array
@default null
@protected
**/
_posAlignUIHandles: null,
// -- Lifecycle Methods ----------------------------------------------------
destructor: function () {
this._detachPosAlignUIHandles();
},
/**
Bind event listeners responsible for updating the UI state in response to
the widget's position-align related state changes.
This method is invoked after `bindUI` has been invoked for the `Widget`
class using the AOP infrastructure.
@method _bindUIPosAlign
@protected
**/
_bindUIPosAlign: function () {
this.after('alignChange', this._afterAlignChange);
this.after('alignOnChange', this._afterAlignOnChange);
this.after('visibleChange', this._syncUIPosAlign);
},
/**
Synchronizes the current `align` Attribute value to the DOM.
This method is invoked after `syncUI` has been invoked for the `Widget`
class using the AOP infrastructure.
@method _syncUIPosAlign
@protected
**/
_syncUIPosAlign: function () {
var align = this.get(ALIGN);
this._uiSetVisiblePosAlign(this.get(VISIBLE));
if (align) {
this._uiSetAlign(align.node, align.points);
}
},
// -- Public Methods -------------------------------------------------------
/**
Aligns this widget to the provided `Node` (or viewport) using the provided
points. This method can be invoked with no arguments which will cause the
widget's current `align` Attribute value to be synced to the DOM.
@example Aligning to the top-left corner of the `<body>`:
myWidget.align('body',
[Y.WidgetPositionAlign.TL, Y.WidgetPositionAlign.TR]);
@method align
@param {Node|String|null} [node] A reference (or selector String) for the
`Node` which with the widget is to be aligned. If null is passed in, the
widget will be aligned with the viewport.
@param {Array[2]} [points] A two item array specifying the points on the
widget and `Node`/viewport which will to be aligned. The first entry is
the point on the widget, and the second entry is the point on the
`Node`/viewport. Valid point references are defined as static constants on
the `WidgetPositionAlign` extension.
@chainable
**/
align: function (node, points) {
if (arguments.length) {
// Set the `align` Attribute.
this.set(ALIGN, {
node : node,
points: points
});
} else {
// Sync the current `align` Attribute value to the DOM.
this._syncUIPosAlign();
}
return this;
},
/**
Centers the widget in the viewport, or if a `Node` is passed in, it will
be centered to that `Node`.
@method centered
@param {Node|String} [node] A `Node` reference or selector String defining
the `Node` which the widget should be centered. If a `Node` is not passed
in, then the widget will be centered to the viewport.
@chainable
**/
centered: function (node) {
return this.align(node, [PositionAlign.CC, PositionAlign.CC]);
},
// -- Protected Methods ----------------------------------------------------
/**
Default setter for `center` Attribute changes. Sets up the appropriate
value, and passes it through the to the align attribute.
@method _setAlignCenter
@param {Boolean|Node} val The Attribute value being set.
@return {Boolean|Node} the value passed in.
@protected
**/
_setAlignCenter: function (val) {
if (val) {
this.set(ALIGN, {
node : val === true ? null : val,
points: [PositionAlign.CC, PositionAlign.CC]
});
}
return val;
},
/**
Updates the UI to reflect the `align` value passed in.
**Note:** See the `align` Attribute documentation, for the Object structure
expected.
@method _uiSetAlign
@param {Node|String|null} [node] The node to align to, or null to indicate
the viewport.
@param {Array} points The alignment points.
@protected
**/
_uiSetAlign: function (node, points) {
if ( ! Lang.isArray(points) || points.length !== 2) {
Y.error('align: Invalid Points Arguments');
return;
}
var nodeRegion = this._getRegion(node),
widgetPoint, nodePoint, xy;
if ( ! nodeRegion) {
// No-op, nothing to align to.
return;
}
widgetPoint = points[0];
nodePoint = points[1];
// TODO: Optimize KWeight - Would lookup table help?
switch (nodePoint) {
case PositionAlign.TL:
xy = [nodeRegion.left, nodeRegion.top];
break;
case PositionAlign.TR:
xy = [nodeRegion.right, nodeRegion.top];
break;
case PositionAlign.BL:
xy = [nodeRegion.left, nodeRegion.bottom];
break;
case PositionAlign.BR:
xy = [nodeRegion.right, nodeRegion.bottom];
break;
case PositionAlign.TC:
xy = [
nodeRegion.left + Math.floor(nodeRegion.width / 2),
nodeRegion.top
];
break;
case PositionAlign.BC:
xy = [
nodeRegion.left + Math.floor(nodeRegion.width / 2),
nodeRegion.bottom
];
break;
case PositionAlign.LC:
xy = [
nodeRegion.left,
nodeRegion.top + Math.floor(nodeRegion.height / 2)
];
break;
case PositionAlign.RC:
xy = [
nodeRegion.right,
nodeRegion.top + Math.floor(nodeRegion.height / 2)
];
break;
case PositionAlign.CC:
xy = [
nodeRegion.left + Math.floor(nodeRegion.width / 2),
nodeRegion.top + Math.floor(nodeRegion.height / 2)
];
break;
default:
Y.log('align: Invalid Points Arguments', 'info',
'widget-position-align');
break;
}
if (xy) {
this._doAlign(widgetPoint, xy[0], xy[1]);
}
},
/**
Attaches or detaches alignment-syncing event handlers based on the widget's
`visible` Attribute state.
@method _uiSetVisiblePosAlign
@param {Boolean} visible The current value of the widget's `visible`
Attribute.
@protected
**/
_uiSetVisiblePosAlign: function (visible) {
if (visible) {
this._attachPosAlignUIHandles();
} else {
this._detachPosAlignUIHandles();
}
},
/**
Attaches the alignment-syncing event handlers.
@method _attachPosAlignUIHandles
@protected
**/
_attachPosAlignUIHandles: function () {
if (this._posAlignUIHandles) {
// No-op if we have already setup the event handlers.
return;
}
var bb = this.get(BOUNDING_BOX),
syncAlign = Y.bind(this._syncUIPosAlign, this),
handles = [];
Y.Array.each(this.get(ALIGN_ON), function (o) {
var event = o.eventName,
node = Y.one(o.node) || bb;
if (event) {
handles.push(node.on(event, syncAlign));
}
});
this._posAlignUIHandles = handles;
},
/**
Detaches the alignment-syncing event handlers.
@method _detachPosAlignUIHandles
@protected
**/
_detachPosAlignUIHandles: function () {
var handles = this._posAlignUIHandles;
if (handles) {
new Y.EventHandle(handles).detach();
this._posAlignUIHandles = null;
}
},
// -- Private Methods ------------------------------------------------------
/**
Helper method, used to align the given point on the widget, with the XY page
coordinates provided.
@method _doAlign
@param {String} widgetPoint Supported point constant
(e.g. WidgetPositionAlign.TL)
@param {Number} x X page coordinate to align to.
@param {Number} y Y page coordinate to align to.
@private
**/
_doAlign: function (widgetPoint, x, y) {
var widgetNode = this._posNode,
xy;
switch (widgetPoint) {
case PositionAlign.TL:
xy = [x, y];
break;
case PositionAlign.TR:
xy = [
x - widgetNode.get(OFFSET_WIDTH),
y
];
break;
case PositionAlign.BL:
xy = [
x,
y - widgetNode.get(OFFSET_HEIGHT)
];
break;
case PositionAlign.BR:
xy = [
x - widgetNode.get(OFFSET_WIDTH),
y - widgetNode.get(OFFSET_HEIGHT)
];
break;
case PositionAlign.TC:
xy = [
x - (widgetNode.get(OFFSET_WIDTH) / 2),
y
];
break;
case PositionAlign.BC:
xy = [
x - (widgetNode.get(OFFSET_WIDTH) / 2),
y - widgetNode.get(OFFSET_HEIGHT)
];
break;
case PositionAlign.LC:
xy = [
x,
y - (widgetNode.get(OFFSET_HEIGHT) / 2)
];
break;
case PositionAlign.RC:
xy = [
x - widgetNode.get(OFFSET_WIDTH),
y - (widgetNode.get(OFFSET_HEIGHT) / 2)
];
break;
case PositionAlign.CC:
xy = [
x - (widgetNode.get(OFFSET_WIDTH) / 2),
y - (widgetNode.get(OFFSET_HEIGHT) / 2)
];
break;
default:
Y.log('align: Invalid Points Argument', 'info',
'widget-position-align');
break;
}
if (xy) {
this.move(xy);
}
},
/**
Returns the region of the passed-in `Node`, or the viewport region if
calling with passing in a `Node`.
@method _getRegion
@param {Node} [node] The node to get the region of.
@return {Object} The node's region.
@private
**/
_getRegion: function (node) {
var nodeRegion;
if ( ! node) {
nodeRegion = this._posNode.get(VIEWPORT_REGION);
} else {
node = Y.Node.one(node);
if (node) {
nodeRegion = node.get(REGION);
}
}
return nodeRegion;
},
// -- Protected Event Handlers ---------------------------------------------
/**
Handles `alignChange` events by updating the UI in response to `align`
Attribute changes.
@method _afterAlignChange
@param {EventFacade} e
@protected
**/
_afterAlignChange: function (e) {
var align = e.newVal;
if (align) {
this._uiSetAlign(align.node, align.points);
}
},
/**
Handles `alignOnChange` events by updating the alignment-syncing event
handlers.
@method _afterAlignOnChange
@param {EventFacade} e
@protected
**/
_afterAlignOnChange: function(e) {
this._detachPosAlignUIHandles();
if (this.get(VISIBLE)) {
this._attachPosAlignUIHandles();
}
}
};
Y.WidgetPositionAlign = PositionAlign;