File yui3/src/dd/js/constrain.js
/**
* The Drag & Drop Utility allows you to create a draggable interface efficiently,
* buffering you from browser-level abnormalities and enabling you to focus on the interesting
* logic surrounding your particular implementation. This component enables you to create a
* variety of standard draggable objects with just a few lines of code and then,
* using its extensive API, add your own specific implementation logic.
* @module dd
* @main dd
* @submodule dd-constrain
*/
/**
* Plugin for the dd-drag module to add the constraining methods to it.
* It supports constraining to a node or viewport. It supports tick based moves and XY axis constraints.
* @class DDConstrained
* @extends Base
* @constructor
* @namespace Plugin
*/
var DRAG_NODE = 'dragNode',
OFFSET_HEIGHT = 'offsetHeight',
OFFSET_WIDTH = 'offsetWidth',
HOST = 'host',
TICK_X_ARRAY = 'tickXArray',
TICK_Y_ARRAY = 'tickYArray',
DDM = Y.DD.DDM,
TOP = 'top',
RIGHT = 'right',
BOTTOM = 'bottom',
LEFT = 'left',
VIEW = 'view',
proto = null,
/**
* Fires when this node is aligned with the tickX value.
* @event drag:tickAlignX
* @param {EventFacade} event An Event Facade object
* @type {CustomEvent}
*/
EV_TICK_ALIGN_X = 'drag:tickAlignX',
/**
* Fires when this node is aligned with the tickY value.
* @event drag:tickAlignY
* @param {EventFacade} event An Event Facade object
* @type {CustomEvent}
*/
EV_TICK_ALIGN_Y = 'drag:tickAlignY',
C = function() {
this._lazyAddAttrs = false;
C.superclass.constructor.apply(this, arguments);
};
C.NAME = 'ddConstrained';
/**
* The Constrained instance will be placed on the Drag instance under the con namespace.
* @property NS
* @default con
* @readonly
* @protected
* @static
* @type {String}
*/
C.NS = 'con';
C.ATTRS = {
host: {
},
/**
* Stick the drag movement to the X-Axis. Default: false
* @attribute stickX
* @type Boolean
*/
stickX: {
value: false
},
/**
* Stick the drag movement to the Y-Axis
* @type Boolean
* @attribute stickY
*/
stickY: {
value: false
},
/**
* The X tick offset the drag node should snap to on each drag move. False for no ticks. Default: false
* @type Number/false
* @attribute tickX
*/
tickX: {
value: false
},
/**
* The Y tick offset the drag node should snap to on each drag move. False for no ticks. Default: false
* @type Number/false
* @attribute tickY
*/
tickY: {
value: false
},
/**
* An array of page coordinates to use as X ticks for drag movement.
* @type Array
* @attribute tickXArray
*/
tickXArray: {
value: false
},
/**
* An array of page coordinates to use as Y ticks for drag movement.
* @type Array
* @attribute tickYArray
*/
tickYArray: {
value: false
},
/**
* CSS style string for the gutter of a region (supports negative values): '5 0'
* (sets top and bottom to 5px, left and right to 0px), '1 2 3 4' (top 1px, right 2px, bottom 3px, left 4px)
* @attribute gutter
* @type String
*/
gutter: {
value: '0',
setter: function(gutter) {
return Y.DD.DDM.cssSizestoObject(gutter);
}
},
/**
* Will attempt to constrain the drag node to the boundaries. Arguments:<br>
* 'view': Contrain to Viewport<br>
* '#selector_string': Constrain to this node<br>
* '{Region Object}': An Object Literal containing a valid region (top, right, bottom, left) of page positions
* @attribute constrain
* @type {String/Object/Node}
*/
constrain: {
value: VIEW,
setter: function(con) {
var node = Y.one(con);
if (node) {
con = node;
}
return con;
}
},
/**
* An Object Literal containing a valid region (top, right, bottom, left) of page positions to constrain the drag node to.
* @deprecated
* @attribute constrain2region
* @type Object
*/
constrain2region: {
setter: function(r) {
return this.set('constrain', r);
}
},
/**
* Will attempt to constrain the drag node to the boundaries of this node.
* @deprecated
* @attribute constrain2node
* @type Object
*/
constrain2node: {
setter: function(n) {
return this.set('constrain', Y.one(n));
}
},
/**
* Will attempt to constrain the drag node to the boundaries of the viewport region.
* @deprecated
* @attribute constrain2view
* @type Object
*/
constrain2view: {
setter: function() {
return this.set('constrain', VIEW);
}
},
/**
* Should the region be cached for performace. Default: true
* @attribute cacheRegion
* @type Boolean
*/
cacheRegion: {
value: true
}
};
proto = {
_lastTickXFired: null,
_lastTickYFired: null,
initializer: function() {
this._createEvents();
this._eventHandles = [
this.get(HOST).on('drag:end', Y.bind(this._handleEnd, this)),
this.get(HOST).on('drag:start', Y.bind(this._handleStart, this)),
this.get(HOST).after('drag:align', Y.bind(this.align, this)),
this.get(HOST).after('drag:drag', Y.bind(this.drag, this))
];
},
destructor: function() {
Y.Array.each(
this._eventHandles,
function(handle) {
handle.detach();
}
);
this._eventHandles.length = 0;
},
/**
* This method creates all the events for this Event Target and publishes them so we get Event Bubbling.
* @private
* @method _createEvents
*/
_createEvents: function() {
var ev = [
EV_TICK_ALIGN_X,
EV_TICK_ALIGN_Y
];
Y.Array.each(ev, function(v) {
this.publish(v, {
type: v,
emitFacade: true,
bubbles: true,
queuable: false,
prefix: 'drag'
});
}, this);
},
/**
* Fires on drag:end
* @private
* @method _handleEnd
*/
_handleEnd: function() {
this._lastTickYFired = null;
this._lastTickXFired = null;
},
/**
* Fires on drag:start and clears the _regionCache
* @private
* @method _handleStart
*/
_handleStart: function() {
this.resetCache();
},
/**
* Store a cache of the region that we are constraining to
* @private
* @property _regionCache
* @type Object
*/
_regionCache: null,
/**
* Get's the region and caches it, called from window.resize and when the cache is null
* @private
* @method _cacheRegion
*/
_cacheRegion: function() {
this._regionCache = this.get('constrain').get('region');
},
/**
* Reset the internal region cache.
* @method resetCache
*/
resetCache: function() {
this._regionCache = null;
},
/**
* Standardizes the 'constraint' attribute
* @private
* @method _getConstraint
*/
_getConstraint: function() {
var con = this.get('constrain'),
g = this.get('gutter'),
region;
if (con) {
if (con instanceof Y.Node) {
if (!this._regionCache) {
this._eventHandles.push(Y.on('resize', Y.bind(this._cacheRegion, this), Y.config.win));
this._cacheRegion();
}
region = Y.clone(this._regionCache);
if (!this.get('cacheRegion')) {
this.resetCache();
}
} else if (Y.Lang.isObject(con)) {
region = Y.clone(con);
}
}
if (!con || !region) {
con = VIEW;
}
if (con === VIEW) {
region = this.get(HOST).get(DRAG_NODE).get('viewportRegion');
}
Y.Object.each(g, function(i, n) {
if ((n === RIGHT) || (n === BOTTOM)) {
region[n] -= i;
} else {
region[n] += i;
}
});
return region;
},
/**
* Get the active region: viewport, node, custom region
* @method getRegion
* @param {Boolean} inc Include the node's height and width
* @return {Object} The active region.
*/
getRegion: function(inc) {
var r = {}, oh = null, ow = null,
host = this.get(HOST);
r = this._getConstraint();
if (inc) {
oh = host.get(DRAG_NODE).get(OFFSET_HEIGHT);
ow = host.get(DRAG_NODE).get(OFFSET_WIDTH);
r[RIGHT] = r[RIGHT] - ow;
r[BOTTOM] = r[BOTTOM] - oh;
}
return r;
},
/**
* Check if xy is inside a given region, if not change to it be inside.
* @private
* @method _checkRegion
* @param {Array} _xy The XY to check if it's in the current region, if it isn't
* inside the region, it will reset the xy array to be inside the region.
* @return {Array} The new XY that is inside the region
*/
_checkRegion: function(_xy) {
var oxy = _xy,
r = this.getRegion(),
host = this.get(HOST),
oh = host.get(DRAG_NODE).get(OFFSET_HEIGHT),
ow = host.get(DRAG_NODE).get(OFFSET_WIDTH);
if (oxy[1] > (r[BOTTOM] - oh)) {
_xy[1] = (r[BOTTOM] - oh);
}
if (r[TOP] > oxy[1]) {
_xy[1] = r[TOP];
}
if (oxy[0] > (r[RIGHT] - ow)) {
_xy[0] = (r[RIGHT] - ow);
}
if (r[LEFT] > oxy[0]) {
_xy[0] = r[LEFT];
}
return _xy;
},
/**
* Checks if the XY passed or the dragNode is inside the active region.
* @method inRegion
* @param {Array} xy Optional XY to check, if not supplied this.get('dragNode').getXY() is used.
* @return {Boolean} True if the XY is inside the region, false otherwise.
*/
inRegion: function(xy) {
xy = xy || this.get(HOST).get(DRAG_NODE).getXY();
var _xy = this._checkRegion([xy[0], xy[1]]),
inside = false;
if ((xy[0] === _xy[0]) && (xy[1] === _xy[1])) {
inside = true;
}
return inside;
},
/**
* Modifies the Drag.actXY method from the after drag:align event. This is where the constraining happens.
* @method align
*/
align: function() {
var host = this.get(HOST),
_xy = [host.actXY[0], host.actXY[1]],
r = this.getRegion(true);
if (this.get('stickX')) {
_xy[1] = (host.startXY[1] - host.deltaXY[1]);
}
if (this.get('stickY')) {
_xy[0] = (host.startXY[0] - host.deltaXY[0]);
}
if (r) {
_xy = this._checkRegion(_xy);
}
_xy = this._checkTicks(_xy, r);
host.actXY = _xy;
},
/**
* Fires after drag:drag. Handle the tickX and tickX align events.
* @method drag
*/
drag: function() {
var host = this.get(HOST),
xt = this.get('tickX'),
yt = this.get('tickY'),
_xy = [host.actXY[0], host.actXY[1]];
if ((Y.Lang.isNumber(xt) || this.get(TICK_X_ARRAY)) && (this._lastTickXFired !== _xy[0])) {
this._tickAlignX();
this._lastTickXFired = _xy[0];
}
if ((Y.Lang.isNumber(yt) || this.get(TICK_Y_ARRAY)) && (this._lastTickYFired !== _xy[1])) {
this._tickAlignY();
this._lastTickYFired = _xy[1];
}
},
/**
* This method delegates the proper helper method for tick calculations
* @private
* @method _checkTicks
* @param {Array} xy The XY coords for the Drag
* @param {Object} r The optional region that we are bound to.
* @return {Array} The calced XY coords
*/
_checkTicks: function(xy, r) {
var host = this.get(HOST),
lx = (host.startXY[0] - host.deltaXY[0]),
ly = (host.startXY[1] - host.deltaXY[1]),
xt = this.get('tickX'),
yt = this.get('tickY');
if (xt && !this.get(TICK_X_ARRAY)) {
xy[0] = DDM._calcTicks(xy[0], lx, xt, r[LEFT], r[RIGHT]);
}
if (yt && !this.get(TICK_Y_ARRAY)) {
xy[1] = DDM._calcTicks(xy[1], ly, yt, r[TOP], r[BOTTOM]);
}
if (this.get(TICK_X_ARRAY)) {
xy[0] = DDM._calcTickArray(xy[0], this.get(TICK_X_ARRAY), r[LEFT], r[RIGHT]);
}
if (this.get(TICK_Y_ARRAY)) {
xy[1] = DDM._calcTickArray(xy[1], this.get(TICK_Y_ARRAY), r[TOP], r[BOTTOM]);
}
return xy;
},
/**
* Fires when the actXY[0] reach a new value respecting the tickX gap.
* @private
* @method _tickAlignX
*/
_tickAlignX: function() {
this.fire(EV_TICK_ALIGN_X);
},
/**
* Fires when the actXY[1] reach a new value respecting the tickY gap.
* @private
* @method _tickAlignY
*/
_tickAlignY: function() {
this.fire(EV_TICK_ALIGN_Y);
}
};
Y.namespace('Plugin');
Y.extend(C, Y.Base, proto);
Y.Plugin.DDConstrained = C;
Y.mix(DDM, {
/**
* Helper method to calculate the tick offsets for a given position
* @for DDM
* @namespace DD
* @private
* @method _calcTicks
* @param {Number} pos The current X or Y position
* @param {Number} start The start X or Y position
* @param {Number} tick The X or Y tick increment
* @param {Number} off1 The min offset that we can't pass (region)
* @param {Number} off2 The max offset that we can't pass (region)
* @return {Number} The new position based on the tick calculation
*/
_calcTicks: function(pos, start, tick, off1, off2) {
var ix = ((pos - start) / tick),
min = Math.floor(ix),
max = Math.ceil(ix);
if ((min !== 0) || (max !== 0)) {
if ((ix >= min) && (ix <= max)) {
pos = (start + (tick * min));
if (off1 && off2) {
if (pos < off1) {
pos = (start + (tick * (min + 1)));
}
if (pos > off2) {
pos = (start + (tick * (min - 1)));
}
}
}
}
return pos;
},
/**
* This method is used with the tickXArray and tickYArray config options
* @for DDM
* @namespace DD
* @private
* @method _calcTickArray
* @param {Number} pos The current X or Y position
* @param {Number} ticks The array containing our custom tick positions.
* @param {Number} off1 The min offset that we can't pass (region)
* @param {Number} off2 The max offset that we can't pass (region)
* @return The tick position
*/
_calcTickArray: function(pos, ticks, off1, off2) {
var i = 0, len = ticks.length, next = 0,
diff1, diff2, ret;
if (!ticks || (ticks.length === 0)) {
return pos;
}
if (ticks[0] >= pos) {
return ticks[0];
}
for (i = 0; i < len; i++) {
next = (i + 1);
if (ticks[next] && ticks[next] >= pos) {
diff1 = pos - ticks[i];
diff2 = ticks[next] - pos;
ret = (diff2 > diff1) ? ticks[i] : ticks[next];
if (off1 && off2) {
if (ret > off2) {
if (ticks[i]) {
ret = ticks[i];
} else {
ret = ticks[len - 1];
}
}
}
return ret;
}
}
return ticks[ticks.length - 1];
}
});