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// Copyright 2006 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
* @fileoverview Anchored viewport positioning class.
*
* @author eae@google.com (Emil A Eklund)
*/
goog.provide('goog.positioning.AnchoredViewportPosition');
goog.require('goog.math.Box');
goog.require('goog.positioning');
goog.require('goog.positioning.AnchoredPosition');
goog.require('goog.positioning.Corner');
goog.require('goog.positioning.Overflow');
goog.require('goog.positioning.OverflowStatus');
/**
* Encapsulates a popup position where the popup is anchored at a corner of
* an element. The corners are swapped if dictated by the viewport. For instance
* if a popup is anchored with its top left corner to the bottom left corner of
* the anchor the popup is either displayed below the anchor (as specified) or
* above it if there's not enough room to display it below.
*
* When using this positioning object it's recommended that the movable element
* be absolutely positioned.
*
* @param {Element} anchorElement Element the movable element should be
* anchored against.
* @param {goog.positioning.Corner} corner Corner of anchored element the
* movable element should be positioned at.
* @param {boolean=} opt_adjust Whether the positioning should be adjusted until
* the element fits inside the viewport even if that means that the anchored
* corners are ignored.
* @param {goog.math.Box=} opt_overflowConstraint Box object describing the
* dimensions in which the movable element could be shown.
* @constructor
* @extends {goog.positioning.AnchoredPosition}
*/
goog.positioning.AnchoredViewportPosition = function(anchorElement,
corner,
opt_adjust,
opt_overflowConstraint) {
goog.positioning.AnchoredPosition.call(this, anchorElement, corner);
/**
* The last resort algorithm to use if the algorithm can't fit inside
* the viewport.
*
* IGNORE = do nothing, just display at the preferred position.
*
* ADJUST_X | ADJUST_Y = Adjust until the element fits, even if that means
* that the anchored corners are ignored.
*
* @type {number}
* @private
*/
this.lastResortOverflow_ = opt_adjust ?
(goog.positioning.Overflow.ADJUST_X |
goog.positioning.Overflow.ADJUST_Y) :
goog.positioning.Overflow.IGNORE;
/**
* The dimensions in which the movable element could be shown.
* @type {goog.math.Box|undefined}
* @private
*/
this.overflowConstraint_ = opt_overflowConstraint || undefined;
};
goog.inherits(goog.positioning.AnchoredViewportPosition,
goog.positioning.AnchoredPosition);
/**
* @return {number} A bitmask for the "last resort" overflow.
*/
goog.positioning.AnchoredViewportPosition.prototype.getLastResortOverflow =
function() {
return this.lastResortOverflow_;
};
/**
* @param {number} lastResortOverflow A bitmask for the "last resort" overflow,
* if we fail to fit the element on-screen.
*/
goog.positioning.AnchoredViewportPosition.prototype.setLastResortOverflow =
function(lastResortOverflow) {
this.lastResortOverflow_ = lastResortOverflow;
};
/**
* Repositions the movable element.
*
* @param {Element} movableElement Element to position.
* @param {goog.positioning.Corner} movableCorner Corner of the movable element
* that should be positioned adjacent to the anchored element.
* @param {goog.math.Box=} opt_margin A margin specified in pixels.
* @param {goog.math.Size=} opt_preferredSize The preferred size of the
* movableElement.
* @override
*/
goog.positioning.AnchoredViewportPosition.prototype.reposition = function(
movableElement, movableCorner, opt_margin, opt_preferredSize) {
var status = goog.positioning.positionAtAnchor(this.element, this.corner,
movableElement, movableCorner, null, opt_margin,
goog.positioning.Overflow.FAIL_X | goog.positioning.Overflow.FAIL_Y,
opt_preferredSize, this.overflowConstraint_);
// If the desired position is outside the viewport try mirroring the corners
// horizontally or vertically.
if (status & goog.positioning.OverflowStatus.FAILED) {
var cornerFallback = this.adjustCorner(status, this.corner);
var movableCornerFallback = this.adjustCorner(status, movableCorner);
status = goog.positioning.positionAtAnchor(this.element, cornerFallback,
movableElement, movableCornerFallback, null, opt_margin,
goog.positioning.Overflow.FAIL_X | goog.positioning.Overflow.FAIL_Y,
opt_preferredSize, this.overflowConstraint_);
if (status & goog.positioning.OverflowStatus.FAILED) {
// If that also fails, pick the best corner from the two tries,
// and adjust the position until it fits.
cornerFallback = this.adjustCorner(status, cornerFallback);
movableCornerFallback = this.adjustCorner(
status, movableCornerFallback);
goog.positioning.positionAtAnchor(this.element, cornerFallback,
movableElement, movableCornerFallback, null, opt_margin,
this.getLastResortOverflow(), opt_preferredSize,
this.overflowConstraint_);
}
}
};
/**
* Adjusts the corner if X or Y positioning failed.
* @param {number} status The status of the last positionAtAnchor call.
* @param {goog.positioning.Corner} corner The corner to adjust.
* @return {goog.positioning.Corner} The adjusted corner.
* @protected
*/
goog.positioning.AnchoredViewportPosition.prototype.adjustCorner = function(
status, corner) {
if (status & goog.positioning.OverflowStatus.FAILED_HORIZONTAL) {
corner = goog.positioning.flipCornerHorizontal(corner);
}
if (status & goog.positioning.OverflowStatus.FAILED_VERTICAL) {
corner = goog.positioning.flipCornerVertical(corner);
}
return corner;
};
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