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// Copyright 2006 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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 * @fileoverview Common positioning code.
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 *
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 * @author [email protected] (Emil A Eklund)
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 */
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goog.provide('goog.positioning');
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goog.provide('goog.positioning.Corner');
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goog.provide('goog.positioning.CornerBit');
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goog.provide('goog.positioning.Overflow');
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goog.provide('goog.positioning.OverflowStatus');
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goog.require('goog.asserts');
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goog.require('goog.dom');
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goog.require('goog.dom.TagName');
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goog.require('goog.math.Coordinate');
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goog.require('goog.math.Rect');
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goog.require('goog.math.Size');
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goog.require('goog.style');
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goog.require('goog.style.bidi');
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/**
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 * Enum for bits in the {@see goog.positioning.Corner) bitmap.
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 *
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 * @enum {number}
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 */
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goog.positioning.CornerBit = {
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  BOTTOM: 1,
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  CENTER: 2,
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  RIGHT: 4,
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  FLIP_RTL: 8
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};
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/**
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 * Enum for representing an element corner for positioning the popup.
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 *
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 * The START constants map to LEFT if element directionality is left
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 * to right and RIGHT if the directionality is right to left.
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 * Likewise END maps to RIGHT or LEFT depending on the directionality.
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 *
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 * @enum {number}
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 */
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goog.positioning.Corner = {
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  TOP_LEFT: 0,
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  TOP_RIGHT: goog.positioning.CornerBit.RIGHT,
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  BOTTOM_LEFT: goog.positioning.CornerBit.BOTTOM,
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  BOTTOM_RIGHT:
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      goog.positioning.CornerBit.BOTTOM | goog.positioning.CornerBit.RIGHT,
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  TOP_START: goog.positioning.CornerBit.FLIP_RTL,
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  TOP_END:
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      goog.positioning.CornerBit.FLIP_RTL | goog.positioning.CornerBit.RIGHT,
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  BOTTOM_START:
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      goog.positioning.CornerBit.BOTTOM | goog.positioning.CornerBit.FLIP_RTL,
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  BOTTOM_END: goog.positioning.CornerBit.BOTTOM |
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      goog.positioning.CornerBit.RIGHT | goog.positioning.CornerBit.FLIP_RTL,
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  TOP_CENTER: goog.positioning.CornerBit.CENTER,
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  BOTTOM_CENTER:
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      goog.positioning.CornerBit.BOTTOM | goog.positioning.CornerBit.CENTER
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};
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/**
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 * Enum for representing position handling in cases where the element would be
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 * positioned outside the viewport.
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 *
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 * @enum {number}
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 */
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goog.positioning.Overflow = {
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  /** Ignore overflow */
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  IGNORE: 0,
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  /** Try to fit horizontally in the viewport at all costs. */
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  ADJUST_X: 1,
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  /** If the element can't fit horizontally, report positioning failure. */
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  FAIL_X: 2,
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  /** Try to fit vertically in the viewport at all costs. */
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  ADJUST_Y: 4,
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  /** If the element can't fit vertically, report positioning failure. */
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  FAIL_Y: 8,
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  /** Resize the element's width to fit in the viewport. */
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  RESIZE_WIDTH: 16,
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  /** Resize the element's height to fit in the viewport. */
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  RESIZE_HEIGHT: 32,
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  /**
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   * If the anchor goes off-screen in the x-direction, position the movable
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   * element off-screen. Otherwise, try to fit horizontally in the viewport.
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   */
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  ADJUST_X_EXCEPT_OFFSCREEN: 64 | 1,
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  /**
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   * If the anchor goes off-screen in the y-direction, position the movable
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   * element off-screen. Otherwise, try to fit vertically in the viewport.
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   */
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  ADJUST_Y_EXCEPT_OFFSCREEN: 128 | 4
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};
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/**
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 * Enum for representing the outcome of a positioning call.
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 *
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 * @enum {number}
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 */
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goog.positioning.OverflowStatus = {
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  NONE: 0,
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  ADJUSTED_X: 1,
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  ADJUSTED_Y: 2,
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  WIDTH_ADJUSTED: 4,
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  HEIGHT_ADJUSTED: 8,
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  FAILED_LEFT: 16,
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  FAILED_RIGHT: 32,
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  FAILED_TOP: 64,
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  FAILED_BOTTOM: 128,
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  FAILED_OUTSIDE_VIEWPORT: 256
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};
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/**
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 * Shorthand to check if a status code contains any fail code.
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 * @type {number}
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 */
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goog.positioning.OverflowStatus.FAILED =
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    goog.positioning.OverflowStatus.FAILED_LEFT |
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    goog.positioning.OverflowStatus.FAILED_RIGHT |
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    goog.positioning.OverflowStatus.FAILED_TOP |
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    goog.positioning.OverflowStatus.FAILED_BOTTOM |
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    goog.positioning.OverflowStatus.FAILED_OUTSIDE_VIEWPORT;
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/**
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 * Shorthand to check if horizontal positioning failed.
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 * @type {number}
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 */
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goog.positioning.OverflowStatus.FAILED_HORIZONTAL =
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    goog.positioning.OverflowStatus.FAILED_LEFT |
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    goog.positioning.OverflowStatus.FAILED_RIGHT;
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/**
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 * Shorthand to check if vertical positioning failed.
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 * @type {number}
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 */
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goog.positioning.OverflowStatus.FAILED_VERTICAL =
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    goog.positioning.OverflowStatus.FAILED_TOP |
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    goog.positioning.OverflowStatus.FAILED_BOTTOM;
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/**
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 * Positions a movable element relative to an anchor element. The caller
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 * specifies the corners that should touch. This functions then moves the
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 * movable element accordingly.
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 *
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 * @param {Element} anchorElement The element that is the anchor for where
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 *    the movable element should position itself.
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 * @param {goog.positioning.Corner} anchorElementCorner The corner of the
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 *     anchorElement for positioning the movable element.
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 * @param {Element} movableElement The element to move.
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 * @param {goog.positioning.Corner} movableElementCorner The corner of the
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 *     movableElement that that should be positioned adjacent to the anchor
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 *     element.
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 * @param {goog.math.Coordinate=} opt_offset An offset specified in pixels.
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 *    After the normal positioning algorithm is applied, the offset is then
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 *    applied. Positive coordinates move the popup closer to the center of the
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 *    anchor element. Negative coordinates move the popup away from the center
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 *    of the anchor element.
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 * @param {goog.math.Box=} opt_margin A margin specified in pixels.
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 *    After the normal positioning algorithm is applied and any offset, the
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 *    margin is then applied. Positive coordinates move the popup away from the
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 *    spot it was positioned towards its center. Negative coordinates move it
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 *    towards the spot it was positioned away from its center.
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 * @param {?number=} opt_overflow Overflow handling mode. Defaults to IGNORE if
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 *     not specified. Bitmap, {@see goog.positioning.Overflow}.
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 * @param {goog.math.Size=} opt_preferredSize The preferred size of the
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 *     movableElement.
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 * @param {goog.math.Box=} opt_viewport Box object describing the dimensions of
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 *     the viewport. The viewport is specified relative to offsetParent of
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 *     {@code movableElement}. In other words, the viewport can be thought of as
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 *     describing a "position: absolute" element contained in the offsetParent.
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 *     It defaults to visible area of nearest scrollable ancestor of
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 *     {@code movableElement} (see {@code goog.style.getVisibleRectForElement}).
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 * @return {goog.positioning.OverflowStatus} Status bitmap,
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 *     {@see goog.positioning.OverflowStatus}.
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 */
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goog.positioning.positionAtAnchor = function(
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    anchorElement, anchorElementCorner, movableElement, movableElementCorner,
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    opt_offset, opt_margin, opt_overflow, opt_preferredSize, opt_viewport) {
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  goog.asserts.assert(movableElement);
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  var movableParentTopLeft =
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      goog.positioning.getOffsetParentPageOffset(movableElement);
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  // Get the visible part of the anchor element.  anchorRect is
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  // relative to anchorElement's page.
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  var anchorRect = goog.positioning.getVisiblePart_(anchorElement);
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  // Translate anchorRect to be relative to movableElement's page.
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  goog.style.translateRectForAnotherFrame(
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      anchorRect, goog.dom.getDomHelper(anchorElement),
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      goog.dom.getDomHelper(movableElement));
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  // Offset based on which corner of the element we want to position against.
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  var corner =
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      goog.positioning.getEffectiveCorner(anchorElement, anchorElementCorner);
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  var offsetLeft = anchorRect.left;
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  if (corner & goog.positioning.CornerBit.RIGHT) {
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    offsetLeft += anchorRect.width;
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  } else if (corner & goog.positioning.CornerBit.CENTER) {
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    offsetLeft += anchorRect.width / 2;
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  }
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  // absolutePos is a candidate position relative to the
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  // movableElement's window.
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  var absolutePos = new goog.math.Coordinate(
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      offsetLeft, anchorRect.top +
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          (corner & goog.positioning.CornerBit.BOTTOM ? anchorRect.height : 0));
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  // Translate absolutePos to be relative to the offsetParent.
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  absolutePos =
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      goog.math.Coordinate.difference(absolutePos, movableParentTopLeft);
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  // Apply offset, if specified
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  if (opt_offset) {
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    absolutePos.x +=
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        (corner & goog.positioning.CornerBit.RIGHT ? -1 : 1) * opt_offset.x;
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    absolutePos.y +=
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        (corner & goog.positioning.CornerBit.BOTTOM ? -1 : 1) * opt_offset.y;
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  }
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  // Determine dimension of viewport.
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  var viewport;
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  if (opt_overflow) {
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    if (opt_viewport) {
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      viewport = opt_viewport;
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    } else {
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      viewport = goog.style.getVisibleRectForElement(movableElement);
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      if (viewport) {
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        viewport.top -= movableParentTopLeft.y;
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        viewport.right -= movableParentTopLeft.x;
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        viewport.bottom -= movableParentTopLeft.y;
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        viewport.left -= movableParentTopLeft.x;
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      }
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    }
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  }
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  return goog.positioning.positionAtCoordinate(
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      absolutePos, movableElement, movableElementCorner, opt_margin, viewport,
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      opt_overflow, opt_preferredSize);
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};
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/**
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 * Calculates the page offset of the given element's
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 * offsetParent. This value can be used to translate any x- and
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 * y-offset relative to the page to an offset relative to the
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 * offsetParent, which can then be used directly with as position
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 * coordinate for {@code positionWithCoordinate}.
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 * @param {!Element} movableElement The element to calculate.
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 * @return {!goog.math.Coordinate} The page offset, may be (0, 0).
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 */
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goog.positioning.getOffsetParentPageOffset = function(movableElement) {
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  // Ignore offset for the BODY element unless its position is non-static.
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  // For cases where the offset parent is HTML rather than the BODY (such as in
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  // IE strict mode) there's no need to get the position of the BODY as it
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  // doesn't affect the page offset.
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  var movableParentTopLeft;
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  var parent = /** @type {?} */ (movableElement).offsetParent;
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  if (parent) {
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    var isBody = parent.tagName == goog.dom.TagName.HTML ||
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        parent.tagName == goog.dom.TagName.BODY;
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    if (!isBody || goog.style.getComputedPosition(parent) != 'static') {
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      // Get the top-left corner of the parent, in page coordinates.
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      movableParentTopLeft = goog.style.getPageOffset(parent);
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      if (!isBody) {
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        movableParentTopLeft = goog.math.Coordinate.difference(
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            movableParentTopLeft,
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            new goog.math.Coordinate(
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                goog.style.bidi.getScrollLeft(parent), parent.scrollTop));
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      }
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    }
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  }
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  return movableParentTopLeft || new goog.math.Coordinate();
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};
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/**
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 * Returns intersection of the specified element and
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 * goog.style.getVisibleRectForElement for it.
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 *
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 * @param {Element} el The target element.
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 * @return {!goog.math.Rect} Intersection of getVisibleRectForElement
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 *     and the current bounding rectangle of the element.  If the
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 *     intersection is empty, returns the bounding rectangle.
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 * @private
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 */
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goog.positioning.getVisiblePart_ = function(el) {
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  var rect = goog.style.getBounds(el);
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  var visibleBox = goog.style.getVisibleRectForElement(el);
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  if (visibleBox) {
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    rect.intersection(goog.math.Rect.createFromBox(visibleBox));
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  }
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  return rect;
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};
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/**
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 * Positions the specified corner of the movable element at the
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 * specified coordinate.
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 *
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 * @param {goog.math.Coordinate} absolutePos The coordinate to position the
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 *     element at.
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 * @param {Element} movableElement The element to be positioned.
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 * @param {goog.positioning.Corner} movableElementCorner The corner of the
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 *     movableElement that that should be positioned.
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 * @param {goog.math.Box=} opt_margin A margin specified in pixels.
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 *    After the normal positioning algorithm is applied and any offset, the
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 *    margin is then applied. Positive coordinates move the popup away from the
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 *    spot it was positioned towards its center. Negative coordinates move it
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 *    towards the spot it was positioned away from its center.
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 * @param {goog.math.Box=} opt_viewport Box object describing the dimensions of
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 *     the viewport. Required if opt_overflow is specified.
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 * @param {?number=} opt_overflow Overflow handling mode. Defaults to IGNORE if
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 *     not specified, {@see goog.positioning.Overflow}.
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 * @param {goog.math.Size=} opt_preferredSize The preferred size of the
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 *     movableElement. Defaults to the current size.
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 * @return {goog.positioning.OverflowStatus} Status bitmap.
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 */
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goog.positioning.positionAtCoordinate = function(
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    absolutePos, movableElement, movableElementCorner, opt_margin, opt_viewport,
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    opt_overflow, opt_preferredSize) {
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  absolutePos = absolutePos.clone();
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  // Offset based on attached corner and desired margin.
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  var corner =
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      goog.positioning.getEffectiveCorner(movableElement, movableElementCorner);
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  var elementSize = goog.style.getSize(movableElement);
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  var size =
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      opt_preferredSize ? opt_preferredSize.clone() : elementSize.clone();
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  var positionResult = goog.positioning.getPositionAtCoordinate(
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      absolutePos, size, corner, opt_margin, opt_viewport, opt_overflow);
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365
  if (positionResult.status & goog.positioning.OverflowStatus.FAILED) {
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    return positionResult.status;
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  }
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  goog.style.setPosition(movableElement, positionResult.rect.getTopLeft());
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  size = positionResult.rect.getSize();
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  if (!goog.math.Size.equals(elementSize, size)) {
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    goog.style.setBorderBoxSize(movableElement, size);
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  }
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  return positionResult.status;
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};
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/**
380
 * Computes the position for an element to be placed on-screen at the
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 * specified coordinates. Returns an object containing both the resulting
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 * rectangle, and the overflow status bitmap.
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 *
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 * @param {!goog.math.Coordinate} absolutePos The coordinate to position the
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 *     element at.
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 * @param {!goog.math.Size} elementSize The size of the element to be
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 *     positioned.
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 * @param {goog.positioning.Corner} elementCorner The corner of the
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 *     movableElement that that should be positioned.
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 * @param {goog.math.Box=} opt_margin A margin specified in pixels.
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 *    After the normal positioning algorithm is applied and any offset, the
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 *    margin is then applied. Positive coordinates move the popup away from the
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 *    spot it was positioned towards its center. Negative coordinates move it
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 *    towards the spot it was positioned away from its center.
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 * @param {goog.math.Box=} opt_viewport Box object describing the dimensions of
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 *     the viewport. Required if opt_overflow is specified.
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 * @param {?number=} opt_overflow Overflow handling mode. Defaults to IGNORE
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 *     if not specified, {@see goog.positioning.Overflow}.
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 * @return {{rect:!goog.math.Rect, status:goog.positioning.OverflowStatus}}
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 *     Object containing the computed position and status bitmap.
401
 */
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goog.positioning.getPositionAtCoordinate = function(
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    absolutePos, elementSize, elementCorner, opt_margin, opt_viewport,
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    opt_overflow) {
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  absolutePos = absolutePos.clone();
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  elementSize = elementSize.clone();
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  var status = goog.positioning.OverflowStatus.NONE;
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409
  if (opt_margin || elementCorner != goog.positioning.Corner.TOP_LEFT) {
410
    if (elementCorner & goog.positioning.CornerBit.RIGHT) {
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      absolutePos.x -= elementSize.width + (opt_margin ? opt_margin.right : 0);
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    } else if (elementCorner & goog.positioning.CornerBit.CENTER) {
413
      absolutePos.x -= elementSize.width / 2;
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    } else if (opt_margin) {
415
      absolutePos.x += opt_margin.left;
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    }
417
    if (elementCorner & goog.positioning.CornerBit.BOTTOM) {
418
      absolutePos.y -=
419
          elementSize.height + (opt_margin ? opt_margin.bottom : 0);
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    } else if (opt_margin) {
421
      absolutePos.y += opt_margin.top;
422
    }
423
  }
424

425
  // Adjust position to fit inside viewport.
426
  if (opt_overflow) {
427
    status = opt_viewport ?
428
        goog.positioning.adjustForViewport_(
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            absolutePos, elementSize, opt_viewport, opt_overflow) :
430
        goog.positioning.OverflowStatus.FAILED_OUTSIDE_VIEWPORT;
431
  }
432

433
  var rect = new goog.math.Rect(0, 0, 0, 0);
434
  rect.left = absolutePos.x;
435
  rect.top = absolutePos.y;
436
  rect.width = elementSize.width;
437
  rect.height = elementSize.height;
438
  return {rect: rect, status: status};
439
};
440

441

442
/**
443
 * Adjusts the position and/or size of an element, identified by its position
444
 * and size, to fit inside the viewport. If the position or size of the element
445
 * is adjusted the pos or size objects, respectively, are modified.
446
 *
447
 * @param {goog.math.Coordinate} pos Position of element, updated if the
448
 *     position is adjusted.
449
 * @param {goog.math.Size} size Size of element, updated if the size is
450
 *     adjusted.
451
 * @param {goog.math.Box} viewport Bounding box describing the viewport.
452
 * @param {number} overflow Overflow handling mode,
453
 *     {@see goog.positioning.Overflow}.
454
 * @return {goog.positioning.OverflowStatus} Status bitmap,
455
 *     {@see goog.positioning.OverflowStatus}.
456
 * @private
457
 */
458
goog.positioning.adjustForViewport_ = function(pos, size, viewport, overflow) {
459
  var status = goog.positioning.OverflowStatus.NONE;
460

461
  var ADJUST_X_EXCEPT_OFFSCREEN =
462
      goog.positioning.Overflow.ADJUST_X_EXCEPT_OFFSCREEN;
463
  var ADJUST_Y_EXCEPT_OFFSCREEN =
464
      goog.positioning.Overflow.ADJUST_Y_EXCEPT_OFFSCREEN;
465
  if ((overflow & ADJUST_X_EXCEPT_OFFSCREEN) == ADJUST_X_EXCEPT_OFFSCREEN &&
466
      (pos.x < viewport.left || pos.x >= viewport.right)) {
467
    overflow &= ~goog.positioning.Overflow.ADJUST_X;
468
  }
469
  if ((overflow & ADJUST_Y_EXCEPT_OFFSCREEN) == ADJUST_Y_EXCEPT_OFFSCREEN &&
470
      (pos.y < viewport.top || pos.y >= viewport.bottom)) {
471
    overflow &= ~goog.positioning.Overflow.ADJUST_Y;
472
  }
473

474
  // Left edge outside viewport, try to move it.
475
  if (pos.x < viewport.left && overflow & goog.positioning.Overflow.ADJUST_X) {
476
    pos.x = viewport.left;
477
    status |= goog.positioning.OverflowStatus.ADJUSTED_X;
478
  }
479

480
  // Ensure object is inside the viewport width if required.
481
  if (overflow & goog.positioning.Overflow.RESIZE_WIDTH) {
482
    // Move left edge inside viewport.
483
    var originalX = pos.x;
484
    if (pos.x < viewport.left) {
485
      pos.x = viewport.left;
486
      status |= goog.positioning.OverflowStatus.WIDTH_ADJUSTED;
487
    }
488

489
    // Shrink width to inside right of viewport.
490
    if (pos.x + size.width > viewport.right) {
491
      // Set the width to be either the new maximum width within the viewport
492
      // or the width originally within the viewport, whichever is less.
493
      size.width = Math.min(
494
          viewport.right - pos.x, originalX + size.width - viewport.left);
495
      size.width = Math.max(size.width, 0);
496
      status |= goog.positioning.OverflowStatus.WIDTH_ADJUSTED;
497
    }
498
  }
499

500
  // Right edge outside viewport, try to move it.
501
  if (pos.x + size.width > viewport.right &&
502
      overflow & goog.positioning.Overflow.ADJUST_X) {
503
    pos.x = Math.max(viewport.right - size.width, viewport.left);
504
    status |= goog.positioning.OverflowStatus.ADJUSTED_X;
505
  }
506

507
  // Left or right edge still outside viewport, fail if the FAIL_X option was
508
  // specified, ignore it otherwise.
509
  if (overflow & goog.positioning.Overflow.FAIL_X) {
510
    status |=
511
        (pos.x < viewport.left ? goog.positioning.OverflowStatus.FAILED_LEFT :
512
                                 0) |
513
        (pos.x + size.width > viewport.right ?
514
             goog.positioning.OverflowStatus.FAILED_RIGHT :
515
             0);
516
  }
517

518
  // Top edge outside viewport, try to move it.
519
  if (pos.y < viewport.top && overflow & goog.positioning.Overflow.ADJUST_Y) {
520
    pos.y = viewport.top;
521
    status |= goog.positioning.OverflowStatus.ADJUSTED_Y;
522
  }
523

524
  // Ensure object is inside the viewport height if required.
525
  if (overflow & goog.positioning.Overflow.RESIZE_HEIGHT) {
526
    // Move top edge inside viewport.
527
    var originalY = pos.y;
528
    if (pos.y < viewport.top) {
529
      pos.y = viewport.top;
530
      status |= goog.positioning.OverflowStatus.HEIGHT_ADJUSTED;
531
    }
532

533
    // Shrink height to inside bottom of viewport.
534
    if (pos.y + size.height > viewport.bottom) {
535
      // Set the height to be either the new maximum height within the viewport
536
      // or the height originally within the viewport, whichever is less.
537
      size.height = Math.min(
538
          viewport.bottom - pos.y, originalY + size.height - viewport.top);
539
      size.height = Math.max(size.height, 0);
540
      status |= goog.positioning.OverflowStatus.HEIGHT_ADJUSTED;
541
    }
542
  }
543

544
  // Bottom edge outside viewport, try to move it.
545
  if (pos.y + size.height > viewport.bottom &&
546
      overflow & goog.positioning.Overflow.ADJUST_Y) {
547
    pos.y = Math.max(viewport.bottom - size.height, viewport.top);
548
    status |= goog.positioning.OverflowStatus.ADJUSTED_Y;
549
  }
550

551
  // Top or bottom edge still outside viewport, fail if the FAIL_Y option was
552
  // specified, ignore it otherwise.
553
  if (overflow & goog.positioning.Overflow.FAIL_Y) {
554
    status |=
555
        (pos.y < viewport.top ? goog.positioning.OverflowStatus.FAILED_TOP :
556
                                0) |
557
        (pos.y + size.height > viewport.bottom ?
558
             goog.positioning.OverflowStatus.FAILED_BOTTOM :
559
             0);
560
  }
561

562
  return status;
563
};
564

565

566
/**
567
 * Returns an absolute corner (top/bottom left/right) given an absolute
568
 * or relative (top/bottom start/end) corner and the direction of an element.
569
 * Absolute corners remain unchanged.
570
 * @param {Element} element DOM element to test for RTL direction.
571
 * @param {goog.positioning.Corner} corner The popup corner used for
572
 *     positioning.
573
 * @return {goog.positioning.Corner} Effective corner.
574
 */
575
goog.positioning.getEffectiveCorner = function(element, corner) {
576
  return /** @type {goog.positioning.Corner} */ (
577
      (corner & goog.positioning.CornerBit.FLIP_RTL &&
578
               goog.style.isRightToLeft(element) ?
579
           corner ^ goog.positioning.CornerBit.RIGHT :
580
           corner) &
581
      ~goog.positioning.CornerBit.FLIP_RTL);
582
};
583

584

585
/**
586
 * Returns the corner opposite the given one horizontally.
587
 * @param {goog.positioning.Corner} corner The popup corner used to flip.
588
 * @return {goog.positioning.Corner} The opposite corner horizontally.
589
 */
590
goog.positioning.flipCornerHorizontal = function(corner) {
591
  return /** @type {goog.positioning.Corner} */ (
592
      corner ^ goog.positioning.CornerBit.RIGHT);
593
};
594

595

596
/**
597
 * Returns the corner opposite the given one vertically.
598
 * @param {goog.positioning.Corner} corner The popup corner used to flip.
599
 * @return {goog.positioning.Corner} The opposite corner vertically.
600
 */
601
goog.positioning.flipCornerVertical = function(corner) {
602
  return /** @type {goog.positioning.Corner} */ (
603
      corner ^ goog.positioning.CornerBit.BOTTOM);
604
};
605

606

607
/**
608
 * Returns the corner opposite the given one horizontally and vertically.
609
 * @param {goog.positioning.Corner} corner The popup corner used to flip.
610
 * @return {goog.positioning.Corner} The opposite corner horizontally and
611
 *     vertically.
612
 */
613
goog.positioning.flipCorner = function(corner) {
614
  return /** @type {goog.positioning.Corner} */ (
615
      corner ^ goog.positioning.CornerBit.BOTTOM ^
616
      goog.positioning.CornerBit.RIGHT);
617
};
618

619