text: /**
   * @license
   * Visual Blocks Editor
   *
   * Copyright 2013 Google Inc.
   * https://developers.google.com/blockly/
   *
   * 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 A div that floats on top of Blockly.  This singleton contains
   *     temporary HTML UI widgets that the user is currently interacting with.
   *     E.g. text input areas, colour pickers, context menus.
   * @author fraser@google.com (Neil Fraser)
   */
  'use strict';
  
  goog.provide('Blockly.WidgetDiv');
  
  goog.require('Blockly.Css');
  goog.require('goog.dom');
  goog.require('goog.style');
  
  
  /**
   * The HTML container.  Set once by Blockly.WidgetDiv.createDom.
   * @type {Element}
   */
  Blockly.WidgetDiv.DIV = null;
  
  /**
   * The object currently using this container.
   * @type {Object}
   * @private
   */
  Blockly.WidgetDiv.owner_ = null;
  
  /**
   * Optional cleanup function set by whichever object uses the widget.
   * @type {Function}
   * @private
   */
  Blockly.WidgetDiv.dispose_ = null;
  
  /**
   * Create the widget div and inject it onto the page.
   */
  Blockly.WidgetDiv.createDom = function() {
    if (Blockly.WidgetDiv.DIV) {
      return;  // Already created.
    }
    // Create an HTML container for popup overlays (e.g. editor widgets).
    Blockly.WidgetDiv.DIV = goog.dom.createDom('div', 'blocklyWidgetDiv');
    document.body.appendChild(Blockly.WidgetDiv.DIV);
  };
  
  /**
   * Initialize and display the widget div.  Close the old one if needed.
   * @param {!Object} newOwner The object that will be using this container.
   * @param {boolean} rtl Right-to-left (true) or left-to-right (false).
   * @param {Function} dispose Optional cleanup function to be run when the widget
   *   is closed.
   */
  Blockly.WidgetDiv.show = function(newOwner, rtl, dispose) {
    Blockly.WidgetDiv.hide();
    Blockly.WidgetDiv.owner_ = newOwner;
    Blockly.WidgetDiv.dispose_ = dispose;
    // Temporarily move the widget to the top of the screen so that it does not
    // cause a scrollbar jump in Firefox when displayed.
    var xy = goog.style.getViewportPageOffset(document);
    Blockly.WidgetDiv.DIV.style.top = xy.y + 'px';
    Blockly.WidgetDiv.DIV.style.direction = rtl ? 'rtl' : 'ltr';
    Blockly.WidgetDiv.DIV.style.display = 'block';
  };
  
  /**
   * Destroy the widget and hide the div.
   */
  Blockly.WidgetDiv.hide = function() {
    if (Blockly.WidgetDiv.owner_) {
      Blockly.WidgetDiv.DIV.style.display = 'none';
      Blockly.WidgetDiv.DIV.style.left = '';
      Blockly.WidgetDiv.DIV.style.top = '';
      Blockly.WidgetDiv.DIV.style.height = '';
      Blockly.WidgetDiv.dispose_ && Blockly.WidgetDiv.dispose_();
      Blockly.WidgetDiv.owner_ = null;
      Blockly.WidgetDiv.dispose_ = null;
      goog.dom.removeChildren(Blockly.WidgetDiv.DIV);
    }
  };
  
  /**
   * Is the container visible?
   * @return {boolean} True if visible.
   */
  Blockly.WidgetDiv.isVisible = function() {
    return !!Blockly.WidgetDiv.owner_;
  };
  
  /**
   * Destroy the widget and hide the div if it is being used by the specified
   *   object.
   * @param {!Object} oldOwner The object that was using this container.
   */
  Blockly.WidgetDiv.hideIfOwner = function(oldOwner) {
    if (Blockly.WidgetDiv.owner_ == oldOwner) {
      Blockly.WidgetDiv.hide();
    }
  };
  
  /**
   * Position the widget at a given location.  Prevent the widget from going
   * offscreen top or left (right in RTL).
   * @param {number} anchorX Horizontal location (window coorditates, not body).
   * @param {number} anchorY Vertical location (window coorditates, not body).
   * @param {!goog.math.Size} windowSize Height/width of window.
   * @param {!goog.math.Coordinate} scrollOffset X/y of window scrollbars.
   * @param {boolean} rtl True if RTL, false if LTR.
   */
  Blockly.WidgetDiv.position = function(anchorX, anchorY, windowSize,
                                        scrollOffset, rtl) {
    // Don't let the widget go above the top edge of the window.
    if (anchorY < scrollOffset.y) {
      anchorY = scrollOffset.y;
    }
    if (rtl) {
      // Don't let the widget go right of the right edge of the window.
      if (anchorX > windowSize.width + scrollOffset.x) {
        anchorX = windowSize.width + scrollOffset.x;
      }
    } else {
      // Don't let the widget go left of the left edge of the window.
      if (anchorX < scrollOffset.x) {
        anchorX = scrollOffset.x;
      }
    }
    Blockly.WidgetDiv.DIV.style.left = anchorX + 'px';
    Blockly.WidgetDiv.DIV.style.top = anchorY + 'px';
    Blockly.WidgetDiv.DIV.style.height =
        (windowSize.height - anchorY + scrollOffset.y) + 'px';
  };
  