text: // 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 A slider implementation that allows to select a value within a
   * range by dragging a thumb. The selected value is exposed through getValue().
   *
   * To decorate, the slider should be bound to an element with the class name
   * 'goog-slider' containing a child with the class name 'goog-slider-thumb',
   * whose position is set to relative.
   * Note that you won't be able to see these elements unless they are styled.
   *
   * Slider orientation is horizontal by default.
   * Use setOrientation(goog.ui.Slider.Orientation.VERTICAL) for a vertical
   * slider.
   *
   * Decorate Example:
   * <div id="slider" class="goog-slider">
   *   <div class="goog-slider-thumb"></div>
   * </div>
   *
   * JavaScript code:
   * <code>
   *   var slider = new goog.ui.Slider;
   *   slider.decorate(document.getElementById('slider'));
   * </code>
   *
   * @author arv@google.com (Erik Arvidsson)
   * @see ../demos/slider.html
   */
  
  // Implementation note: We implement slider by inheriting from baseslider,
  // which allows to select sub-ranges within a range using two thumbs. All we do
  // is we co-locate the two thumbs into one.
  
  goog.provide("goog.ui.Slider")
  goog.provide("goog.ui.Slider.Orientation")
  
  goog.require("goog.a11y.aria")
  goog.require("goog.a11y.aria.Role")
  goog.require("goog.dom")
  goog.require("goog.dom.TagName")
  goog.require("goog.ui.SliderBase")
  
  /**
   * This creates a slider object.
   * @param {goog.dom.DomHelper=} opt_domHelper Optional DOM helper.
   * @param {(function(number):?string)=} opt_labelFn An optional function mapping
   *     slider values to a description of the value.
   * @constructor
   * @extends {goog.ui.SliderBase}
   */
  goog.ui.Slider = function(opt_domHelper, opt_labelFn) {
    goog.ui.SliderBase.call(this, opt_domHelper, opt_labelFn)
    this.rangeModel.setExtent(0)
  }
  goog.inherits(goog.ui.Slider, goog.ui.SliderBase)
  goog.tagUnsealableClass(goog.ui.Slider)
  
  /**
   * Expose Enum of superclass (representing the orientation of the slider) within
   * Slider namespace.
   *
   * @enum {string}
   */
  goog.ui.Slider.Orientation = goog.ui.SliderBase.Orientation
  
  /**
   * The prefix we use for the CSS class names for the slider and its elements.
   * @type {string}
   */
  goog.ui.Slider.CSS_CLASS_PREFIX = goog.getCssName("goog-slider")
  
  /**
   * CSS class name for the single thumb element.
   * @type {string}
   */
  goog.ui.Slider.THUMB_CSS_CLASS = goog.getCssName(
    goog.ui.Slider.CSS_CLASS_PREFIX,
    "thumb"
  )
  
  /**
   * Returns CSS class applied to the slider element.
   * @param {goog.ui.SliderBase.Orientation} orient Orientation of the slider.
   * @return {string} The CSS class applied to the slider element.
   * @protected
   * @override
   */
  goog.ui.Slider.prototype.getCssClass = function(orient) {
    return orient == goog.ui.SliderBase.Orientation.VERTICAL
      ? goog.getCssName(goog.ui.Slider.CSS_CLASS_PREFIX, "vertical")
      : goog.getCssName(goog.ui.Slider.CSS_CLASS_PREFIX, "horizontal")
  }
  
  /**
   * Returns CSS class applied to the slider's thumb element.
   * @return {string} The CSS class applied to the slider's thumb element.
   * @protected
   */
  goog.ui.Slider.prototype.getThumbCssClass = function() {
    return goog.ui.Slider.THUMB_CSS_CLASS
  }
  
  /** @override */
  goog.ui.Slider.prototype.createThumbs = function() {
    // find thumb
    var element = this.getElement()
    var thumb = goog.dom.getElementsByTagNameAndClass(
      null,
      this.getThumbCssClass(),
      element
    )[0]
    if (!thumb) {
      thumb = this.createThumb_()
      element.appendChild(thumb)
    }
    this.valueThumb = this.extentThumb = /** @type {!HTMLDivElement} */ (thumb)
  }
  
  /**
   * Creates the thumb element.
   * @return {!HTMLDivElement} The created thumb element.
   * @private
   */
  goog.ui.Slider.prototype.createThumb_ = function() {
    var thumb = this.getDomHelper().createDom(
      goog.dom.TagName.DIV,
      this.getThumbCssClass()
    )
    goog.a11y.aria.setRole(thumb, goog.a11y.aria.Role.BUTTON)
    return /** @type {!HTMLDivElement} */ (thumb)
  }
  