/*!
 * viewer.js v1.10.4
 * https://fengyuanchen.github.io/viewerjs
 *
 * copyright 2015-present chen fengyuan
 * released under the mit license
 *
 * date: 2022-02-13t08:40:00.127z
 */

(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global = typeof globalthis !== 'undefined' ? globalthis : global || self, global.viewer = factory());
})(this, (function () { 'use strict';

  function ownkeys(object, enumerableonly) {
    var keys = object.keys(object);

    if (object.getownpropertysymbols) {
      var symbols = object.getownpropertysymbols(object);
      enumerableonly && (symbols = symbols.filter(function (sym) {
        return object.getownpropertydescriptor(object, sym).enumerable;
      })), keys.push.apply(keys, symbols);
    }

    return keys;
  }

  function _objectspread2(target) {
    for (var i = 1; i < arguments.length; i++) {
      var source = null != arguments[i] ? arguments[i] : {};
      i % 2 ? ownkeys(object(source), !0).foreach(function (key) {
        _defineproperty(target, key, source[key]);
      }) : object.getownpropertydescriptors ? object.defineproperties(target, object.getownpropertydescriptors(source)) : ownkeys(object(source)).foreach(function (key) {
        object.defineproperty(target, key, object.getownpropertydescriptor(source, key));
      });
    }

    return target;
  }

  function _typeof(obj) {
    "@babel/helpers - typeof";

    return _typeof = "function" == typeof symbol && "symbol" == typeof symbol.iterator ? function (obj) {
      return typeof obj;
    } : function (obj) {
      return obj && "function" == typeof symbol && obj.constructor === symbol && obj !== symbol.prototype ? "symbol" : typeof obj;
    }, _typeof(obj);
  }

  function _classcallcheck(instance, constructor) {
    if (!(instance instanceof constructor)) {
      throw new typeerror("cannot call a class as a function");
    }
  }

  function _defineproperties(target, props) {
    for (var i = 0; i < props.length; i++) {
      var descriptor = props[i];
      descriptor.enumerable = descriptor.enumerable || false;
      descriptor.configurable = true;
      if ("value" in descriptor) descriptor.writable = true;
      object.defineproperty(target, descriptor.key, descriptor);
    }
  }

  function _createclass(constructor, protoprops, staticprops) {
    if (protoprops) _defineproperties(constructor.prototype, protoprops);
    if (staticprops) _defineproperties(constructor, staticprops);
    object.defineproperty(constructor, "prototype", {
      writable: false
    });
    return constructor;
  }

  function _defineproperty(obj, key, value) {
    if (key in obj) {
      object.defineproperty(obj, key, {
        value: value,
        enumerable: true,
        configurable: true,
        writable: true
      });
    } else {
      obj[key] = value;
    }

    return obj;
  }

  var defaults = {
    /**
     * enable a modal backdrop, specify `static` for a backdrop
     * which doesn't close the modal on click.
     * @type {boolean}
     */
    backdrop: true,

    /**
     * show the button on the top-right of the viewer.
     * @type {boolean}
     */
    button: true,

    /**
     * show the navbar.
     * @type {boolean | number}
     */
    navbar: true,

    /**
     * specify the visibility and the content of the title.
     * @type {boolean | number | function | array}
     */
    title: true,

    /**
     * show the toolbar.
     * @type {boolean | number | object}
     */
    toolbar: true,

    /**
     * custom class name(s) to add to the viewer's root element.
     * @type {string}
     */
    classname: '',

    /**
     * define where to put the viewer in modal mode.
     * @type {string | element}
     */
    container: 'body',

    /**
     * filter the images for viewing. return true if the image is viewable.
     * @type {function}
     */
    filter: null,

    /**
     * enable to request fullscreen when play.
     * {@link https://developer.mozilla.org/en-us/docs/web/api/fullscreenoptions}
     * @type {boolean|fullscreenoptions}
     */
    fullscreen: true,

    /**
     * define the extra attributes to inherit from the original image.
     * @type {array}
     */
    inheritedattributes: ['crossorigin', 'decoding', 'ismap', 'loading', 'referrerpolicy', 'sizes', 'srcset', 'usemap'],

    /**
     * define the initial index of image for viewing.
     * @type {number}
     */
    initialviewindex: 0,

    /**
     * enable inline mode.
     * @type {boolean}
     */
    inline: false,

    /**
     * the amount of time to delay between automatically cycling an image when playing.
     * @type {number}
     */
    interval: 5000,

    /**
     * enable keyboard support.
     * @type {boolean}
     */
    keyboard: true,

    /**
     * focus the viewer when initialized.
     * @type {boolean}
     */
    focus: true,

    /**
     * indicate if show a loading spinner when load image or not.
     * @type {boolean}
     */
    loading: true,

    /**
     * indicate if enable loop viewing or not.
     * @type {boolean}
     */
    loop: true,

    /**
     * min width of the viewer in inline mode.
     * @type {number}
     */
    minwidth: 200,

    /**
     * min height of the viewer in inline mode.
     * @type {number}
     */
    minheight: 100,

    /**
     * enable to move the image.
     * @type {boolean}
     */
    movable: true,

    /**
     * enable to rotate the image.
     * @type {boolean}
     */
    rotatable: true,

    /**
     * enable to scale the image.
     * @type {boolean}
     */
    scalable: true,

    /**
     * enable to zoom the image.
     * @type {boolean}
     */
    zoomable: true,

    /**
     * enable to zoom the current image by dragging on the touch screen.
     * @type {boolean}
     */
    zoomontouch: true,

    /**
     * enable to zoom the image by wheeling mouse.
     * @type {boolean}
     */
    zoomonwheel: true,

    /**
     * enable to slide to the next or previous image by swiping on the touch screen.
     * @type {boolean}
     */
    slideontouch: true,

    /**
     * indicate if toggle the image size between its natural size
     * and initial size when double click on the image or not.
     * @type {boolean}
     */
    toggleondblclick: true,

    /**
     * show the tooltip with image ratio (percentage) when zoom in or zoom out.
     * @type {boolean}
     */
    tooltip: true,

    /**
     * enable css3 transition for some special elements.
     * @type {boolean}
     */
    transition: true,

    /**
     * define the css `z-index` value of viewer in modal mode.
     * @type {number}
     */
    zindex: 2015,

    /**
     * define the css `z-index` value of viewer in inline mode.
     * @type {number}
     */
    zindexinline: 0,

    /**
     * define the ratio when zoom the image by wheeling mouse.
     * @type {number}
     */
    zoomratio: 0.1,

    /**
     * define the min ratio of the image when zoom out.
     * @type {number}
     */
    minzoomratio: 0.01,

    /**
     * define the max ratio of the image when zoom in.
     * @type {number}
     */
    maxzoomratio: 100,

    /**
     * define where to get the original image url for viewing.
     * @type {string | function}
     */
    url: 'src',

    /**
     * event shortcuts.
     * @type {function}
     */
    ready: null,
    show: null,
    shown: null,
    hide: null,
    hidden: null,
    view: null,
    viewed: null,
    move: null,
    moved: null,
    rotate: null,
    rotated: null,
    scale: null,
    scaled: null,
    zoom: null,
    zoomed: null,
    play: null,
    stop: null
  };

  var template = '<div class="viewer-container" tabindex="-1" touch-action="none">' + '<div class="viewer-canvas"></div>' + '<div class="viewer-footer">' + '<div class="viewer-title"></div>' + '<div class="viewer-toolbar"></div>' + '<div class="viewer-navbar">' + '<ul class="viewer-list" role="navigation"></ul>' + '</div>' + '</div>' + '<div class="viewer-tooltip" role="alert" aria-hidden="true"></div>' + '<div class="viewer-button" data-viewer-action="mix" role="button"></div>' + '<div class="viewer-player"></div>' + '</div>';

  var is_browser = typeof window !== 'undefined' && typeof window.document !== 'undefined';
  var window = is_browser ? window : {};
  var is_touch_device = is_browser && window.document.documentelement ? 'ontouchstart' in window.document.documentelement : false;
  var has_pointer_event = is_browser ? 'pointerevent' in window : false;
  var namespace = 'viewer'; // actions

  var action_move = 'move';
  var action_switch = 'switch';
  var action_zoom = 'zoom'; // classes

  var class_active = "".concat(namespace, "-active");
  var class_close = "".concat(namespace, "-close");
  var class_fade = "".concat(namespace, "-fade");
  var class_fixed = "".concat(namespace, "-fixed");
  var class_fullscreen = "".concat(namespace, "-fullscreen");
  var class_fullscreen_exit = "".concat(namespace, "-fullscreen-exit");
  var class_hide = "".concat(namespace, "-hide");
  var class_hide_md_down = "".concat(namespace, "-hide-md-down");
  var class_hide_sm_down = "".concat(namespace, "-hide-sm-down");
  var class_hide_xs_down = "".concat(namespace, "-hide-xs-down");
  var class_in = "".concat(namespace, "-in");
  var class_invisible = "".concat(namespace, "-invisible");
  var class_loading = "".concat(namespace, "-loading");
  var class_move = "".concat(namespace, "-move");
  var class_open = "".concat(namespace, "-open");
  var class_show = "".concat(namespace, "-show");
  var class_transition = "".concat(namespace, "-transition"); // native events

  var event_click = 'click';
  var event_dblclick = 'dblclick';
  var event_drag_start = 'dragstart';
  var event_focusin = 'focusin';
  var event_key_down = 'keydown';
  var event_load = 'load';
  var event_error = 'error';
  var event_touch_end = is_touch_device ? 'touchend touchcancel' : 'mouseup';
  var event_touch_move = is_touch_device ? 'touchmove' : 'mousemove';
  var event_touch_start = is_touch_device ? 'touchstart' : 'mousedown';
  var event_pointer_down = has_pointer_event ? 'pointerdown' : event_touch_start;
  var event_pointer_move = has_pointer_event ? 'pointermove' : event_touch_move;
  var event_pointer_up = has_pointer_event ? 'pointerup pointercancel' : event_touch_end;
  var event_resize = 'resize';
  var event_transition_end = 'transitionend';
  var event_wheel = 'wheel'; // custom events

  var event_ready = 'ready';
  var event_show = 'show';
  var event_shown = 'shown';
  var event_hide = 'hide';
  var event_hidden = 'hidden';
  var event_view = 'view';
  var event_viewed = 'viewed';
  var event_move = 'move';
  var event_moved = 'moved';
  var event_rotate = 'rotate';
  var event_rotated = 'rotated';
  var event_scale = 'scale';
  var event_scaled = 'scaled';
  var event_zoom = 'zoom';
  var event_zoomed = 'zoomed';
  var event_play = 'play';
  var event_stop = 'stop'; // data keys

  var data_action = "".concat(namespace, "action"); // regexps

  var regexp_spaces = /\s\s*/; // misc

  var buttons = ['zoom-in', 'zoom-out', 'one-to-one', 'reset', 'prev', 'play', 'next', 'rotate-left', 'rotate-right', 'flip-horizontal', 'flip-vertical'];

  /**
   * check if the given value is a string.
   * @param {*} value - the value to check.
   * @returns {boolean} returns `true` if the given value is a string, else `false`.
   */

  function isstring(value) {
    return typeof value === 'string';
  }
  /**
   * check if the given value is not a number.
   */

  var isnan = number.isnan || window.isnan;
  /**
   * check if the given value is a number.
   * @param {*} value - the value to check.
   * @returns {boolean} returns `true` if the given value is a number, else `false`.
   */

  function isnumber(value) {
    return typeof value === 'number' && !isnan(value);
  }
  /**
   * check if the given value is undefined.
   * @param {*} value - the value to check.
   * @returns {boolean} returns `true` if the given value is undefined, else `false`.
   */

  function isundefined(value) {
    return typeof value === 'undefined';
  }
  /**
   * check if the given value is an object.
   * @param {*} value - the value to check.
   * @returns {boolean} returns `true` if the given value is an object, else `false`.
   */

  function isobject(value) {
    return _typeof(value) === 'object' && value !== null;
  }
  var hasownproperty = object.prototype.hasownproperty;
  /**
   * check if the given value is a plain object.
   * @param {*} value - the value to check.
   * @returns {boolean} returns `true` if the given value is a plain object, else `false`.
   */

  function isplainobject(value) {
    if (!isobject(value)) {
      return false;
    }

    try {
      var _constructor = value.constructor;
      var prototype = _constructor.prototype;
      return _constructor && prototype && hasownproperty.call(prototype, 'isprototypeof');
    } catch (error) {
      return false;
    }
  }
  /**
   * check if the given value is a function.
   * @param {*} value - the value to check.
   * @returns {boolean} returns `true` if the given value is a function, else `false`.
   */

  function isfunction(value) {
    return typeof value === 'function';
  }
  /**
   * iterate the given data.
   * @param {*} data - the data to iterate.
   * @param {function} callback - the process function for each element.
   * @returns {*} the original data.
   */

  function foreach(data, callback) {
    if (data && isfunction(callback)) {
      if (array.isarray(data) || isnumber(data.length)
      /* array-like */
      ) {
        var length = data.length;
        var i;

        for (i = 0; i < length; i += 1) {
          if (callback.call(data, data[i], i, data) === false) {
            break;
          }
        }
      } else if (isobject(data)) {
        object.keys(data).foreach(function (key) {
          callback.call(data, data[key], key, data);
        });
      }
    }

    return data;
  }
  /**
   * extend the given object.
   * @param {*} obj - the object to be extended.
   * @param {*} args - the rest objects which will be merged to the first object.
   * @returns {object} the extended object.
   */

  var assign = object.assign || function assign(obj) {
    for (var _len = arguments.length, args = new array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
      args[_key - 1] = arguments[_key];
    }

    if (isobject(obj) && args.length > 0) {
      args.foreach(function (arg) {
        if (isobject(arg)) {
          object.keys(arg).foreach(function (key) {
            obj[key] = arg[key];
          });
        }
      });
    }

    return obj;
  };
  var regexp_suffix = /^(?:width|height|left|top|marginleft|margintop)$/;
  /**
   * apply styles to the given element.
   * @param {element} element - the target element.
   * @param {object} styles - the styles for applying.
   */

  function setstyle(element, styles) {
    var style = element.style;
    foreach(styles, function (value, property) {
      if (regexp_suffix.test(property) && isnumber(value)) {
        value += 'px';
      }

      style[property] = value;
    });
  }
  /**
   * escape a string for using in html.
   * @param {string} value - the string to escape.
   * @returns {string} returns the escaped string.
   */

  function escapehtmlentities(value) {
    return isstring(value) ? value.replace(/&(?!amp;|quot;|#39;|lt;|gt;)/g, '&amp;').replace(/"/g, '&quot;').replace(/'/g, '&#39;').replace(/</g, '&lt;').replace(/>/g, '&gt;') : value;
  }
  /**
   * check if the given element has a special class.
   * @param {element} element - the element to check.
   * @param {string} value - the class to search.
   * @returns {boolean} returns `true` if the special class was found.
   */

  function hasclass(element, value) {
    if (!element || !value) {
      return false;
    }

    return element.classlist ? element.classlist.contains(value) : element.classname.indexof(value) > -1;
  }
  /**
   * add classes to the given element.
   * @param {element} element - the target element.
   * @param {string} value - the classes to be added.
   */

  function addclass(element, value) {
    if (!element || !value) {
      return;
    }

    if (isnumber(element.length)) {
      foreach(element, function (elem) {
        addclass(elem, value);
      });
      return;
    }

    if (element.classlist) {
      element.classlist.add(value);
      return;
    }

    var classname = element.classname.trim();

    if (!classname) {
      element.classname = value;
    } else if (classname.indexof(value) < 0) {
      element.classname = "".concat(classname, " ").concat(value);
    }
  }
  /**
   * remove classes from the given element.
   * @param {element} element - the target element.
   * @param {string} value - the classes to be removed.
   */

  function removeclass(element, value) {
    if (!element || !value) {
      return;
    }

    if (isnumber(element.length)) {
      foreach(element, function (elem) {
        removeclass(elem, value);
      });
      return;
    }

    if (element.classlist) {
      element.classlist.remove(value);
      return;
    }

    if (element.classname.indexof(value) >= 0) {
      element.classname = element.classname.replace(value, '');
    }
  }
  /**
   * add or remove classes from the given element.
   * @param {element} element - the target element.
   * @param {string} value - the classes to be toggled.
   * @param {boolean} added - add only.
   */

  function toggleclass(element, value, added) {
    if (!value) {
      return;
    }

    if (isnumber(element.length)) {
      foreach(element, function (elem) {
        toggleclass(elem, value, added);
      });
      return;
    } // ie10-11 doesn't support the second parameter of `classlist.toggle`


    if (added) {
      addclass(element, value);
    } else {
      removeclass(element, value);
    }
  }
  var regexp_hyphenate = /([a-z\d])([a-z])/g;
  /**
   * transform the given string from camelcase to kebab-case
   * @param {string} value - the value to transform.
   * @returns {string} the transformed value.
   */

  function hyphenate(value) {
    return value.replace(regexp_hyphenate, '$1-$2').tolowercase();
  }
  /**
   * get data from the given element.
   * @param {element} element - the target element.
   * @param {string} name - the data key to get.
   * @returns {string} the data value.
   */

  function getdata(element, name) {
    if (isobject(element[name])) {
      return element[name];
    }

    if (element.dataset) {
      return element.dataset[name];
    }

    return element.getattribute("data-".concat(hyphenate(name)));
  }
  /**
   * set data to the given element.
   * @param {element} element - the target element.
   * @param {string} name - the data key to set.
   * @param {string} data - the data value.
   */

  function setdata(element, name, data) {
    if (isobject(data)) {
      element[name] = data;
    } else if (element.dataset) {
      element.dataset[name] = data;
    } else {
      element.setattribute("data-".concat(hyphenate(name)), data);
    }
  }

  var oncesupported = function () {
    var supported = false;

    if (is_browser) {
      var once = false;

      var listener = function listener() {};

      var options = object.defineproperty({}, 'once', {
        get: function get() {
          supported = true;
          return once;
        },

        /**
         * this setter can fix a `typeerror` in strict mode
         * {@link https://developer.mozilla.org/en-us/docs/web/javascript/reference/errors/getter_only}
         * @param {boolean} value - the value to set
         */
        set: function set(value) {
          once = value;
        }
      });
      window.addeventlistener('test', listener, options);
      window.removeeventlistener('test', listener, options);
    }

    return supported;
  }();
  /**
   * remove event listener from the target element.
   * @param {element} element - the event target.
   * @param {string} type - the event type(s).
   * @param {function} listener - the event listener.
   * @param {object} options - the event options.
   */


  function removelistener(element, type, listener) {
    var options = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : {};
    var handler = listener;
    type.trim().split(regexp_spaces).foreach(function (event) {
      if (!oncesupported) {
        var listeners = element.listeners;

        if (listeners && listeners[event] && listeners[event][listener]) {
          handler = listeners[event][listener];
          delete listeners[event][listener];

          if (object.keys(listeners[event]).length === 0) {
            delete listeners[event];
          }

          if (object.keys(listeners).length === 0) {
            delete element.listeners;
          }
        }
      }

      element.removeeventlistener(event, handler, options);
    });
  }
  /**
   * add event listener to the target element.
   * @param {element} element - the event target.
   * @param {string} type - the event type(s).
   * @param {function} listener - the event listener.
   * @param {object} options - the event options.
   */

  function addlistener(element, type, listener) {
    var options = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : {};
    var _handler = listener;
    type.trim().split(regexp_spaces).foreach(function (event) {
      if (options.once && !oncesupported) {
        var _element$listeners = element.listeners,
            listeners = _element$listeners === void 0 ? {} : _element$listeners;

        _handler = function handler() {
          delete listeners[event][listener];
          element.removeeventlistener(event, _handler, options);

          for (var _len2 = arguments.length, args = new array(_len2), _key2 = 0; _key2 < _len2; _key2++) {
            args[_key2] = arguments[_key2];
          }

          listener.apply(element, args);
        };

        if (!listeners[event]) {
          listeners[event] = {};
        }

        if (listeners[event][listener]) {
          element.removeeventlistener(event, listeners[event][listener], options);
        }

        listeners[event][listener] = _handler;
        element.listeners = listeners;
      }

      element.addeventlistener(event, _handler, options);
    });
  }
  /**
   * dispatch event on the target element.
   * @param {element} element - the event target.
   * @param {string} type - the event type(s).
   * @param {object} data - the additional event data.
   * @param {object} options - the additional event options.
   * @returns {boolean} indicate if the event is default prevented or not.
   */

  function dispatchevent(element, type, data, options) {
    var event; // event and customevent on ie9-11 are global objects, not constructors

    if (isfunction(event) && isfunction(customevent)) {
      event = new customevent(type, _objectspread2({
        bubbles: true,
        cancelable: true,
        detail: data
      }, options));
    } else {
      event = document.createevent('customevent');
      event.initcustomevent(type, true, true, data);
    }

    return element.dispatchevent(event);
  }
  /**
   * get the offset base on the document.
   * @param {element} element - the target element.
   * @returns {object} the offset data.
   */

  function getoffset(element) {
    var box = element.getboundingclientrect();
    return {
      left: box.left + (window.pagexoffset - document.documentelement.clientleft),
      top: box.top + (window.pageyoffset - document.documentelement.clienttop)
    };
  }
  /**
   * get transforms base on the given object.
   * @param {object} obj - the target object.
   * @returns {string} a string contains transform values.
   */

  function gettransforms(_ref) {
    var rotate = _ref.rotate,
        scalex = _ref.scalex,
        scaley = _ref.scaley,
        translatex = _ref.translatex,
        translatey = _ref.translatey;
    var values = [];

    if (isnumber(translatex) && translatex !== 0) {
      values.push("translatex(".concat(translatex, "px)"));
    }

    if (isnumber(translatey) && translatey !== 0) {
      values.push("translatey(".concat(translatey, "px)"));
    } // rotate should come first before scale to match orientation transform


    if (isnumber(rotate) && rotate !== 0) {
      values.push("rotate(".concat(rotate, "deg)"));
    }

    if (isnumber(scalex) && scalex !== 1) {
      values.push("scalex(".concat(scalex, ")"));
    }

    if (isnumber(scaley) && scaley !== 1) {
      values.push("scaley(".concat(scaley, ")"));
    }

    var transform = values.length ? values.join(' ') : 'none';
    return {
      webkittransform: transform,
      mstransform: transform,
      transform: transform
    };
  }
  /**
   * get an image name from an image url.
   * @param {string} url - the target url.
   * @example
   * // picture.jpg
   * getimagenamefromurl('https://domain.com/path/to/picture.jpg?size=1280×960')
   * @returns {string} a string contains the image name.
   */

  function getimagenamefromurl(url) {
    return isstring(url) ? decodeuricomponent(url.replace(/^.*\//, '').replace(/[?&#].*$/, '')) : '';
  }
  var is_safari = window.navigator && /(macintosh|iphone|ipod|ipad).*applewebkit/i.test(window.navigator.useragent);
  /**
   * get an image's natural sizes.
   * @param {string} image - the target image.
   * @param {object} options - the viewer options.
   * @param {function} callback - the callback function.
   * @returns {htmlimageelement} the new image.
   */

  function getimagenaturalsizes(image, options, callback) {
    var newimage = document.createelement('img'); // modern browsers (except safari)

    if (image.naturalwidth && !is_safari) {
      callback(image.naturalwidth, image.naturalheight);
      return newimage;
    }

    var body = document.body || document.documentelement;

    newimage.onload = function () {
      callback(newimage.width, newimage.height);

      if (!is_safari) {
        body.removechild(newimage);
      }
    };

    foreach(options.inheritedattributes, function (name) {
      var value = image.getattribute(name);

      if (value !== null) {
        newimage.setattribute(name, value);
      }
    });
    newimage.src = image.src; // ios safari will convert the image automatically
    // with its orientation once append it into dom

    if (!is_safari) {
      newimage.style.csstext = 'left:0;' + 'max-height:none!important;' + 'max-width:none!important;' + 'min-height:0!important;' + 'min-width:0!important;' + 'opacity:0;' + 'position:absolute;' + 'top:0;' + 'z-index:-1;';
      body.appendchild(newimage);
    }

    return newimage;
  }
  /**
   * get the related class name of a responsive type number.
   * @param {string} type - the responsive type.
   * @returns {string} the related class name.
   */

  function getresponsiveclass(type) {
    switch (type) {
      case 2:
        return class_hide_xs_down;

      case 3:
        return class_hide_sm_down;

      case 4:
        return class_hide_md_down;

      default:
        return '';
    }
  }
  /**
   * get the max ratio of a group of pointers.
   * @param {string} pointers - the target pointers.
   * @returns {number} the result ratio.
   */

  function getmaxzoomratio(pointers) {
    var pointers2 = _objectspread2({}, pointers);

    var ratios = [];
    foreach(pointers, function (pointer, pointerid) {
      delete pointers2[pointerid];
      foreach(pointers2, function (pointer2) {
        var x1 = math.abs(pointer.startx - pointer2.startx);
        var y1 = math.abs(pointer.starty - pointer2.starty);
        var x2 = math.abs(pointer.endx - pointer2.endx);
        var y2 = math.abs(pointer.endy - pointer2.endy);
        var z1 = math.sqrt(x1 * x1 + y1 * y1);
        var z2 = math.sqrt(x2 * x2 + y2 * y2);
        var ratio = (z2 - z1) / z1;
        ratios.push(ratio);
      });
    });
    ratios.sort(function (a, b) {
      return math.abs(a) < math.abs(b);
    });
    return ratios[0];
  }
  /**
   * get a pointer from an event object.
   * @param {object} event - the target event object.
   * @param {boolean} endonly - indicates if only returns the end point coordinate or not.
   * @returns {object} the result pointer contains start and/or end point coordinates.
   */

  function getpointer(_ref2, endonly) {
    var pagex = _ref2.pagex,
        pagey = _ref2.pagey;
    var end = {
      endx: pagex,
      endy: pagey
    };
    return endonly ? end : _objectspread2({
      timestamp: date.now(),
      startx: pagex,
      starty: pagey
    }, end);
  }
  /**
   * get the center point coordinate of a group of pointers.
   * @param {object} pointers - the target pointers.
   * @returns {object} the center point coordinate.
   */

  function getpointerscenter(pointers) {
    var pagex = 0;
    var pagey = 0;
    var count = 0;
    foreach(pointers, function (_ref3) {
      var startx = _ref3.startx,
          starty = _ref3.starty;
      pagex += startx;
      pagey += starty;
      count += 1;
    });
    pagex /= count;
    pagey /= count;
    return {
      pagex: pagex,
      pagey: pagey
    };
  }

  var render = {
    render: function render() {
      this.initcontainer();
      this.initviewer();
      this.initlist();
      this.renderviewer();
    },
    initbody: function initbody() {
      var ownerdocument = this.element.ownerdocument;
      var body = ownerdocument.body || ownerdocument.documentelement;
      this.body = body;
      this.scrollbarwidth = window.innerwidth - ownerdocument.documentelement.clientwidth;
      this.initialbodypaddingright = body.style.paddingright;
      this.initialbodycomputedpaddingright = window.getcomputedstyle(body).paddingright;
    },
    initcontainer: function initcontainer() {
      this.containerdata = {
        width: window.innerwidth,
        height: window.innerheight
      };
    },
    initviewer: function initviewer() {
      var options = this.options,
          parent = this.parent;
      var viewerdata;

      if (options.inline) {
        viewerdata = {
          width: math.max(parent.offsetwidth, options.minwidth),
          height: math.max(parent.offsetheight, options.minheight)
        };
        this.parentdata = viewerdata;
      }

      if (this.fulled || !viewerdata) {
        viewerdata = this.containerdata;
      }

      this.viewerdata = assign({}, viewerdata);
    },
    renderviewer: function renderviewer() {
      if (this.options.inline && !this.fulled) {
        setstyle(this.viewer, this.viewerdata);
      }
    },
    initlist: function initlist() {
      var _this = this;

      var element = this.element,
          options = this.options,
          list = this.list;
      var items = []; // initlist may be called in this.update, so should keep idempotent

      list.innerhtml = '';
      foreach(this.images, function (image, index) {
        var src = image.src;
        var alt = image.alt || getimagenamefromurl(src);

        var url = _this.getimageurl(image);

        if (src || url) {
          var item = document.createelement('li');
          var img = document.createelement('img');
          foreach(options.inheritedattributes, function (name) {
            var value = image.getattribute(name);

            if (value !== null) {
              img.setattribute(name, value);
            }
          });
          img.src = src || url;
          img.alt = alt;
          img.setattribute('data-original-url', url || src);
          item.setattribute('data-index', index);
          item.setattribute('data-viewer-action', 'view');
          item.setattribute('role', 'button');

          if (options.keyboard) {
            item.setattribute('tabindex', 0);
          }

          item.appendchild(img);
          list.appendchild(item);
          items.push(item);
        }
      });
      this.items = items;
      foreach(items, function (item) {
        var image = item.firstelementchild;
        var onload;
        var onerror;
        setdata(image, 'filled', true);

        if (options.loading) {
          addclass(item, class_loading);
        }

        addlistener(image, event_load, onload = function onload(event) {
          removelistener(image, event_error, onerror);

          if (options.loading) {
            removeclass(item, class_loading);
          }

          _this.loadimage(event);
        }, {
          once: true
        });
        addlistener(image, event_error, onerror = function onerror() {
          removelistener(image, event_load, onload);

          if (options.loading) {
            removeclass(item, class_loading);
          }
        }, {
          once: true
        });
      });

      if (options.transition) {
        addlistener(element, event_viewed, function () {
          addclass(list, class_transition);
        }, {
          once: true
        });
      }
    },
    renderlist: function renderlist() {
      var index = this.index;
      var item = this.items[index];

      if (!item) {
        return;
      }

      var next = item.nextelementsibling;
      var gutter = parseint(window.getcomputedstyle(next || item).marginleft, 10);
      var offsetwidth = item.offsetwidth;
      var outerwidth = offsetwidth + gutter; // place the active item in the center of the screen

      setstyle(this.list, assign({
        width: outerwidth * this.length - gutter
      }, gettransforms({
        translatex: (this.viewerdata.width - offsetwidth) / 2 - outerwidth * index
      })));
    },
    resetlist: function resetlist() {
      var list = this.list;
      list.innerhtml = '';
      removeclass(list, class_transition);
      setstyle(list, gettransforms({
        translatex: 0
      }));
    },
    initimage: function initimage(done) {
      var _this2 = this;

      var options = this.options,
          image = this.image,
          viewerdata = this.viewerdata;
      var footerheight = this.footer.offsetheight;
      var viewerwidth = viewerdata.width;
      var viewerheight = math.max(viewerdata.height - footerheight, footerheight);
      var oldimagedata = this.imagedata || {};
      var sizingimage;
      this.imageinitializing = {
        abort: function abort() {
          sizingimage.onload = null;
        }
      };
      sizingimage = getimagenaturalsizes(image, options, function (naturalwidth, naturalheight) {
        var aspectratio = naturalwidth / naturalheight;
        var width = viewerwidth;
        var height = viewerheight;
        _this2.imageinitializing = false;

        if (viewerheight * aspectratio > viewerwidth) {
          height = viewerwidth / aspectratio;
        } else {
          width = viewerheight * aspectratio;
        }

        width = math.min(width * 0.9, naturalwidth);
        height = math.min(height * 0.9, naturalheight);
        var left = (viewerwidth - width) / 2;
        var top = (viewerheight - height) / 2;
        var imagedata = {
          left: left,
          top: top,
          x: left,
          y: top,
          width: width,
          height: height,
          oldratio: 1,
          ratio: width / naturalwidth,
          aspectratio: aspectratio,
          naturalwidth: naturalwidth,
          naturalheight: naturalheight
        };
        var initialimagedata = assign({}, imagedata);

        if (options.rotatable) {
          imagedata.rotate = oldimagedata.rotate || 0;
          initialimagedata.rotate = 0;
        }

        if (options.scalable) {
          imagedata.scalex = oldimagedata.scalex || 1;
          imagedata.scaley = oldimagedata.scaley || 1;
          initialimagedata.scalex = 1;
          initialimagedata.scaley = 1;
        }

        _this2.imagedata = imagedata;
        _this2.initialimagedata = initialimagedata;

        if (done) {
          done();
        }
      });
    },
    renderimage: function renderimage(done) {
      var _this3 = this;

      var image = this.image,
          imagedata = this.imagedata;
      setstyle(image, assign({
        width: imagedata.width,
        height: imagedata.height,
        // xxx: not to use translatex/y to avoid image shaking when zooming
        marginleft: imagedata.x,
        margintop: imagedata.y
      }, gettransforms(imagedata)));

      if (done) {
        if ((this.viewing || this.moving || this.rotating || this.scaling || this.zooming) && this.options.transition && hasclass(image, class_transition)) {
          var ontransitionend = function ontransitionend() {
            _this3.imagerendering = false;
            done();
          };

          this.imagerendering = {
            abort: function abort() {
              removelistener(image, event_transition_end, ontransitionend);
            }
          };
          addlistener(image, event_transition_end, ontransitionend, {
            once: true
          });
        } else {
          done();
        }
      }
    },
    resetimage: function resetimage() {
      // this.image only defined after viewed
      if (this.viewing || this.viewed) {
        var image = this.image;

        if (this.viewing) {
          this.viewing.abort();
        }

        image.parentnode.removechild(image);
        this.image = null;
      }
    }
  };

  var events = {
    bind: function bind() {
      var options = this.options,
          viewer = this.viewer,
          canvas = this.canvas;
      var document = this.element.ownerdocument;
      addlistener(viewer, event_click, this.onclick = this.click.bind(this));
      addlistener(viewer, event_drag_start, this.ondragstart = this.dragstart.bind(this));
      addlistener(canvas, event_pointer_down, this.onpointerdown = this.pointerdown.bind(this));
      addlistener(document, event_pointer_move, this.onpointermove = this.pointermove.bind(this));
      addlistener(document, event_pointer_up, this.onpointerup = this.pointerup.bind(this));
      addlistener(document, event_key_down, this.onkeydown = this.keydown.bind(this));
      addlistener(window, event_resize, this.onresize = this.resize.bind(this));

      if (options.zoomable && options.zoomonwheel) {
        addlistener(viewer, event_wheel, this.onwheel = this.wheel.bind(this), {
          passive: false,
          capture: true
        });
      }

      if (options.toggleondblclick) {
        addlistener(canvas, event_dblclick, this.ondblclick = this.dblclick.bind(this));
      }
    },
    unbind: function unbind() {
      var options = this.options,
          viewer = this.viewer,
          canvas = this.canvas;
      var document = this.element.ownerdocument;
      removelistener(viewer, event_click, this.onclick);
      removelistener(viewer, event_drag_start, this.ondragstart);
      removelistener(canvas, event_pointer_down, this.onpointerdown);
      removelistener(document, event_pointer_move, this.onpointermove);
      removelistener(document, event_pointer_up, this.onpointerup);
      removelistener(document, event_key_down, this.onkeydown);
      removelistener(window, event_resize, this.onresize);

      if (options.zoomable && options.zoomonwheel) {
        removelistener(viewer, event_wheel, this.onwheel, {
          passive: false,
          capture: true
        });
      }

      if (options.toggleondblclick) {
        removelistener(canvas, event_dblclick, this.ondblclick);
      }
    }
  };

  var handlers = {
    click: function click(event) {
      var options = this.options,
          imagedata = this.imagedata;
      var target = event.target;
      var action = getdata(target, data_action);

      if (!action && target.localname === 'img' && target.parentelement.localname === 'li') {
        target = target.parentelement;
        action = getdata(target, data_action);
      } // cancel the emulated click when the native click event was triggered.


      if (is_touch_device && event.istrusted && target === this.canvas) {
        cleartimeout(this.clickcanvastimeout);
      }

      switch (action) {
        case 'mix':
          if (this.played) {
            this.stop();
          } else if (options.inline) {
            if (this.fulled) {
              this.exit();
            } else {
              this.full();
            }
          } else {
            this.hide();
          }

          break;

        case 'hide':
          this.hide();
          break;

        case 'view':
          this.view(getdata(target, 'index'));
          break;

        case 'zoom-in':
          this.zoom(0.1, true);
          break;

        case 'zoom-out':
          this.zoom(-0.1, true);
          break;

        case 'one-to-one':
          this.toggle();
          break;

        case 'reset':
          this.reset();
          break;

        case 'prev':
          this.prev(options.loop);
          break;

        case 'play':
          this.play(options.fullscreen);
          break;

        case 'next':
          this.next(options.loop);
          break;

        case 'rotate-left':
          this.rotate(-90);
          break;

        case 'rotate-right':
          this.rotate(90);
          break;

        case 'flip-horizontal':
          this.scalex(-imagedata.scalex || -1);
          break;

        case 'flip-vertical':
          this.scaley(-imagedata.scaley || -1);
          break;

        default:
          if (this.played) {
            this.stop();
          }

      }
    },
    dblclick: function dblclick(event) {
      event.preventdefault();

      if (this.viewed && event.target === this.image) {
        // cancel the emulated double click when the native dblclick event was triggered.
        if (is_touch_device && event.istrusted) {
          cleartimeout(this.doubleclickimagetimeout);
        } // xxx: no pagex/y properties in custom event, fallback to the original event.


        this.toggle(event.istrusted ? event : event.detail && event.detail.originalevent);
      }
    },
    load: function load() {
      var _this = this;

      if (this.timeout) {
        cleartimeout(this.timeout);
        this.timeout = false;
      }

      var element = this.element,
          options = this.options,
          image = this.image,
          index = this.index,
          viewerdata = this.viewerdata;
      removeclass(image, class_invisible);

      if (options.loading) {
        removeclass(this.canvas, class_loading);
      }

      image.style.csstext = 'height:0;' + "margin-left:".concat(viewerdata.width / 2, "px;") + "margin-top:".concat(viewerdata.height / 2, "px;") + 'max-width:none!important;' + 'position:relative;' + 'width:0;';
      this.initimage(function () {
        toggleclass(image, class_move, options.movable);
        toggleclass(image, class_transition, options.transition);

        _this.renderimage(function () {
          _this.viewed = true;
          _this.viewing = false;

          if (isfunction(options.viewed)) {
            addlistener(element, event_viewed, options.viewed, {
              once: true
            });
          }

          dispatchevent(element, event_viewed, {
            originalimage: _this.images[index],
            index: index,
            image: image
          }, {
            cancelable: false
          });
        });
      });
    },
    loadimage: function loadimage(event) {
      var image = event.target;
      var parent = image.parentnode;
      var parentwidth = parent.offsetwidth || 30;
      var parentheight = parent.offsetheight || 50;
      var filled = !!getdata(image, 'filled');
      getimagenaturalsizes(image, this.options, function (naturalwidth, naturalheight) {
        var aspectratio = naturalwidth / naturalheight;
        var width = parentwidth;
        var height = parentheight;

        if (parentheight * aspectratio > parentwidth) {
          if (filled) {
            width = parentheight * aspectratio;
          } else {
            height = parentwidth / aspectratio;
          }
        } else if (filled) {
          height = parentwidth / aspectratio;
        } else {
          width = parentheight * aspectratio;
        }

        setstyle(image, assign({
          width: width,
          height: height
        }, gettransforms({
          translatex: (parentwidth - width) / 2,
          translatey: (parentheight - height) / 2
        })));
      });
    },
    keydown: function keydown(event) {
      var options = this.options;

      if (!options.keyboard) {
        return;
      }

      var keycode = event.keycode || event.which || event.charcode;

      switch (keycode) {
        // enter
        case 13:
          if (this.viewer.contains(event.target)) {
            this.click(event);
          }

          break;
      }

      if (!this.fulled) {
        return;
      }

      switch (keycode) {
        // escape
        case 27:
          if (this.played) {
            this.stop();
          } else if (options.inline) {
            if (this.fulled) {
              this.exit();
            }
          } else {
            this.hide();
          }

          break;
        // space

        case 32:
          if (this.played) {
            this.stop();
          }

          break;
        // arrowleft

        case 37:
          this.prev(options.loop);
          break;
        // arrowup

        case 38:
          // prevent scroll on firefox
          event.preventdefault(); // zoom in

          this.zoom(options.zoomratio, true);
          break;
        // arrowright

        case 39:
          this.next(options.loop);
          break;
        // arrowdown

        case 40:
          // prevent scroll on firefox
          event.preventdefault(); // zoom out

          this.zoom(-options.zoomratio, true);
          break;
        // ctrl + 0

        case 48: // fall through
        // ctrl + 1
        // eslint-disable-next-line no-fallthrough

        case 49:
          if (event.ctrlkey) {
            event.preventdefault();
            this.toggle();
          }

          break;
      }
    },
    dragstart: function dragstart(event) {
      if (event.target.localname === 'img') {
        event.preventdefault();
      }
    },
    pointerdown: function pointerdown(event) {
      var options = this.options,
          pointers = this.pointers;
      var buttons = event.buttons,
          button = event.button;

      if (!this.viewed || this.showing || this.viewing || this.hiding // handle mouse event and pointer event and ignore touch event
      || (event.type === 'mousedown' || event.type === 'pointerdown' && event.pointertype === 'mouse') && ( // no primary button (usually the left button)
      isnumber(buttons) && buttons !== 1 || isnumber(button) && button !== 0 // open context menu
      || event.ctrlkey)) {
        return;
      } // prevent default behaviours as page zooming in touch devices.


      event.preventdefault();

      if (event.changedtouches) {
        foreach(event.changedtouches, function (touch) {
          pointers[touch.identifier] = getpointer(touch);
        });
      } else {
        pointers[event.pointerid || 0] = getpointer(event);
      }

      var action = options.movable ? action_move : false;

      if (options.zoomontouch && options.zoomable && object.keys(pointers).length > 1) {
        action = action_zoom;
      } else if (options.slideontouch && (event.pointertype === 'touch' || event.type === 'touchstart') && this.isswitchable()) {
        action = action_switch;
      }

      if (options.transition && (action === action_move || action === action_zoom)) {
        removeclass(this.image, class_transition);
      }

      this.action = action;
    },
    pointermove: function pointermove(event) {
      var pointers = this.pointers,
          action = this.action;

      if (!this.viewed || !action) {
        return;
      }

      event.preventdefault();

      if (event.changedtouches) {
        foreach(event.changedtouches, function (touch) {
          assign(pointers[touch.identifier] || {}, getpointer(touch, true));
        });
      } else {
        assign(pointers[event.pointerid || 0] || {}, getpointer(event, true));
      }

      this.change(event);
    },
    pointerup: function pointerup(event) {
      var _this2 = this;

      var options = this.options,
          action = this.action,
          pointers = this.pointers;
      var pointer;

      if (event.changedtouches) {
        foreach(event.changedtouches, function (touch) {
          pointer = pointers[touch.identifier];
          delete pointers[touch.identifier];
        });
      } else {
        pointer = pointers[event.pointerid || 0];
        delete pointers[event.pointerid || 0];
      }

      if (!action) {
        return;
      }

      event.preventdefault();

      if (options.transition && (action === action_move || action === action_zoom)) {
        addclass(this.image, class_transition);
      }

      this.action = false; // emulate click and double click in touch devices to support backdrop and image zooming (#210).

      if (is_touch_device && action !== action_zoom && pointer && date.now() - pointer.timestamp < 500) {
        cleartimeout(this.clickcanvastimeout);
        cleartimeout(this.doubleclickimagetimeout);

        if (options.toggleondblclick && this.viewed && event.target === this.image) {
          if (this.imageclicked) {
            this.imageclicked = false; // this timeout will be cleared later when a native dblclick event is triggering

            this.doubleclickimagetimeout = settimeout(function () {
              dispatchevent(_this2.image, event_dblclick, {
                originalevent: event
              });
            }, 50);
          } else {
            this.imageclicked = true; // the default timing of a double click in windows is 500 ms

            this.doubleclickimagetimeout = settimeout(function () {
              _this2.imageclicked = false;
            }, 500);
          }
        } else {
          this.imageclicked = false;

          if (options.backdrop && options.backdrop !== 'static' && event.target === this.canvas) {
            // this timeout will be cleared later when a native click event is triggering
            this.clickcanvastimeout = settimeout(function () {
              dispatchevent(_this2.canvas, event_click, {
                originalevent: event
              });
            }, 50);
          }
        }
      }
    },
    resize: function resize() {
      var _this3 = this;

      if (!this.isshown || this.hiding) {
        return;
      }

      if (this.fulled) {
        this.close();
        this.initbody();
        this.open();
      }

      this.initcontainer();
      this.initviewer();
      this.renderviewer();
      this.renderlist();

      if (this.viewed) {
        this.initimage(function () {
          _this3.renderimage();
        });
      }

      if (this.played) {
        if (this.options.fullscreen && this.fulled && !(document.fullscreenelement || document.webkitfullscreenelement || document.mozfullscreenelement || document.msfullscreenelement)) {
          this.stop();
          return;
        }

        foreach(this.player.getelementsbytagname('img'), function (image) {
          addlistener(image, event_load, _this3.loadimage.bind(_this3), {
            once: true
          });
          dispatchevent(image, event_load);
        });
      }
    },
    wheel: function wheel(event) {
      var _this4 = this;

      if (!this.viewed) {
        return;
      }

      event.preventdefault(); // limit wheel speed to prevent zoom too fast

      if (this.wheeling) {
        return;
      }

      this.wheeling = true;
      settimeout(function () {
        _this4.wheeling = false;
      }, 50);
      var ratio = number(this.options.zoomratio) || 0.1;
      var delta = 1;

      if (event.deltay) {
        delta = event.deltay > 0 ? 1 : -1;
      } else if (event.wheeldelta) {
        delta = -event.wheeldelta / 120;
      } else if (event.detail) {
        delta = event.detail > 0 ? 1 : -1;
      }

      this.zoom(-delta * ratio, true, event);
    }
  };

  var methods = {
    /** show the viewer (only available in modal mode)
     * @param {boolean} [immediate=false] - indicates if show the viewer immediately or not.
     * @returns {viewer} this
     */
    show: function show() {
      var immediate = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : false;
      var element = this.element,
          options = this.options;

      if (options.inline || this.showing || this.isshown || this.showing) {
        return this;
      }

      if (!this.ready) {
        this.build();

        if (this.ready) {
          this.show(immediate);
        }

        return this;
      }

      if (isfunction(options.show)) {
        addlistener(element, event_show, options.show, {
          once: true
        });
      }

      if (dispatchevent(element, event_show) === false || !this.ready) {
        return this;
      }

      if (this.hiding) {
        this.transitioning.abort();
      }

      this.showing = true;
      this.open();
      var viewer = this.viewer;
      removeclass(viewer, class_hide);
      viewer.setattribute('role', 'dialog');
      viewer.setattribute('aria-labelledby', this.title.id);
      viewer.setattribute('aria-modal', true);
      viewer.removeattribute('aria-hidden');

      if (options.transition && !immediate) {
        var shown = this.shown.bind(this);
        this.transitioning = {
          abort: function abort() {
            removelistener(viewer, event_transition_end, shown);
            removeclass(viewer, class_in);
          }
        };
        addclass(viewer, class_transition); // force reflow to enable css3 transition

        viewer.initialoffsetwidth = viewer.offsetwidth;
        addlistener(viewer, event_transition_end, shown, {
          once: true
        });
        addclass(viewer, class_in);
      } else {
        addclass(viewer, class_in);
        this.shown();
      }

      return this;
    },

    /**
     * hide the viewer (only available in modal mode)
     * @param {boolean} [immediate=false] - indicates if hide the viewer immediately or not.
     * @returns {viewer} this
     */
    hide: function hide() {
      var _this = this;

      var immediate = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : false;
      var element = this.element,
          options = this.options;

      if (options.inline || this.hiding || !(this.isshown || this.showing)) {
        return this;
      }

      if (isfunction(options.hide)) {
        addlistener(element, event_hide, options.hide, {
          once: true
        });
      }

      if (dispatchevent(element, event_hide) === false) {
        return this;
      }

      if (this.showing) {
        this.transitioning.abort();
      }

      this.hiding = true;

      if (this.played) {
        this.stop();
      } else if (this.viewing) {
        this.viewing.abort();
      }

      var viewer = this.viewer,
          image = this.image;

      var hideimmediately = function hideimmediately() {
        removeclass(viewer, class_in);

        _this.hidden();
      };

      if (options.transition && !immediate) {
        var onviewertransitionend = function onviewertransitionend(event) {
          // ignore all propagating `transitionend` events (#275).
          if (event && event.target === viewer) {
            removelistener(viewer, event_transition_end, onviewertransitionend);

            _this.hidden();
          }
        };

        var onimagetransitionend = function onimagetransitionend() {
          // in case of show the viewer by `viewer.show(true)` previously (#407).
          if (hasclass(viewer, class_transition)) {
            addlistener(viewer, event_transition_end, onviewertransitionend);
            removeclass(viewer, class_in);
          } else {
            hideimmediately();
          }
        };

        this.transitioning = {
          abort: function abort() {
            if (_this.viewed && hasclass(image, class_transition)) {
              removelistener(image, event_transition_end, onimagetransitionend);
            } else if (hasclass(viewer, class_transition)) {
              removelistener(viewer, event_transition_end, onviewertransitionend);
            }
          }
        }; // in case of hiding the viewer when holding on the image (#255),
        // note that the `class_transition` class will be removed on pointer down.

        if (this.viewed && hasclass(image, class_transition)) {
          addlistener(image, event_transition_end, onimagetransitionend, {
            once: true
          });
          this.zoomto(0, false, null, true);
        } else {
          onimagetransitionend();
        }
      } else {
        hideimmediately();
      }

      return this;
    },

    /**
     * view one of the images with image's index
     * @param {number} index - the index of the image to view.
     * @returns {viewer} this
     */
    view: function view() {
      var _this2 = this;

      var index = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : this.options.initialviewindex;
      index = number(index) || 0;

      if (this.hiding || this.played || index < 0 || index >= this.length || this.viewed && index === this.index) {
        return this;
      }

      if (!this.isshown) {
        this.index = index;
        return this.show();
      }

      if (this.viewing) {
        this.viewing.abort();
      }

      var element = this.element,
          options = this.options,
          title = this.title,
          canvas = this.canvas;
      var item = this.items[index];
      var img = item.queryselector('img');
      var url = getdata(img, 'originalurl');
      var alt = img.getattribute('alt');
      var image = document.createelement('img');
      foreach(options.inheritedattributes, function (name) {
        var value = img.getattribute(name);

        if (value !== null) {
          image.setattribute(name, value);
        }
      });
      image.src = url;
      image.alt = alt;

      if (isfunction(options.view)) {
        addlistener(element, event_view, options.view, {
          once: true
        });
      }

      if (dispatchevent(element, event_view, {
        originalimage: this.images[index],
        index: index,
        image: image
      }) === false || !this.isshown || this.hiding || this.played) {
        return this;
      }

      var activeitem = this.items[this.index];

      if (activeitem) {
        removeclass(activeitem, class_active);
        activeitem.removeattribute('aria-selected');
      }

      addclass(item, class_active);
      item.setattribute('aria-selected', true);

      if (options.focus) {
        item.focus();
      }

      this.image = image;
      this.viewed = false;
      this.index = index;
      this.imagedata = {};
      addclass(image, class_invisible);

      if (options.loading) {
        addclass(canvas, class_loading);
      }

      canvas.innerhtml = '';
      canvas.appendchild(image); // center current item

      this.renderlist(); // clear title

      title.innerhtml = ''; // generate title after viewed

      var onviewed = function onviewed() {
        var imagedata = _this2.imagedata;
        var render = array.isarray(options.title) ? options.title[1] : options.title;
        title.innerhtml = escapehtmlentities(isfunction(render) ? render.call(_this2, image, imagedata) : "".concat(alt, " (").concat(imagedata.naturalwidth, " \xd7 ").concat(imagedata.naturalheight, ")"));
      };

      var onload;
      var onerror;
      addlistener(element, event_viewed, onviewed, {
        once: true
      });
      this.viewing = {
        abort: function abort() {
          removelistener(element, event_viewed, onviewed);

          if (image.complete) {
            if (_this2.imagerendering) {
              _this2.imagerendering.abort();
            } else if (_this2.imageinitializing) {
              _this2.imageinitializing.abort();
            }
          } else {
            // cancel download to save bandwidth.
            image.src = '';
            removelistener(image, event_load, onload);

            if (_this2.timeout) {
              cleartimeout(_this2.timeout);
            }
          }
        }
      };

      if (image.complete) {
        this.load();
      } else {
        addlistener(image, event_load, onload = function onload() {
          removelistener(image, event_error, onerror);

          _this2.load();
        }, {
          once: true
        });
        addlistener(image, event_error, onerror = function onerror() {
          removelistener(image, event_load, onload);

          if (_this2.timeout) {
            cleartimeout(_this2.timeout);
            _this2.timeout = false;
          }

          removeclass(image, class_invisible);

          if (options.loading) {
            removeclass(_this2.canvas, class_loading);
          }
        }, {
          once: true
        });

        if (this.timeout) {
          cleartimeout(this.timeout);
        } // make the image visible if it fails to load within 1s


        this.timeout = settimeout(function () {
          removeclass(image, class_invisible);
          _this2.timeout = false;
        }, 1000);
      }

      return this;
    },

    /**
     * view the previous image
     * @param {boolean} [loop=false] - indicate if view the last one
     * when it is the first one at present.
     * @returns {viewer} this
     */
    prev: function prev() {
      var loop = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : false;
      var index = this.index - 1;

      if (index < 0) {
        index = loop ? this.length - 1 : 0;
      }

      this.view(index);
      return this;
    },

    /**
     * view the next image
     * @param {boolean} [loop=false] - indicate if view the first one
     * when it is the last one at present.
     * @returns {viewer} this
     */
    next: function next() {
      var loop = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : false;
      var maxindex = this.length - 1;
      var index = this.index + 1;

      if (index > maxindex) {
        index = loop ? 0 : maxindex;
      }

      this.view(index);
      return this;
    },

    /**
     * move the image with relative offsets.
     * @param {number} x - the moving distance in the horizontal direction.
     * @param {number} [y=x] the moving distance in the vertical direction.
     * @returns {viewer} this
     */
    move: function move(x) {
      var y = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : x;
      var imagedata = this.imagedata;
      this.moveto(isundefined(x) ? x : imagedata.x + number(x), isundefined(y) ? y : imagedata.y + number(y));
      return this;
    },

    /**
     * move the image to an absolute point.
     * @param {number} x - the new position in the horizontal direction.
     * @param {number} [y=x] - the new position in the vertical direction.
     * @param {event} [_originalevent=null] - the original event if any.
     * @returns {viewer} this
     */
    moveto: function moveto(x) {
      var _this3 = this;

      var y = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : x;

      var _originalevent = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : null;

      var element = this.element,
          options = this.options,
          imagedata = this.imagedata;
      x = number(x);
      y = number(y);

      if (this.viewed && !this.played && options.movable) {
        var oldx = imagedata.x;
        var oldy = imagedata.y;
        var changed = false;

        if (isnumber(x)) {
          changed = true;
        } else {
          x = oldx;
        }

        if (isnumber(y)) {
          changed = true;
        } else {
          y = oldy;
        }

        if (changed) {
          if (isfunction(options.move)) {
            addlistener(element, event_move, options.move, {
              once: true
            });
          }

          if (dispatchevent(element, event_move, {
            x: x,
            y: y,
            oldx: oldx,
            oldy: oldy,
            originalevent: _originalevent
          }) === false) {
            return this;
          }

          imagedata.x = x;
          imagedata.y = y;
          imagedata.left = x;
          imagedata.top = y;
          this.moving = true;
          this.renderimage(function () {
            _this3.moving = false;

            if (isfunction(options.moved)) {
              addlistener(element, event_moved, options.moved, {
                once: true
              });
            }

            dispatchevent(element, event_moved, {
              x: x,
              y: y,
              oldx: oldx,
              oldy: oldy,
              originalevent: _originalevent
            }, {
              cancelable: false
            });
          });
        }
      }

      return this;
    },

    /**
     * rotate the image with a relative degree.
     * @param {number} degree - the rotate degree.
     * @returns {viewer} this
     */
    rotate: function rotate(degree) {
      this.rotateto((this.imagedata.rotate || 0) + number(degree));
      return this;
    },

    /**
     * rotate the image to an absolute degree.
     * @param {number} degree - the rotate degree.
     * @returns {viewer} this
     */
    rotateto: function rotateto(degree) {
      var _this4 = this;

      var element = this.element,
          options = this.options,
          imagedata = this.imagedata;
      degree = number(degree);

      if (isnumber(degree) && this.viewed && !this.played && options.rotatable) {
        var olddegree = imagedata.rotate;

        if (isfunction(options.rotate)) {
          addlistener(element, event_rotate, options.rotate, {
            once: true
          });
        }

        if (dispatchevent(element, event_rotate, {
          degree: degree,
          olddegree: olddegree
        }) === false) {
          return this;
        }

        imagedata.rotate = degree;
        this.rotating = true;
        this.renderimage(function () {
          _this4.rotating = false;

          if (isfunction(options.rotated)) {
            addlistener(element, event_rotated, options.rotated, {
              once: true
            });
          }

          dispatchevent(element, event_rotated, {
            degree: degree,
            olddegree: olddegree
          }, {
            cancelable: false
          });
        });
      }

      return this;
    },

    /**
     * scale the image on the x-axis.
     * @param {number} scalex - the scale ratio on the x-axis.
     * @returns {viewer} this
     */
    scalex: function scalex(_scalex) {
      this.scale(_scalex, this.imagedata.scaley);
      return this;
    },

    /**
     * scale the image on the y-axis.
     * @param {number} scaley - the scale ratio on the y-axis.
     * @returns {viewer} this
     */
    scaley: function scaley(_scaley) {
      this.scale(this.imagedata.scalex, _scaley);
      return this;
    },

    /**
     * scale the image.
     * @param {number} scalex - the scale ratio on the x-axis.
     * @param {number} [scaley=scalex] - the scale ratio on the y-axis.
     * @returns {viewer} this
     */
    scale: function scale(scalex) {
      var _this5 = this;

      var scaley = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : scalex;
      var element = this.element,
          options = this.options,
          imagedata = this.imagedata;
      scalex = number(scalex);
      scaley = number(scaley);

      if (this.viewed && !this.played && options.scalable) {
        var oldscalex = imagedata.scalex;
        var oldscaley = imagedata.scaley;
        var changed = false;

        if (isnumber(scalex)) {
          changed = true;
        } else {
          scalex = oldscalex;
        }

        if (isnumber(scaley)) {
          changed = true;
        } else {
          scaley = oldscaley;
        }

        if (changed) {
          if (isfunction(options.scale)) {
            addlistener(element, event_scale, options.scale, {
              once: true
            });
          }

          if (dispatchevent(element, event_scale, {
            scalex: scalex,
            scaley: scaley,
            oldscalex: oldscalex,
            oldscaley: oldscaley
          }) === false) {
            return this;
          }

          imagedata.scalex = scalex;
          imagedata.scaley = scaley;
          this.scaling = true;
          this.renderimage(function () {
            _this5.scaling = false;

            if (isfunction(options.scaled)) {
              addlistener(element, event_scaled, options.scaled, {
                once: true
              });
            }

            dispatchevent(element, event_scaled, {
              scalex: scalex,
              scaley: scaley,
              oldscalex: oldscalex,
              oldscaley: oldscaley
            }, {
              cancelable: false
            });
          });
        }
      }

      return this;
    },

    /**
     * zoom the image with a relative ratio.
     * @param {number} ratio - the target ratio.
     * @param {boolean} [hastooltip=false] - indicates if it has a tooltip or not.
     * @param {event} [_originalevent=null] - the original event if any.
     * @returns {viewer} this
     */
    zoom: function zoom(ratio) {
      var hastooltip = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;

      var _originalevent = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : null;

      var imagedata = this.imagedata;
      ratio = number(ratio);

      if (ratio < 0) {
        ratio = 1 / (1 - ratio);
      } else {
        ratio = 1 + ratio;
      }

      this.zoomto(imagedata.width * ratio / imagedata.naturalwidth, hastooltip, _originalevent);
      return this;
    },

    /**
     * zoom the image to an absolute ratio.
     * @param {number} ratio - the target ratio.
     * @param {boolean} [hastooltip=false] - indicates if it has a tooltip or not.
     * @param {event} [_originalevent=null] - the original event if any.
     * @param {event} [_zoomable=false] - indicates if the current zoom is available or not.
     * @returns {viewer} this
     */
    zoomto: function zoomto(ratio) {
      var _this6 = this;

      var hastooltip = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;

      var _originalevent = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : null;

      var _zoomable = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : false;

      var element = this.element,
          options = this.options,
          pointers = this.pointers,
          imagedata = this.imagedata;
      var x = imagedata.x,
          y = imagedata.y,
          width = imagedata.width,
          height = imagedata.height,
          naturalwidth = imagedata.naturalwidth,
          naturalheight = imagedata.naturalheight;
      ratio = math.max(0, ratio);

      if (isnumber(ratio) && this.viewed && !this.played && (_zoomable || options.zoomable)) {
        if (!_zoomable) {
          var minzoomratio = math.max(0.01, options.minzoomratio);
          var maxzoomratio = math.min(100, options.maxzoomratio);
          ratio = math.min(math.max(ratio, minzoomratio), maxzoomratio);
        }

        if (_originalevent) {
          switch (_originalevent.type) {
            case 'wheel':
              if (options.zoomratio >= 0.055 && ratio > 0.95 && ratio < 1.05) {
                ratio = 1;
              }

              break;

            case 'pointermove':
            case 'touchmove':
            case 'mousemove':
              if (ratio > 0.99 && ratio < 1.01) {
                ratio = 1;
              }

              break;
          }
        }

        var newwidth = naturalwidth * ratio;
        var newheight = naturalheight * ratio;
        var offsetwidth = newwidth - width;
        var offsetheight = newheight - height;
        var oldratio = imagedata.ratio;

        if (isfunction(options.zoom)) {
          addlistener(element, event_zoom, options.zoom, {
            once: true
          });
        }

        if (dispatchevent(element, event_zoom, {
          ratio: ratio,
          oldratio: oldratio,
          originalevent: _originalevent
        }) === false) {
          return this;
        }

        this.zooming = true;

        if (_originalevent) {
          var offset = getoffset(this.viewer);
          var center = pointers && object.keys(pointers).length > 0 ? getpointerscenter(pointers) : {
            pagex: _originalevent.pagex,
            pagey: _originalevent.pagey
          }; // zoom from the triggering point of the event

          imagedata.x -= offsetwidth * ((center.pagex - offset.left - x) / width);
          imagedata.y -= offsetheight * ((center.pagey - offset.top - y) / height);
        } else {
          // zoom from the center of the image
          imagedata.x -= offsetwidth / 2;
          imagedata.y -= offsetheight / 2;
        }

        imagedata.left = imagedata.x;
        imagedata.top = imagedata.y;
        imagedata.width = newwidth;
        imagedata.height = newheight;
        imagedata.oldratio = oldratio;
        imagedata.ratio = ratio;
        this.renderimage(function () {
          _this6.zooming = false;

          if (isfunction(options.zoomed)) {
            addlistener(element, event_zoomed, options.zoomed, {
              once: true
            });
          }

          dispatchevent(element, event_zoomed, {
            ratio: ratio,
            oldratio: oldratio,
            originalevent: _originalevent
          }, {
            cancelable: false
          });
        });

        if (hastooltip) {
          this.tooltip();
        }
      }

      return this;
    },

    /**
     * play the images
     * @param {boolean|fullscreenoptions} [fullscreen=false] - indicate if request fullscreen or not.
     * @returns {viewer} this
     */
    play: function play() {
      var _this7 = this;

      var fullscreen = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : false;

      if (!this.isshown || this.played) {
        return this;
      }

      var element = this.element,
          options = this.options;

      if (isfunction(options.play)) {
        addlistener(element, event_play, options.play, {
          once: true
        });
      }

      if (dispatchevent(element, event_play) === false) {
        return this;
      }

      var player = this.player;
      var onload = this.loadimage.bind(this);
      var list = [];
      var total = 0;
      var index = 0;
      this.played = true;
      this.onloadwhenplay = onload;

      if (fullscreen) {
        this.requestfullscreen(fullscreen);
      }

      addclass(player, class_show);
      foreach(this.items, function (item, i) {
        var img = item.queryselector('img');
        var image = document.createelement('img');
        image.src = getdata(img, 'originalurl');
        image.alt = img.getattribute('alt');
        image.referrerpolicy = img.referrerpolicy;
        total += 1;
        addclass(image, class_fade);
        toggleclass(image, class_transition, options.transition);

        if (hasclass(item, class_active)) {
          addclass(image, class_in);
          index = i;
        }

        list.push(image);
        addlistener(image, event_load, onload, {
          once: true
        });
        player.appendchild(image);
      });

      if (isnumber(options.interval) && options.interval > 0) {
        var play = function play() {
          _this7.playing = settimeout(function () {
            removeclass(list[index], class_in);
            index += 1;
            index = index < total ? index : 0;
            addclass(list[index], class_in);
            play();
          }, options.interval);
        };

        if (total > 1) {
          play();
        }
      }

      return this;
    },
    // stop play
    stop: function stop() {
      var _this8 = this;

      if (!this.played) {
        return this;
      }

      var element = this.element,
          options = this.options;

      if (isfunction(options.stop)) {
        addlistener(element, event_stop, options.stop, {
          once: true
        });
      }

      if (dispatchevent(element, event_stop) === false) {
        return this;
      }

      var player = this.player;
      this.played = false;
      cleartimeout(this.playing);
      foreach(player.getelementsbytagname('img'), function (image) {
        removelistener(image, event_load, _this8.onloadwhenplay);
      });
      removeclass(player, class_show);
      player.innerhtml = '';
      this.exitfullscreen();
      return this;
    },
    // enter modal mode (only available in inline mode)
    full: function full() {
      var _this9 = this;

      var options = this.options,
          viewer = this.viewer,
          image = this.image,
          list = this.list;

      if (!this.isshown || this.played || this.fulled || !options.inline) {
        return this;
      }

      this.fulled = true;
      this.open();
      addclass(this.button, class_fullscreen_exit);

      if (options.transition) {
        removeclass(list, class_transition);

        if (this.viewed) {
          removeclass(image, class_transition);
        }
      }

      addclass(viewer, class_fixed);
      viewer.setattribute('role', 'dialog');
      viewer.setattribute('aria-labelledby', this.title.id);
      viewer.setattribute('aria-modal', true);
      viewer.removeattribute('style');
      setstyle(viewer, {
        zindex: options.zindex
      });

      if (options.focus) {
        this.enforcefocus();
      }

      this.initcontainer();
      this.viewerdata = assign({}, this.containerdata);
      this.renderlist();

      if (this.viewed) {
        this.initimage(function () {
          _this9.renderimage(function () {
            if (options.transition) {
              settimeout(function () {
                addclass(image, class_transition);
                addclass(list, class_transition);
              }, 0);
            }
          });
        });
      }

      return this;
    },
    // exit modal mode (only available in inline mode)
    exit: function exit() {
      var _this10 = this;

      var options = this.options,
          viewer = this.viewer,
          image = this.image,
          list = this.list;

      if (!this.isshown || this.played || !this.fulled || !options.inline) {
        return this;
      }

      this.fulled = false;
      this.close();
      removeclass(this.button, class_fullscreen_exit);

      if (options.transition) {
        removeclass(list, class_transition);

        if (this.viewed) {
          removeclass(image, class_transition);
        }
      }

      if (options.focus) {
        this.clearenforcefocus();
      }

      viewer.removeattribute('role');
      viewer.removeattribute('aria-labelledby');
      viewer.removeattribute('aria-modal');
      removeclass(viewer, class_fixed);
      setstyle(viewer, {
        zindex: options.zindexinline
      });
      this.viewerdata = assign({}, this.parentdata);
      this.renderviewer();
      this.renderlist();

      if (this.viewed) {
        this.initimage(function () {
          _this10.renderimage(function () {
            if (options.transition) {
              settimeout(function () {
                addclass(image, class_transition);
                addclass(list, class_transition);
              }, 0);
            }
          });
        });
      }

      return this;
    },
    // show the current ratio of the image with percentage
    tooltip: function tooltip() {
      var _this11 = this;

      var options = this.options,
          tooltipbox = this.tooltipbox,
          imagedata = this.imagedata;

      if (!this.viewed || this.played || !options.tooltip) {
        return this;
      }

      tooltipbox.textcontent = "".concat(math.round(imagedata.ratio * 100), "%");

      if (!this.tooltipping) {
        if (options.transition) {
          if (this.fading) {
            dispatchevent(tooltipbox, event_transition_end);
          }

          addclass(tooltipbox, class_show);
          addclass(tooltipbox, class_fade);
          addclass(tooltipbox, class_transition);
          tooltipbox.removeattribute('aria-hidden'); // force reflow to enable css3 transition

          tooltipbox.initialoffsetwidth = tooltipbox.offsetwidth;
          addclass(tooltipbox, class_in);
        } else {
          addclass(tooltipbox, class_show);
          tooltipbox.removeattribute('aria-hidden');
        }
      } else {
        cleartimeout(this.tooltipping);
      }

      this.tooltipping = settimeout(function () {
        if (options.transition) {
          addlistener(tooltipbox, event_transition_end, function () {
            removeclass(tooltipbox, class_show);
            removeclass(tooltipbox, class_fade);
            removeclass(tooltipbox, class_transition);
            tooltipbox.setattribute('aria-hidden', true);
            _this11.fading = false;
          }, {
            once: true
          });
          removeclass(tooltipbox, class_in);
          _this11.fading = true;
        } else {
          removeclass(tooltipbox, class_show);
          tooltipbox.setattribute('aria-hidden', true);
        }

        _this11.tooltipping = false;
      }, 1000);
      return this;
    },

    /**
     * toggle the image size between its current size and natural size
     * @param {event} [_originalevent=null] - the original event if any.
     * @returns {viewer} this
     */
    toggle: function toggle() {
      var _originalevent = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : null;

      if (this.imagedata.ratio === 1) {
        this.zoomto(this.imagedata.oldratio, true, _originalevent);
      } else {
        this.zoomto(1, true, _originalevent);
      }

      return this;
    },
    // reset the image to its initial state
    reset: function reset() {
      if (this.viewed && !this.played) {
        this.imagedata = assign({}, this.initialimagedata);
        this.renderimage();
      }

      return this;
    },
    // update viewer when images changed
    update: function update() {
      var _this12 = this;

      var element = this.element,
          options = this.options,
          isimg = this.isimg; // destroy viewer if the target image was deleted

      if (isimg && !element.parentnode) {
        return this.destroy();
      }

      var images = [];
      foreach(isimg ? [element] : element.queryselectorall('img'), function (image) {
        if (isfunction(options.filter)) {
          if (options.filter.call(_this12, image)) {
            images.push(image);
          }
        } else if (_this12.getimageurl(image)) {
          images.push(image);
        }
      });

      if (!images.length) {
        return this;
      }

      this.images = images;
      this.length = images.length;

      if (this.ready) {
        var changedindexes = [];
        foreach(this.items, function (item, i) {
          var img = item.queryselector('img');
          var image = images[i];

          if (image && img) {
            if (image.src !== img.src // title changed (#408)
            || image.alt !== img.alt) {
              changedindexes.push(i);
            }
          } else {
            changedindexes.push(i);
          }
        });
        setstyle(this.list, {
          width: 'auto'
        });
        this.initlist();

        if (this.isshown) {
          if (this.length) {
            if (this.viewed) {
              var changedindex = changedindexes.indexof(this.index);

              if (changedindex >= 0) {
                this.viewed = false;
                this.view(math.max(math.min(this.index - changedindex, this.length - 1), 0));
              } else {
                var activeitem = this.items[this.index]; // reactivate the current viewing item after reset the list.

                addclass(activeitem, class_active);
                activeitem.setattribute('aria-selected', true);
              }
            }
          } else {
            this.image = null;
            this.viewed = false;
            this.index = 0;
            this.imagedata = {};
            this.canvas.innerhtml = '';
            this.title.innerhtml = '';
          }
        }
      } else {
        this.build();
      }

      return this;
    },
    // destroy the viewer
    destroy: function destroy() {
      var element = this.element,
          options = this.options;

      if (!element[namespace]) {
        return this;
      }

      this.destroyed = true;

      if (this.ready) {
        if (this.played) {
          this.stop();
        }

        if (options.inline) {
          if (this.fulled) {
            this.exit();
          }

          this.unbind();
        } else if (this.isshown) {
          if (this.viewing) {
            if (this.imagerendering) {
              this.imagerendering.abort();
            } else if (this.imageinitializing) {
              this.imageinitializing.abort();
            }
          }

          if (this.hiding) {
            this.transitioning.abort();
          }

          this.hidden();
        } else if (this.showing) {
          this.transitioning.abort();
          this.hidden();
        }

        this.ready = false;
        this.viewer.parentnode.removechild(this.viewer);
      } else if (options.inline) {
        if (this.delaying) {
          this.delaying.abort();
        } else if (this.initializing) {
          this.initializing.abort();
        }
      }

      if (!options.inline) {
        removelistener(element, event_click, this.onstart);
      }

      element[namespace] = undefined;
      return this;
    }
  };

  var others = {
    getimageurl: function getimageurl(image) {
      var url = this.options.url;

      if (isstring(url)) {
        url = image.getattribute(url);
      } else if (isfunction(url)) {
        url = url.call(this, image);
      } else {
        url = '';
      }

      return url;
    },
    enforcefocus: function enforcefocus() {
      var _this = this;

      this.clearenforcefocus();
      addlistener(document, event_focusin, this.onfocusin = function (event) {
        var viewer = _this.viewer;
        var target = event.target;

        if (target !== document && target !== viewer && !viewer.contains(target) // avoid conflicts with other modals (#474)
        && (target.getattribute('tabindex') === null || target.getattribute('aria-modal') !== 'true')) {
          viewer.focus();
        }
      });
    },
    clearenforcefocus: function clearenforcefocus() {
      if (this.onfocusin) {
        removelistener(document, event_focusin, this.onfocusin);
        this.onfocusin = null;
      }
    },
    open: function open() {
      var body = this.body;
      addclass(body, class_open);
      body.style.paddingright = "".concat(this.scrollbarwidth + (parsefloat(this.initialbodycomputedpaddingright) || 0), "px");
    },
    close: function close() {
      var body = this.body;
      removeclass(body, class_open);
      body.style.paddingright = this.initialbodypaddingright;
    },
    shown: function shown() {
      var element = this.element,
          options = this.options,
          viewer = this.viewer;
      this.fulled = true;
      this.isshown = true;
      this.render();
      this.bind();
      this.showing = false;

      if (options.focus) {
        viewer.focus();
        this.enforcefocus();
      }

      if (isfunction(options.shown)) {
        addlistener(element, event_shown, options.shown, {
          once: true
        });
      }

      if (dispatchevent(element, event_shown) === false) {
        return;
      }

      if (this.ready && this.isshown && !this.hiding) {
        this.view(this.index);
      }
    },
    hidden: function hidden() {
      var element = this.element,
          options = this.options,
          viewer = this.viewer;

      if (options.fucus) {
        this.clearenforcefocus();
      }

      this.fulled = false;
      this.viewed = false;
      this.isshown = false;
      this.close();
      this.unbind();
      addclass(viewer, class_hide);
      viewer.removeattribute('role');
      viewer.removeattribute('aria-labelledby');
      viewer.removeattribute('aria-modal');
      viewer.setattribute('aria-hidden', true);
      this.resetlist();
      this.resetimage();
      this.hiding = false;

      if (!this.destroyed) {
        if (isfunction(options.hidden)) {
          addlistener(element, event_hidden, options.hidden, {
            once: true
          });
        }

        dispatchevent(element, event_hidden, null, {
          cancelable: false
        });
      }
    },
    requestfullscreen: function requestfullscreen(options) {
      var document = this.element.ownerdocument;

      if (this.fulled && !(document.fullscreenelement || document.webkitfullscreenelement || document.mozfullscreenelement || document.msfullscreenelement)) {
        var documentelement = document.documentelement; // element.requestfullscreen()

        if (documentelement.requestfullscreen) {
          // avoid typeerror when convert `options` to dictionary
          if (isplainobject(options)) {
            documentelement.requestfullscreen(options);
          } else {
            documentelement.requestfullscreen();
          }
        } else if (documentelement.webkitrequestfullscreen) {
          documentelement.webkitrequestfullscreen(element.allow_keyboard_input);
        } else if (documentelement.mozrequestfullscreen) {
          documentelement.mozrequestfullscreen();
        } else if (documentelement.msrequestfullscreen) {
          documentelement.msrequestfullscreen();
        }
      }
    },
    exitfullscreen: function exitfullscreen() {
      var document = this.element.ownerdocument;

      if (this.fulled && (document.fullscreenelement || document.webkitfullscreenelement || document.mozfullscreenelement || document.msfullscreenelement)) {
        // document.exitfullscreen()
        if (document.exitfullscreen) {
          document.exitfullscreen();
        } else if (document.webkitexitfullscreen) {
          document.webkitexitfullscreen();
        } else if (document.mozcancelfullscreen) {
          document.mozcancelfullscreen();
        } else if (document.msexitfullscreen) {
          document.msexitfullscreen();
        }
      }
    },
    change: function change(event) {
      var options = this.options,
          pointers = this.pointers;
      var pointer = pointers[object.keys(pointers)[0]]; // in the case of the `pointers` object is empty (#421)

      if (!pointer) {
        return;
      }

      var offsetx = pointer.endx - pointer.startx;
      var offsety = pointer.endy - pointer.starty;

      switch (this.action) {
        // move the current image
        case action_move:
          this.move(offsetx, offsety, event);
          break;
        // zoom the current image

        case action_zoom:
          this.zoom(getmaxzoomratio(pointers), false, event);
          break;

        case action_switch:
          {
            this.action = 'switched';
            var absoluteoffsetx = math.abs(offsetx);

            if (absoluteoffsetx > 1 && absoluteoffsetx > math.abs(offsety)) {
              // empty `pointers` as `touchend` event will not be fired after swiped in ios browsers.
              this.pointers = {};

              if (offsetx > 1) {
                this.prev(options.loop);
              } else if (offsetx < -1) {
                this.next(options.loop);
              }
            }

            break;
          }
      } // override


      foreach(pointers, function (p) {
        p.startx = p.endx;
        p.starty = p.endy;
      });
    },
    isswitchable: function isswitchable() {
      var imagedata = this.imagedata,
          viewerdata = this.viewerdata;
      return this.length > 1 && imagedata.x >= 0 && imagedata.y >= 0 && imagedata.width <= viewerdata.width && imagedata.height <= viewerdata.height;
    }
  };

  var anotherviewer = window.viewer;

  var getuniqueid = function (id) {
    return function () {
      id += 1;
      return id;
    };
  }(-1);

  var viewer = /*#__pure__*/function () {
    /**
     * create a new viewer.
     * @param {element} element - the target element for viewing.
     * @param {object} [options={}] - the configuration options.
     */
    function viewer(element) {
      var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};

      _classcallcheck(this, viewer);

      if (!element || element.nodetype !== 1) {
        throw new error('the first argument is required and must be an element.');
      }

      this.element = element;
      this.options = assign({}, defaults, isplainobject(options) && options);
      this.action = false;
      this.fading = false;
      this.fulled = false;
      this.hiding = false;
      this.imageclicked = false;
      this.imagedata = {};
      this.index = this.options.initialviewindex;
      this.isimg = false;
      this.isshown = false;
      this.length = 0;
      this.moving = false;
      this.played = false;
      this.playing = false;
      this.pointers = {};
      this.ready = false;
      this.rotating = false;
      this.scaling = false;
      this.showing = false;
      this.timeout = false;
      this.tooltipping = false;
      this.viewed = false;
      this.viewing = false;
      this.wheeling = false;
      this.zooming = false;
      this.id = getuniqueid();
      this.init();
    }

    _createclass(viewer, [{
      key: "init",
      value: function init() {
        var _this = this;

        var element = this.element,
            options = this.options;

        if (element[namespace]) {
          return;
        }

        element[namespace] = this; // the `focus` option requires the `keyboard` option set to `true`.

        if (options.focus && !options.keyboard) {
          options.focus = false;
        }

        var isimg = element.localname === 'img';
        var images = [];
        foreach(isimg ? [element] : element.queryselectorall('img'), function (image) {
          if (isfunction(options.filter)) {
            if (options.filter.call(_this, image)) {
              images.push(image);
            }
          } else if (_this.getimageurl(image)) {
            images.push(image);
          }
        });
        this.isimg = isimg;
        this.length = images.length;
        this.images = images;
        this.initbody(); // override `transition` option if it is not supported

        if (isundefined(document.createelement(namespace).style.transition)) {
          options.transition = false;
        }

        if (options.inline) {
          var count = 0;

          var progress = function progress() {
            count += 1;

            if (count === _this.length) {
              var timeout;
              _this.initializing = false;
              _this.delaying = {
                abort: function abort() {
                  cleartimeout(timeout);
                }
              }; // build asynchronously to keep `this.viewer` is accessible in `ready` event handler.

              timeout = settimeout(function () {
                _this.delaying = false;

                _this.build();
              }, 0);
            }
          };

          this.initializing = {
            abort: function abort() {
              foreach(images, function (image) {
                if (!image.complete) {
                  removelistener(image, event_load, progress);
                }
              });
            }
          };
          foreach(images, function (image) {
            if (image.complete) {
              progress();
            } else {
              addlistener(image, event_load, progress, {
                once: true
              });
            }
          });
        } else {
          addlistener(element, event_click, this.onstart = function (_ref) {
            var target = _ref.target;

            if (target.localname === 'img' && (!isfunction(options.filter) || options.filter.call(_this, target))) {
              _this.view(_this.images.indexof(target));
            }
          });
        }
      }
    }, {
      key: "build",
      value: function build() {
        if (this.ready) {
          return;
        }

        var element = this.element,
            options = this.options;
        var parent = element.parentnode;
        var template = document.createelement('div');
        template.innerhtml = template;
        var viewer = template.queryselector(".".concat(namespace, "-container"));
        var title = viewer.queryselector(".".concat(namespace, "-title"));
        var toolbar = viewer.queryselector(".".concat(namespace, "-toolbar"));
        var navbar = viewer.queryselector(".".concat(namespace, "-navbar"));
        var button = viewer.queryselector(".".concat(namespace, "-button"));
        var canvas = viewer.queryselector(".".concat(namespace, "-canvas"));
        this.parent = parent;
        this.viewer = viewer;
        this.title = title;
        this.toolbar = toolbar;
        this.navbar = navbar;
        this.button = button;
        this.canvas = canvas;
        this.footer = viewer.queryselector(".".concat(namespace, "-footer"));
        this.tooltipbox = viewer.queryselector(".".concat(namespace, "-tooltip"));
        this.player = viewer.queryselector(".".concat(namespace, "-player"));
        this.list = viewer.queryselector(".".concat(namespace, "-list"));
        viewer.id = "".concat(namespace).concat(this.id);
        title.id = "".concat(namespace, "title").concat(this.id);
        addclass(title, !options.title ? class_hide : getresponsiveclass(array.isarray(options.title) ? options.title[0] : options.title));
        addclass(navbar, !options.navbar ? class_hide : getresponsiveclass(options.navbar));
        toggleclass(button, class_hide, !options.button);

        if (options.keyboard) {
          button.setattribute('tabindex', 0);
        }

        if (options.backdrop) {
          addclass(viewer, "".concat(namespace, "-backdrop"));

          if (!options.inline && options.backdrop !== 'static') {
            setdata(canvas, data_action, 'hide');
          }
        }

        if (isstring(options.classname) && options.classname) {
          // in case there are multiple class names
          options.classname.split(regexp_spaces).foreach(function (classname) {
            addclass(viewer, classname);
          });
        }

        if (options.toolbar) {
          var list = document.createelement('ul');
          var custom = isplainobject(options.toolbar);
          var zoombuttons = buttons.slice(0, 3);
          var rotatebuttons = buttons.slice(7, 9);
          var scalebuttons = buttons.slice(9);

          if (!custom) {
            addclass(toolbar, getresponsiveclass(options.toolbar));
          }

          foreach(custom ? options.toolbar : buttons, function (value, index) {
            var deep = custom && isplainobject(value);
            var name = custom ? hyphenate(index) : value;
            var show = deep && !isundefined(value.show) ? value.show : value;

            if (!show || !options.zoomable && zoombuttons.indexof(name) !== -1 || !options.rotatable && rotatebuttons.indexof(name) !== -1 || !options.scalable && scalebuttons.indexof(name) !== -1) {
              return;
            }

            var size = deep && !isundefined(value.size) ? value.size : value;
            var click = deep && !isundefined(value.click) ? value.click : value;
            var item = document.createelement('li');

            if (options.keyboard) {
              item.setattribute('tabindex', 0);
            }

            item.setattribute('role', 'button');
            addclass(item, "".concat(namespace, "-").concat(name));

            if (!isfunction(click)) {
              setdata(item, data_action, name);
            }

            if (isnumber(show)) {
              addclass(item, getresponsiveclass(show));
            }

            if (['small', 'large'].indexof(size) !== -1) {
              addclass(item, "".concat(namespace, "-").concat(size));
            } else if (name === 'play') {
              addclass(item, "".concat(namespace, "-large"));
            }

            if (isfunction(click)) {
              addlistener(item, event_click, click);
            }

            list.appendchild(item);
          });
          toolbar.appendchild(list);
        } else {
          addclass(toolbar, class_hide);
        }

        if (!options.rotatable) {
          var rotates = toolbar.queryselectorall('li[class*="rotate"]');
          addclass(rotates, class_invisible);
          foreach(rotates, function (rotate) {
            toolbar.appendchild(rotate);
          });
        }

        if (options.inline) {
          addclass(button, class_fullscreen);
          setstyle(viewer, {
            zindex: options.zindexinline
          });

          if (window.getcomputedstyle(parent).position === 'static') {
            setstyle(parent, {
              position: 'relative'
            });
          }

          parent.insertbefore(viewer, element.nextsibling);
        } else {
          addclass(button, class_close);
          addclass(viewer, class_fixed);
          addclass(viewer, class_fade);
          addclass(viewer, class_hide);
          setstyle(viewer, {
            zindex: options.zindex
          });
          var container = options.container;

          if (isstring(container)) {
            container = element.ownerdocument.queryselector(container);
          }

          if (!container) {
            container = this.body;
          }

          container.appendchild(viewer);
        }

        if (options.inline) {
          this.render();
          this.bind();
          this.isshown = true;
        }

        this.ready = true;

        if (isfunction(options.ready)) {
          addlistener(element, event_ready, options.ready, {
            once: true
          });
        }

        if (dispatchevent(element, event_ready) === false) {
          this.ready = false;
          return;
        }

        if (this.ready && options.inline) {
          this.view(this.index);
        }
      }
      /**
       * get the no conflict viewer class.
       * @returns {viewer} the viewer class.
       */

    }], [{
      key: "noconflict",
      value: function noconflict() {
        window.viewer = anotherviewer;
        return viewer;
      }
      /**
       * change the default options.
       * @param {object} options - the new default options.
       */

    }, {
      key: "setdefaults",
      value: function setdefaults(options) {
        assign(defaults, isplainobject(options) && options);
      }
    }]);

    return viewer;
  }();

  assign(viewer.prototype, render, events, handlers, methods, others);

  return viewer;

}));