p5.dom.js

/*! p5.js v0.9.0 July 01, 2019 */
/**
 * <p>The web is much more than just canvas and p5.dom makes it easy to interact
 * with other HTML5 objects, including text, hyperlink, image, input, video,
 * audio, and webcam.</p>
 * <p>There is a set of creation methods, DOM manipulation methods, and
 * an extended <a href="#/p5.Element">p5.Element</a> that supports a range of HTML elements. See the
 * <a href='https://github.com/processing/p5.js/wiki/Beyond-the-canvas'>
 * beyond the canvas tutorial</a> for a full overview of how this addon works.
 *
 * <p>Methods and properties shown in black are part of the p5.js core, items in
 * blue are part of the p5.dom library. You will need to include an extra file
 * in order to access the blue functions. See the
 * <a href='http://p5js.org/libraries/#using-a-library'>using a library</a>
 * section for information on how to include this library. p5.dom comes with
 * <a href='http://p5js.org/download'>p5 complete</a> or you can download the single file
 * <a href='https://raw.githubusercontent.com/lmccart/p5.js/master/lib/addons/p5.dom.js'>
 * here</a>.</p>
 * <p>See <a href='https://github.com/processing/p5.js/wiki/Beyond-the-canvas'>tutorial: beyond the canvas</a>
 * for more info on how to use this library.</a>
 *
 * @module p5.dom
 * @submodule p5.dom
 * @for p5
 * @main
 */

(function(root, factory) {
  if (typeof define === 'function' && define.amd)
    define('p5.dom', ['p5'], function(p5) {
      factory(p5);
    });
  else if (typeof exports === 'object') factory(require('../p5'));
  else factory(root['p5']);
})(this, function(p5) {
  // =============================================================================
  //                         p5 additions
  // =============================================================================

  /**
   * Searches the page for an element with the given ID, class, or tag name (using the '#' or '.'
   * prefixes to specify an ID or class respectively, and none for a tag) and returns it as
   * a <a href="#/p5.Element">p5.Element</a>. If a class or tag name is given with more than 1 element,
   * only the first element will be returned.
   * The DOM node itself can be accessed with .elt.
   * Returns null if none found. You can also specify a container to search within.
   *
   * @method select
   * @param  {String} name id, class, or tag name of element to search for
   * @param  {String|p5.Element|HTMLElement} [container] id, <a href="#/p5.Element">p5.Element</a>, or
   *                                             HTML element to search within
   * @return {p5.Element|null} <a href="#/p5.Element">p5.Element</a> containing node found
   * @example
   * <div ><code class='norender'>
   * function setup() {
   *   createCanvas(100, 100);
   *   //translates canvas 50px down
   *   select('canvas').position(100, 100);
   * }
   * </code></div>
   * <div><code class='norender'>
   * // these are all valid calls to select()
   * var a = select('#moo');
   * var b = select('#blah', '#myContainer');
   * var c, e;
   * if (b) {
   *   c = select('#foo', b);
   * }
   * var d = document.getElementById('beep');
   * if (d) {
   *   e = select('p', d);
   * }
   * [a, b, c, d, e]; // unused
   * </code></div>
   *
   */
  p5.prototype.select = function(e, p) {
    p5._validateParameters('select', arguments);
    var res = null;
    var container = getContainer(p);
    if (e[0] === '.') {
      e = e.slice(1);
      res = container.getElementsByClassName(e);
      if (res.length) {
        res = res[0];
      } else {
        res = null;
      }
    } else if (e[0] === '#') {
      e = e.slice(1);
      res = container.getElementById(e);
    } else {
      res = container.getElementsByTagName(e);
      if (res.length) {
        res = res[0];
      } else {
        res = null;
      }
    }
    if (res) {
      return this._wrapElement(res);
    } else {
      return null;
    }
  };

  /**
   * Searches the page for elements with the given class or tag name (using the '.' prefix
   * to specify a class and no prefix for a tag) and returns them as <a href="#/p5.Element">p5.Element</a>s
   * in an array.
   * The DOM node itself can be accessed with .elt.
   * Returns an empty array if none found.
   * You can also specify a container to search within.
   *
   * @method selectAll
   * @param  {String} name class or tag name of elements to search for
   * @param  {String} [container] id, <a href="#/p5.Element">p5.Element</a>, or HTML element to search within
   * @return {p5.Element[]} Array of <a href="#/p5.Element">p5.Element</a>s containing nodes found
   * @example
   * <div class='norender'><code>
   * function setup() {
   *   createButton('btn');
   *   createButton('2nd btn');
   *   createButton('3rd btn');
   *   var buttons = selectAll('button');
   *
   *   for (var i = 0; i < buttons.length; i++) {
   *     buttons[i].size(100, 100);
   *   }
   * }
   * </code></div>
   * <div class='norender'><code>
   * // these are all valid calls to selectAll()
   * var a = selectAll('.moo');
   * a = selectAll('div');
   * a = selectAll('button', '#myContainer');
   *
   * var d = select('#container');
   * a = selectAll('p', d);
   *
   * var f = document.getElementById('beep');
   * a = select('.blah', f);
   *
   * a; // unused
   * </code></div>
   *
   */
  p5.prototype.selectAll = function(e, p) {
    p5._validateParameters('selectAll', arguments);
    var arr = [];
    var res;
    var container = getContainer(p);
    if (e[0] === '.') {
      e = e.slice(1);
      res = container.getElementsByClassName(e);
    } else {
      res = container.getElementsByTagName(e);
    }
    if (res) {
      for (var j = 0; j < res.length; j++) {
        var obj = this._wrapElement(res[j]);
        arr.push(obj);
      }
    }
    return arr;
  };

  /**
   * Helper function for select and selectAll
   */
  function getContainer(p) {
    var container = document;
    if (typeof p === 'string' && p[0] === '#') {
      p = p.slice(1);
      container = document.getElementById(p) || document;
    } else if (p instanceof p5.Element) {
      container = p.elt;
    } else if (p instanceof HTMLElement) {
      container = p;
    }
    return container;
  }

  /**
   * Helper function for getElement and getElements.
   */
  p5.prototype._wrapElement = function(elt) {
    var children = Array.prototype.slice.call(elt.children);
    if (elt.tagName === 'INPUT' && elt.type === 'checkbox') {
      var converted = new p5.Element(elt, this);
      converted.checked = function() {
        if (arguments.length === 0) {
          return this.elt.checked;
        } else if (arguments[0]) {
          this.elt.checked = true;
        } else {
          this.elt.checked = false;
        }
        return this;
      };
      return converted;
    } else if (elt.tagName === 'VIDEO' || elt.tagName === 'AUDIO') {
      return new p5.MediaElement(elt, this);
    } else if (elt.tagName === 'SELECT') {
      return this.createSelect(new p5.Element(elt, this));
    } else if (
      children.length > 0 &&
      children.every(function(c) {
        return c.tagName === 'INPUT' || c.tagName === 'LABEL';
      })
    ) {
      return this.createRadio(new p5.Element(elt, this));
    } else {
      return new p5.Element(elt, this);
    }
  };

  /**
   * Removes all elements created by p5, except any canvas / graphics
   * elements created by <a href="#/p5/createCanvas">createCanvas</a> or <a href="#/p5/createGraphics">createGraphics</a>.
   * Event handlers are removed, and element is removed from the DOM.
   * @method removeElements
   * @example
   * <div class='norender'><code>
   * function setup() {
   *   createCanvas(100, 100);
   *   createDiv('this is some text');
   *   createP('this is a paragraph');
   * }
   * function mousePressed() {
   *   removeElements(); // this will remove the div and p, not canvas
   * }
   * </code></div>
   *
   */
  p5.prototype.removeElements = function(e) {
    p5._validateParameters('removeElements', arguments);
    for (var i = 0; i < this._elements.length; i++) {
      if (!(this._elements[i].elt instanceof HTMLCanvasElement)) {
        this._elements[i].remove();
      }
    }
  };

  /**
   * The .<a href="#/p5.Element/changed">changed()</a> function is called when the value of an
   * element changes.
   * This can be used to attach an element specific event listener.
   *
   * @method changed
   * @param  {Function|Boolean} fxn function to be fired when the value of
   *                                an element changes.
   *                                if `false` is passed instead, the previously
   *                                firing function will no longer fire.
   * @chainable
   * @example
   * <div><code>
   * var sel;
   *
   * function setup() {
   *   textAlign(CENTER);
   *   background(200);
   *   sel = createSelect();
   *   sel.position(10, 10);
   *   sel.option('pear');
   *   sel.option('kiwi');
   *   sel.option('grape');
   *   sel.changed(mySelectEvent);
   * }
   *
   * function mySelectEvent() {
   *   var item = sel.value();
   *   background(200);
   *   text("it's a " + item + '!', 50, 50);
   * }
   * </code></div>
   *
   * <div><code>
   * var checkbox;
   * var cnv;
   *
   * function setup() {
   *   checkbox = createCheckbox(' fill');
   *   checkbox.changed(changeFill);
   *   cnv = createCanvas(100, 100);
   *   cnv.position(0, 30);
   *   noFill();
   * }
   *
   * function draw() {
   *   background(200);
   *   ellipse(50, 50, 50, 50);
   * }
   *
   * function changeFill() {
   *   if (checkbox.checked()) {
   *     fill(0);
   *   } else {
   *     noFill();
   *   }
   * }
   * </code></div>
   *
   * @alt
   * dropdown: pear, kiwi, grape. When selected text "its a" + selection shown.
   *
   */
  p5.Element.prototype.changed = function(fxn) {
    p5.Element._adjustListener('change', fxn, this);
    return this;
  };

  /**
   * The .<a href="#/p5.Element/input">input()</a> function is called when any user input is
   * detected with an element. The input event is often used
   * to detect keystrokes in a input element, or changes on a
   * slider element. This can be used to attach an element specific
   * event listener.
   *
   * @method input
   * @param  {Function|Boolean} fxn function to be fired when any user input is
   *                                detected within the element.
   *                                if `false` is passed instead, the previously
   *                                firing function will no longer fire.
   * @chainable
   * @example
   * <div class='norender'><code>
   * // Open your console to see the output
   * function setup() {
   *   var inp = createInput('');
   *   inp.input(myInputEvent);
   * }
   *
   * function myInputEvent() {
   *   console.log('you are typing: ', this.value());
   * }
   * </code></div>
   *
   * @alt
   * no display.
   *
   */
  p5.Element.prototype.input = function(fxn) {
    p5.Element._adjustListener('input', fxn, this);
    return this;
  };

  /**
   * Helpers for create methods.
   */
  function addElement(elt, pInst, media) {
    var node = pInst._userNode ? pInst._userNode : document.body;
    node.appendChild(elt);
    var c = media
      ? new p5.MediaElement(elt, pInst)
      : new p5.Element(elt, pInst);
    pInst._elements.push(c);
    return c;
  }

  /**
   * Creates a &lt;div&gt;&lt;/div&gt; element in the DOM with given inner HTML.
   * Appends to the container node if one is specified, otherwise
   * appends to body.
   *
   * @method createDiv
   * @param  {String} [html] inner HTML for element created
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div class='norender'><code>
   * createDiv('this is some text');
   * </code></div>
   */

  /**
   * Creates a &lt;p&gt;&lt;/p&gt; element in the DOM with given inner HTML. Used
   * for paragraph length text.
   * Appends to the container node if one is specified, otherwise
   * appends to body.
   *
   * @method createP
   * @param  {String} [html] inner HTML for element created
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div class='norender'><code>
   * createP('this is some text');
   * </code></div>
   */

  /**
   * Creates a &lt;span&gt;&lt;/span&gt; element in the DOM with given inner HTML.
   * Appends to the container node if one is specified, otherwise
   * appends to body.
   *
   * @method createSpan
   * @param  {String} [html] inner HTML for element created
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div class='norender'><code>
   * createSpan('this is some text');
   * </code></div>
   */
  var tags = ['div', 'p', 'span'];
  tags.forEach(function(tag) {
    var method = 'create' + tag.charAt(0).toUpperCase() + tag.slice(1);
    p5.prototype[method] = function(html) {
      var elt = document.createElement(tag);
      elt.innerHTML = typeof html === 'undefined' ? '' : html;
      return addElement(elt, this);
    };
  });

  /**
   * Creates an &lt;img&gt; element in the DOM with given src and
   * alternate text.
   * Appends to the container node if one is specified, otherwise
   * appends to body.
   *
   * @method createImg
   * @param  {String} src src path or url for image
   * @param  {String} [alt] alternate text to be used if image does not load
   * @param  {Function} [successCallback] callback to be called once image data is loaded
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div class='norender'><code>
   * createImg('http://p5js.org/img/asterisk-01.png');
   * </code></div>
   */
  /**
   * @method createImg
   * @param  {String} src
   * @param  {Function} successCallback
   * @return {Object|p5.Element}
   */
  p5.prototype.createImg = function() {
    p5._validateParameters('createImg', arguments);
    var elt = document.createElement('img');
    elt.crossOrigin = 'Anonymous';
    var args = arguments;
    var self;
    var setAttrs = function() {
      self.width = elt.offsetWidth || elt.width;
      self.height = elt.offsetHeight || elt.height;
      if (args.length > 1 && typeof args[1] === 'function') {
        self.fn = args[1];
        self.fn();
      } else if (args.length > 1 && typeof args[2] === 'function') {
        self.fn = args[2];
        self.fn();
      }
    };
    elt.src = args[0];
    if (args.length > 1 && typeof args[1] === 'string') {
      elt.alt = args[1];
    }
    elt.onload = function() {
      setAttrs();
    };
    self = addElement(elt, this);
    return self;
  };

  /**
   * Creates an &lt;a&gt;&lt;/a&gt; element in the DOM for including a hyperlink.
   * Appends to the container node if one is specified, otherwise
   * appends to body.
   *
   * @method createA
   * @param  {String} href       url of page to link to
   * @param  {String} html       inner html of link element to display
   * @param  {String} [target]   target where new link should open,
   *                             could be _blank, _self, _parent, _top.
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div class='norender'><code>
   * createA('http://p5js.org/', 'this is a link');
   * </code></div>
   */
  p5.prototype.createA = function(href, html, target) {
    p5._validateParameters('createA', arguments);
    var elt = document.createElement('a');
    elt.href = href;
    elt.innerHTML = html;
    if (target) elt.target = target;
    return addElement(elt, this);
  };

  /** INPUT **/

  /**
   * Creates a slider &lt;input&gt;&lt;/input&gt; element in the DOM.
   * Use .size() to set the display length of the slider.
   * Appends to the container node if one is specified, otherwise
   * appends to body.
   *
   * @method createSlider
   * @param  {Number} min minimum value of the slider
   * @param  {Number} max maximum value of the slider
   * @param  {Number} [value] default value of the slider
   * @param  {Number} [step] step size for each tick of the slider (if step is set to 0, the slider will move continuously from the minimum to the maximum value)
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div><code>
   * var slider;
   * function setup() {
   *   slider = createSlider(0, 255, 100);
   *   slider.position(10, 10);
   *   slider.style('width', '80px');
   * }
   *
   * function draw() {
   *   var val = slider.value();
   *   background(val);
   * }
   * </code></div>
   *
   * <div><code>
   * var slider;
   * function setup() {
   *   colorMode(HSB);
   *   slider = createSlider(0, 360, 60, 40);
   *   slider.position(10, 10);
   *   slider.style('width', '80px');
   * }
   *
   * function draw() {
   *   var val = slider.value();
   *   background(val, 100, 100, 1);
   * }
   * </code></div>
   */
  p5.prototype.createSlider = function(min, max, value, step) {
    p5._validateParameters('createSlider', arguments);
    var elt = document.createElement('input');
    elt.type = 'range';
    elt.min = min;
    elt.max = max;
    if (step === 0) {
      elt.step = 0.000000000000000001; // smallest valid step
    } else if (step) {
      elt.step = step;
    }
    if (typeof value === 'number') elt.value = value;
    return addElement(elt, this);
  };

  /**
   * Creates a &lt;button&gt;&lt;/button&gt; element in the DOM.
   * Use .size() to set the display size of the button.
   * Use .mousePressed() to specify behavior on press.
   * Appends to the container node if one is specified, otherwise
   * appends to body.
   *
   * @method createButton
   * @param  {String} label label displayed on the button
   * @param  {String} [value] value of the button
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div class='norender'><code>
   * var button;
   * function setup() {
   *   createCanvas(100, 100);
   *   background(0);
   *   button = createButton('click me');
   *   button.position(19, 19);
   *   button.mousePressed(changeBG);
   * }
   *
   * function changeBG() {
   *   var val = random(255);
   *   background(val);
   * }
   * </code></div>
   */
  p5.prototype.createButton = function(label, value) {
    p5._validateParameters('createButton', arguments);
    var elt = document.createElement('button');
    elt.innerHTML = label;
    if (value) elt.value = value;
    return addElement(elt, this);
  };

  /**
   * Creates a checkbox &lt;input&gt;&lt;/input&gt; element in the DOM.
   * Calling .checked() on a checkbox returns if it is checked or not
   *
   * @method createCheckbox
   * @param  {String} [label] label displayed after checkbox
   * @param  {boolean} [value] value of the checkbox; checked is true, unchecked is false
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div class='norender'><code>
   * var checkbox;
   *
   * function setup() {
   *   checkbox = createCheckbox('label', false);
   *   checkbox.changed(myCheckedEvent);
   * }
   *
   * function myCheckedEvent() {
   *   if (this.checked()) {
   *     console.log('Checking!');
   *   } else {
   *     console.log('Unchecking!');
   *   }
   * }
   * </code></div>
   */
  p5.prototype.createCheckbox = function() {
    p5._validateParameters('createCheckbox', arguments);
    var elt = document.createElement('div');
    var checkbox = document.createElement('input');
    checkbox.type = 'checkbox';
    elt.appendChild(checkbox);
    //checkbox must be wrapped in p5.Element before label so that label appears after
    var self = addElement(elt, this);
    self.checked = function() {
      var cb = self.elt.getElementsByTagName('input')[0];
      if (cb) {
        if (arguments.length === 0) {
          return cb.checked;
        } else if (arguments[0]) {
          cb.checked = true;
        } else {
          cb.checked = false;
        }
      }
      return self;
    };
    this.value = function(val) {
      self.value = val;
      return this;
    };
    if (arguments[0]) {
      var ran = Math.random()
        .toString(36)
        .slice(2);
      var label = document.createElement('label');
      checkbox.setAttribute('id', ran);
      label.htmlFor = ran;
      self.value(arguments[0]);
      label.appendChild(document.createTextNode(arguments[0]));
      elt.appendChild(label);
    }
    if (arguments[1]) {
      checkbox.checked = true;
    }
    return self;
  };

  /**
   * Creates a dropdown menu &lt;select&gt;&lt;/select&gt; element in the DOM.
   * It also helps to assign select-box methods to <a href="#/p5.Element">p5.Element</a> when selecting existing select box
   * @method createSelect
   * @param {boolean} [multiple] true if dropdown should support multiple selections
   * @return {p5.Element}
   * @example
   * <div><code>
   * var sel;
   *
   * function setup() {
   *   textAlign(CENTER);
   *   background(200);
   *   sel = createSelect();
   *   sel.position(10, 10);
   *   sel.option('pear');
   *   sel.option('kiwi');
   *   sel.option('grape');
   *   sel.changed(mySelectEvent);
   * }
   *
   * function mySelectEvent() {
   *   var item = sel.value();
   *   background(200);
   *   text('It is a ' + item + '!', 50, 50);
   * }
   * </code></div>
   */
  /**
   * @method createSelect
   * @param {Object} existing DOM select element
   * @return {p5.Element}
   */

  p5.prototype.createSelect = function() {
    p5._validateParameters('createSelect', arguments);
    var elt, self;
    var arg = arguments[0];
    if (typeof arg === 'object' && arg.elt.nodeName === 'SELECT') {
      self = arg;
      elt = this.elt = arg.elt;
    } else {
      elt = document.createElement('select');
      if (arg && typeof arg === 'boolean') {
        elt.setAttribute('multiple', 'true');
      }
      self = addElement(elt, this);
    }
    self.option = function(name, value) {
      var index;
      //see if there is already an option with this name
      for (var i = 0; i < this.elt.length; i++) {
        if (this.elt[i].innerHTML === name) {
          index = i;
          break;
        }
      }
      //if there is an option with this name we will modify it
      if (index !== undefined) {
        //if the user passed in false then delete that option
        if (value === false) {
          this.elt.remove(index);
        } else {
          //otherwise if the name and value are the same then change both
          if (this.elt[index].innerHTML === this.elt[index].value) {
            this.elt[index].innerHTML = this.elt[index].value = value;
            //otherwise just change the value
          } else {
            this.elt[index].value = value;
          }
        }
      } else {
        //if it doesn't exist make it
        var opt = document.createElement('option');
        opt.innerHTML = name;
        if (arguments.length > 1) opt.value = value;
        else opt.value = name;
        elt.appendChild(opt);
      }
    };
    self.selected = function(value) {
      var arr = [],
        i;
      if (arguments.length > 0) {
        for (i = 0; i < this.elt.length; i++) {
          if (value.toString() === this.elt[i].value) {
            this.elt.selectedIndex = i;
          }
        }
        return this;
      } else {
        if (this.elt.getAttribute('multiple')) {
          for (i = 0; i < this.elt.selectedOptions.length; i++) {
            arr.push(this.elt.selectedOptions[i].value);
          }
          return arr;
        } else {
          return this.elt.value;
        }
      }
    };
    return self;
  };

  /**
   * Creates a radio button &lt;input&gt;&lt;/input&gt; element in the DOM.
   * The .option() method can be used to set options for the radio after it is
   * created. The .value() method will return the currently selected option.
   *
   * @method createRadio
   * @param  {String} [divId] the id and name of the created div and input field respectively
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div><code>
   * var radio;
   *
   * function setup() {
   *   radio = createRadio();
   *   radio.option('black');
   *   radio.option('white');
   *   radio.option('gray');
   *   radio.style('width', '60px');
   *   textAlign(CENTER);
   *   fill(255, 0, 0);
   * }
   *
   * function draw() {
   *   var val = radio.value();
   *   background(val);
   *   text(val, width / 2, height / 2);
   * }
   * </code></div>
   * <div><code>
   * var radio;
   *
   * function setup() {
   *   radio = createRadio();
   *   radio.option('apple', 1);
   *   radio.option('bread', 2);
   *   radio.option('juice', 3);
   *   radio.style('width', '60px');
   *   textAlign(CENTER);
   * }
   *
   * function draw() {
   *   background(200);
   *   var val = radio.value();
   *   if (val) {
   *     text('item cost is $' + val, width / 2, height / 2);
   *   }
   * }
   * </code></div>
   */
  p5.prototype.createRadio = function(existing_radios) {
    p5._validateParameters('createRadio', arguments);
    // do some prep by counting number of radios on page
    var radios = document.querySelectorAll('input[type=radio]');
    var count = 0;
    if (radios.length > 1) {
      var length = radios.length;
      var prev = radios[0].name;
      var current = radios[1].name;
      count = 1;
      for (var i = 1; i < length; i++) {
        current = radios[i].name;
        if (prev !== current) {
          count++;
        }
        prev = current;
      }
    } else if (radios.length === 1) {
      count = 1;
    }
    // see if we got an existing set of radios from callee
    var elt, self;
    if (typeof existing_radios === 'object') {
      // use existing elements
      self = existing_radios;
      elt = this.elt = existing_radios.elt;
    } else {
      // create a set of radio buttons
      elt = document.createElement('div');
      self = addElement(elt, this);
    }
    // setup member functions
    self._getInputChildrenArray = function() {
      return Array.prototype.slice.call(this.elt.children).filter(function(c) {
        return c.tagName === 'INPUT';
      });
    };

    var times = -1;
    self.option = function(name, value) {
      var opt = document.createElement('input');
      opt.type = 'radio';
      opt.innerHTML = name;
      if (value) opt.value = value;
      else opt.value = name;
      opt.setAttribute('name', 'defaultradio' + count);
      elt.appendChild(opt);
      if (name) {
        times++;
        var label = document.createElement('label');
        opt.setAttribute('id', 'defaultradio' + count + '-' + times);
        label.htmlFor = 'defaultradio' + count + '-' + times;
        label.appendChild(document.createTextNode(name));
        elt.appendChild(label);
      }
      return opt;
    };
    self.selected = function(value) {
      var i;
      var inputChildren = self._getInputChildrenArray();
      if (value) {
        for (i = 0; i < inputChildren.length; i++) {
          if (inputChildren[i].value === value) inputChildren[i].checked = true;
        }
        return this;
      } else {
        for (i = 0; i < inputChildren.length; i++) {
          if (inputChildren[i].checked === true) return inputChildren[i].value;
        }
      }
    };
    self.value = function(value) {
      var i;
      var inputChildren = self._getInputChildrenArray();
      if (value) {
        for (i = 0; i < inputChildren.length; i++) {
          if (inputChildren[i].value === value) inputChildren[i].checked = true;
        }
        return this;
      } else {
        for (i = 0; i < inputChildren.length; i++) {
          if (inputChildren[i].checked === true) return inputChildren[i].value;
        }
        return '';
      }
    };
    return self;
  };

  /**
   * Creates a colorPicker element in the DOM for color input.
   * The .value() method will return a hex string (#rrggbb) of the color.
   * The .color() method will return a p5.Color object with the current chosen color.
   *
   * @method createColorPicker
   * @param {String|p5.Color} [value] default color of element
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div>
   * <code>
   * var inp1, inp2;
   * function setup() {
   *   createCanvas(100, 100);
   *   background('grey');
   *   inp1 = createColorPicker('#ff0000');
   *   inp2 = createColorPicker(color('yellow'));
   *   inp1.input(setShade1);
   *   inp2.input(setShade2);
   *   setMidShade();
   * }
   *
   * function setMidShade() {
   *   // Finding a shade between the two
   *   var commonShade = lerpColor(inp1.color(), inp2.color(), 0.5);
   *   fill(commonShade);
   *   rect(20, 20, 60, 60);
   * }
   *
   * function setShade1() {
   *   setMidShade();
   *   console.log('You are choosing shade 1 to be : ', this.value());
   * }
   * function setShade2() {
   *   setMidShade();
   *   console.log('You are choosing shade 2 to be : ', this.value());
   * }
   * </code>
   * </div>
   */
  p5.prototype.createColorPicker = function(value) {
    p5._validateParameters('createColorPicker', arguments);
    var elt = document.createElement('input');
    var self;
    elt.type = 'color';
    if (value) {
      if (value instanceof p5.Color) {
        elt.value = value.toString('#rrggbb');
      } else {
        p5.prototype._colorMode = 'rgb';
        p5.prototype._colorMaxes = {
          rgb: [255, 255, 255, 255],
          hsb: [360, 100, 100, 1],
          hsl: [360, 100, 100, 1]
        };
        elt.value = p5.prototype.color(value).toString('#rrggbb');
      }
    } else {
      elt.value = '#000000';
    }
    self = addElement(elt, this);
    // Method to return a p5.Color object for the given color.
    self.color = function() {
      if (value.mode) {
        p5.prototype._colorMode = value.mode;
      }
      if (value.maxes) {
        p5.prototype._colorMaxes = value.maxes;
      }
      return p5.prototype.color(this.elt.value);
    };
    return self;
  };

  /**
   * Creates an &lt;input&gt;&lt;/input&gt; element in the DOM for text input.
   * Use .<a href="#/p5.Element/size">size()</a> to set the display length of the box.
   * Appends to the container node if one is specified, otherwise
   * appends to body.
   *
   * @method createInput
   * @param {String} [value] default value of the input box
   * @param {String} [type] type of text, ie text, password etc. Defaults to text
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div class='norender'><code>
   * function setup() {
   *   var inp = createInput('');
   *   inp.input(myInputEvent);
   * }
   *
   * function myInputEvent() {
   *   console.log('you are typing: ', this.value());
   * }
   * </code></div>
   */
  p5.prototype.createInput = function(value, type) {
    p5._validateParameters('createInput', arguments);
    var elt = document.createElement('input');
    elt.type = type ? type : 'text';
    if (value) elt.value = value;
    return addElement(elt, this);
  };

  /**
   * Creates an &lt;input&gt;&lt;/input&gt; element in the DOM of type 'file'.
   * This allows users to select local files for use in a sketch.
   *
   * @method createFileInput
   * @param  {Function} [callback] callback function for when a file loaded
   * @param  {String} [multiple] optional to allow multiple files selected
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created DOM element
   * @example
   * <div><code>
   * let input;
   * let img;
   *
   * function setup() {
   *   input = createFileInput(handleFile);
   *   input.position(0, 0);
   * }
   *
   * function draw() {
   *   background(255);
   *   if (img) {
   *     image(img, 0, 0, width, height);
   *   }
   * }
   *
   * function handleFile(file) {
   *   print(file);
   *   if (file.type === 'image') {
   *     img = createImg(file.data);
   *     img.hide();
   *   } else {
   *     img = null;
   *   }
   * }
   * </code></div>
   */
  p5.prototype.createFileInput = function(callback, multiple) {
    p5._validateParameters('createFileInput', arguments);
    // Function to handle when a file is selected
    // We're simplifying life and assuming that we always
    // want to load every selected file
    function handleFileSelect(evt) {
      // These are the files
      var files = evt.target.files;
      // Load each one and trigger a callback
      for (var i = 0; i < files.length; i++) {
        var f = files[i];
        p5.File._load(f, callback);
      }
    }
    // Is the file stuff supported?
    if (window.File && window.FileReader && window.FileList && window.Blob) {
      // Yup, we're ok and make an input file selector
      var elt = document.createElement('input');
      elt.type = 'file';

      // If we get a second argument that evaluates to true
      // then we are looking for multiple files
      if (multiple) {
        // Anything gets the job done
        elt.multiple = 'multiple';
      }

      // Now let's handle when a file was selected
      elt.addEventListener('change', handleFileSelect, false);
      return addElement(elt, this);
    } else {
      console.log(
        'The File APIs are not fully supported in this browser. Cannot create element.'
      );
    }
  };

  /** VIDEO STUFF **/

  function createMedia(pInst, type, src, callback) {
    var elt = document.createElement(type);

    // allow src to be empty
    src = src || '';
    if (typeof src === 'string') {
      src = [src];
    }
    for (var i = 0; i < src.length; i++) {
      var source = document.createElement('source');
      source.src = src[i];
      elt.appendChild(source);
    }
    if (typeof callback !== 'undefined') {
      var callbackHandler = function() {
        callback();
        elt.removeEventListener('canplaythrough', callbackHandler);
      };
      elt.addEventListener('canplaythrough', callbackHandler);
    }

    var c = addElement(elt, pInst, true);
    c.loadedmetadata = false;
    // set width and height onload metadata
    elt.addEventListener('loadedmetadata', function() {
      c.width = elt.videoWidth;
      c.height = elt.videoHeight;
      //c.elt.playbackRate = s;
      // set elt width and height if not set
      if (c.elt.width === 0) c.elt.width = elt.videoWidth;
      if (c.elt.height === 0) c.elt.height = elt.videoHeight;
      if (c.presetPlaybackRate) {
        c.elt.playbackRate = c.presetPlaybackRate;
        delete c.presetPlaybackRate;
      }
      c.loadedmetadata = true;
    });

    return c;
  }
  /**
   * Creates an HTML5 &lt;video&gt; element in the DOM for simple playback
   * of audio/video. Shown by default, can be hidden with .<a href="#/p5.Element/hide">hide()</a>
   * and drawn into canvas using video(). Appends to the container
   * node if one is specified, otherwise appends to body. The first parameter
   * can be either a single string path to a video file, or an array of string
   * paths to different formats of the same video. This is useful for ensuring
   * that your video can play across different browsers, as each supports
   * different formats. See <a href='https://developer.mozilla.org/en-US/docs/Web/HTML/Supported_media_formats'>this
   * page</a> for further information about supported formats.
   *
   * @method createVideo
   * @param  {String|String[]} src path to a video file, or array of paths for
   *                             supporting different browsers
   * @param  {Function} [callback] callback function to be called upon
   *                             'canplaythrough' event fire, that is, when the
   *                             browser can play the media, and estimates that
   *                             enough data has been loaded to play the media
   *                             up to its end without having to stop for
   *                             further buffering of content
   * @return {p5.MediaElement}   pointer to video <a href="#/p5.Element">p5.Element</a>
   * @example
   * <div><code>
   * var vid;
   * function setup() {
   *   noCanvas();
   *
   *   vid = createVideo(
   *     ['assets/small.mp4', 'assets/small.ogv', 'assets/small.webm'],
   *     vidLoad
   *   );
   *
   *   vid.size(100, 100);
   * }
   *
   * // This function is called when the video loads
   * function vidLoad() {
   *   vid.loop();
   *   vid.volume(0);
   * }
   * </code></div>
   */
  p5.prototype.createVideo = function(src, callback) {
    p5._validateParameters('createVideo', arguments);
    return createMedia(this, 'video', src, callback);
  };

  /** AUDIO STUFF **/

  /**
   * Creates a hidden HTML5 &lt;audio&gt; element in the DOM for simple audio
   * playback. Appends to the container node if one is specified,
   * otherwise appends to body. The first parameter
   * can be either a single string path to a audio file, or an array of string
   * paths to different formats of the same audio. This is useful for ensuring
   * that your audio can play across different browsers, as each supports
   * different formats. See <a href='https://developer.mozilla.org/en-US/docs/Web/HTML/Supported_media_formats'>this
   * page for further information about supported formats</a>.
   *
   * @method createAudio
   * @param  {String|String[]} [src] path to an audio file, or array of paths
   *                             for supporting different browsers
   * @param  {Function} [callback] callback function to be called upon
   *                             'canplaythrough' event fire, that is, when the
   *                             browser can play the media, and estimates that
   *                             enough data has been loaded to play the media
   *                             up to its end without having to stop for
   *                             further buffering of content
   * @return {p5.MediaElement}   pointer to audio <a href="#/p5.Element">p5.Element</a>
   * @example
   * <div><code>
   * var ele;
   * function setup() {
   *   ele = createAudio('assets/beat.mp3');
   *
   *   // here we set the element to autoplay
   *   // The element will play as soon
   *   // as it is able to do so.
   *   ele.autoplay(true);
   * }
   * </code></div>
   */
  p5.prototype.createAudio = function(src, callback) {
    p5._validateParameters('createAudio', arguments);
    return createMedia(this, 'audio', src, callback);
  };

  /** CAMERA STUFF **/

  /**
   * @property {String} VIDEO
   * @final
   * @category Constants
   */
  p5.prototype.VIDEO = 'video';
  /**
   * @property {String} AUDIO
   * @final
   * @category Constants
   */
  p5.prototype.AUDIO = 'audio';

  // from: https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices/getUserMedia
  // Older browsers might not implement mediaDevices at all, so we set an empty object first
  if (navigator.mediaDevices === undefined) {
    navigator.mediaDevices = {};
  }

  // Some browsers partially implement mediaDevices. We can't just assign an object
  // with getUserMedia as it would overwrite existing properties.
  // Here, we will just add the getUserMedia property if it's missing.
  if (navigator.mediaDevices.getUserMedia === undefined) {
    navigator.mediaDevices.getUserMedia = function(constraints) {
      // First get ahold of the legacy getUserMedia, if present
      var getUserMedia =
        navigator.webkitGetUserMedia || navigator.mozGetUserMedia;

      // Some browsers just don't implement it - return a rejected promise with an error
      // to keep a consistent interface
      if (!getUserMedia) {
        return Promise.reject(
          new Error('getUserMedia is not implemented in this browser')
        );
      }

      // Otherwise, wrap the call to the old navigator.getUserMedia with a Promise
      return new Promise(function(resolve, reject) {
        getUserMedia.call(navigator, constraints, resolve, reject);
      });
    };
  }

  /**
   * <p>Creates a new HTML5 &lt;video&gt; element that contains the audio/video
   * feed from a webcam. The element is separate from the canvas and is
   * displayed by default. The element can be hidden using .<a href="#/p5.Element/hide">hide()</a>. The feed
   * can be drawn onto the canvas using <a href="#/p5/image">image()</a>. The loadedmetadata property can
   * be used to detect when the element has fully loaded (see second example).</p>
   * <p>More specific properties of the feed can be passing in a Constraints object.
   * See the
   * <a href='http://w3c.github.io/mediacapture-main/getusermedia.html#media-track-constraints'> W3C
   * spec</a> for possible properties. Note that not all of these are supported
   * by all browsers.</p>
   * <p>Security note: A new browser security specification requires that getUserMedia,
   * which is behind <a href="#/p5/createCapture">createCapture()</a>, only works when you're running the code locally,
   * or on HTTPS. Learn more <a href='http://stackoverflow.com/questions/34197653/getusermedia-in-chrome-47-without-using-https'>here</a>
   * and <a href='https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices/getUserMedia'>here</a>.</p>
   *
   * @method createCapture
   * @param  {String|Constant|Object}   type type of capture, either VIDEO or
   *                                   AUDIO if none specified, default both,
   *                                   or a Constraints object
   * @param  {Function}                 [callback] function to be called once
   *                                   stream has loaded
   * @return {p5.Element} capture video <a href="#/p5.Element">p5.Element</a>
   * @example
   * <div class='norender notest'><code>
   * var capture;
   *
   * function setup() {
   *   createCanvas(480, 480);
   *   capture = createCapture(VIDEO);
   *   capture.hide();
   * }
   *
   * function draw() {
   *   image(capture, 0, 0, width, width * capture.height / capture.width);
   *   filter(INVERT);
   * }
   * </code></div>
   * <div class='norender notest'><code>
   * function setup() {
   *   createCanvas(480, 120);
   *   var constraints = {
   *     video: {
   *       mandatory: {
   *         minWidth: 1280,
   *         minHeight: 720
   *       },
   *       optional: [{ maxFrameRate: 10 }]
   *     },
   *     audio: true
   *   };
   *   createCapture(constraints, function(stream) {
   *     console.log(stream);
   *   });
   * }
   * </code></div>
   * <code><div class='norender notest'>
   * var capture;
   *
   * function setup() {
   *   createCanvas(640, 480);
   *   capture = createCapture(VIDEO);
   * }
   * function draw() {
   *   background(0);
   *   if (capture.loadedmetadata) {
   *     var c = capture.get(0, 0, 100, 100);
   *     image(c, 0, 0);
   *   }
   * }
   * </code></div>
   */
  p5.prototype.createCapture = function() {
    p5._validateParameters('createCapture', arguments);
    var useVideo = true;
    var useAudio = true;
    var constraints;
    var cb;
    for (var i = 0; i < arguments.length; i++) {
      if (arguments[i] === p5.prototype.VIDEO) {
        useAudio = false;
      } else if (arguments[i] === p5.prototype.AUDIO) {
        useVideo = false;
      } else if (typeof arguments[i] === 'object') {
        constraints = arguments[i];
      } else if (typeof arguments[i] === 'function') {
        cb = arguments[i];
      }
    }
    if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
      var elt = document.createElement('video');
      // required to work in iOS 11 & up:
      elt.setAttribute('playsinline', '');

      if (!constraints) {
        constraints = { video: useVideo, audio: useAudio };
      }

      navigator.mediaDevices.getUserMedia(constraints).then(
        function(stream) {
          try {
            if ('srcObject' in elt) {
              elt.srcObject = stream;
            } else {
              elt.src = window.URL.createObjectURL(stream);
            }
          } catch (err) {
            elt.src = stream;
          }
        },
        function(e) {
          console.log(e);
        }
      );
    } else {
      throw 'getUserMedia not supported in this browser';
    }
    var c = addElement(elt, this, true);
    c.loadedmetadata = false;
    // set width and height onload metadata
    elt.addEventListener('loadedmetadata', function() {
      elt.play();
      if (elt.width) {
        c.width = elt.videoWidth = elt.width;
        c.height = elt.videoHeight = elt.height;
      } else {
        c.width = c.elt.width = elt.videoWidth;
        c.height = c.elt.height = elt.videoHeight;
      }
      c.loadedmetadata = true;
      if (cb) {
        cb(elt.srcObject);
      }
    });
    return c;
  };

  /**
   * Creates element with given tag in the DOM with given content.
   * Appends to the container node if one is specified, otherwise
   * appends to body.
   *
   * @method createElement
   * @param  {String} tag tag for the new element
   * @param  {String} [content] html content to be inserted into the element
   * @return {p5.Element} pointer to <a href="#/p5.Element">p5.Element</a> holding created node
   * @example
   * <div class='norender'><code>
   * createElement('h2', 'im an h2 p5.element!');
   * </code></div>
   */
  p5.prototype.createElement = function(tag, content) {
    p5._validateParameters('createElement', arguments);
    var elt = document.createElement(tag);
    if (typeof content !== 'undefined') {
      elt.innerHTML = content;
    }
    return addElement(elt, this);
  };

  // =============================================================================
  //                         p5.Element additions
  // =============================================================================
  /**
   *
   * Adds specified class to the element.
   *
   * @for p5.Element
   * @method addClass
   * @param  {String} class name of class to add
   * @chainable
   * @example
   * <div class='norender'><code>
   * var div = createDiv('div');
   * div.addClass('myClass');
   * </code></div>
   */
  p5.Element.prototype.addClass = function(c) {
    if (this.elt.className) {
      if (!this.hasClass(c)) {
        this.elt.className = this.elt.className + ' ' + c;
      }
    } else {
      this.elt.className = c;
    }
    return this;
  };

  /**
   *
   * Removes specified class from the element.
   *
   * @method removeClass
   * @param  {String} class name of class to remove
   * @chainable
   * @example
   * <div class='norender'><code>
   * // In this example, a class is set when the div is created
   * // and removed when mouse is pressed. This could link up
   * // with a CSS style rule to toggle style properties.
   *
   * var div;
   *
   * function setup() {
   *   div = createDiv('div');
   *   div.addClass('myClass');
   * }
   *
   * function mousePressed() {
   *   div.removeClass('myClass');
   * }
   * </code></div>
   */
  p5.Element.prototype.removeClass = function(c) {
    // Note: Removing a class that does not exist does NOT throw an error in classList.remove method
    this.elt.classList.remove(c);
    return this;
  };

  /**
   *
   * Checks if specified class already set to element
   *
   * @method hasClass
   * @returns {boolean} a boolean value if element has specified class
   * @param c {String} class name of class to check
   * @example
   * <div class='norender'><code>
   * var div;
   *
   * function setup() {
   *   div = createDiv('div');
   *   div.addClass('show');
   * }
   *
   * function mousePressed() {
   *   if (div.hasClass('show')) {
   *     div.addClass('show');
   *   } else {
   *     div.removeClass('show');
   *   }
   * }
   * </code></div>
   */
  p5.Element.prototype.hasClass = function(c) {
    return this.elt.classList.contains(c);
  };

  /**
   *
   * Toggles element class
   *
   * @method toggleClass
   * @param c {String} class name to toggle
   * @chainable
   * @example
   * <div class='norender'><code>
   * var div;
   *
   * function setup() {
   *   div = createDiv('div');
   *   div.addClass('show');
   * }
   *
   * function mousePressed() {
   *   div.toggleClass('show');
   * }
   * </code></div>
   */
  p5.Element.prototype.toggleClass = function(c) {
    // classList also has a toggle() method, but we cannot use that yet as support is unclear.
    // See https://github.com/processing/p5.js/issues/3631
    // this.elt.classList.toggle(c);
    if (this.elt.classList.contains(c)) {
      this.elt.classList.remove(c);
    } else {
      this.elt.classList.add(c);
    }
    return this;
  };

  /**
   *
   * Attaches the element  as a child to the parent specified.
   * Accepts either a string ID, DOM node, or <a href="#/p5.Element">p5.Element</a>.
   * If no argument is specified, an array of children DOM nodes is returned.
   *
   * @method child
   * @returns {Node[]} an array of child nodes
   * @example
   * <div class='norender'><code>
   * var div0 = createDiv('this is the parent');
   * var div1 = createDiv('this is the child');
   * div0.child(div1); // use p5.Element
   * </code></div>
   * <div class='norender'><code>
   * var div0 = createDiv('this is the parent');
   * var div1 = createDiv('this is the child');
   * div1.id('apples');
   * div0.child('apples'); // use id
   * </code></div>
   * <div class='norender notest'><code>
   * // this example assumes there is a div already on the page
   * // with id "myChildDiv"
   * var div0 = createDiv('this is the parent');
   * var elt = document.getElementById('myChildDiv');
   * div0.child(elt); // use element from page
   * </code></div>
   */
  /**
   * @method child
   * @param  {String|p5.Element} [child] the ID, DOM node, or <a href="#/p5.Element">p5.Element</a>
   *                         to add to the current element
   * @chainable
   */
  p5.Element.prototype.child = function(c) {
    if (typeof c === 'undefined') {
      return this.elt.childNodes;
    }
    if (typeof c === 'string') {
      if (c[0] === '#') {
        c = c.substring(1);
      }
      c = document.getElementById(c);
    } else if (c instanceof p5.Element) {
      c = c.elt;
    }
    this.elt.appendChild(c);
    return this;
  };

  /**
   * Centers a p5 Element either vertically, horizontally,
   * or both, relative to its parent or according to
   * the body if the Element has no parent. If no argument is passed
   * the Element is aligned both vertically and horizontally.
   *
   * @method center
   * @param  {String} [align]       passing 'vertical', 'horizontal' aligns element accordingly
   * @chainable
   *
   * @example
   * <div><code>
   * function setup() {
   *   var div = createDiv('').size(10, 10);
   *   div.style('background-color', 'orange');
   *   div.center();
   * }
   * </code></div>
   */
  p5.Element.prototype.center = function(align) {
    var style = this.elt.style.display;
    var hidden = this.elt.style.display === 'none';
    var parentHidden = this.parent().style.display === 'none';
    var pos = { x: this.elt.offsetLeft, y: this.elt.offsetTop };

    if (hidden) this.show();

    this.elt.style.display = 'block';
    this.position(0, 0);

    if (parentHidden) this.parent().style.display = 'block';

    var wOffset = Math.abs(this.parent().offsetWidth - this.elt.offsetWidth);
    var hOffset = Math.abs(this.parent().offsetHeight - this.elt.offsetHeight);
    var y = pos.y;
    var x = pos.x;

    if (align === 'both' || align === undefined) {
      this.position(wOffset / 2, hOffset / 2);
    } else if (align === 'horizontal') {
      this.position(wOffset / 2, y);
    } else if (align === 'vertical') {
      this.position(x, hOffset / 2);
    }

    this.style('display', style);

    if (hidden) this.hide();

    if (parentHidden) this.parent().style.display = 'none';

    return this;
  };

  /**
   *
   * If an argument is given, sets the inner HTML of the element,
   * replacing any existing html. If true is included as a second
   * argument, html is appended instead of replacing existing html.
   * If no arguments are given, returns
   * the inner HTML of the element.
   *
   * @for p5.Element
   * @method html
   * @returns {String} the inner HTML of the element
   * @example
   * <div class='norender'><code>
   * var div = createDiv('').size(100, 100);
   * div.html('hi');
   * </code></div>
   * <div class='norender'><code>
   * var div = createDiv('Hello ').size(100, 100);
   * div.html('World', true);
   * </code></div>
   */
  /**
   * @method html
   * @param  {String} [html] the HTML to be placed inside the element
   * @param  {boolean} [append] whether to append HTML to existing
   * @chainable
   */
  p5.Element.prototype.html = function() {
    if (arguments.length === 0) {
      return this.elt.innerHTML;
    } else if (arguments[1]) {
      this.elt.innerHTML += arguments[0];
      return this;
    } else {
      this.elt.innerHTML = arguments[0];
      return this;
    }
  };

  /**
   *
   * Sets the position of the element relative to (0, 0) of the
   * window. Essentially, sets position:absolute and left and top
   * properties of style. If no arguments given returns the x and y position
   * of the element in an object.
   *
   * @method position
   * @returns {Object} the x and y position of the element in an object
   * @example
   * <div><code class='norender'>
   * function setup() {
   *   var cnv = createCanvas(100, 100);
   *   // positions canvas 50px to the right and 100px
   *   // below upper left corner of the window
   *   cnv.position(50, 100);
   * }
   * </code></div>
   */
  /**
   * @method position
   * @param  {Number} [x] x-position relative to upper left of window
   * @param  {Number} [y] y-position relative to upper left of window
   * @chainable
   */
  p5.Element.prototype.position = function() {
    if (arguments.length === 0) {
      return { x: this.elt.offsetLeft, y: this.elt.offsetTop };
    } else {
      this.elt.style.position = 'absolute';
      this.elt.style.left = arguments[0] + 'px';
      this.elt.style.top = arguments[1] + 'px';
      this.x = arguments[0];
      this.y = arguments[1];
      return this;
    }
  };

  /* Helper method called by p5.Element.style() */
  p5.Element.prototype._translate = function() {
    this.elt.style.position = 'absolute';
    // save out initial non-translate transform styling
    var transform = '';
    if (this.elt.style.transform) {
      transform = this.elt.style.transform.replace(/translate3d\(.*\)/g, '');
      transform = transform.replace(/translate[X-Z]?\(.*\)/g, '');
    }
    if (arguments.length === 2) {
      this.elt.style.transform =
        'translate(' + arguments[0] + 'px, ' + arguments[1] + 'px)';
    } else if (arguments.length > 2) {
      this.elt.style.transform =
        'translate3d(' +
        arguments[0] +
        'px,' +
        arguments[1] +
        'px,' +
        arguments[2] +
        'px)';
      if (arguments.length === 3) {
        this.elt.parentElement.style.perspective = '1000px';
      } else {
        this.elt.parentElement.style.perspective = arguments[3] + 'px';
      }
    }
    // add any extra transform styling back on end
    this.elt.style.transform += transform;
    return this;
  };

  /* Helper method called by p5.Element.style() */
  p5.Element.prototype._rotate = function() {
    // save out initial non-rotate transform styling
    var transform = '';
    if (this.elt.style.transform) {
      transform = this.elt.style.transform.replace(/rotate3d\(.*\)/g, '');
      transform = transform.replace(/rotate[X-Z]?\(.*\)/g, '');
    }

    if (arguments.length === 1) {
      this.elt.style.transform = 'rotate(' + arguments[0] + 'deg)';
    } else if (arguments.length === 2) {
      this.elt.style.transform =
        'rotate(' + arguments[0] + 'deg, ' + arguments[1] + 'deg)';
    } else if (arguments.length === 3) {
      this.elt.style.transform = 'rotateX(' + arguments[0] + 'deg)';
      this.elt.style.transform += 'rotateY(' + arguments[1] + 'deg)';
      this.elt.style.transform += 'rotateZ(' + arguments[2] + 'deg)';
    }
    // add remaining transform back on
    this.elt.style.transform += transform;
    return this;
  };

  /**
   * Sets the given style (css) property (1st arg) of the element with the
   * given value (2nd arg). If a single argument is given, .style()
   * returns the value of the given property; however, if the single argument
   * is given in css syntax ('text-align:center'), .style() sets the css
   * appropriately.
   *
   * @method style
   * @param  {String} property   property to be set
   * @returns {String} value of property
   * @example
   * <div><code class='norender'>
   * var myDiv = createDiv('I like pandas.');
   * myDiv.style('font-size', '18px');
   * myDiv.style('color', '#ff0000');
   * </code></div>
   * <div><code class='norender'>
   * var col = color(25, 23, 200, 50);
   * var button = createButton('button');
   * button.style('background-color', col);
   * button.position(10, 10);
   * </code></div>
   * <div><code class='norender'>
   * var myDiv;
   * function setup() {
   *   background(200);
   *   myDiv = createDiv('I like gray.');
   *   myDiv.position(20, 20);
   * }
   *
   * function draw() {
   *   myDiv.style('font-size', mouseX + 'px');
   * }
   * </code></div>
   */
  /**
   * @method style
   * @param  {String} property
   * @param  {String|Number|p5.Color} value     value to assign to property
   * @return {String} current value of property, if no value is given as second argument
   * @chainable
   */
  p5.Element.prototype.style = function(prop, val) {
    var self = this;

    if (val instanceof p5.Color) {
      val =
        'rgba(' +
        val.levels[0] +
        ',' +
        val.levels[1] +
        ',' +
        val.levels[2] +
        ',' +
        val.levels[3] / 255 +
        ')';
    }

    if (typeof val === 'undefined') {
      // input provided as single line string
      if (prop.indexOf(':') === -1) {
        var styles = window.getComputedStyle(self.elt);
        var style = styles.getPropertyValue(prop);
        return style;
      } else {
        var attrs = prop.split(';');
        for (var i = 0; i < attrs.length; i++) {
          var parts = attrs[i].split(':');
          if (parts[0] && parts[1]) {
            this.elt.style[parts[0].trim()] = parts[1].trim();
          }
        }
      }
    } else {
      // input provided as key,val pair
      this.elt.style[prop] = val;
      if (
        prop === 'width' ||
        prop === 'height' ||
        prop === 'left' ||
        prop === 'top'
      ) {
        var numVal = val.replace(/\D+/g, '');
        this[prop] = parseInt(numVal, 10);
      }
    }
    return this;
  };

  /**
   *
   * Adds a new attribute or changes the value of an existing attribute
   * on the specified element. If no value is specified, returns the
   * value of the given attribute, or null if attribute is not set.
   *
   * @method attribute
   * @return {String} value of attribute
   *
   * @example
   * <div class='norender'><code>
   * var myDiv = createDiv('I like pandas.');
   * myDiv.attribute('align', 'center');
   * </code></div>
   */
  /**
   * @method attribute
   * @param  {String} attr       attribute to set
   * @param  {String} value      value to assign to attribute
   * @chainable
   */
  p5.Element.prototype.attribute = function(attr, value) {
    //handling for checkboxes and radios to ensure options get
    //attributes not divs
    if (
      this.elt.firstChild != null &&
      (this.elt.firstChild.type === 'checkbox' ||
        this.elt.firstChild.type === 'radio')
    ) {
      if (typeof value === 'undefined') {
        return this.elt.firstChild.getAttribute(attr);
      } else {
        for (var i = 0; i < this.elt.childNodes.length; i++) {
          this.elt.childNodes[i].setAttribute(attr, value);
        }
      }
    } else if (typeof value === 'undefined') {
      return this.elt.getAttribute(attr);
    } else {
      this.elt.setAttribute(attr, value);
      return this;
    }
  };

  /**
   *
   * Removes an attribute on the specified element.
   *
   * @method removeAttribute
   * @param  {String} attr       attribute to remove
   * @chainable
   *
   * @example
   * <div><code>
   * var button;
   * var checkbox;
   *
   * function setup() {
   *   checkbox = createCheckbox('enable', true);
   *   checkbox.changed(enableButton);
   *   button = createButton('button');
   *   button.position(10, 10);
   * }
   *
   * function enableButton() {
   *   if (this.checked()) {
   *     // Re-enable the button
   *     button.removeAttribute('disabled');
   *   } else {
   *     // Disable the button
   *     button.attribute('disabled', '');
   *   }
   * }
   * </code></div>
   */
  p5.Element.prototype.removeAttribute = function(attr) {
    if (
      this.elt.firstChild != null &&
      (this.elt.firstChild.type === 'checkbox' ||
        this.elt.firstChild.type === 'radio')
    ) {
      for (var i = 0; i < this.elt.childNodes.length; i++) {
        this.elt.childNodes[i].removeAttribute(attr);
      }
    }
    this.elt.removeAttribute(attr);
    return this;
  };

  /**
   * Either returns the value of the element if no arguments
   * given, or sets the value of the element.
   *
   * @method value
   * @return {String|Number} value of the element
   * @example
   * <div class='norender'><code>
   * // gets the value
   * var inp;
   * function setup() {
   *   inp = createInput('');
   * }
   *
   * function mousePressed() {
   *   print(inp.value());
   * }
   * </code></div>
   * <div class='norender'><code>
   * // sets the value
   * var inp;
   * function setup() {
   *   inp = createInput('myValue');
   * }
   *
   * function mousePressed() {
   *   inp.value('myValue');
   * }
   * </code></div>
   */
  /**
   * @method value
   * @param  {String|Number}     value
   * @chainable
   */
  p5.Element.prototype.value = function() {
    if (arguments.length > 0) {
      this.elt.value = arguments[0];
      return this;
    } else {
      if (this.elt.type === 'range') {
        return parseFloat(this.elt.value);
      } else return this.elt.value;
    }
  };

  /**
   *
   * Shows the current element. Essentially, setting display:block for the style.
   *
   * @method show
   * @chainable
   * @example
   * <div class='norender'><code>
   * var div = createDiv('div');
   * div.style('display', 'none');
   * div.show(); // turns display to block
   * </code></div>
   */
  p5.Element.prototype.show = function() {
    this.elt.style.display = 'block';
    return this;
  };

  /**
   * Hides the current element. Essentially, setting display:none for the style.
   *
   * @method hide
   * @chainable
   * @example
   * <div class='norender'><code>
   * var div = createDiv('this is a div');
   * div.hide();
   * </code></div>
   */
  p5.Element.prototype.hide = function() {
    this.elt.style.display = 'none';
    return this;
  };

  /**
   *
   * Sets the width and height of the element. AUTO can be used to
   * only adjust one dimension at a time. If no arguments are given, it
   * returns the width and height of the element in an object. In case of
   * elements which need to be loaded, such as images, it is recommended
   * to call the function after the element has finished loading.
   *
   * @method size
   * @return {Object} the width and height of the element in an object
   * @example
   * <div class='norender'><code>
   * let div = createDiv('this is a div');
   * div.size(100, 100);
   * let img = createImg('assets/laDefense.jpg', () => {
   *   img.size(10, AUTO);
   * });
   * </code></div>
   */
  /**
   * @method size
   * @param  {Number|Constant} w    width of the element, either AUTO, or a number
   * @param  {Number|Constant} [h] height of the element, either AUTO, or a number
   * @chainable
   */
  p5.Element.prototype.size = function(w, h) {
    if (arguments.length === 0) {
      return { width: this.elt.offsetWidth, height: this.elt.offsetHeight };
    } else {
      var aW = w;
      var aH = h;
      var AUTO = p5.prototype.AUTO;
      if (aW !== AUTO || aH !== AUTO) {
        if (aW === AUTO) {
          aW = h * this.width / this.height;
        } else if (aH === AUTO) {
          aH = w * this.height / this.width;
        }
        // set diff for cnv vs normal div
        if (this.elt instanceof HTMLCanvasElement) {
          var j = {};
          var k = this.elt.getContext('2d');
          var prop;
          for (prop in k) {
            j[prop] = k[prop];
          }
          this.elt.setAttribute('width', aW * this._pInst._pixelDensity);
          this.elt.setAttribute('height', aH * this._pInst._pixelDensity);
          this.elt.style.width = aW + 'px';
          this.elt.style.height = aH + 'px';
          this._pInst.scale(
            this._pInst._pixelDensity,
            this._pInst._pixelDensity
          );
          for (prop in j) {
            this.elt.getContext('2d')[prop] = j[prop];
          }
        } else {
          this.elt.style.width = aW + 'px';
          this.elt.style.height = aH + 'px';
          this.elt.width = aW;
          this.elt.height = aH;
        }

        this.width = this.elt.offsetWidth;
        this.height = this.elt.offsetHeight;

        if (this._pInst && this._pInst._curElement) {
          // main canvas associated with p5 instance
          if (this._pInst._curElement.elt === this.elt) {
            this._pInst._setProperty('width', this.elt.offsetWidth);
            this._pInst._setProperty('height', this.elt.offsetHeight);
          }
        }
      }
      return this;
    }
  };

  /**
   * Removes the element and deregisters all listeners.
   * @method remove
   * @example
   * <div class='norender'><code>
   * var myDiv = createDiv('this is some text');
   * myDiv.remove();
   * </code></div>
   */
  p5.Element.prototype.remove = function() {
    // deregister events
    for (var ev in this._events) {
      this.elt.removeEventListener(ev, this._events[ev]);
    }
    if (this.elt.parentNode) {
      this.elt.parentNode.removeChild(this.elt);
    }
    delete this;
  };

  /**
   * Registers a callback that gets called every time a file that is
   * dropped on the element has been loaded.
   * p5 will load every dropped file into memory and pass it as a p5.File object to the callback.
   * Multiple files dropped at the same time will result in multiple calls to the callback.
   *
   * You can optionally pass a second callback which will be registered to the raw
   * <a href="https://developer.mozilla.org/en-US/docs/Web/Events/drop">drop</a> event.
   * The callback will thus be provided the original
   * <a href="https://developer.mozilla.org/en-US/docs/Web/API/DragEvent">DragEvent</a>.
   * Dropping multiple files at the same time will trigger the second callback once per drop,
   * whereas the first callback will trigger for each loaded file.
   *
   * @method drop
   * @param  {Function} callback  callback to receive loaded file, called for each file dropped.
   * @param  {Function} [fxn]     callback triggered once when files are dropped with the drop event.
   * @chainable
   * @example
   * <div><code>
   * function setup() {
   *   var c = createCanvas(100, 100);
   *   background(200);
   *   textAlign(CENTER);
   *   text('drop file', width / 2, height / 2);
   *   c.drop(gotFile);
   * }
   *
   * function gotFile(file) {
   *   background(200);
   *   text('received file:', width / 2, height / 2);
   *   text(file.name, width / 2, height / 2 + 50);
   * }
   * </code></div>
   *
   * <div><code>
   * var img;
   *
   * function setup() {
   *   var c = createCanvas(100, 100);
   *   background(200);
   *   textAlign(CENTER);
   *   text('drop image', width / 2, height / 2);
   *   c.drop(gotFile);
   * }
   *
   * function draw() {
   *   if (img) {
   *     image(img, 0, 0, width, height);
   *   }
   * }
   *
   * function gotFile(file) {
   *   img = createImg(file.data).hide();
   * }
   * </code></div>
   *
   * @alt
   * Canvas turns into whatever image is dragged/dropped onto it.
   */
  p5.Element.prototype.drop = function(callback, fxn) {
    // Is the file stuff supported?
    if (window.File && window.FileReader && window.FileList && window.Blob) {
      if (!this._dragDisabled) {
        this._dragDisabled = true;

        var preventDefault = function(evt) {
          evt.preventDefault();
        };

        // If you want to be able to drop you've got to turn off
        // a lot of default behavior.
        // avoid `attachListener` here, since it overrides other handlers.
        this.elt.addEventListener('dragover', preventDefault);

        // If this is a drag area we need to turn off the default behavior
        this.elt.addEventListener('dragleave', preventDefault);
      }

      // Deal with the files
      p5.Element._attachListener(
        'drop',
        function(evt) {
          evt.preventDefault();
          // Call the second argument as a callback that receives the raw drop event
          if (typeof fxn === 'function') {
            fxn.call(this, evt);
          }
          // A FileList
          var files = evt.dataTransfer.files;

          // Load each one and trigger the callback
          for (var i = 0; i < files.length; i++) {
            var f = files[i];
            p5.File._load(f, callback);
          }
        },
        this
      );
    } else {
      console.log('The File APIs are not fully supported in this browser.');
    }

    return this;
  };

  // =============================================================================
  //                         p5.MediaElement additions
  // =============================================================================

  /**
   * Extends <a href="#/p5.Element">p5.Element</a> to handle audio and video. In addition to the methods
   * of <a href="#/p5.Element">p5.Element</a>, it also contains methods for controlling media. It is not
   * called directly, but <a href="#/p5.MediaElement">p5.MediaElement</a>s are created by calling <a href="#/p5/createVideo">createVideo</a>,
   * <a href="#/p5/createAudio">createAudio</a>, and <a href="#/p5/createCapture">createCapture</a>.
   *
   * @class p5.MediaElement
   * @constructor
   * @param {String} elt DOM node that is wrapped
   */
  p5.MediaElement = function(elt, pInst) {
    p5.Element.call(this, elt, pInst);

    var self = this;
    this.elt.crossOrigin = 'anonymous';

    this._prevTime = 0;
    this._cueIDCounter = 0;
    this._cues = [];
    this._pixelsState = this;
    this._pixelDensity = 1;
    this._modified = false;
    this._pixelsDirty = true;
    this._pixelsTime = -1; // the time at which we last updated 'pixels'

    /**
     * Path to the media element source.
     *
     * @property src
     * @return {String} src
     * @example
     * <div><code>
     * var ele;
     *
     * function setup() {
     *   background(250);
     *
     *   //p5.MediaElement objects are usually created
     *   //by calling the createAudio(), createVideo(),
     *   //and createCapture() functions.
     *
     *   //In this example we create
     *   //a new p5.MediaElement via createAudio().
     *   ele = createAudio('assets/beat.mp3');
     *
     *   //We'll set up our example so that
     *   //when you click on the text,
     *   //an alert box displays the MediaElement's
     *   //src field.
     *   textAlign(CENTER);
     *   text('Click Me!', width / 2, height / 2);
     * }
     *
     * function mouseClicked() {
     *   //here we test if the mouse is over the
     *   //canvas element when it's clicked
     *   if (mouseX >= 0 && mouseX <= width && mouseY >= 0 && mouseY <= height) {
     *     //Show our p5.MediaElement's src field
     *     alert(ele.src);
     *   }
     * }
     * </code></div>
     */
    Object.defineProperty(self, 'src', {
      get: function() {
        var firstChildSrc = self.elt.children[0].src;
        var srcVal = self.elt.src === window.location.href ? '' : self.elt.src;
        var ret =
          firstChildSrc === window.location.href ? srcVal : firstChildSrc;
        return ret;
      },
      set: function(newValue) {
        for (var i = 0; i < self.elt.children.length; i++) {
          self.elt.removeChild(self.elt.children[i]);
        }
        var source = document.createElement('source');
        source.src = newValue;
        elt.appendChild(source);
        self.elt.src = newValue;
        self.modified = true;
      }
    });

    // private _onended callback, set by the method: onended(callback)
    self._onended = function() {};
    self.elt.onended = function() {
      self._onended(self);
    };
  };
  p5.MediaElement.prototype = Object.create(p5.Element.prototype);

  /**
   * Play an HTML5 media element.
   *
   * @method play
   * @chainable
   * @example
   * <div><code>
   * var ele;
   *
   * function setup() {
   *   //p5.MediaElement objects are usually created
   *   //by calling the createAudio(), createVideo(),
   *   //and createCapture() functions.
   *
   *   //In this example we create
   *   //a new p5.MediaElement via createAudio().
   *   ele = createAudio('assets/beat.mp3');
   *
   *   background(250);
   *   textAlign(CENTER);
   *   text('Click to Play!', width / 2, height / 2);
   * }
   *
   * function mouseClicked() {
   *   //here we test if the mouse is over the
   *   //canvas element when it's clicked
   *   if (mouseX >= 0 && mouseX <= width && mouseY >= 0 && mouseY <= height) {
   *     //Here we call the play() function on
   *     //the p5.MediaElement we created above.
   *     //This will start the audio sample.
   *     ele.play();
   *
   *     background(200);
   *     text('You clicked Play!', width / 2, height / 2);
   *   }
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.play = function() {
    if (this.elt.currentTime === this.elt.duration) {
      this.elt.currentTime = 0;
    }
    var promise;
    if (this.elt.readyState > 1) {
      promise = this.elt.play();
    } else {
      // in Chrome, playback cannot resume after being stopped and must reload
      this.elt.load();
      promise = this.elt.play();
    }
    if (promise && promise.catch) {
      promise.catch(function(e) {
        console.log(
          'WARN: Element play method raised an error asynchronously',
          e
        );
      });
    }
    return this;
  };

  /**
   * Stops an HTML5 media element (sets current time to zero).
   *
   * @method stop
   * @chainable
   * @example
   * <div><code>
   * //This example both starts
   * //and stops a sound sample
   * //when the user clicks the canvas
   *
   * //We will store the p5.MediaElement
   * //object in here
   * var ele;
   *
   * //while our audio is playing,
   * //this will be set to true
   * var sampleIsPlaying = false;
   *
   * function setup() {
   *   //Here we create a p5.MediaElement object
   *   //using the createAudio() function.
   *   ele = createAudio('assets/beat.mp3');
   *   background(200);
   *   textAlign(CENTER);
   *   text('Click to play!', width / 2, height / 2);
   * }
   *
   * function mouseClicked() {
   *   //here we test if the mouse is over the
   *   //canvas element when it's clicked
   *   if (mouseX >= 0 && mouseX <= width && mouseY >= 0 && mouseY <= height) {
   *     background(200);
   *
   *     if (sampleIsPlaying) {
   *       //if the sample is currently playing
   *       //calling the stop() function on
   *       //our p5.MediaElement will stop
   *       //it and reset its current
   *       //time to 0 (i.e. it will start
   *       //at the beginning the next time
   *       //you play it)
   *       ele.stop();
   *
   *       sampleIsPlaying = false;
   *       text('Click to play!', width / 2, height / 2);
   *     } else {
   *       //loop our sound element until we
   *       //call ele.stop() on it.
   *       ele.loop();
   *
   *       sampleIsPlaying = true;
   *       text('Click to stop!', width / 2, height / 2);
   *     }
   *   }
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.stop = function() {
    this.elt.pause();
    this.elt.currentTime = 0;
    return this;
  };

  /**
   * Pauses an HTML5 media element.
   *
   * @method pause
   * @chainable
   * @example
   * <div><code>
   * //This example both starts
   * //and pauses a sound sample
   * //when the user clicks the canvas
   *
   * //We will store the p5.MediaElement
   * //object in here
   * var ele;
   *
   * //while our audio is playing,
   * //this will be set to true
   * var sampleIsPlaying = false;
   *
   * function setup() {
   *   //Here we create a p5.MediaElement object
   *   //using the createAudio() function.
   *   ele = createAudio('assets/lucky_dragons.mp3');
   *   background(200);
   *   textAlign(CENTER);
   *   text('Click to play!', width / 2, height / 2);
   * }
   *
   * function mouseClicked() {
   *   //here we test if the mouse is over the
   *   //canvas element when it's clicked
   *   if (mouseX >= 0 && mouseX <= width && mouseY >= 0 && mouseY <= height) {
   *     background(200);
   *
   *     if (sampleIsPlaying) {
   *       //Calling pause() on our
   *       //p5.MediaElement will stop it
   *       //playing, but when we call the
   *       //loop() or play() functions
   *       //the sample will start from
   *       //where we paused it.
   *       ele.pause();
   *
   *       sampleIsPlaying = false;
   *       text('Click to resume!', width / 2, height / 2);
   *     } else {
   *       //loop our sound element until we
   *       //call ele.pause() on it.
   *       ele.loop();
   *
   *       sampleIsPlaying = true;
   *       text('Click to pause!', width / 2, height / 2);
   *     }
   *   }
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.pause = function() {
    this.elt.pause();
    return this;
  };

  /**
   * Set 'loop' to true for an HTML5 media element, and starts playing.
   *
   * @method loop
   * @chainable
   * @example
   * <div><code>
   * //Clicking the canvas will loop
   * //the audio sample until the user
   * //clicks again to stop it
   *
   * //We will store the p5.MediaElement
   * //object in here
   * var ele;
   *
   * //while our audio is playing,
   * //this will be set to true
   * var sampleIsLooping = false;
   *
   * function setup() {
   *   //Here we create a p5.MediaElement object
   *   //using the createAudio() function.
   *   ele = createAudio('assets/lucky_dragons.mp3');
   *   background(200);
   *   textAlign(CENTER);
   *   text('Click to loop!', width / 2, height / 2);
   * }
   *
   * function mouseClicked() {
   *   //here we test if the mouse is over the
   *   //canvas element when it's clicked
   *   if (mouseX >= 0 && mouseX <= width && mouseY >= 0 && mouseY <= height) {
   *     background(200);
   *
   *     if (!sampleIsLooping) {
   *       //loop our sound element until we
   *       //call ele.stop() on it.
   *       ele.loop();
   *
   *       sampleIsLooping = true;
   *       text('Click to stop!', width / 2, height / 2);
   *     } else {
   *       ele.stop();
   *
   *       sampleIsLooping = false;
   *       text('Click to loop!', width / 2, height / 2);
   *     }
   *   }
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.loop = function() {
    this.elt.setAttribute('loop', true);
    this.play();
    return this;
  };
  /**
   * Set 'loop' to false for an HTML5 media element. Element will stop
   * when it reaches the end.
   *
   * @method noLoop
   * @chainable
   * @example
   * <div><code>
   * //This example both starts
   * //and stops loop of sound sample
   * //when the user clicks the canvas
   *
   * //We will store the p5.MediaElement
   * //object in here
   * var ele;
   * //while our audio is playing,
   * //this will be set to true
   * var sampleIsPlaying = false;
   *
   * function setup() {
   *   //Here we create a p5.MediaElement object
   *   //using the createAudio() function.
   *   ele = createAudio('assets/beat.mp3');
   *   background(200);
   *   textAlign(CENTER);
   *   text('Click to play!', width / 2, height / 2);
   * }
   *
   * function mouseClicked() {
   *   //here we test if the mouse is over the
   *   //canvas element when it's clicked
   *   if (mouseX >= 0 && mouseX <= width && mouseY >= 0 && mouseY <= height) {
   *     background(200);
   *
   *     if (sampleIsPlaying) {
   *       ele.noLoop();
   *       text('No more Loops!', width / 2, height / 2);
   *     } else {
   *       ele.loop();
   *       sampleIsPlaying = true;
   *       text('Click to stop looping!', width / 2, height / 2);
   *     }
   *   }
   * }
   * </code></div>
   *
   */
  p5.MediaElement.prototype.noLoop = function() {
    this.elt.setAttribute('loop', false);
    return this;
  };

  /**
   * Set HTML5 media element to autoplay or not.
   *
   * @method autoplay
   * @param {Boolean} autoplay whether the element should autoplay
   * @chainable
   */
  p5.MediaElement.prototype.autoplay = function(val) {
    this.elt.setAttribute('autoplay', val);
    return this;
  };

  /**
   * Sets volume for this HTML5 media element. If no argument is given,
   * returns the current volume.
   *
   * @method volume
   * @return {Number} current volume
   *
   * @example
   * <div><code>
   * var ele;
   * function setup() {
   *   // p5.MediaElement objects are usually created
   *   // by calling the createAudio(), createVideo(),
   *   // and createCapture() functions.
   *   // In this example we create
   *   // a new p5.MediaElement via createAudio().
   *   ele = createAudio('assets/lucky_dragons.mp3');
   *   background(250);
   *   textAlign(CENTER);
   *   text('Click to Play!', width / 2, height / 2);
   * }
   * function mouseClicked() {
   *   // Here we call the volume() function
   *   // on the sound element to set its volume
   *   // Volume must be between 0.0 and 1.0
   *   ele.volume(0.2);
   *   ele.play();
   *   background(200);
   *   text('You clicked Play!', width / 2, height / 2);
   * }
   * </code></div>
   * <div><code>
   * var audio;
   * var counter = 0;
   *
   * function loaded() {
   *   audio.play();
   * }
   *
   * function setup() {
   *   audio = createAudio('assets/lucky_dragons.mp3', loaded);
   *   textAlign(CENTER);
   * }
   *
   * function draw() {
   *   if (counter === 0) {
   *     background(0, 255, 0);
   *     text('volume(0.9)', width / 2, height / 2);
   *   } else if (counter === 1) {
   *     background(255, 255, 0);
   *     text('volume(0.5)', width / 2, height / 2);
   *   } else if (counter === 2) {
   *     background(255, 0, 0);
   *     text('volume(0.1)', width / 2, height / 2);
   *   }
   * }
   *
   * function mousePressed() {
   *   counter++;
   *   if (counter === 0) {
   *     audio.volume(0.9);
   *   } else if (counter === 1) {
   *     audio.volume(0.5);
   *   } else if (counter === 2) {
   *     audio.volume(0.1);
   *   } else {
   *     counter = 0;
   *     audio.volume(0.9);
   *   }
   * }
   * </code>
   * </div>
   */
  /**
   * @method volume
   * @param {Number}            val volume between 0.0 and 1.0
   * @chainable
   */
  p5.MediaElement.prototype.volume = function(val) {
    if (typeof val === 'undefined') {
      return this.elt.volume;
    } else {
      this.elt.volume = val;
    }
  };

  /**
   * If no arguments are given, returns the current playback speed of the
   * element. The speed parameter sets the speed where 2.0 will play the
   * element twice as fast, 0.5 will play at half the speed, and -1 will play
   * the element in normal speed in reverse.(Note that not all browsers support
   * backward playback and even if they do, playback might not be smooth.)
   *
   * @method speed
   * @return {Number} current playback speed of the element
   *
   * @example
   * <div class='norender notest'><code>
   * //Clicking the canvas will loop
   * //the audio sample until the user
   * //clicks again to stop it
   *
   * //We will store the p5.MediaElement
   * //object in here
   * var ele;
   * var button;
   *
   * function setup() {
   *   createCanvas(710, 400);
   *   //Here we create a p5.MediaElement object
   *   //using the createAudio() function.
   *   ele = createAudio('assets/beat.mp3');
   *   ele.loop();
   *   background(200);
   *
   *   button = createButton('2x speed');
   *   button.position(100, 68);
   *   button.mousePressed(twice_speed);
   *
   *   button = createButton('half speed');
   *   button.position(200, 68);
   *   button.mousePressed(half_speed);
   *
   *   button = createButton('reverse play');
   *   button.position(300, 68);
   *   button.mousePressed(reverse_speed);
   *
   *   button = createButton('STOP');
   *   button.position(400, 68);
   *   button.mousePressed(stop_song);
   *
   *   button = createButton('PLAY!');
   *   button.position(500, 68);
   *   button.mousePressed(play_speed);
   * }
   *
   * function twice_speed() {
   *   ele.speed(2);
   * }
   *
   * function half_speed() {
   *   ele.speed(0.5);
   * }
   *
   * function reverse_speed() {
   *   ele.speed(-1);
   * }
   *
   * function stop_song() {
   *   ele.stop();
   * }
   *
   * function play_speed() {
   *   ele.play();
   * }
   * </code></div>
   */
  /**
   * @method speed
   * @param {Number} speed  speed multiplier for element playback
   * @chainable
   */
  p5.MediaElement.prototype.speed = function(val) {
    if (typeof val === 'undefined') {
      return this.presetPlaybackRate || this.elt.playbackRate;
    } else {
      if (this.loadedmetadata) {
        this.elt.playbackRate = val;
      } else {
        this.presetPlaybackRate = val;
      }
    }
  };

  /**
   * If no arguments are given, returns the current time of the element.
   * If an argument is given the current time of the element is set to it.
   *
   * @method time
   * @return {Number} current time (in seconds)
   *
   * @example
   * <div><code>
   * var ele;
   * var beginning = true;
   * function setup() {
   *   //p5.MediaElement objects are usually created
   *   //by calling the createAudio(), createVideo(),
   *   //and createCapture() functions.
   *
   *   //In this example we create
   *   //a new p5.MediaElement via createAudio().
   *   ele = createAudio('assets/lucky_dragons.mp3');
   *   background(250);
   *   textAlign(CENTER);
   *   text('start at beginning', width / 2, height / 2);
   * }
   *
   * // this function fires with click anywhere
   * function mousePressed() {
   *   if (beginning === true) {
   *     // here we start the sound at the beginning
   *     // time(0) is not necessary here
   *     // as this produces the same result as
   *     // play()
   *     ele.play().time(0);
   *     background(200);
   *     text('jump 2 sec in', width / 2, height / 2);
   *     beginning = false;
   *   } else {
   *     // here we jump 2 seconds into the sound
   *     ele.play().time(2);
   *     background(250);
   *     text('start at beginning', width / 2, height / 2);
   *     beginning = true;
   *   }
   * }
   * </code></div>
   */
  /**
   * @method time
   * @param {Number} time time to jump to (in seconds)
   * @chainable
   */
  p5.MediaElement.prototype.time = function(val) {
    if (typeof val === 'undefined') {
      return this.elt.currentTime;
    } else {
      this.elt.currentTime = val;
      return this;
    }
  };

  /**
   * Returns the duration of the HTML5 media element.
   *
   * @method duration
   * @return {Number} duration
   *
   * @example
   * <div><code>
   * var ele;
   * function setup() {
   *   //p5.MediaElement objects are usually created
   *   //by calling the createAudio(), createVideo(),
   *   //and createCapture() functions.
   *   //In this example we create
   *   //a new p5.MediaElement via createAudio().
   *   ele = createAudio('assets/doorbell.mp3');
   *   background(250);
   *   textAlign(CENTER);
   *   text('Click to know the duration!', 10, 25, 70, 80);
   * }
   * function mouseClicked() {
   *   ele.play();
   *   background(200);
   *   //ele.duration dislpays the duration
   *   text(ele.duration() + ' seconds', width / 2, height / 2);
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.duration = function() {
    return this.elt.duration;
  };
  p5.MediaElement.prototype.pixels = [];
  p5.MediaElement.prototype._ensureCanvas = function() {
    if (!this.canvas) {
      this.canvas = document.createElement('canvas');
      this.drawingContext = this.canvas.getContext('2d');
      this.setModified(true);
    }
    if (this.loadedmetadata) {
      // wait for metadata for w/h
      if (this.canvas.width !== this.elt.width) {
        this.canvas.width = this.elt.width;
        this.canvas.height = this.elt.height;
        this.width = this.canvas.width;
        this.height = this.canvas.height;
        this._pixelsDirty = true;
      }

      var currentTime = this.elt.currentTime;
      if (this._pixelsDirty || this._pixelsTime !== currentTime) {
        // only update the pixels array if it's dirty, or
        // if the video time has changed.
        this._pixelsTime = currentTime;
        this._pixelsDirty = true;

        this.drawingContext.drawImage(
          this.elt,
          0,
          0,
          this.canvas.width,
          this.canvas.height
        );
        this.setModified(true);
      }
    }
  };
  p5.MediaElement.prototype.loadPixels = function() {
    this._ensureCanvas();
    return p5.Renderer2D.prototype.loadPixels.apply(this, arguments);
  };
  p5.MediaElement.prototype.updatePixels = function(x, y, w, h) {
    if (this.loadedmetadata) {
      // wait for metadata
      this._ensureCanvas();
      p5.Renderer2D.prototype.updatePixels.call(this, x, y, w, h);
    }
    this.setModified(true);
    return this;
  };
  p5.MediaElement.prototype.get = function() {
    this._ensureCanvas();
    return p5.Renderer2D.prototype.get.apply(this, arguments);
  };
  p5.MediaElement.prototype._getPixel = function() {
    this.loadPixels();
    return p5.Renderer2D.prototype._getPixel.apply(this, arguments);
  };

  p5.MediaElement.prototype.set = function(x, y, imgOrCol) {
    if (this.loadedmetadata) {
      // wait for metadata
      this._ensureCanvas();
      p5.Renderer2D.prototype.set.call(this, x, y, imgOrCol);
      this.setModified(true);
    }
  };
  p5.MediaElement.prototype.copy = function() {
    this._ensureCanvas();
    p5.Renderer2D.prototype.copy.apply(this, arguments);
  };
  p5.MediaElement.prototype.mask = function() {
    this.loadPixels();
    this.setModified(true);
    p5.Image.prototype.mask.apply(this, arguments);
  };
  /**
   * helper method for web GL mode to figure out if the element
   * has been modified and might need to be re-uploaded to texture
   * memory between frames.
   * @method isModified
   * @private
   * @return {boolean} a boolean indicating whether or not the
   * image has been updated or modified since last texture upload.
   */
  p5.MediaElement.prototype.isModified = function() {
    return this._modified;
  };
  /**
   * helper method for web GL mode to indicate that an element has been
   * changed or unchanged since last upload. gl texture upload will
   * set this value to false after uploading the texture; or might set
   * it to true if metadata has become available but there is no actual
   * texture data available yet..
   * @method setModified
   * @param {boolean} val sets whether or not the element has been
   * modified.
   * @private
   */
  p5.MediaElement.prototype.setModified = function(value) {
    this._modified = value;
  };
  /**
   * Schedule an event to be called when the audio or video
   * element reaches the end. If the element is looping,
   * this will not be called. The element is passed in
   * as the argument to the onended callback.
   *
   * @method  onended
   * @param  {Function} callback function to call when the
   *                             soundfile has ended. The
   *                             media element will be passed
   *                             in as the argument to the
   *                             callback.
   * @chainable
   * @example
   * <div><code>
   * function setup() {
   *   var audioEl = createAudio('assets/beat.mp3');
   *   audioEl.showControls();
   *   audioEl.onended(sayDone);
   * }
   *
   * function sayDone(elt) {
   *   alert('done playing ' + elt.src);
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.onended = function(callback) {
    this._onended = callback;
    return this;
  };

  /*** CONNECT TO WEB AUDIO API / p5.sound.js ***/

  /**
   * Send the audio output of this element to a specified audioNode or
   * p5.sound object. If no element is provided, connects to p5's master
   * output. That connection is established when this method is first called.
   * All connections are removed by the .disconnect() method.
   *
   * This method is meant to be used with the p5.sound.js addon library.
   *
   * @method  connect
   * @param  {AudioNode|Object} audioNode AudioNode from the Web Audio API,
   * or an object from the p5.sound library
   */
  p5.MediaElement.prototype.connect = function(obj) {
    var audioContext, masterOutput;

    // if p5.sound exists, same audio context
    if (typeof p5.prototype.getAudioContext === 'function') {
      audioContext = p5.prototype.getAudioContext();
      masterOutput = p5.soundOut.input;
    } else {
      try {
        audioContext = obj.context;
        masterOutput = audioContext.destination;
      } catch (e) {
        throw 'connect() is meant to be used with Web Audio API or p5.sound.js';
      }
    }

    // create a Web Audio MediaElementAudioSourceNode if none already exists
    if (!this.audioSourceNode) {
      this.audioSourceNode = audioContext.createMediaElementSource(this.elt);

      // connect to master output when this method is first called
      this.audioSourceNode.connect(masterOutput);
    }

    // connect to object if provided
    if (obj) {
      if (obj.input) {
        this.audioSourceNode.connect(obj.input);
      } else {
        this.audioSourceNode.connect(obj);
      }
    } else {
      // otherwise connect to master output of p5.sound / AudioContext
      this.audioSourceNode.connect(masterOutput);
    }
  };

  /**
   * Disconnect all Web Audio routing, including to master output.
   * This is useful if you want to re-route the output through
   * audio effects, for example.
   *
   * @method  disconnect
   */
  p5.MediaElement.prototype.disconnect = function() {
    if (this.audioSourceNode) {
      this.audioSourceNode.disconnect();
    } else {
      throw 'nothing to disconnect';
    }
  };

  /*** SHOW / HIDE CONTROLS ***/

  /**
   * Show the default MediaElement controls, as determined by the web browser.
   *
   * @method  showControls
   * @example
   * <div><code>
   * var ele;
   * function setup() {
   *   //p5.MediaElement objects are usually created
   *   //by calling the createAudio(), createVideo(),
   *   //and createCapture() functions.
   *   //In this example we create
   *   //a new p5.MediaElement via createAudio()
   *   ele = createAudio('assets/lucky_dragons.mp3');
   *   background(200);
   *   textAlign(CENTER);
   *   text('Click to Show Controls!', 10, 25, 70, 80);
   * }
   * function mousePressed() {
   *   ele.showControls();
   *   background(200);
   *   text('Controls Shown', width / 2, height / 2);
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.showControls = function() {
    // must set style for the element to show on the page
    this.elt.style['text-align'] = 'inherit';
    this.elt.controls = true;
  };

  /**
   * Hide the default mediaElement controls.
   * @method hideControls
   * @example
   * <div><code>
   * var ele;
   * function setup() {
   *   //p5.MediaElement objects are usually created
   *   //by calling the createAudio(), createVideo(),
   *   //and createCapture() functions.
   *   //In this example we create
   *   //a new p5.MediaElement via createAudio()
   *   ele = createAudio('assets/lucky_dragons.mp3');
   *   ele.showControls();
   *   background(200);
   *   textAlign(CENTER);
   *   text('Click to hide Controls!', 10, 25, 70, 80);
   * }
   * function mousePressed() {
   *   ele.hideControls();
   *   background(200);
   *   text('Controls hidden', width / 2, height / 2);
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.hideControls = function() {
    this.elt.controls = false;
  };

  /*** SCHEDULE EVENTS ***/

  // Cue inspired by JavaScript setTimeout, and the
  // Tone.js Transport Timeline Event, MIT License Yotam Mann 2015 tonejs.org
  var Cue = function(callback, time, id, val) {
    this.callback = callback;
    this.time = time;
    this.id = id;
    this.val = val;
  };

  /**
   * Schedule events to trigger every time a MediaElement
   * (audio/video) reaches a playback cue point.
   *
   * Accepts a callback function, a time (in seconds) at which to trigger
   * the callback, and an optional parameter for the callback.
   *
   * Time will be passed as the first parameter to the callback function,
   * and param will be the second parameter.
   *
   *
   * @method  addCue
   * @param {Number}   time     Time in seconds, relative to this media
   *                             element's playback. For example, to trigger
   *                             an event every time playback reaches two
   *                             seconds, pass in the number 2. This will be
   *                             passed as the first parameter to
   *                             the callback function.
   * @param {Function} callback Name of a function that will be
   *                             called at the given time. The callback will
   *                             receive time and (optionally) param as its
   *                             two parameters.
   * @param {Object} [value]    An object to be passed as the
   *                             second parameter to the
   *                             callback function.
   * @return {Number} id ID of this cue,
   *                     useful for removeCue(id)
   * @example
   * <div><code>
   * //
   * //
   * function setup() {
   *   noCanvas();
   *
   *   var audioEl = createAudio('assets/beat.mp3');
   *   audioEl.showControls();
   *
   *   // schedule three calls to changeBackground
   *   audioEl.addCue(0.5, changeBackground, color(255, 0, 0));
   *   audioEl.addCue(1.0, changeBackground, color(0, 255, 0));
   *   audioEl.addCue(2.5, changeBackground, color(0, 0, 255));
   *   audioEl.addCue(3.0, changeBackground, color(0, 255, 255));
   *   audioEl.addCue(4.2, changeBackground, color(255, 255, 0));
   *   audioEl.addCue(5.0, changeBackground, color(255, 255, 0));
   * }
   *
   * function changeBackground(val) {
   *   background(val);
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.addCue = function(time, callback, val) {
    var id = this._cueIDCounter++;

    var cue = new Cue(callback, time, id, val);
    this._cues.push(cue);

    if (!this.elt.ontimeupdate) {
      this.elt.ontimeupdate = this._onTimeUpdate.bind(this);
    }

    return id;
  };

  /**
   * Remove a callback based on its ID. The ID is returned by the
   * addCue method.
   * @method removeCue
   * @param  {Number} id ID of the cue, as returned by addCue
   * @example
   * <div><code>
   * var audioEl, id1, id2;
   * function setup() {
   *   background(255, 255, 255);
   *   audioEl = createAudio('assets/beat.mp3');
   *   audioEl.showControls();
   *   // schedule five calls to changeBackground
   *   id1 = audioEl.addCue(0.5, changeBackground, color(255, 0, 0));
   *   audioEl.addCue(1.0, changeBackground, color(0, 255, 0));
   *   audioEl.addCue(2.5, changeBackground, color(0, 0, 255));
   *   audioEl.addCue(3.0, changeBackground, color(0, 255, 255));
   *   id2 = audioEl.addCue(4.2, changeBackground, color(255, 255, 0));
   *   text('Click to remove first and last Cue!', 10, 25, 70, 80);
   * }
   * function mousePressed() {
   *   audioEl.removeCue(id1);
   *   audioEl.removeCue(id2);
   * }
   * function changeBackground(val) {
   *   background(val);
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.removeCue = function(id) {
    for (var i = 0; i < this._cues.length; i++) {
      if (this._cues[i].id === id) {
        console.log(id);
        this._cues.splice(i, 1);
      }
    }

    if (this._cues.length === 0) {
      this.elt.ontimeupdate = null;
    }
  };

  /**
   * Remove all of the callbacks that had originally been scheduled
   * via the addCue method.
   * @method  clearCues
   * @param  {Number} id ID of the cue, as returned by addCue
   * @example
   * <div><code>
   * var audioEl;
   * function setup() {
   *   background(255, 255, 255);
   *   audioEl = createAudio('assets/beat.mp3');
   *   //Show the default MediaElement controls, as determined by the web browser
   *   audioEl.showControls();
   *   // schedule calls to changeBackground
   *   background(200);
   *   text('Click to change Cue!', 10, 25, 70, 80);
   *   audioEl.addCue(0.5, changeBackground, color(255, 0, 0));
   *   audioEl.addCue(1.0, changeBackground, color(0, 255, 0));
   *   audioEl.addCue(2.5, changeBackground, color(0, 0, 255));
   *   audioEl.addCue(3.0, changeBackground, color(0, 255, 255));
   *   audioEl.addCue(4.2, changeBackground, color(255, 255, 0));
   * }
   * function mousePressed() {
   *   // here we clear the scheduled callbacks
   *   audioEl.clearCues();
   *   // then we add some more callbacks
   *   audioEl.addCue(1, changeBackground, color(2, 2, 2));
   *   audioEl.addCue(3, changeBackground, color(255, 255, 0));
   * }
   * function changeBackground(val) {
   *   background(val);
   * }
   * </code></div>
   */
  p5.MediaElement.prototype.clearCues = function() {
    this._cues = [];
    this.elt.ontimeupdate = null;
  };

  // private method that checks for cues to be fired if events
  // have been scheduled using addCue(callback, time).
  p5.MediaElement.prototype._onTimeUpdate = function() {
    var playbackTime = this.time();

    for (var i = 0; i < this._cues.length; i++) {
      var callbackTime = this._cues[i].time;
      var val = this._cues[i].val;

      if (this._prevTime < callbackTime && callbackTime <= playbackTime) {
        // pass the scheduled callbackTime as parameter to the callback
        this._cues[i].callback(val);
      }
    }

    this._prevTime = playbackTime;
  };

  /**
   * Base class for a file.
   * Used for Element.drop and createFileInput.
   *
   * @class p5.File
   * @constructor
   * @param {File} file File that is wrapped
   */
  p5.File = function(file, pInst) {
    /**
     * Underlying File object. All normal File methods can be called on this.
     *
     * @property file
     */
    this.file = file;

    this._pInst = pInst;

    // Splitting out the file type into two components
    // This makes determining if image or text etc simpler
    var typeList = file.type.split('/');
    /**
     * File type (image, text, etc.)
     *
     * @property type
     */
    this.type = typeList[0];
    /**
     * File subtype (usually the file extension jpg, png, xml, etc.)
     *
     * @property subtype
     */
    this.subtype = typeList[1];
    /**
     * File name
     *
     * @property name
     */
    this.name = file.name;
    /**
     * File size
     *
     * @property size
     */
    this.size = file.size;

    /**
     * URL string containing image data.
     *
     * @property data
     */
    this.data = undefined;
  };

  p5.File._createLoader = function(theFile, callback) {
    var reader = new FileReader();
    reader.onload = function(e) {
      var p5file = new p5.File(theFile);
      p5file.data = e.target.result;
      callback(p5file);
    };
    return reader;
  };

  p5.File._load = function(f, callback) {
    // Text or data?
    // This should likely be improved
    if (/^text\//.test(f.type)) {
      p5.File._createLoader(f, callback).readAsText(f);
    } else if (!/^(video|audio)\//.test(f.type)) {
      p5.File._createLoader(f, callback).readAsDataURL(f);
    } else {
      var file = new p5.File(f);
      file.data = URL.createObjectURL(f);
      callback(file);
    }
  };
});