dygraph-combined-dev.js

   YYYYMMDD,A2,sigmaA2,B2,sigmaB2,...

 If the 'fractions' option is set, the input should be of the form:

   Date,SeriesA,SeriesB,...
   YYYYMMDD,A1/B1,A2/B2,...
   YYYYMMDD,A1/B1,A2/B2,...

 And error bars will be calculated automatically using a binomial distribution.

 For further documentation and examples, see http://dygraphs.com/

 */

// For "production" code, this gets set to false by uglifyjs.
if (typeof(DEBUG) === 'undefined') DEBUG=true;

var Dygraph = (function() {
/*global DygraphLayout:false, DygraphCanvasRenderer:false, DygraphOptions:false, G_vmlCanvasManager:false,ActiveXObject:false */
"use strict";

/**
 * Creates an interactive, zoomable chart.
 *
 * @constructor
 * @param {div | String} div A div or the id of a div into which to construct
 * the chart.
 * @param {String | Function} file A file containing CSV data or a function
 * that returns this data. The most basic expected format for each line is
 * "YYYY/MM/DD,val1,val2,...". For more information, see
 * http://dygraphs.com/data.html.
 * @param {Object} attrs Various other attributes, e.g. errorBars determines
 * whether the input data contains error ranges. For a complete list of
 * options, see http://dygraphs.com/options.html.
 */
var Dygraph = function(div, data, opts, opt_fourth_param) {
  // These have to go above the "Hack for IE" in __init__ since .ready() can be
  // called as soon as the constructor returns. Once support for OldIE is
  // dropped, this can go down with the rest of the initializers.
  this.is_initial_draw_ = true;
  this.readyFns_ = [];

  if (opt_fourth_param !== undefined) {
    // Old versions of dygraphs took in the series labels as a constructor
    // parameter. This doesn't make sense anymore, but it's easy to continue
    // to support this usage.
    console.warn("Using deprecated four-argument dygraph constructor");
    this.__old_init__(div, data, opts, opt_fourth_param);
  } else {
    this.__init__(div, data, opts);
  }
};

Dygraph.NAME = "Dygraph";
Dygraph.VERSION = "1.1.1";
Dygraph.__repr__ = function() {
  return "[" + Dygraph.NAME + " " + Dygraph.VERSION + "]";
};

/**
 * Returns information about the Dygraph class.
 */
Dygraph.toString = function() {
  return Dygraph.__repr__();
};

// Various default values
Dygraph.DEFAULT_ROLL_PERIOD = 1;
Dygraph.DEFAULT_WIDTH = 480;
Dygraph.DEFAULT_HEIGHT = 320;

// For max 60 Hz. animation:
Dygraph.ANIMATION_STEPS = 12;
Dygraph.ANIMATION_DURATION = 200;

// Label constants for the labelsKMB and labelsKMG2 options.
// (i.e. '100000' -> '100K')
Dygraph.KMB_LABELS = [ 'K', 'M', 'B', 'T', 'Q' ];
Dygraph.KMG2_BIG_LABELS = [ 'k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y' ];
Dygraph.KMG2_SMALL_LABELS = [ 'm', 'u', 'n', 'p', 'f', 'a', 'z', 'y' ];

// These are defined before DEFAULT_ATTRS so that it can refer to them.
/**
 * @private
 * Return a string version of a number. This respects the digitsAfterDecimal
 * and maxNumberWidth options.
 * @param {number} x The number to be formatted
 * @param {Dygraph} opts An options view
 */
Dygraph.numberValueFormatter = function(x, opts) {
  var sigFigs = opts('sigFigs');

  if (sigFigs !== null) {
    // User has opted for a fixed number of significant figures.
    return Dygraph.floatFormat(x, sigFigs);
  }

  var digits = opts('digitsAfterDecimal');
  var maxNumberWidth = opts('maxNumberWidth');

  var kmb = opts('labelsKMB');
  var kmg2 = opts('labelsKMG2');

  var label;

  // switch to scientific notation if we underflow or overflow fixed display.
  if (x !== 0.0 &&
      (Math.abs(x) >= Math.pow(10, maxNumberWidth) ||
       Math.abs(x) < Math.pow(10, -digits))) {
    label = x.toExponential(digits);
  } else {
    label = '' + Dygraph.round_(x, digits);
  }

  if (kmb || kmg2) {
    var k;
    var k_labels = [];
    var m_labels = [];
    if (kmb) {
      k = 1000;
      k_labels = Dygraph.KMB_LABELS;
    }
    if (kmg2) {
      if (kmb) console.warn("Setting both labelsKMB and labelsKMG2. Pick one!");
      k = 1024;
      k_labels = Dygraph.KMG2_BIG_LABELS;
      m_labels = Dygraph.KMG2_SMALL_LABELS;
    }

    var absx = Math.abs(x);
    var n = Dygraph.pow(k, k_labels.length);
    for (var j = k_labels.length - 1; j >= 0; j--, n /= k) {
      if (absx >= n) {
        label = Dygraph.round_(x / n, digits) + k_labels[j];
        break;
      }
    }
    if (kmg2) {
      // TODO(danvk): clean up this logic. Why so different than kmb?
      var x_parts = String(x.toExponential()).split('e-');
      if (x_parts.length === 2 && x_parts[1] >= 3 && x_parts[1] <= 24) {
        if (x_parts[1] % 3 > 0) {
          label = Dygraph.round_(x_parts[0] /
              Dygraph.pow(10, (x_parts[1] % 3)),
              digits);
        } else {
          label = Number(x_parts[0]).toFixed(2);
        }
        label += m_labels[Math.floor(x_parts[1] / 3) - 1];
      }
    }
  }

  return label;
};

/**
 * variant for use as an axisLabelFormatter.
 * @private
 */
Dygraph.numberAxisLabelFormatter = function(x, granularity, opts) {
  return Dygraph.numberValueFormatter.call(this, x, opts);
};

/**
 * @type {!Array.<string>}
 * @private
 * @constant
 */
Dygraph.SHORT_MONTH_NAMES_ = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];


/**
 * Convert a JS date to a string appropriate to display on an axis that
 * is displaying values at the stated granularity. This respects the 
 * labelsUTC option.
 * @param {Date} date The date to format
 * @param {number} granularity One of the Dygraph granularity constants
 * @param {Dygraph} opts An options view
 * @return {string} The date formatted as local time
 * @private
 */
Dygraph.dateAxisLabelFormatter = function(date, granularity, opts) {
  var utc = opts('labelsUTC');
  var accessors = utc ? Dygraph.DateAccessorsUTC : Dygraph.DateAccessorsLocal;

  var year = accessors.getFullYear(date),
      month = accessors.getMonth(date),
      day = accessors.getDate(date),
      hours = accessors.getHours(date),
      mins = accessors.getMinutes(date),
      secs = accessors.getSeconds(date),
      millis = accessors.getSeconds(date);

  if (granularity >= Dygraph.DECADAL) {
    return '' + year;
  } else if (granularity >= Dygraph.MONTHLY) {
    return Dygraph.SHORT_MONTH_NAMES_[month] + '&#160;' + year;
  } else {
    var frac = hours * 3600 + mins * 60 + secs + 1e-3 * millis;
    if (frac === 0 || granularity >= Dygraph.DAILY) {
      // e.g. '21 Jan' (%d%b)
      return Dygraph.zeropad(day) + '&#160;' + Dygraph.SHORT_MONTH_NAMES_[month];
    } else {
      return Dygraph.hmsString_(hours, mins, secs);
    }
  }
};
// alias in case anyone is referencing the old method.
Dygraph.dateAxisFormatter = Dygraph.dateAxisLabelFormatter;

/**
 * Return a string version of a JS date for a value label. This respects the 
 * labelsUTC option.
 * @param {Date} date The date to be formatted
 * @param {Dygraph} opts An options view
 * @private
 */
Dygraph.dateValueFormatter = function(d, opts) {
  return Dygraph.dateString_(d, opts('labelsUTC'));
};

/**
 * Standard plotters. These may be used by clients.
 * Available plotters are:
 * - Dygraph.Plotters.linePlotter: draws central lines (most common)
 * - Dygraph.Plotters.errorPlotter: draws error bars
 * - Dygraph.Plotters.fillPlotter: draws fills under lines (used with fillGraph)
 *
 * By default, the plotter is [fillPlotter, errorPlotter, linePlotter].
 * This causes all the lines to be drawn over all the fills/error bars.
 */
Dygraph.Plotters = DygraphCanvasRenderer._Plotters;


// Default attribute values.
Dygraph.DEFAULT_ATTRS = {
  highlightCircleSize: 3,
  highlightSeriesOpts: null,
  highlightSeriesBackgroundAlpha: 0.5,

  labelsDivWidth: 250,
  labelsDivStyles: {
    // TODO(danvk): move defaults from createStatusMessage_ here.
  },
  labelsSeparateLines: false,
  labelsShowZeroValues: true,
  labelsKMB: false,
  labelsKMG2: false,
  showLabelsOnHighlight: true,

  digitsAfterDecimal: 2,
  maxNumberWidth: 6,
  sigFigs: null,

  strokeWidth: 1.0,
  strokeBorderWidth: 0,
  strokeBorderColor: "white",

  axisTickSize: 3,
  axisLabelFontSize: 14,
  rightGap: 5,

  showRoller: false,
  xValueParser: Dygraph.dateParser,

  delimiter: ',',

  sigma: 2.0,
  errorBars: false,
  fractions: false,
  wilsonInterval: true,  // only relevant if fractions is true
  customBars: false,
  fillGraph: false,
  fillAlpha: 0.15,
  connectSeparatedPoints: false,

  stackedGraph: false,
  stackedGraphNaNFill: 'all',
  hideOverlayOnMouseOut: true,

  legend: 'onmouseover',
  stepPlot: false,
  avoidMinZero: false,
  xRangePad: 0,
  yRangePad: null,
  drawAxesAtZero: false,

  // Sizes of the various chart labels.
  titleHeight: 28,
  xLabelHeight: 18,
  yLabelWidth: 18,

  drawXAxis: true,
  drawYAxis: true,
  axisLineColor: "black",
  axisLineWidth: 0.3,
  gridLineWidth: 0.3,
  axisLabelColor: "black",
  axisLabelWidth: 50,
  drawYGrid: true,
  drawXGrid: true,
  gridLineColor: "rgb(128,128,128)",

  interactionModel: null,  // will be set to Dygraph.Interaction.defaultModel
  animatedZooms: false,  // (for now)

  // Range selector options
  showRangeSelector: false,
  rangeSelectorHeight: 40,
  rangeSelectorPlotStrokeColor: "#808FAB",
  rangeSelectorPlotFillColor: "#A7B1C4",
  showInRangeSelector: null,

  // The ordering here ensures that central lines always appear above any
  // fill bars/error bars.
  plotter: [
    Dygraph.Plotters.fillPlotter,
    Dygraph.Plotters.errorPlotter,
    Dygraph.Plotters.linePlotter
  ],

  plugins: [ ],

  // per-axis options
  axes: {
    x: {
      pixelsPerLabel: 70,
      axisLabelWidth: 60,
      axisLabelFormatter: Dygraph.dateAxisLabelFormatter,
      valueFormatter: Dygraph.dateValueFormatter,
      drawGrid: true,
      drawAxis: true,
      independentTicks: true,
      ticker: null  // will be set in dygraph-tickers.js
    },
    y: {
      axisLabelWidth: 50,
      pixelsPerLabel: 30,
      valueFormatter: Dygraph.numberValueFormatter,
      axisLabelFormatter: Dygraph.numberAxisLabelFormatter,
      drawGrid: true,
      drawAxis: true,
      independentTicks: true,
      ticker: null  // will be set in dygraph-tickers.js
    },
    y2: {
      axisLabelWidth: 50,
      pixelsPerLabel: 30,
      valueFormatter: Dygraph.numberValueFormatter,
      axisLabelFormatter: Dygraph.numberAxisLabelFormatter,
      drawAxis: true,  // only applies when there are two axes of data.
      drawGrid: false,
      independentTicks: false,
      ticker: null  // will be set in dygraph-tickers.js
    }
  }
};

// Directions for panning and zooming. Use bit operations when combined
// values are possible.
Dygraph.HORIZONTAL = 1;
Dygraph.VERTICAL = 2;

// Installed plugins, in order of precedence (most-general to most-specific).
// Plugins are installed after they are defined, in plugins/install.js.
Dygraph.PLUGINS = [
];

// Used for initializing annotation CSS rules only once.
Dygraph.addedAnnotationCSS = false;

Dygraph.prototype.__old_init__ = function(div, file, labels, attrs) {
  // Labels is no longer a constructor parameter, since it's typically set
  // directly from the data source. It also conains a name for the x-axis,
  // which the previous constructor form did not.
  if (labels !== null) {
    var new_labels = ["Date"];
    for (var i = 0; i < labels.length; i++) new_labels.push(labels[i]);
    Dygraph.update(attrs, { 'labels': new_labels });
  }
  this.__init__(div, file, attrs);
};

/**
 * Initializes the Dygraph. This creates a new DIV and constructs the PlotKit
 * and context &lt;canvas&gt; inside of it. See the constructor for details.
 * on the parameters.
 * @param {Element} div the Element to render the graph into.
 * @param {string | Function} file Source data
 * @param {Object} attrs Miscellaneous other options
 * @private
 */
Dygraph.prototype.__init__ = function(div, file, attrs) {
  // Hack for IE: if we're using excanvas and the document hasn't finished
  // loading yet (and hence may not have initialized whatever it needs to
  // initialize), then keep calling this routine periodically until it has.
  if (/MSIE/.test(navigator.userAgent) && !window.opera &&
      typeof(G_vmlCanvasManager) != 'undefined' &&
      document.readyState != 'complete') {
    var self = this;
    setTimeout(function() { self.__init__(div, file, attrs); }, 100);
    return;
  }

  // Support two-argument constructor
  if (attrs === null || attrs === undefined) { attrs = {}; }

  attrs = Dygraph.mapLegacyOptions_(attrs);

  if (typeof(div) == 'string') {
    div = document.getElementById(div);
  }

  if (!div) {
    console.error("Constructing dygraph with a non-existent div!");
    return;
  }

  this.isUsingExcanvas_ = typeof(G_vmlCanvasManager) != 'undefined';

  // Copy the important bits into the object
  // TODO(danvk): most of these should just stay in the attrs_ dictionary.
  this.maindiv_ = div;
  this.file_ = file;
  this.rollPeriod_ = attrs.rollPeriod || Dygraph.DEFAULT_ROLL_PERIOD;
  this.previousVerticalX_ = -1;
  this.fractions_ = attrs.fractions || false;
  this.dateWindow_ = attrs.dateWindow || null;

  this.annotations_ = [];

  // Zoomed indicators - These indicate when the graph has been zoomed and on what axis.
  this.zoomed_x_ = false;
  this.zoomed_y_ = false;

  // Clear the div. This ensure that, if multiple dygraphs are passed the same
  // div, then only one will be drawn.
  div.innerHTML = "";

  // For historical reasons, the 'width' and 'height' options trump all CSS
  // rules _except_ for an explicit 'width' or 'height' on the div.
  // As an added convenience, if the div has zero height (like <div></div> does
  // without any styles), then we use a default height/width.
  if (div.style.width === '' && attrs.width) {
    div.style.width = attrs.width + "px";
  }
  if (div.style.height === '' && attrs.height) {
    div.style.height = attrs.height + "px";
  }
  if (div.style.height === '' && div.clientHeight === 0) {
    div.style.height = Dygraph.DEFAULT_HEIGHT + "px";
    if (div.style.width === '') {
      div.style.width = Dygraph.DEFAULT_WIDTH + "px";
    }
  }
  // These will be zero if the dygraph's div is hidden. In that case,
  // use the user-specified attributes if present. If not, use zero
  // and assume the user will call resize to fix things later.
  this.width_ = div.clientWidth || attrs.width || 0;
  this.height_ = div.clientHeight || attrs.height || 0;

  // TODO(danvk): set fillGraph to be part of attrs_ here, not user_attrs_.
  if (attrs.stackedGraph) {
    attrs.fillGraph = true;
    // TODO(nikhilk): Add any other stackedGraph checks here.
  }

  // DEPRECATION WARNING: All option processing should be moved from
  // attrs_ and user_attrs_ to options_, which holds all this information.
  //
  // Dygraphs has many options, some of which interact with one another.
  // To keep track of everything, we maintain two sets of options:
  //
  //  this.user_attrs_   only options explicitly set by the user.
  //  this.attrs_        defaults, options derived from user_attrs_, data.
  //
  // Options are then accessed this.attr_('attr'), which first looks at
  // user_attrs_ and then computed attrs_. This way Dygraphs can set intelligent
  // defaults without overriding behavior that the user specifically asks for.
  this.user_attrs_ = {};
  Dygraph.update(this.user_attrs_, attrs);

  // This sequence ensures that Dygraph.DEFAULT_ATTRS is never modified.
  this.attrs_ = {};
  Dygraph.updateDeep(this.attrs_, Dygraph.DEFAULT_ATTRS);

  this.boundaryIds_ = [];
  this.setIndexByName_ = {};
  this.datasetIndex_ = [];

  this.registeredEvents_ = [];
  this.eventListeners_ = {};

  this.attributes_ = new DygraphOptions(this);

  // Create the containing DIV and other interactive elements
  this.createInterface_();

  // Activate plugins.
  this.plugins_ = [];
  var plugins = Dygraph.PLUGINS.concat(this.getOption('plugins'));
  for (var i = 0; i < plugins.length; i++) {
    // the plugins option may contain either plugin classes or instances.
    // Plugin instances contain an activate method.
    var Plugin = plugins[i];  // either a constructor or an instance.
    var pluginInstance;
    if (typeof(Plugin.activate) !== 'undefined') {
      pluginInstance = Plugin;
    } else {
      pluginInstance = new Plugin();
    }

    var pluginDict = {
      plugin: pluginInstance,
      events: {},
      options: {},
      pluginOptions: {}
    };

    var handlers = pluginInstance.activate(this);
    for (var eventName in handlers) {
      if (!handlers.hasOwnProperty(eventName)) continue;
      // TODO(danvk): validate eventName.
      pluginDict.events[eventName] = handlers[eventName];
    }

    this.plugins_.push(pluginDict);
  }

  // At this point, plugins can no longer register event handlers.
  // Construct a map from event -> ordered list of [callback, plugin].
  for (var i = 0; i < this.plugins_.length; i++) {
    var plugin_dict = this.plugins_[i];
    for (var eventName in plugin_dict.events) {
      if (!plugin_dict.events.hasOwnProperty(eventName)) continue;
      var callback = plugin_dict.events[eventName];

      var pair = [plugin_dict.plugin, callback];
      if (!(eventName in this.eventListeners_)) {
        this.eventListeners_[eventName] = [pair];
      } else {
        this.eventListeners_[eventName].push(pair);
      }
    }
  }

  this.createDragInterface_();

  this.start_();
};

/**
 * Triggers a cascade of events to the various plugins which are interested in them.
 * Returns true if the "default behavior" should be prevented, i.e. if one
 * of the event listeners called event.preventDefault().
 * @private
 */
Dygraph.prototype.cascadeEvents_ = function(name, extra_props) {
  if (!(name in this.eventListeners_)) return false;

  // QUESTION: can we use objects & prototypes to speed this up?
  var e = {
    dygraph: this,
    cancelable: false,
    defaultPrevented: false,
    preventDefault: function() {
      if (!e.cancelable) throw "Cannot call preventDefault on non-cancelable event.";
      e.defaultPrevented = true;
    },
    propagationStopped: false,
    stopPropagation: function() {
      e.propagationStopped = true;
    }
  };
  Dygraph.update(e, extra_props);

  var callback_plugin_pairs = this.eventListeners_[name];
  if (callback_plugin_pairs) {
    for (var i = callback_plugin_pairs.length - 1; i >= 0; i--) {
      var plugin = callback_plugin_pairs[i][0];
      var callback = callback_plugin_pairs[i][1];
      callback.call(plugin, e);
      if (e.propagationStopped) break;
    }
  }
  return e.defaultPrevented;
};

/**
 * Fetch a plugin instance of a particular class. Only for testing.
 * @private
 * @param {!Class} type The type of the plugin.
 * @return {Object} Instance of the plugin, or null if there is none.
 */
Dygraph.prototype.getPluginInstance_ = function(type) {
  for (var i = 0; i < this.plugins_.length; i++) {
    var p = this.plugins_[i];
    if (p.plugin instanceof type) {
      return p.plugin;
    }
  }
  return null;
};

/**
 * Returns the zoomed status of the chart for one or both axes.
 *
 * Axis is an optional parameter. Can be set to 'x' or 'y'.
 *
 * The zoomed status for an axis is set whenever a user zooms using the mouse
 * or when the dateWindow or valueRange are updated (unless the
 * isZoomedIgnoreProgrammaticZoom option is also specified).
 */
Dygraph.prototype.isZoomed = function(axis) {
  if (axis === null || axis === undefined) {
    return this.zoomed_x_ || this.zoomed_y_;
  }
  if (axis === 'x') return this.zoomed_x_;
  if (axis === 'y') return this.zoomed_y_;
  throw "axis parameter is [" + axis + "] must be null, 'x' or 'y'.";
};

/**
 * Returns information about the Dygraph object, including its containing ID.
 */
Dygraph.prototype.toString = function() {
  var maindiv = this.maindiv_;
  var id = (maindiv && maindiv.id) ? maindiv.id : maindiv;
  return "[Dygraph " + id + "]";
};

/**
 * @private
 * Returns the value of an option. This may be set by the user (either in the
 * constructor or by calling updateOptions) or by dygraphs, and may be set to a
 * per-series value.
 * @param {string} name The name of the option, e.g. 'rollPeriod'.
 * @param {string} [seriesName] The name of the series to which the option
 * will be applied. If no per-series value of this option is available, then
 * the global value is returned. This is optional.
 * @return { ... } The value of the option.
 */
Dygraph.prototype.attr_ = function(name, seriesName) {
  if (DEBUG) {
    if (typeof(Dygraph.OPTIONS_REFERENCE) === 'undefined') {
      console.error('Must include options reference JS for testing');
    } else if (!Dygraph.OPTIONS_REFERENCE.hasOwnProperty(name)) {
      console.error('Dygraphs is using property ' + name + ', which has no ' +
                    'entry in the Dygraphs.OPTIONS_REFERENCE listing.');
      // Only log this error once.
      Dygraph.OPTIONS_REFERENCE[name] = true;
    }
  }
  return seriesName ? this.attributes_.getForSeries(name, seriesName) : this.attributes_.get(name);
};

/**
 * Returns the current value for an option, as set in the constructor or via
 * updateOptions. You may pass in an (optional) series name to get per-series
 * values for the option.
 *
 * All values returned by this method should be considered immutable. If you
 * modify them, there is no guarantee that the changes will be honored or that
 * dygraphs will remain in a consistent state. If you want to modify an option,
 * use updateOptions() instead.
 *
 * @param {string} name The name of the option (e.g. 'strokeWidth')
 * @param {string=} opt_seriesName Series name to get per-series values.
 * @return {*} The value of the option.
 */
Dygraph.prototype.getOption = function(name, opt_seriesName) {
  return this.attr_(name, opt_seriesName);
};

/**
 * Like getOption(), but specifically returns a number.
 * This is a convenience function for working with the Closure Compiler.
 * @param {string} name The name of the option (e.g. 'strokeWidth')
 * @param {string=} opt_seriesName Series name to get per-series values.
 * @return {number} The value of the option.
 * @private
 */
Dygraph.prototype.getNumericOption = function(name, opt_seriesName) {
  return /** @type{number} */(this.getOption(name, opt_seriesName));
};

/**
 * Like getOption(), but specifically returns a string.
 * This is a convenience function for working with the Closure Compiler.
 * @param {string} name The name of the option (e.g. 'strokeWidth')
 * @param {string=} opt_seriesName Series name to get per-series values.
 * @return {string} The value of the option.
 * @private
 */
Dygraph.prototype.getStringOption = function(name, opt_seriesName) {
  return /** @type{string} */(this.getOption(name, opt_seriesName));
};

/**
 * Like getOption(), but specifically returns a boolean.
 * This is a convenience function for working with the Closure Compiler.
 * @param {string} name The name of the option (e.g. 'strokeWidth')
 * @param {string=} opt_seriesName Series name to get per-series values.
 * @return {boolean} The value of the option.
 * @private
 */
Dygraph.prototype.getBooleanOption = function(name, opt_seriesName) {
  return /** @type{boolean} */(this.getOption(name, opt_seriesName));
};

/**
 * Like getOption(), but specifically returns a function.
 * This is a convenience function for working with the Closure Compiler.
 * @param {string} name The name of the option (e.g. 'strokeWidth')
 * @param {string=} opt_seriesName Series name to get per-series values.
 * @return {function(...)} The value of the option.
 * @private
 */
Dygraph.prototype.getFunctionOption = function(name, opt_seriesName) {
  return /** @type{function(...)} */(this.getOption(name, opt_seriesName));
};

Dygraph.prototype.getOptionForAxis = function(name, axis) {
  return this.attributes_.getForAxis(name, axis);
};

/**
 * @private
 * @param {string} axis The name of the axis (i.e. 'x', 'y' or 'y2')
 * @return { ... } A function mapping string -> option value
 */
Dygraph.prototype.optionsViewForAxis_ = function(axis) {
  var self = this;
  return function(opt) {
    var axis_opts = self.user_attrs_.axes;
    if (axis_opts && axis_opts[axis] && axis_opts[axis].hasOwnProperty(opt)) {
      return axis_opts[axis][opt];
    }

    // I don't like that this is in a second spot.
    if (axis === 'x' && opt === 'logscale') {
      // return the default value.
      // TODO(konigsberg): pull the default from a global default.
      return false;
    }

    // user-specified attributes always trump defaults, even if they're less
    // specific.
    if (typeof(self.user_attrs_[opt]) != 'undefined') {
      return self.user_attrs_[opt];
    }

    axis_opts = self.attrs_.axes;
    if (axis_opts && axis_opts[axis] && axis_opts[axis].hasOwnProperty(opt)) {
      return axis_opts[axis][opt];
    }
    // check old-style axis options
    // TODO(danvk): add a deprecation warning if either of these match.
    if (axis == 'y' && self.axes_[0].hasOwnProperty(opt)) {
      return self.axes_[0][opt];
    } else if (axis == 'y2' && self.axes_[1].hasOwnProperty(opt)) {
      return self.axes_[1][opt];
    }
    return self.attr_(opt);
  };
};

/**
 * Returns the current rolling period, as set by the user or an option.
 * @return {number} The number of points in the rolling window
 */
Dygraph.prototype.rollPeriod = function() {
  return this.rollPeriod_;
};

/**
 * Returns the currently-visible x-range. This can be affected by zooming,
 * panning or a call to updateOptions.
 * Returns a two-element array: [left, right].
 * If the Dygraph has dates on the x-axis, these will be millis since epoch.
 */
Dygraph.prototype.xAxisRange = function() {
  return this.dateWindow_ ? this.dateWindow_ : this.xAxisExtremes();
};

/**
 * Returns the lower- and upper-bound x-axis values of the
 * data set.
 */
Dygraph.prototype.xAxisExtremes = function() {
  var pad = this.getNumericOption('xRangePad') / this.plotter_.area.w;
  if (this.numRows() === 0) {
    return [0 - pad, 1 + pad];
  }
  var left = this.rawData_[0][0];
  var right = this.rawData_[this.rawData_.length - 1][0];
  if (pad) {
    // Must keep this in sync with dygraph-layout _evaluateLimits()
    var range = right - left;
    left -= range * pad;
    right += range * pad;
  }
  return [left, right];
};

/**
 * Returns the currently-visible y-range for an axis. This can be affected by
 * zooming, panning or a call to updateOptions. Axis indices are zero-based. If
 * called with no arguments, returns the range of the first axis.
 * Returns a two-element array: [bottom, top].
 */
Dygraph.prototype.yAxisRange = function(idx) {
  if (typeof(idx) == "undefined") idx = 0;
  if (idx < 0 || idx >= this.axes_.length) {
    return null;
  }
  var axis = this.axes_[idx];
  return [ axis.computedValueRange[0], axis.computedValueRange[1] ];
};

/**
 * Returns the currently-visible y-ranges for each axis. This can be affected by
 * zooming, panning, calls to updateOptions, etc.
 * Returns an array of [bottom, top] pairs, one for each y-axis.
 */
Dygraph.prototype.yAxisRanges = function() {
  var ret = [];
  for (var i = 0; i < this.axes_.length; i++) {
    ret.push(this.yAxisRange(i));
  }
  return ret;
};

// TODO(danvk): use these functions throughout dygraphs.
/**
 * Convert from data coordinates to canvas/div X/Y coordinates.
 * If specified, do this conversion for the coordinate system of a particular
 * axis. Uses the first axis by default.
 * Returns a two-element array: [X, Y]
 *
 * Note: use toDomXCoord instead of toDomCoords(x, null) and use toDomYCoord
 * instead of toDomCoords(null, y, axis).
 */
Dygraph.prototype.toDomCoords = function(x, y, axis) {
  return [ this.toDomXCoord(x), this.toDomYCoord(y, axis) ];
};

/**
 * Convert from data x coordinates to canvas/div X coordinate.
 * If specified, do this conversion for the coordinate system of a particular
 * axis.
 * Returns a single value or null if x is null.
 */
Dygraph.prototype.toDomXCoord = function(x) {
  if (x === null) {
    return null;
  }

  var area = this.plotter_.area;
  var xRange = this.xAxisRange();
  return area.x + (x - xRange[0]) / (xRange[1] - xRange[0]) * area.w;
};

/**
 * Convert from data x coordinates to canvas/div Y coordinate and optional
 * axis. Uses the first axis by default.
 *
 * returns a single value or null if y is null.
 */
Dygraph.prototype.toDomYCoord = function(y, axis) {
  var pct = this.toPercentYCoord(y, axis);

  if (pct === null) {
    return null;
  }
  var area = this.plotter_.area;
  return area.y + pct * area.h;
};

/**
 * Convert from canvas/div coords to data coordinates.
 * If specified, do this conversion for the coordinate system of a particular
 * axis. Uses the first axis by default.
 * Returns a two-element array: [X, Y].
 *
 * Note: use toDataXCoord instead of toDataCoords(x, null) and use toDataYCoord
 * instead of toDataCoords(null, y, axis).
 */
Dygraph.prototype.toDataCoords = function(x, y, axis) {
  return [ this.toDataXCoord(x), this.toDataYCoord(y, axis) ];
};

/**
 * Convert from canvas/div x coordinate to data coordinate.
 *
 * If x is null, this returns null.
 */
Dygraph.prototype.toDataXCoord = function(x) {
  if (x === null) {
    return null;
  }

  var area = this.plotter_.area;
  var xRange = this.xAxisRange();

  if (!this.attributes_.getForAxis("logscale", 'x')) {
    return xRange[0] + (x - area.x) / area.w * (xRange[1] - xRange[0]);
  } else {
    // TODO: remove duplicate code?
    // Computing the inverse of toDomCoord.
    var pct = (x - area.x) / area.w;

    // Computing the inverse of toPercentXCoord. The function was arrived at with
    // the following steps:
    //
    // Original calcuation:
    // pct = (log(x) - log(xRange[0])) / (log(xRange[1]) - log(xRange[0])));
    //
    // Multiply both sides by the right-side demoninator.
    // pct * (log(xRange[1] - log(xRange[0]))) = log(x) - log(xRange[0])
    //
    // add log(xRange[0]) to both sides
    // log(xRange[0]) + (pct * (log(xRange[1]) - log(xRange[0])) = log(x);
    //
    // Swap both sides of the equation,
    // log(x) = log(xRange[0]) + (pct * (log(xRange[1]) - log(xRange[0]))
    //
    // Use both sides as the exponent in 10^exp and we're done.
    // x = 10 ^ (log(xRange[0]) + (pct * (log(xRange[1]) - log(xRange[0])))
    var logr0 = Dygraph.log10(xRange[0]);
    var logr1 = Dygraph.log10(xRange[1]);
    var exponent = logr0 + (pct * (logr1 - logr0));
    var value = Math.pow(Dygraph.LOG_SCALE, exponent);
    return value;
  }
};

/**
 * Convert from canvas/div y coord to value.
 *
 * If y is null, this returns null.
 * if axis is null, this uses the first axis.
 */
Dygraph.prototype.toDataYCoord = function(y, axis) {
  if (y === null) {
    return null;
  }

  var area = this.plotter_.area;
  var yRange = this.yAxisRange(axis);

  if (typeof(axis) == "undefined") axis = 0;
  if (!this.attributes_.getForAxis("logscale", axis)) {
    return yRange[0] + (area.y + area.h - y) / area.h * (yRange[1] - yRange[0]);
  } else {
    // Computing the inverse of toDomCoord.
    var pct = (y - area.y) / area.h;

    // Computing the inverse of toPercentYCoord. The function was arrived at with
    // the following steps:
    //
    // Original calcuation:
    // pct = (log(yRange[1]) - log(y)) / (log(yRange[1]) - log(yRange[0]));
    //
    // Multiply both sides by the right-side demoninator.
    // pct * (log(yRange[1]) - log(yRange[0])) = log(yRange[1]) - log(y);
    //
    // subtract log(yRange[1]) from both sides.
    // (pct * (log(yRange[1]) - log(yRange[0]))) - log(yRange[1]) = -log(y);
    //
    // and multiply both sides by -1.
    // log(yRange[1]) - (pct * (logr1 - log(yRange[0])) = log(y);
    //
    // Swap both sides of the equation,
    // log(y) = log(yRange[1]) - (pct * (log(yRange[1]) - log(yRange[0])));
    //
    // Use both sides as the exponent in 10^exp and we're done.
    // y = 10 ^ (log(yRange[1]) - (pct * (log(yRange[1]) - log(yRange[0]))));
    var logr0 = Dygraph.log10(yRange[0]);
    var logr1 = Dygraph.log10(yRange[1]);
    var exponent = logr1 - (pct * (logr1 - logr0));
    var value = Math.pow(Dygraph.LOG_SCALE, exponent);
    return value;
  }
};

/**
 * Converts a y for an axis to a percentage from the top to the
 * bottom of the drawing area.
 *
 * If the coordinate represents a value visible on the canvas, then
 * the value will be between 0 and 1, where 0 is the top of the canvas.
 * However, this method will return values outside the range, as
 * values can fall outside the canvas.
 *
 * If y is null, this returns null.
 * if axis is null, this uses the first axis.
 *
 * @param {number} y The data y-coordinate.