dygraph-gviz.js

/**
 * @license
 * Copyright 2011 Dan Vanderkam (danvdk@gmail.com)
 * MIT-licensed (http://opensource.org/licenses/MIT)
 */

/**
 * @fileoverview A wrapper around the Dygraph class which implements the
 * interface for a GViz (aka Google Visualization API) visualization.
 * It is designed to be a drop-in replacement for Google's AnnotatedTimeline,
 * so the documentation at
 * http://code.google.com/apis/chart/interactive/docs/gallery/annotatedtimeline.html
 * translates over directly.
 *
 * For a full demo, see:
 * - http://dygraphs.com/tests/gviz.html
 * - http://dygraphs.com/tests/annotation-gviz.html
 */

/*jshint globalstrict: true */
/*global Dygraph:false */
"use strict";

/**
 * A wrapper around Dygraph that implements the gviz API.
 * @param {Object} container The DOM object the visualization should live in.
 */
Dygraph.GVizChart = function(container) {
  this.container = container;
};

Dygraph.GVizChart.prototype.draw = function(data, options) {
  // Clear out any existing dygraph.
  // TODO(danvk): would it make more sense to simply redraw using the current
  // date_graph object?
  this.container.innerHTML = '';
  if (typeof(this.date_graph) != 'undefined') {
    this.date_graph.destroy();
  }

  this.date_graph = new Dygraph(this.container, data, options);
};

/**
 * Google charts compatible setSelection
 * Only row selection is supported, all points in the row will be highlighted
 * @param {Array} array of the selected cells
 * @public
 */
Dygraph.GVizChart.prototype.setSelection = function(selection_array) {
  var row = false;
  if (selection_array.length) {
    row = selection_array[0].row;
  }
  this.date_graph.setSelection(row);
};

/**
 * Google charts compatible getSelection implementation
 * @return {Array} array of the selected cells
 * @public
 */
Dygraph.GVizChart.prototype.getSelection = function() {
  var selection = [];

  var row = this.date_graph.getSelection();

  if (row < 0) return selection;

  var datasets = this.date_graph.layout_.datasets;
  for (var setIdx = 0; setIdx < datasets.length; ++setIdx) {
    selection.push({row: row, column: setIdx + 1});
  }

  return selection;
};