reasonable behavior for title

[dygraphs.git] / plugins / chart-labels.js

/**
 * @license
 * Copyright 2012 Dan Vanderkam (danvdk@gmail.com)
 * MIT-licensed (http://opensource.org/licenses/MIT)
 */
Dygraph.Plugins.ChartLabels = (function() {

// TODO(danvk): move chart label options out of dygraphs and into the plugin.

var chart_labels = function() {
  this.title_div_ = null;
  this.xlabel_div_ = null;
  this.ylabel_div_ = null;
  this.y2label_div_ = null;
};

chart_labels.prototype.toString = function() {
  return "ChartLabels Plugin";
};

chart_labels.prototype.activate = function(g) {
  return {
    layout: this.layout,
    // clearChart: this.clearChart,
    drawChart: this.drawChart
  };
};

// QUESTION: should there be a plugin-utils.js?
var createDivInRect = function(r) {
  var div = document.createElement('div');
  div.style.position = 'absolute';
  div.style.left = r.x + 'px';
  div.style.top = r.y + 'px';
  div.style.width = r.w + 'px';
  div.style.height = r.h + 'px';
  return div;
};

// Detach and null out any existing nodes.
chart_labels.prototype.detachLabels_ = function() {
  var els = [ this.title_div_,
              this.xlabel_div_,
              this.ylabel_div_,
              this.y2label_div_ ];
  for (var i = 0; i < els.length; i++) {
    var el = els[i];
    if (!el) continue;
    if (el.parentNode) el.parentNode.removeChild(el);
  }

  this.title_div_ = null;
  this.xlabel_div_ = null;
  this.ylabel_div_ = null;
  this.y2label_div_ = null;
};

chart_labels.prototype.layout = function(e) {
  this.detachLabels_();

  var g = e.dygraph;
  var div = e.chart_div;
  if (g.getOption('title')) {
    // QUESTION: should this return an absolutely-positioned div instead?
    var title_rect = e.reserveSpaceTop(g.getOption('titleHeight'));
    this.title_div_ = createDivInRect(title_rect);
    this.title_div_.innerHTML = g.getOption('title');
    this.title_div_.style.textAlign = 'center';
    this.title_div_.style.fontSize = (g.getOption('titleHeight') - 8) + 'px';
    this.title_div_.style.fontWeight = 'bold';
    div.appendChild(this.title_div_);
  }

/*
  if (g.getOption('xlabel')) {
    var x_rect = e.reserveSpaceBottom(g.getOption('xLabelHeight'));
  }

  if (g.getOption('ylabel')) {
    var y_rect = e.reserveSpaceLeft(0);
  }

  if (g.getOption('y2label')) {
    var y2_rect = e.reserveSpaceRight(0);
  }
  */
};

chart_labels.prototype.drawChart = function(e) {
  var g = e.dygraph;
  if (this.title_div_) {
    this.title_div_.innerHTML = g.getOption('title');
  }
};

chart_labels.prototype.clearChart = function() {
};

chart_labels.prototype.destroy = function() {
  detachLabels();
};


return chart_labels;
})();