dygraph-layout.js

   1 /**
   2  * @license
   3  * Copyright 2011 Dan Vanderkam (danvdk@gmail.com)
   4  * MIT-licensed (http://opensource.org/licenses/MIT)
   5  */
   6
   7 /**
   8  * @fileoverview Based on PlotKitLayout, but modified to meet the needs of
   9  * dygraphs.
  10  */
  11
  12 /*jshint globalstrict: true */
  13 /*global Dygraph:false */
  14 "use strict";
  15
  16 /**
  17  * Creates a new DygraphLayout object.
  18  *
  19  * This class contains all the data to be charted.
  20  * It uses data coordinates, but also records the chart range (in data
  21  * coordinates) and hence is able to calculate percentage positions ('In this
  22  * view, Point A lies 25% down the x-axis.')
  23  *
  24  * Two things that it does not do are:
  25  * 1. Record pixel coordinates for anything.
  26  * 2. (oddly) determine anything about the layout of chart elements.
  27  *
  28  * The naming is a vestige of Dygraph's original PlotKit roots.
  29  *
  30  * @constructor
  31  */
  32 var DygraphLayout = function(dygraph) {
  33   this.dygraph_ = dygraph;
  34   this.datasets = [];
  35   this.annotations = [];
  36   this.yAxes_ = null;
  37
  38   // TODO(danvk): it's odd that xTicks_ and yTicks_ are inputs, but xticks and
  39   // yticks are outputs. Clean this up.
  40   this.xTicks_ = null;
  41   this.yTicks_ = null;
  42 };
  43
  44 DygraphLayout.prototype.attr_ = function(name) {
  45   return this.dygraph_.attr_(name);
  46 };
  47
  48 DygraphLayout.prototype.addDataset = function(setname, set_xy) {
  49   this.datasets[setname] = set_xy;
  50 };
  51
  52 DygraphLayout.prototype.getPlotArea = function() {
  53   return this.computePlotArea_();
  54 };
  55
  56 // Compute the box which the chart should be drawn in. This is the canvas's
  57 // box, less space needed for axis and chart labels.
  58 DygraphLayout.prototype.computePlotArea_ = function() {
  59   var area = {
  60     // TODO(danvk): per-axis setting.
  61     x: 0,
  62     y: 0
  63   };
  64   if (this.attr_('drawYAxis')) {
  65    area.x = this.attr_('yAxisLabelWidth') + 2 * this.attr_('axisTickSize');
  66   }
  67
  68   area.w = this.dygraph_.width_ - area.x - this.attr_('rightGap');
  69   area.h = this.dygraph_.height_;
  70   if (this.attr_('drawXAxis')) {
  71     if (this.attr_('xAxisHeight')) {
  72       area.h -= this.attr_('xAxisHeight');
  73     } else {
  74       area.h -= this.attr_('axisLabelFontSize') + 2 * this.attr_('axisTickSize');
  75     }
  76   }
  77
  78   // Shrink the drawing area to accomodate additional y-axes.
  79   if (this.dygraph_.numAxes() == 2) {
  80     // TODO(danvk): per-axis setting.
  81     area.w -= (this.attr_('yAxisLabelWidth') + 2 * this.attr_('axisTickSize'));
  82   } else if (this.dygraph_.numAxes() > 2) {
  83     this.dygraph_.error("Only two y-axes are supported at this time. (Trying " +
  84                         "to use " + this.dygraph_.numAxes() + ")");
  85   }
  86
  87   // Add space for chart labels: title, xlabel and ylabel.
  88   if (this.attr_('title')) {
  89     area.h -= this.attr_('titleHeight');
  90     area.y += this.attr_('titleHeight');
  91   }
  92   if (this.attr_('xlabel')) {
  93     area.h -= this.attr_('xLabelHeight');
  94   }
  95   if (this.attr_('ylabel')) {
  96     // It would make sense to shift the chart here to make room for the y-axis
  97     // label, but the default yAxisLabelWidth is large enough that this results
  98     // in overly-padded charts. The y-axis label should fit fine. If it
  99     // doesn't, the yAxisLabelWidth option can be increased.
 100   }
 101
 102   if (this.attr_('y2label')) {
 103     // same logic applies here as for ylabel.
 104     // TODO(danvk): make yAxisLabelWidth a per-axis property
 105   }
 106
 107   // Add space for range selector, if needed.
 108   if (this.attr_('showRangeSelector')) {
 109     area.h -= this.attr_('rangeSelectorHeight') + 4;
 110   }
 111
 112   return area;
 113 };
 114
 115 DygraphLayout.prototype.setAnnotations = function(ann) {
 116   // The Dygraph object's annotations aren't parsed. We parse them here and
 117   // save a copy. If there is no parser, then the user must be using raw format.
 118   this.annotations = [];
 119   var parse = this.attr_('xValueParser') || function(x) { return x; };
 120   for (var i = 0; i < ann.length; i++) {
 121     var a = {};
 122     if (!ann[i].xval && !ann[i].x) {
 123       this.dygraph_.error("Annotations must have an 'x' property");
 124       return;
 125     }
 126     if (ann[i].icon &&
 127         !(ann[i].hasOwnProperty('width') &&
 128           ann[i].hasOwnProperty('height'))) {
 129       this.dygraph_.error("Must set width and height when setting " +
 130                           "annotation.icon property");
 131       return;
 132     }
 133     Dygraph.update(a, ann[i]);
 134     if (!a.xval) a.xval = parse(a.x);
 135     this.annotations.push(a);
 136   }
 137 };
 138
 139 DygraphLayout.prototype.setXTicks = function(xTicks) {
 140   this.xTicks_ = xTicks;
 141 };
 142
 143 // TODO(danvk): add this to the Dygraph object's API or move it into Layout.
 144 DygraphLayout.prototype.setYAxes = function (yAxes) {
 145   this.yAxes_ = yAxes;
 146 };
 147
 148 DygraphLayout.prototype.setDateWindow = function(dateWindow) {
 149   this.dateWindow_ = dateWindow;
 150 };
 151
 152 DygraphLayout.prototype.evaluate = function() {
 153   this._evaluateLimits();
 154   this._evaluateLineCharts();
 155   this._evaluateLineTicks();
 156   this._evaluateAnnotations();
 157 };
 158
 159 DygraphLayout.prototype._evaluateLimits = function() {
 160   this.minxval = this.maxxval = null;
 161   if (this.dateWindow_) {
 162     this.minxval = this.dateWindow_[0];
 163     this.maxxval = this.dateWindow_[1];
 164   } else {
 165     for (var name in this.datasets) {
 166       if (!this.datasets.hasOwnProperty(name)) continue;
 167       var series = this.datasets[name];
 168       if (series.length > 1) {
 169         var x1 = series[0][0];
 170         if (!this.minxval || x1 < this.minxval) this.minxval = x1;
 171
 172         var x2 = series[series.length - 1][0];
 173         if (!this.maxxval || x2 > this.maxxval) this.maxxval = x2;
 174       }
 175     }
 176   }
 177   this.xrange = this.maxxval - this.minxval;
 178   this.xscale = (this.xrange !== 0 ? 1/this.xrange : 1.0);
 179
 180   for (var i = 0; i < this.yAxes_.length; i++) {
 181     var axis = this.yAxes_[i];
 182     axis.minyval = axis.computedValueRange[0];
 183     axis.maxyval = axis.computedValueRange[1];
 184     axis.yrange = axis.maxyval - axis.minyval;
 185     axis.yscale = (axis.yrange !== 0 ? 1.0 / axis.yrange : 1.0);
 186
 187     if (axis.g.attr_("logscale")) {
 188       axis.ylogrange = Dygraph.log10(axis.maxyval) - Dygraph.log10(axis.minyval);
 189       axis.ylogscale = (axis.ylogrange !== 0 ? 1.0 / axis.ylogrange : 1.0);
 190       if (!isFinite(axis.ylogrange) || isNaN(axis.ylogrange)) {
 191         axis.g.error('axis ' + i + ' of graph at ' + axis.g +
 192             ' can\'t be displayed in log scale for range [' +
 193             axis.minyval + ' - ' + axis.maxyval + ']');
 194       }
 195     }
 196   }
 197 };
 198
 199 DygraphLayout._calcYNormal = function(axis, value) {
 200   if (axis.logscale) {
 201     return 1.0 - ((Dygraph.log10(value) - Dygraph.log10(axis.minyval)) * axis.ylogscale);
 202   } else {
 203     return 1.0 - ((value - axis.minyval) * axis.yscale);
 204   }
 205 };
 206
 207 DygraphLayout.prototype._evaluateLineCharts = function() {
 208   // add all the rects
 209   this.points = [];
 210   // An array to keep track of how many points will be drawn for each set.
 211   // This will allow for the canvas renderer to not have to check every point
 212   // for every data set since the points are added in order of the sets in
 213   // datasets.
 214   this.setPointsLengths = [];
 215
 216   for (var setName in this.datasets) {
 217     if (!this.datasets.hasOwnProperty(setName)) continue;
 218
 219     var dataset = this.datasets[setName];
 220     var axis = this.dygraph_.axisPropertiesForSeries(setName);
 221
 222     var setPointsLength = 0;
 223
 224     for (var j = 0; j < dataset.length; j++) {
 225       var item = dataset[j];
 226       var xValue = parseFloat(item[0]);
 227       var yValue = parseFloat(item[1]);
 228
 229       // Range from 0-1 where 0 represents left and 1 represents right.
 230       var xNormal = (xValue - this.minxval) * this.xscale;
 231       // Range from 0-1 where 0 represents top and 1 represents bottom
 232       var yNormal = DygraphLayout._calcYNormal(axis, yValue);
 233
 234       var point = {
 235         // TODO(danvk): here
 236         x: xNormal,
 237         y: yNormal,
 238         xval: xValue,
 239         yval: yValue,
 240         name: setName
 241       };
 242       this.points.push(point);
 243       setPointsLength += 1;
 244     }
 245     this.setPointsLengths.push(setPointsLength);
 246   }
 247 };
 248
 249 DygraphLayout.prototype._evaluateLineTicks = function() {
 250   var i, tick, label, pos;
 251   this.xticks = [];
 252   for (i = 0; i < this.xTicks_.length; i++) {
 253     tick = this.xTicks_[i];
 254     label = tick.label;
 255     pos = this.xscale * (tick.v - this.minxval);
 256     if ((pos >= 0.0) && (pos <= 1.0)) {
 257       this.xticks.push([pos, label]);
 258     }
 259   }
 260
 261   this.yticks = [];
 262   for (i = 0; i < this.yAxes_.length; i++ ) {
 263     var axis = this.yAxes_[i];
 264     for (var j = 0; j < axis.ticks.length; j++) {
 265       tick = axis.ticks[j];
 266       label = tick.label;
 267       pos = this.dygraph_.toPercentYCoord(tick.v, i);
 268       if ((pos >= 0.0) && (pos <= 1.0)) {
 269         this.yticks.push([i, pos, label]);
 270       }
 271     }
 272   }
 273 };
 274
 275
 276 /**
 277  * Behaves the same way as PlotKit.Layout, but also copies the errors
 278  * @private
 279  */
 280 DygraphLayout.prototype.evaluateWithError = function() {
 281   this.evaluate();
 282   if (!(this.attr_('errorBars') || this.attr_('customBars'))) return;
 283
 284   // Copy over the error terms
 285   var i = 0;  // index in this.points
 286   for (var setName in this.datasets) {
 287     if (!this.datasets.hasOwnProperty(setName)) continue;
 288     var j = 0;
 289     var dataset = this.datasets[setName];
 290     var axis = this.dygraph_.axisPropertiesForSeries(setName);
 291     for (j = 0; j < dataset.length; j++, i++) {
 292       var item = dataset[j];
 293       var xv = parseFloat(item[0]);
 294       var yv = parseFloat(item[1]);
 295
 296       if (xv == this.points[i].xval &&
 297           yv == this.points[i].yval) {
 298         var errorMinus = parseFloat(item[2]);
 299         var errorPlus = parseFloat(item[3]);
 300
 301         var yv_minus = yv - errorMinus;
 302         var yv_plus = yv + errorPlus;
 303         this.points[i].y_top = DygraphLayout._calcYNormal(axis, yv_minus);
 304         this.points[i].y_bottom = DygraphLayout._calcYNormal(axis, yv_plus);
 305       }
 306     }
 307   }
 308 };
 309
 310 DygraphLayout.prototype._evaluateAnnotations = function() {
 311   // Add the annotations to the point to which they belong.
 312   // Make a map from (setName, xval) to annotation for quick lookups.
 313   var i;
 314   var annotations = {};
 315   for (i = 0; i < this.annotations.length; i++) {
 316     var a = this.annotations[i];
 317     annotations[a.xval + "," + a.series] = a;
 318   }
 319
 320   this.annotated_points = [];
 321
 322   // Exit the function early if there are no annotations.
 323   if (!this.annotations || !this.annotations.length) {
 324     return;
 325   }
 326
 327   // TODO(antrob): loop through annotations not points.
 328   for (i = 0; i < this.points.length; i++) {
 329     var p = this.points[i];
 330     var k = p.xval + "," + p.name;
 331     if (k in annotations) {
 332       p.annotation = annotations[k];
 333       this.annotated_points.push(p);
 334     }
 335   }
 336 };
 337
 338 /**
 339  * Convenience function to remove all the data sets from a graph
 340  */
 341 DygraphLayout.prototype.removeAllDatasets = function() {
 342   delete this.datasets;
 343   this.datasets = [];
 344 };
 345
 346 /**
 347  * Return a copy of the point at the indicated index, with its yval unstacked.
 348  * @param int index of point in layout_.points
 349  */
 350 DygraphLayout.prototype.unstackPointAtIndex = function(idx) {
 351   var point = this.points[idx];
 352
 353   // Clone the point since we modify it
 354   var unstackedPoint = {};
 355   for (var pt in point) {
 356     unstackedPoint[pt] = point[pt];
 357   }
 358
 359   if (!this.attr_("stackedGraph")) {
 360     return unstackedPoint;
 361   }
 362
 363   // The unstacked yval is equal to the current yval minus the yval of the
 364   // next point at the same xval.
 365   for (var i = idx+1; i < this.points.length; i++) {
 366     if (this.points[i].xval == point.xval) {
 367       unstackedPoint.yval -= this.points[i].yval;
 368       break;
 369     }
 370   }
 371
 372   return unstackedPoint;
 373 };