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