dygraph-layout.js

   1 // Copyright 2011 Dan Vanderkam (danvdk@gmail.com)
   2 // All Rights Reserved.
   3
   4 /**
   5  * @fileoverview Based on PlotKitLayout, but modified to meet the needs of
   6  * dygraphs.
   7  */
   8
   9 /**
  10  * Creates a new DygraphLayout object.
  11  *
  12  * This class contains all the data to be charted.
  13  * It uses data coordinates, but also records the chart range (in data
  14  * coordinates) and hence is able to calculate percentage positions ('In this
  15  * view, Point A lies 25% down the x-axis.')
  16  *
  17  * Two things that it does not do are:
  18  * 1. Record pixel coordinates for anything.
  19  * 2. (oddly) determine anything about the layout of chart elements.
  20  *
  21  * The naming is a vestige of Dygraph's original PlotKit roots.
  22  *
  23  * @constructor
  24  */
  25 DygraphLayout = function(dygraph) {
  26   this.dygraph_ = dygraph;
  27   this.datasets = new Array();
  28   this.annotations = new Array();
  29   this.yAxes_ = null;
  30
  31   // TODO(danvk): it's odd that xTicks_ and yTicks_ are inputs, but xticks and
  32   // yticks are outputs. Clean this up.
  33   this.xTicks_ = null;
  34   this.yTicks_ = null;
  35 };
  36
  37 DygraphLayout.prototype.attr_ = function(name) {
  38   return this.dygraph_.attr_(name);
  39 };
  40
  41 DygraphLayout.prototype.addDataset = function(setname, set_xy) {
  42   this.datasets[setname] = set_xy;
  43 };
  44
  45 DygraphLayout.prototype.setAnnotations = function(ann) {
  46   // The Dygraph object's annotations aren't parsed. We parse them here and
  47   // save a copy. If there is no parser, then the user must be using raw format.
  48   this.annotations = [];
  49   var parse = this.attr_('xValueParser') || function(x) { return x; };
  50   for (var i = 0; i < ann.length; i++) {
  51     var a = {};
  52     if (!ann[i].xval && !ann[i].x) {
  53       this.dygraph_.error("Annotations must have an 'x' property");
  54       return;
  55     }
  56     if (ann[i].icon &&
  57         !(ann[i].hasOwnProperty('width') &&
  58           ann[i].hasOwnProperty('height'))) {
  59       this.dygraph_.error("Must set width and height when setting " +
  60                           "annotation.icon property");
  61       return;
  62     }
  63     Dygraph.update(a, ann[i]);
  64     if (!a.xval) a.xval = parse(a.x);
  65     this.annotations.push(a);
  66   }
  67 };
  68
  69 DygraphLayout.prototype.setXTicks = function(xTicks) {
  70   this.xTicks_ = xTicks;
  71 };
  72
  73 // TODO(danvk): add this to the Dygraph object's API or move it into Layout.
  74 DygraphLayout.prototype.setYAxes = function (yAxes) {
  75   this.yAxes_ = yAxes;
  76 };
  77
  78 DygraphLayout.prototype.setDateWindow = function(dateWindow) {
  79   this.dateWindow_ = dateWindow;
  80 };
  81
  82 DygraphLayout.prototype.evaluate = function() {
  83   this._evaluateLimits();
  84   this._evaluateLineCharts();
  85   this._evaluateLineTicks();
  86   this._evaluateAnnotations();
  87 };
  88
  89 DygraphLayout.prototype._evaluateLimits = function() {
  90   this.minxval = this.maxxval = null;
  91   if (this.dateWindow_) {
  92     this.minxval = this.dateWindow_[0];
  93     this.maxxval = this.dateWindow_[1];
  94   } else {
  95     for (var name in this.datasets) {
  96       if (!this.datasets.hasOwnProperty(name)) continue;
  97       var series = this.datasets[name];
  98       if (series.length > 1) {
  99         var x1 = series[0][0];
 100         if (!this.minxval || x1 < this.minxval) this.minxval = x1;
 101
 102         var x2 = series[series.length - 1][0];
 103         if (!this.maxxval || x2 > this.maxxval) this.maxxval = x2;
 104       }
 105     }
 106   }
 107   this.xrange = this.maxxval - this.minxval;
 108   this.xscale = (this.xrange != 0 ? 1/this.xrange : 1.0);
 109
 110   for (var i = 0; i < this.yAxes_.length; i++) {
 111     var axis = this.yAxes_[i];
 112     axis.minyval = axis.computedValueRange[0];
 113     axis.maxyval = axis.computedValueRange[1];
 114     axis.yrange = axis.maxyval - axis.minyval;
 115     axis.yscale = (axis.yrange != 0 ? 1.0 / axis.yrange : 1.0);
 116
 117     if (axis.g.attr_("logscale")) {
 118       axis.ylogrange = Dygraph.log10(axis.maxyval) - Dygraph.log10(axis.minyval);
 119       axis.ylogscale = (axis.ylogrange != 0 ? 1.0 / axis.ylogrange : 1.0);
 120       if (!isFinite(axis.ylogrange) || isNaN(axis.ylogrange)) {
 121         axis.g.error('axis ' + i + ' of graph at ' + axis.g +
 122             ' can\'t be displayed in log scale for range [' +
 123             axis.minyval + ' - ' + axis.maxyval + ']');
 124       }
 125     }
 126   }
 127 };
 128
 129 DygraphLayout.prototype._evaluateLineCharts = function() {
 130   // add all the rects
 131   this.points = new Array();
 132   // An array to keep track of how many points will be drawn for each set.
 133   // This will allow for the canvas renderer to not have to check every point
 134   // for every data set since the points are added in order of the sets in
 135   // datasets.
 136   this.setPointsLengths = new Array();
 137
 138   for (var setName in this.datasets) {
 139     if (!this.datasets.hasOwnProperty(setName)) continue;
 140
 141     var dataset = this.datasets[setName];
 142     var axis = this.dygraph_.axisPropertiesForSeries(setName);
 143
 144     var graphWidth = this.dygraph_.width_;
 145     var graphHeight = this.dygraph_.height_;
 146     var prevXPx = NaN;
 147     var prevYPx = NaN;
 148     var currXPx = NaN;
 149     var currYPx = NaN;
 150     var setPointsLength = 0;
 151
 152     // Ignore the pixel skipping optimization if there are error bars.
 153     // XXX 2011-07-25 temporarily disabled (see autotests/tests/selection.js)
 154     var skip_opt = (true ||
 155                     this.attr_("errorBars") ||
 156                     this.attr_("customBars") ||
 157                     this.annotations.length > 0);
 158
 159     for (var j = 0; j < dataset.length; j++) {
 160       var item = dataset[j];
 161       var xValue = parseFloat(dataset[j][0]);
 162       var yValue = parseFloat(dataset[j][1]);
 163
 164       // Range from 0-1 where 0 represents top and 1 represents bottom
 165       var xNormal = (xValue - this.minxval) * this.xscale;
 166       // Range from 0-1 where 0 represents left and 1 represents right.
 167       var yNormal;
 168       if (axis.logscale) {
 169         yNormal = 1.0 - ((Dygraph.log10(yValue) - Dygraph.log10(axis.minyval)) * axis.ylogscale);
 170       } else {
 171         yNormal = 1.0 - ((yValue - axis.minyval) * axis.yscale);
 172       }
 173
 174       // Current pixel coordinates that the data point would fill.
 175       currXPx = Math.round(xNormal * graphWidth);
 176       currYPx = Math.round(yNormal * graphHeight);
 177
 178       // Skip over pushing points that lie on the same pixel.
 179       // TODO(antrob): optimize this for graphs with error bars.
 180       if (skip_opt || prevXPx != currXPx || prevYPx != currYPx) {
 181         var point = {
 182           // TODO(danvk): here
 183           x: xNormal,
 184           y: yNormal,
 185           xval: xValue,
 186           yval: yValue,
 187           name: setName
 188         };
 189         this.points.push(point);
 190         setPointsLength += 1;
 191       }
 192       prevXPx = currXPx;
 193       prevYPx = currYPx;
 194     }
 195     this.setPointsLengths.push(setPointsLength);
 196   }
 197 };
 198
 199 DygraphLayout.prototype._evaluateLineTicks = function() {
 200   this.xticks = new Array();
 201   for (var i = 0; i < this.xTicks_.length; i++) {
 202     var tick = this.xTicks_[i];
 203     var label = tick.label;
 204     var pos = this.xscale * (tick.v - this.minxval);
 205     if ((pos >= 0.0) && (pos <= 1.0)) {
 206       this.xticks.push([pos, label]);
 207     }
 208   }
 209
 210   this.yticks = new Array();
 211   for (var i = 0; i < this.yAxes_.length; i++ ) {
 212     var axis = this.yAxes_[i];
 213     for (var j = 0; j < axis.ticks.length; j++) {
 214       var tick = axis.ticks[j];
 215       var label = tick.label;
 216       var pos = this.dygraph_.toPercentYCoord(tick.v, i);
 217       if ((pos >= 0.0) && (pos <= 1.0)) {
 218         this.yticks.push([i, pos, label]);
 219       }
 220     }
 221   }
 222 };
 223
 224
 225 /**
 226  * Behaves the same way as PlotKit.Layout, but also copies the errors
 227  * @private
 228  */
 229 DygraphLayout.prototype.evaluateWithError = function() {
 230   this.evaluate();
 231   if (!(this.attr_('errorBars') || this.attr_('customBars'))) return;
 232
 233   // Copy over the error terms
 234   var i = 0; // index in this.points
 235   for (var setName in this.datasets) {
 236     if (!this.datasets.hasOwnProperty(setName)) continue;
 237     var j = 0;
 238     var dataset = this.datasets[setName];
 239     for (var j = 0; j < dataset.length; j++, i++) {
 240       var item = dataset[j];
 241       var xv = parseFloat(item[0]);
 242       var yv = parseFloat(item[1]);
 243
 244       if (xv == this.points[i].xval &&
 245           yv == this.points[i].yval) {
 246         this.points[i].errorMinus = parseFloat(item[2]);
 247         this.points[i].errorPlus = parseFloat(item[3]);
 248       }
 249     }
 250   }
 251 };
 252
 253 DygraphLayout.prototype._evaluateAnnotations = function() {
 254   // Add the annotations to the point to which they belong.
 255   // Make a map from (setName, xval) to annotation for quick lookups.
 256   var annotations = {};
 257   for (var i = 0; i < this.annotations.length; i++) {
 258     var a = this.annotations[i];
 259     annotations[a.xval + "," + a.series] = a;
 260   }
 261
 262   this.annotated_points = [];
 263
 264   // Exit the function early if there are no annotations.
 265   if (!this.annotations || !this.annotations.length) {
 266     return;
 267   }
 268
 269   // TODO(antrob): loop through annotations not points.
 270   for (var i = 0; i < this.points.length; i++) {
 271     var p = this.points[i];
 272     var k = p.xval + "," + p.name;
 273     if (k in annotations) {
 274       p.annotation = annotations[k];
 275       this.annotated_points.push(p);
 276     }
 277   }
 278 };
 279
 280 /**
 281  * Convenience function to remove all the data sets from a graph
 282  */
 283 DygraphLayout.prototype.removeAllDatasets = function() {
 284   delete this.datasets;
 285   this.datasets = new Array();
 286 };
 287
 288 /**
 289  * Return a copy of the point at the indicated index, with its yval unstacked.
 290  * @param int index of point in layout_.points
 291  */
 292 DygraphLayout.prototype.unstackPointAtIndex = function(idx) {
 293   var point = this.points[idx];
 294
 295   // Clone the point since we modify it
 296   var unstackedPoint = {};
 297   for (var i in point) {
 298     unstackedPoint[i] = point[i];
 299   }
 300
 301   if (!this.attr_("stackedGraph")) {
 302     return unstackedPoint;
 303   }
 304
 305   // The unstacked yval is equal to the current yval minus the yval of the
 306   // next point at the same xval.
 307   for (var i = idx+1; i < this.points.length; i++) {
 308     if (this.points[i].xval == point.xval) {
 309       unstackedPoint.yval -= this.points[i].yval;
 310       break;
 311     }
 312   }
 313
 314   return unstackedPoint;
 315 }