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   /**
  35    * Array of points for each series.
  36    *
  37    * [series index][row index in series] = |Point| structure,
  38    * where series index refers to visible series only, and the
  39    * point index is for the reduced set of points for the current
  40    * zoom region (including one point just outside the window).
  41    * All points in the same row index share the same X value.
  42    *
  43    * @type {Array.<Array.<Dygraph.PointType>>}
  44    */
  45   this.points = [];
  46   this.setNames = [];
  47   this.annotations = [];
  48   this.yAxes_ = null;
  49
  50   // TODO(danvk): it's odd that xTicks_ and yTicks_ are inputs, but xticks and
  51   // yticks are outputs. Clean this up.
  52   this.xTicks_ = null;
  53   this.yTicks_ = null;
  54 };
  55
  56 /**
  57  * Add points for a single series.
  58  *
  59  * @param {string} setname Name of the series.
  60  * @param {Array.<Dygraph.PointType>} set_xy Points for the series.
  61  */
  62 DygraphLayout.prototype.addDataset = function(setname, set_xy) {
  63   this.points.push(set_xy);
  64   this.setNames.push(setname);
  65 };
  66
  67 /**
  68  * Returns the box which the chart should be drawn in. This is the canvas's
  69  * box, less space needed for the axis and chart labels.
  70  *
  71  * @return {{x: number, y: number, w: number, h: number}}
  72  */
  73 DygraphLayout.prototype.getPlotArea = function() {
  74   return this.area_;
  75 };
  76
  77 // Compute the box which the chart should be drawn in. This is the canvas's
  78 // box, less space needed for axis, chart labels, and other plug-ins.
  79 // NOTE: This should only be called by Dygraph.predraw_().
  80 DygraphLayout.prototype.computePlotArea = function() {
  81   var area = {
  82     // TODO(danvk): per-axis setting.
  83     x: 0,
  84     y: 0
  85   };
  86
  87   area.w = this.dygraph_.width_ - area.x - this.dygraph_.getOption('rightGap');
  88   area.h = this.dygraph_.height_;
  89
  90   // Let plugins reserve space.
  91   var e = {
  92     chart_div: this.dygraph_.graphDiv,
  93     reserveSpaceLeft: function(px) {
  94       var r = {
  95         x: area.x,
  96         y: area.y,
  97         w: px,
  98         h: area.h
  99       };
 100       area.x += px;
 101       area.w -= px;
 102       return r;
 103     },
 104     reserveSpaceRight: function(px) {
 105       var r = {
 106         x: area.x + area.w - px,
 107         y: area.y,
 108         w: px,
 109         h: area.h
 110       };
 111       area.w -= px;
 112       return r;
 113     },
 114     reserveSpaceTop: function(px) {
 115       var r = {
 116         x: area.x,
 117         y: area.y,
 118         w: area.w,
 119         h: px
 120       };
 121       area.y += px;
 122       area.h -= px;
 123       return r;
 124     },
 125     reserveSpaceBottom: function(px) {
 126       var r = {
 127         x: area.x,
 128         y: area.y + area.h - px,
 129         w: area.w,
 130         h: px
 131       };
 132       area.h -= px;
 133       return r;
 134     },
 135     chartRect: function() {
 136       return {x:area.x, y:area.y, w:area.w, h:area.h};
 137     }
 138   };
 139   this.dygraph_.cascadeEvents_('layout', e);
 140
 141   this.area_ = area;
 142 };
 143
 144 DygraphLayout.prototype.setAnnotations = function(ann) {
 145   // The Dygraph object's annotations aren't parsed. We parse them here and
 146   // save a copy. If there is no parser, then the user must be using raw format.
 147   this.annotations = [];
 148   var parse = this.dygraph_.getOption('xValueParser') || function(x) { return x; };
 149   for (var i = 0; i < ann.length; i++) {
 150     var a = {};
 151     if (!ann[i].xval && ann[i].x === undefined) {
 152       this.dygraph_.error("Annotations must have an 'x' property");
 153       return;
 154     }
 155     if (ann[i].icon &&
 156         !(ann[i].hasOwnProperty('width') &&
 157           ann[i].hasOwnProperty('height'))) {
 158       this.dygraph_.error("Must set width and height when setting " +
 159                           "annotation.icon property");
 160       return;
 161     }
 162     Dygraph.update(a, ann[i]);
 163     if (!a.xval) a.xval = parse(a.x);
 164     this.annotations.push(a);
 165   }
 166 };
 167
 168 DygraphLayout.prototype.setXTicks = function(xTicks) {
 169   this.xTicks_ = xTicks;
 170 };
 171
 172 // TODO(danvk): add this to the Dygraph object's API or move it into Layout.
 173 DygraphLayout.prototype.setYAxes = function (yAxes) {
 174   this.yAxes_ = yAxes;
 175 };
 176
 177 DygraphLayout.prototype.evaluate = function() {
 178   this._evaluateLimits();
 179   this._evaluateLineCharts();
 180   this._evaluateLineTicks();
 181   this._evaluateAnnotations();
 182 };
 183
 184 DygraphLayout.prototype._evaluateLimits = function() {
 185   var xlimits = this.dygraph_.xAxisRange();
 186   this.minxval = xlimits[0];
 187   this.maxxval = xlimits[1];
 188   var xrange = xlimits[1] - xlimits[0];
 189   this.xscale = (xrange !== 0 ? 1 / xrange : 1.0);
 190
 191   for (var i = 0; i < this.yAxes_.length; i++) {
 192     var axis = this.yAxes_[i];
 193     axis.minyval = axis.computedValueRange[0];
 194     axis.maxyval = axis.computedValueRange[1];
 195     axis.yrange = axis.maxyval - axis.minyval;
 196     axis.yscale = (axis.yrange !== 0 ? 1.0 / axis.yrange : 1.0);
 197
 198     if (axis.g.getOption("logscale")) {
 199       axis.ylogrange = Dygraph.log10(axis.maxyval) - Dygraph.log10(axis.minyval);
 200       axis.ylogscale = (axis.ylogrange !== 0 ? 1.0 / axis.ylogrange : 1.0);
 201       if (!isFinite(axis.ylogrange) || isNaN(axis.ylogrange)) {
 202         axis.g.error('axis ' + i + ' of graph at ' + axis.g +
 203             ' can\'t be displayed in log scale for range [' +
 204             axis.minyval + ' - ' + axis.maxyval + ']');
 205       }
 206     }
 207   }
 208 };
 209
 210 DygraphLayout._calcYNormal = function(axis, value, logscale) {
 211   if (logscale) {
 212     return 1.0 - ((Dygraph.log10(value) - Dygraph.log10(axis.minyval)) * axis.ylogscale);
 213   } else {
 214     return 1.0 - ((value - axis.minyval) * axis.yscale);
 215   }
 216 };
 217
 218 DygraphLayout.prototype._evaluateLineCharts = function() {
 219   var isStacked = this.dygraph_.getOption("stackedGraph");
 220
 221   for (var setIdx = 0; setIdx < this.points.length; setIdx++) {
 222     var points = this.points[setIdx];
 223     var setName = this.setNames[setIdx];
 224     var connectSeparated = this.dygraph_.getOption('connectSeparatedPoints', setName);
 225     var axis = this.dygraph_.axisPropertiesForSeries(setName);
 226     // TODO (konigsberg): use optionsForAxis instead.
 227     var logscale = this.dygraph_.attributes_.getForSeries("logscale", setName);
 228
 229     for (var j = 0; j < points.length; j++) {
 230       var point = points[j];
 231
 232       // Range from 0-1 where 0 represents left and 1 represents right.
 233       point.x = (point.xval - this.minxval) * this.xscale;
 234       // Range from 0-1 where 0 represents top and 1 represents bottom
 235       var yval = point.yval;
 236       if (isStacked) {
 237         point.y_stacked = DygraphLayout._calcYNormal(
 238             axis, point.yval_stacked, logscale);
 239         if (yval !== null && !isNaN(yval)) {
 240           yval = point.yval_stacked;
 241         }
 242       }
 243       if (yval === null) {
 244         yval = NaN;
 245         if (!connectSeparated) {
 246           point.yval = NaN;
 247         }
 248       }
 249       point.y = DygraphLayout._calcYNormal(axis, yval, logscale);
 250     }
 251
 252     this.dygraph_.dataHandler_.onLineEvaluated(points, axis, logscale);
 253   }
 254 };
 255
 256 /**
 257  * Optimized replacement for parseFloat, which was way too slow when almost
 258  * all values were type number, with few edge cases, none of which were strings.
 259  */
 260 DygraphLayout.parseFloat_ = function(val) {
 261   // parseFloat(null) is NaN
 262   if (val === null) {
 263     return NaN;
 264   }
 265
 266   // Assume it's a number or NaN. If it's something else, I'll be shocked.
 267   return val;
 268 };
 269
 270 DygraphLayout.prototype._evaluateLineTicks = function() {
 271   var i, tick, label, pos;
 272   this.xticks = [];
 273   for (i = 0; i < this.xTicks_.length; i++) {
 274     tick = this.xTicks_[i];
 275     label = tick.label;
 276     pos = this.xscale * (tick.v - this.minxval);
 277     if ((pos >= 0.0) && (pos <= 1.0)) {
 278       this.xticks.push([pos, label]);
 279     }
 280   }
 281
 282   this.yticks = [];
 283   for (i = 0; i < this.yAxes_.length; i++ ) {
 284     var axis = this.yAxes_[i];
 285     for (var j = 0; j < axis.ticks.length; j++) {
 286       tick = axis.ticks[j];
 287       label = tick.label;
 288       pos = this.dygraph_.toPercentYCoord(tick.v, i);
 289       if ((pos >= 0.0) && (pos <= 1.0)) {
 290         this.yticks.push([i, pos, label]);
 291       }
 292     }
 293   }
 294 };
 295
 296 DygraphLayout.prototype._evaluateAnnotations = function() {
 297   // Add the annotations to the point to which they belong.
 298   // Make a map from (setName, xval) to annotation for quick lookups.
 299   var i;
 300   var annotations = {};
 301   for (i = 0; i < this.annotations.length; i++) {
 302     var a = this.annotations[i];
 303     annotations[a.xval + "," + a.series] = a;
 304   }
 305
 306   this.annotated_points = [];
 307
 308   // Exit the function early if there are no annotations.
 309   if (!this.annotations || !this.annotations.length) {
 310     return;
 311   }
 312
 313   // TODO(antrob): loop through annotations not points.
 314   for (var setIdx = 0; setIdx < this.points.length; setIdx++) {
 315     var points = this.points[setIdx];
 316     for (i = 0; i < points.length; i++) {
 317       var p = points[i];
 318       var k = p.xval + "," + p.name;
 319       if (k in annotations) {
 320         p.annotation = annotations[k];
 321         this.annotated_points.push(p);
 322       }
 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.points;
 332   delete this.setNames;
 333   delete this.setPointsLengths;
 334   delete this.setPointsOffsets;
 335   this.points = [];
 336   this.setNames = [];
 337   this.setPointsLengths = [];
 338   this.setPointsOffsets = [];
 339 };