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 DygraphLayout.prototype.attr_ = function(name) {
  57   return this.dygraph_.attr_(name);
  58 };
  59
  60 /**
  61  * Add points for a single series.
  62  *
  63  * @param {string} setname Name of the series.
  64  * @param {Array.<Dygraph.PointType>} set_xy Points for the series.
  65  */
  66 DygraphLayout.prototype.addDataset = function(setname, set_xy) {
  67   this.points.push(set_xy);
  68   this.setNames.push(setname);
  69 };
  70
  71 /**
  72  * Returns the box which the chart should be drawn in. This is the canvas's
  73  * box, less space needed for the axis and chart labels.
  74  *
  75  * @return {{x: number, y: number, w: number, h: number}}
  76  */
  77 DygraphLayout.prototype.getPlotArea = function() {
  78   return this.area_;
  79 };
  80
  81 // Compute the box which the chart should be drawn in. This is the canvas's
  82 // box, less space needed for axis, chart labels, and other plug-ins.
  83 // NOTE: This should only be called by Dygraph.predraw_().
  84 DygraphLayout.prototype.computePlotArea = function() {
  85   var area = {
  86     // TODO(danvk): per-axis setting.
  87     x: 0,
  88     y: 0
  89   };
  90
  91   area.w = this.dygraph_.width_ - area.x - this.attr_('rightGap');
  92   area.h = this.dygraph_.height_;
  93
  94   // Let plugins reserve space.
  95   var e = {
  96     chart_div: this.dygraph_.graphDiv,
  97     reserveSpaceLeft: function(px) {
  98       var r = {
  99         x: area.x,
 100         y: area.y,
 101         w: px,
 102         h: area.h
 103       };
 104       area.x += px;
 105       area.w -= px;
 106       return r;
 107     },
 108     reserveSpaceRight: function(px) {
 109       var r = {
 110         x: area.x + area.w - px,
 111         y: area.y,
 112         w: px,
 113         h: area.h
 114       };
 115       area.w -= px;
 116       return r;
 117     },
 118     reserveSpaceTop: function(px) {
 119       var r = {
 120         x: area.x,
 121         y: area.y,
 122         w: area.w,
 123         h: px
 124       };
 125       area.y += px;
 126       area.h -= px;
 127       return r;
 128     },
 129     reserveSpaceBottom: function(px) {
 130       var r = {
 131         x: area.x,
 132         y: area.y + area.h - px,
 133         w: area.w,
 134         h: px
 135       };
 136       area.h -= px;
 137       return r;
 138     },
 139     chartRect: function() {
 140       return {x:area.x, y:area.y, w:area.w, h:area.h};
 141     }
 142   };
 143   this.dygraph_.cascadeEvents_('layout', e);
 144
 145   this.area_ = area;
 146 };
 147
 148 DygraphLayout.prototype.setAnnotations = function(ann) {
 149   // The Dygraph object's annotations aren't parsed. We parse them here and
 150   // save a copy. If there is no parser, then the user must be using raw format.
 151   this.annotations = [];
 152   var parse = this.attr_('xValueParser') || function(x) { return x; };
 153   for (var i = 0; i < ann.length; i++) {
 154     var a = {};
 155     if (!ann[i].xval && ann[i].x === undefined) {
 156       this.dygraph_.error("Annotations must have an 'x' property");
 157       return;
 158     }
 159     if (ann[i].icon &&
 160         !(ann[i].hasOwnProperty('width') &&
 161           ann[i].hasOwnProperty('height'))) {
 162       this.dygraph_.error("Must set width and height when setting " +
 163                           "annotation.icon property");
 164       return;
 165     }
 166     Dygraph.update(a, ann[i]);
 167     if (!a.xval) a.xval = parse(a.x);
 168     this.annotations.push(a);
 169   }
 170 };
 171
 172 DygraphLayout.prototype.setXTicks = function(xTicks) {
 173   this.xTicks_ = xTicks;
 174 };
 175
 176 // TODO(danvk): add this to the Dygraph object's API or move it into Layout.
 177 DygraphLayout.prototype.setYAxes = function (yAxes) {
 178   this.yAxes_ = yAxes;
 179 };
 180
 181 DygraphLayout.prototype.evaluate = function() {
 182   this._evaluateLimits();
 183   this._evaluateLineCharts();
 184   this._evaluateLineTicks();
 185   this._evaluateAnnotations();
 186 };
 187
 188 DygraphLayout.prototype._evaluateLimits = function() {
 189   var xlimits = this.dygraph_.xAxisRange();
 190   this.minxval = xlimits[0];
 191   this.maxxval = xlimits[1];
 192   var xrange = xlimits[1] - xlimits[0];
 193   this.xscale = (xrange !== 0 ? 1 / xrange : 1.0);
 194
 195   for (var i = 0; i < this.yAxes_.length; i++) {
 196     var axis = this.yAxes_[i];
 197     axis.minyval = axis.computedValueRange[0];
 198     axis.maxyval = axis.computedValueRange[1];
 199     axis.yrange = axis.maxyval - axis.minyval;
 200     axis.yscale = (axis.yrange !== 0 ? 1.0 / axis.yrange : 1.0);
 201
 202     if (axis.g.attr_("logscale")) {
 203       axis.ylogrange = Dygraph.log10(axis.maxyval) - Dygraph.log10(axis.minyval);
 204       axis.ylogscale = (axis.ylogrange !== 0 ? 1.0 / axis.ylogrange : 1.0);
 205       if (!isFinite(axis.ylogrange) || isNaN(axis.ylogrange)) {
 206         axis.g.error('axis ' + i + ' of graph at ' + axis.g +
 207             ' can\'t be displayed in log scale for range [' +
 208             axis.minyval + ' - ' + axis.maxyval + ']');
 209       }
 210     }
 211   }
 212 };
 213
 214 DygraphLayout._calcYNormal = function(axis, value, logscale) {
 215   if (logscale) {
 216     return 1.0 - ((Dygraph.log10(value) - Dygraph.log10(axis.minyval)) * axis.ylogscale);
 217   } else {
 218     return 1.0 - ((value - axis.minyval) * axis.yscale);
 219   }
 220 };
 221
 222 DygraphLayout.prototype._evaluateLineCharts = function() {
 223   var connectSeparated = this.attr_('connectSeparatedPoints');
 224   var isStacked = this.attr_("stackedGraph");
 225
 226   for (var setIdx = 0; setIdx < this.points.length; setIdx++) {
 227     var points = this.points[setIdx];
 228     var setName = this.setNames[setIdx];
 229     var axis = this.dygraph_.axisPropertiesForSeries(setName);
 230     // TODO (konigsberg): use optionsForAxis instead.
 231     var logscale = this.dygraph_.attributes_.getForSeries("logscale", setName);
 232
 233     for (var j = 0; j < points.length; j++) {
 234       var point = points[j];
 235
 236       // Range from 0-1 where 0 represents left and 1 represents right.
 237       point.x = (point.xval - this.minxval) * this.xscale;
 238       // Range from 0-1 where 0 represents top and 1 represents bottom
 239       var yval = point.yval;
 240       if (isStacked) {
 241         point.y_stacked = DygraphLayout._calcYNormal(
 242             axis, point.yval_stacked, logscale);
 243         if (yval !== null && !isNaN(yval)) {
 244           yval = point.yval_stacked;
 245         }
 246       }
 247       if (yval === null) {
 248         yval = NaN;
 249         if (!connectSeparated) {
 250           point.yval = NaN;
 251         }
 252       }
 253       point.y = DygraphLayout._calcYNormal(axis, yval, logscale);
 254     }
 255
 256     this.dygraph_.dataHandler_.onLineEvaluated(points, axis, logscale);
 257   }
 258 };
 259
 260 /**
 261  * Optimized replacement for parseFloat, which was way too slow when almost
 262  * all values were type number, with few edge cases, none of which were strings.
 263  */
 264 DygraphLayout.parseFloat_ = function(val) {
 265   // parseFloat(null) is NaN
 266   if (val === null) {
 267     return NaN;
 268   }
 269
 270   // Assume it's a number or NaN. If it's something else, I'll be shocked.
 271   return val;
 272 };
 273
 274 DygraphLayout.prototype._evaluateLineTicks = function() {
 275   var i, tick, label, pos;
 276   this.xticks = [];
 277   for (i = 0; i < this.xTicks_.length; i++) {
 278     tick = this.xTicks_[i];
 279     label = tick.label;
 280     pos = this.xscale * (tick.v - this.minxval);
 281     if ((pos >= 0.0) && (pos <= 1.0)) {
 282       this.xticks.push([pos, label]);
 283     }
 284   }
 285
 286   this.yticks = [];
 287   for (i = 0; i < this.yAxes_.length; i++ ) {
 288     var axis = this.yAxes_[i];
 289     for (var j = 0; j < axis.ticks.length; j++) {
 290       tick = axis.ticks[j];
 291       label = tick.label;
 292       pos = this.dygraph_.toPercentYCoord(tick.v, i);
 293       if ((pos >= 0.0) && (pos <= 1.0)) {
 294         this.yticks.push([i, pos, label]);
 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 i;
 304   var annotations = {};
 305   for (i = 0; i < this.annotations.length; i++) {
 306     var a = this.annotations[i];
 307     annotations[a.xval + "," + a.series] = a;
 308   }
 309
 310   this.annotated_points = [];
 311
 312   // Exit the function early if there are no annotations.
 313   if (!this.annotations || !this.annotations.length) {
 314     return;
 315   }
 316
 317   // TODO(antrob): loop through annotations not points.
 318   for (var setIdx = 0; setIdx < this.points.length; setIdx++) {
 319     var points = this.points[setIdx];
 320     for (i = 0; i < points.length; i++) {
 321       var p = points[i];
 322       var k = p.xval + "," + p.name;
 323       if (k in annotations) {
 324         p.annotation = annotations[k];
 325         this.annotated_points.push(p);
 326       }
 327     }
 328   }
 329 };
 330
 331 /**
 332  * Convenience function to remove all the data sets from a graph
 333  */
 334 DygraphLayout.prototype.removeAllDatasets = function() {
 335   delete this.points;
 336   delete this.setNames;
 337   delete this.setPointsLengths;
 338   delete this.setPointsOffsets;
 339   this.points = [];
 340   this.setNames = [];
 341   this.setPointsLengths = [];
 342   this.setPointsOffsets = [];
 343 };