src/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 var DygraphLayout = (function() {
  13
  14 /*global Dygraph:false */
  15 "use strict";
  16
  17 /**
  18  * Creates a new DygraphLayout object.
  19  *
  20  * This class contains all the data to be charted.
  21  * It uses data coordinates, but also records the chart range (in data
  22  * coordinates) and hence is able to calculate percentage positions ('In this
  23  * view, Point A lies 25% down the x-axis.')
  24  *
  25  * Two things that it does not do are:
  26  * 1. Record pixel coordinates for anything.
  27  * 2. (oddly) determine anything about the layout of chart elements.
  28  *
  29  * The naming is a vestige of Dygraph's original PlotKit roots.
  30  *
  31  * @constructor
  32  */
  33 var DygraphLayout = function(dygraph) {
  34   this.dygraph_ = dygraph;
  35   /**
  36    * Array of points for each series.
  37    *
  38    * [series index][row index in series] = |Point| structure,
  39    * where series index refers to visible series only, and the
  40    * point index is for the reduced set of points for the current
  41    * zoom region (including one point just outside the window).
  42    * All points in the same row index share the same X value.
  43    *
  44    * @type {Array.<Array.<Dygraph.PointType>>}
  45    */
  46   this.points = [];
  47   this.setNames = [];
  48   this.annotations = [];
  49   this.yAxes_ = null;
  50
  51   // TODO(danvk): it's odd that xTicks_ and yTicks_ are inputs, but xticks and
  52   // yticks are outputs. Clean this up.
  53   this.xTicks_ = null;
  54   this.yTicks_ = null;
  55 };
  56
  57 /**
  58  * Add points for a single series.
  59  *
  60  * @param {string} setname Name of the series.
  61  * @param {Array.<Dygraph.PointType>} set_xy Points for the series.
  62  */
  63 DygraphLayout.prototype.addDataset = function(setname, set_xy) {
  64   this.points.push(set_xy);
  65   this.setNames.push(setname);
  66 };
  67
  68 /**
  69  * Returns the box which the chart should be drawn in. This is the canvas's
  70  * box, less space needed for the axis and chart labels.
  71  *
  72  * @return {{x: number, y: number, w: number, h: number}}
  73  */
  74 DygraphLayout.prototype.getPlotArea = function() {
  75   return this.area_;
  76 };
  77
  78 // Compute the box which the chart should be drawn in. This is the canvas's
  79 // box, less space needed for axis, chart labels, and other plug-ins.
  80 // NOTE: This should only be called by Dygraph.predraw_().
  81 DygraphLayout.prototype.computePlotArea = function() {
  82   var area = {
  83     // TODO(danvk): per-axis setting.
  84     x: 0,
  85     y: 0
  86   };
  87
  88   area.w = this.dygraph_.width_ - area.x - this.dygraph_.getOption('rightGap');
  89   area.h = this.dygraph_.height_;
  90
  91   // Let plugins reserve space.
  92   var e = {
  93     chart_div: this.dygraph_.graphDiv,
  94     reserveSpaceLeft: function(px) {
  95       var r = {
  96         x: area.x,
  97         y: area.y,
  98         w: px,
  99         h: area.h
 100       };
 101       area.x += px;
 102       area.w -= px;
 103       return r;
 104     },
 105     reserveSpaceRight: function(px) {
 106       var r = {
 107         x: area.x + area.w - px,
 108         y: area.y,
 109         w: px,
 110         h: area.h
 111       };
 112       area.w -= px;
 113       return r;
 114     },
 115     reserveSpaceTop: function(px) {
 116       var r = {
 117         x: area.x,
 118         y: area.y,
 119         w: area.w,
 120         h: px
 121       };
 122       area.y += px;
 123       area.h -= px;
 124       return r;
 125     },
 126     reserveSpaceBottom: function(px) {
 127       var r = {
 128         x: area.x,
 129         y: area.y + area.h - px,
 130         w: area.w,
 131         h: px
 132       };
 133       area.h -= px;
 134       return r;
 135     },
 136     chartRect: function() {
 137       return {x:area.x, y:area.y, w:area.w, h:area.h};
 138     }
 139   };
 140   this.dygraph_.cascadeEvents_('layout', e);
 141
 142   this.area_ = area;
 143 };
 144
 145 DygraphLayout.prototype.setAnnotations = function(ann) {
 146   // The Dygraph object's annotations aren't parsed. We parse them here and
 147   // save a copy. If there is no parser, then the user must be using raw format.
 148   this.annotations = [];
 149   var parse = this.dygraph_.getOption('xValueParser') || function(x) { return x; };
 150   for (var i = 0; i < ann.length; i++) {
 151     var a = {};
 152     if (!ann[i].xval && ann[i].x === undefined) {
 153       console.error("Annotations must have an 'x' property");
 154       return;
 155     }
 156     if (ann[i].icon &&
 157         !(ann[i].hasOwnProperty('width') &&
 158           ann[i].hasOwnProperty('height'))) {
 159       console.error("Must set width and height when setting " +
 160                     "annotation.icon property");
 161       return;
 162     }
 163     Dygraph.update(a, ann[i]);
 164     if (!a.xval) a.xval = parse(a.x);
 165     this.annotations.push(a);
 166   }
 167 };
 168
 169 DygraphLayout.prototype.setXTicks = function(xTicks) {
 170   this.xTicks_ = xTicks;
 171 };
 172
 173 // TODO(danvk): add this to the Dygraph object's API or move it into Layout.
 174 DygraphLayout.prototype.setYAxes = function (yAxes) {
 175   this.yAxes_ = yAxes;
 176 };
 177
 178 DygraphLayout.prototype.evaluate = function() {
 179   this._xAxis = {};
 180   this._evaluateLimits();
 181   this._evaluateLineCharts();
 182   this._evaluateLineTicks();
 183   this._evaluateAnnotations();
 184 };
 185
 186 DygraphLayout.prototype._evaluateLimits = function() {
 187   var xlimits = this.dygraph_.xAxisRange();
 188   this._xAxis.minval = xlimits[0];
 189   this._xAxis.maxval = xlimits[1];
 190   var xrange = xlimits[1] - xlimits[0];
 191   this._xAxis.scale = (xrange !== 0 ? 1 / xrange : 1.0);
 192
 193   if (this.dygraph_.getOptionForAxis("logscale", 'x')) {
 194     this._xAxis.xlogrange = Dygraph.log10(this._xAxis.maxval) - Dygraph.log10(this._xAxis.minval);
 195     this._xAxis.xlogscale = (this._xAxis.xlogrange !== 0 ? 1.0 / this._xAxis.xlogrange : 1.0);
 196   }
 197   for (var i = 0; i < this.yAxes_.length; i++) {
 198     var axis = this.yAxes_[i];
 199     axis.minyval = axis.computedValueRange[0];
 200     axis.maxyval = axis.computedValueRange[1];
 201     axis.yrange = axis.maxyval - axis.minyval;
 202     axis.yscale = (axis.yrange !== 0 ? 1.0 / axis.yrange : 1.0);
 203
 204     if (this.dygraph_.getOption("logscale")) {
 205       axis.ylogrange = Dygraph.log10(axis.maxyval) - Dygraph.log10(axis.minyval);
 206       axis.ylogscale = (axis.ylogrange !== 0 ? 1.0 / axis.ylogrange : 1.0);
 207       if (!isFinite(axis.ylogrange) || isNaN(axis.ylogrange)) {
 208         console.error('axis ' + i + ' of graph at ' + axis.g +
 209                       ' can\'t be displayed in log scale for range [' +
 210                       axis.minyval + ' - ' + axis.maxyval + ']');
 211       }
 212     }
 213   }
 214 };
 215
 216 DygraphLayout.calcXNormal_ = function(value, xAxis, logscale) {
 217   if (logscale) {
 218     return ((Dygraph.log10(value) - Dygraph.log10(xAxis.minval)) * xAxis.xlogscale);
 219   } else {
 220     return (value - xAxis.minval) * xAxis.scale;
 221   }
 222 };
 223
 224 /**
 225  * @param {DygraphAxisType} axis
 226  * @param {number} value
 227  * @param {boolean} logscale
 228  * @return {number}
 229  */
 230 DygraphLayout.calcYNormal_ = function(axis, value, logscale) {
 231   if (logscale) {
 232     var x = 1.0 - ((Dygraph.log10(value) - Dygraph.log10(axis.minyval)) * axis.ylogscale);
 233     return isFinite(x) ? x : NaN;  // shim for v8 issue; see pull request 276
 234   } else {
 235     return 1.0 - ((value - axis.minyval) * axis.yscale);
 236   }
 237 };
 238
 239 DygraphLayout.prototype._evaluateLineCharts = function() {
 240   var isStacked = this.dygraph_.getOption("stackedGraph");
 241   var isLogscaleForX = this.dygraph_.getOptionForAxis("logscale", 'x');
 242
 243   for (var setIdx = 0; setIdx < this.points.length; setIdx++) {
 244     var points = this.points[setIdx];
 245     var setName = this.setNames[setIdx];
 246     var connectSeparated = this.dygraph_.getOption('connectSeparatedPoints', setName);
 247     var axis = this.dygraph_.axisPropertiesForSeries(setName);
 248     // TODO (konigsberg): use optionsForAxis instead.
 249     var logscale = this.dygraph_.attributes_.getForSeries("logscale", setName);
 250
 251     for (var j = 0; j < points.length; j++) {
 252       var point = points[j];
 253
 254       // Range from 0-1 where 0 represents left and 1 represents right.
 255       point.x = DygraphLayout.calcXNormal_(point.xval, this._xAxis, isLogscaleForX);
 256       // Range from 0-1 where 0 represents top and 1 represents bottom
 257       var yval = point.yval;
 258       if (isStacked) {
 259         point.y_stacked = DygraphLayout.calcYNormal_(
 260             axis, point.yval_stacked, logscale);
 261         if (yval !== null && !isNaN(yval)) {
 262           yval = point.yval_stacked;
 263         }
 264       }
 265       if (yval === null) {
 266         yval = NaN;
 267         if (!connectSeparated) {
 268           point.yval = NaN;
 269         }
 270       }
 271       point.y = DygraphLayout.calcYNormal_(axis, yval, logscale);
 272     }
 273
 274     this.dygraph_.dataHandler_.onLineEvaluated(points, axis, logscale);
 275   }
 276 };
 277
 278 DygraphLayout.prototype._evaluateLineTicks = function() {
 279   var i, tick, label, pos;
 280   this.xticks = [];
 281   for (i = 0; i < this.xTicks_.length; i++) {
 282     tick = this.xTicks_[i];
 283     label = tick.label;
 284     pos = this.dygraph_.toPercentXCoord(tick.v);
 285     if ((pos >= 0.0) && (pos < 1.0)) {
 286       this.xticks.push([pos, label]);
 287     }
 288   }
 289
 290   this.yticks = [];
 291   for (i = 0; i < this.yAxes_.length; i++ ) {
 292     var axis = this.yAxes_[i];
 293     for (var j = 0; j < axis.ticks.length; j++) {
 294       tick = axis.ticks[j];
 295       label = tick.label;
 296       pos = this.dygraph_.toPercentYCoord(tick.v, i);
 297       if ((pos > 0.0) && (pos <= 1.0)) {
 298         this.yticks.push([i, pos, label]);
 299       }
 300     }
 301   }
 302 };
 303
 304 DygraphLayout.prototype._evaluateAnnotations = function() {
 305   // Add the annotations to the point to which they belong.
 306   // Make a map from (setName, xval) to annotation for quick lookups.
 307   var i;
 308   var annotations = {};
 309   for (i = 0; i < this.annotations.length; i++) {
 310     var a = this.annotations[i];
 311     annotations[a.xval + "," + a.series] = a;
 312   }
 313
 314   this.annotated_points = [];
 315
 316   // Exit the function early if there are no annotations.
 317   if (!this.annotations || !this.annotations.length) {
 318     return;
 319   }
 320
 321   // TODO(antrob): loop through annotations not points.
 322   for (var setIdx = 0; setIdx < this.points.length; setIdx++) {
 323     var points = this.points[setIdx];
 324     for (i = 0; i < points.length; i++) {
 325       var p = points[i];
 326       var k = p.xval + "," + p.name;
 327       if (k in annotations) {
 328         p.annotation = annotations[k];
 329         this.annotated_points.push(p);
 330       }
 331     }
 332   }
 333 };
 334
 335 /**
 336  * Convenience function to remove all the data sets from a graph
 337  */
 338 DygraphLayout.prototype.removeAllDatasets = function() {
 339   delete this.points;
 340   delete this.setNames;
 341   delete this.setPointsLengths;
 342   delete this.setPointsOffsets;
 343   this.points = [];
 344   this.setNames = [];
 345   this.setPointsLengths = [];
 346   this.setPointsOffsets = [];
 347 };
 348
 349 return DygraphLayout;
 350
 351 })();