Merge pull request #240 from timeu/bugfix_upstream
[dygraphs.git] / 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 this.datasets = [];
35 this.setNames = [];
36 this.annotations = [];
37 this.yAxes_ = null;
38 this.points = null;
39
40 // TODO(danvk): it's odd that xTicks_ and yTicks_ are inputs, but xticks and
41 // yticks are outputs. Clean this up.
42 this.xTicks_ = null;
43 this.yTicks_ = null;
44 };
45
46 DygraphLayout.prototype.attr_ = function(name) {
47 return this.dygraph_.attr_(name);
48 };
49
50 DygraphLayout.prototype.addDataset = function(setname, set_xy) {
51 this.datasets.push(set_xy);
52 this.setNames.push(setname);
53 };
54
55 DygraphLayout.prototype.getPlotArea = function() {
56 return this.area_;
57 };
58
59 // Compute the box which the chart should be drawn in. This is the canvas's
60 // box, less space needed for axis and chart labels.
61 // NOTE: This should only be called by Dygraph.predraw_().
62 DygraphLayout.prototype.computePlotArea = function() {
63 var area = {
64 // TODO(danvk): per-axis setting.
65 x: 0,
66 y: 0
67 };
68
69 area.w = this.dygraph_.width_ - area.x - this.attr_('rightGap');
70 area.h = this.dygraph_.height_;
71
72 // Let plugins reserve space.
73 var e = {
74 chart_div: this.dygraph_.graphDiv,
75 reserveSpaceLeft: function(px) {
76 var r = {
77 x: area.x,
78 y: area.y,
79 w: px,
80 h: area.h
81 };
82 area.x += px;
83 area.w -= px;
84 return r;
85 },
86 reserveSpaceRight: function(px) {
87 var r = {
88 x: area.x + area.w - px,
89 y: area.y,
90 w: px,
91 h: area.h
92 };
93 area.w -= px;
94 return r;
95 },
96 reserveSpaceTop: function(px) {
97 var r = {
98 x: area.x,
99 y: area.y,
100 w: area.w,
101 h: px
102 };
103 area.y += px;
104 area.h -= px;
105 return r;
106 },
107 reserveSpaceBottom: function(px) {
108 var r = {
109 x: area.x,
110 y: area.y + area.h - px,
111 w: area.w,
112 h: px
113 };
114 area.h -= px;
115 return r;
116 },
117 chartRect: function() {
118 return {x:area.x, y:area.y, w:area.w, h:area.h};
119 }
120 };
121 this.dygraph_.cascadeEvents_('layout', e);
122
123 this.area_ = area;
124 };
125
126 DygraphLayout.prototype.setAnnotations = function(ann) {
127 // The Dygraph object's annotations aren't parsed. We parse them here and
128 // save a copy. If there is no parser, then the user must be using raw format.
129 this.annotations = [];
130 var parse = this.attr_('xValueParser') || function(x) { return x; };
131 for (var i = 0; i < ann.length; i++) {
132 var a = {};
133 if (!ann[i].xval && ann[i].x === undefined) {
134 this.dygraph_.error("Annotations must have an 'x' property");
135 return;
136 }
137 if (ann[i].icon &&
138 !(ann[i].hasOwnProperty('width') &&
139 ann[i].hasOwnProperty('height'))) {
140 this.dygraph_.error("Must set width and height when setting " +
141 "annotation.icon property");
142 return;
143 }
144 Dygraph.update(a, ann[i]);
145 if (!a.xval) a.xval = parse(a.x);
146 this.annotations.push(a);
147 }
148 };
149
150 DygraphLayout.prototype.setXTicks = function(xTicks) {
151 this.xTicks_ = xTicks;
152 };
153
154 // TODO(danvk): add this to the Dygraph object's API or move it into Layout.
155 DygraphLayout.prototype.setYAxes = function (yAxes) {
156 this.yAxes_ = yAxes;
157 };
158
159 DygraphLayout.prototype.setDateWindow = function(dateWindow) {
160 this.dateWindow_ = dateWindow;
161 };
162
163 DygraphLayout.prototype.evaluate = function() {
164 this._evaluateLimits();
165 this._evaluateLineCharts();
166 this._evaluateLineTicks();
167 this._evaluateAnnotations();
168 };
169
170 DygraphLayout.prototype._evaluateLimits = function() {
171 var xlimits = this.dygraph_.xAxisRange();
172 this.minxval = xlimits[0];
173 this.maxxval = xlimits[1];
174 var xrange = xlimits[1] - xlimits[0];
175 this.xscale = (xrange !== 0 ? 1 / xrange : 1.0);
176
177 for (var i = 0; i < this.yAxes_.length; i++) {
178 var axis = this.yAxes_[i];
179 axis.minyval = axis.computedValueRange[0];
180 axis.maxyval = axis.computedValueRange[1];
181 axis.yrange = axis.maxyval - axis.minyval;
182 axis.yscale = (axis.yrange !== 0 ? 1.0 / axis.yrange : 1.0);
183
184 if (axis.g.attr_("logscale")) {
185 axis.ylogrange = Dygraph.log10(axis.maxyval) - Dygraph.log10(axis.minyval);
186 axis.ylogscale = (axis.ylogrange !== 0 ? 1.0 / axis.ylogrange : 1.0);
187 if (!isFinite(axis.ylogrange) || isNaN(axis.ylogrange)) {
188 axis.g.error('axis ' + i + ' of graph at ' + axis.g +
189 ' can\'t be displayed in log scale for range [' +
190 axis.minyval + ' - ' + axis.maxyval + ']');
191 }
192 }
193 }
194 };
195
196 DygraphLayout._calcYNormal = function(axis, value, logscale) {
197 if (logscale) {
198 return 1.0 - ((Dygraph.log10(value) - Dygraph.log10(axis.minyval)) * axis.ylogscale);
199 } else {
200 return 1.0 - ((value - axis.minyval) * axis.yscale);
201 }
202 };
203
204 DygraphLayout.prototype._evaluateLineCharts = function() {
205 var connectSeparated = this.attr_('connectSeparatedPoints');
206
207 // series index -> point index in series -> |point| structure
208 this.points = new Array(this.datasets.length);
209
210 // TODO(bhs): these loops are a hot-spot for high-point-count charts. In fact,
211 // on chrome+linux, they are 6 times more expensive than iterating through the
212 // points and drawing the lines. The brunt of the cost comes from allocating
213 // the |point| structures.
214 var boundaryIdStart = 0;
215 if (this.dygraph_.boundaryIds_.length > 0) {
216 boundaryIdStart = this.dygraph_.boundaryIds_[this.dygraph_.boundaryIds_.length-1][0]
217 }
218 for (var setIdx = 0; setIdx < this.datasets.length; setIdx++) {
219 var dataset = this.datasets[setIdx];
220 var setName = this.setNames[setIdx];
221 var axis = this.dygraph_.axisPropertiesForSeries(setName);
222 // TODO (konigsberg): use optionsForAxis instead.
223 var logscale = this.dygraph_.attributes_.getForSeries("logscale", setName);
224
225 // Preallocating the size of points reduces reallocations, and therefore,
226 // calls to collect garbage.
227 var seriesPoints = new Array(dataset.length);
228
229 for (var j = 0; j < dataset.length; j++) {
230 var item = dataset[j];
231 var xValue = DygraphLayout.parseFloat_(item[0]);
232 var yValue = DygraphLayout.parseFloat_(item[1]);
233
234 // Range from 0-1 where 0 represents left and 1 represents right.
235 var xNormal = (xValue - this.minxval) * this.xscale;
236 // Range from 0-1 where 0 represents top and 1 represents bottom
237 var yNormal = DygraphLayout._calcYNormal(axis, yValue, logscale);
238
239 // TODO(danvk): drop the point in this case, don't null it.
240 // The nulls create complexity in DygraphCanvasRenderer._drawSeries.
241 if (connectSeparated && item[1] === null) {
242 yValue = null;
243 }
244 seriesPoints[j] = {
245 x: xNormal,
246 y: yNormal,
247 xval: xValue,
248 yval: yValue,
249 name: setName, // TODO(danvk): is this really necessary?
250 idx: j + boundaryIdStart
251 };
252 }
253
254 this.points[setIdx] = seriesPoints;
255 }
256 };
257
258 /**
259 * Optimized replacement for parseFloat, which was way too slow when almost
260 * all values were type number, with few edge cases, none of which were strings.
261 */
262 DygraphLayout.parseFloat_ = function(val) {
263 // parseFloat(null) is NaN
264 if (val === null) {
265 return NaN;
266 }
267
268 // Assume it's a number or NaN. If it's something else, I'll be shocked.
269 return val;
270 };
271
272 DygraphLayout.prototype._evaluateLineTicks = function() {
273 var i, tick, label, pos;
274 this.xticks = [];
275 for (i = 0; i < this.xTicks_.length; i++) {
276 tick = this.xTicks_[i];
277 label = tick.label;
278 pos = this.xscale * (tick.v - this.minxval);
279 if ((pos >= 0.0) && (pos <= 1.0)) {
280 this.xticks.push([pos, label]);
281 }
282 }
283
284 this.yticks = [];
285 for (i = 0; i < this.yAxes_.length; i++ ) {
286 var axis = this.yAxes_[i];
287 for (var j = 0; j < axis.ticks.length; j++) {
288 tick = axis.ticks[j];
289 label = tick.label;
290 pos = this.dygraph_.toPercentYCoord(tick.v, i);
291 if ((pos >= 0.0) && (pos <= 1.0)) {
292 this.yticks.push([i, pos, label]);
293 }
294 }
295 }
296 };
297
298
299 /**
300 * Behaves the same way as PlotKit.Layout, but also copies the errors
301 * @private
302 */
303 DygraphLayout.prototype.evaluateWithError = function() {
304 this.evaluate();
305 if (!(this.attr_('errorBars') || this.attr_('customBars'))) return;
306
307 // Copy over the error terms
308 var i = 0; // index in this.points
309 for (var setIdx = 0; setIdx < this.datasets.length; ++setIdx) {
310 var points = this.points[setIdx];
311 var j = 0;
312 var dataset = this.datasets[setIdx];
313 var setName = this.setNames[setIdx];
314 var axis = this.dygraph_.axisPropertiesForSeries(setName);
315 // TODO (konigsberg): use optionsForAxis instead.
316 var logscale = this.dygraph_.attributes_.getForSeries("logscale", setName);
317
318 for (j = 0; j < dataset.length; j++, i++) {
319 var item = dataset[j];
320 var xv = DygraphLayout.parseFloat_(item[0]);
321 var yv = DygraphLayout.parseFloat_(item[1]);
322
323 if (xv == points[j].xval &&
324 yv == points[j].yval) {
325 var errorMinus = DygraphLayout.parseFloat_(item[2]);
326 var errorPlus = DygraphLayout.parseFloat_(item[3]);
327
328 var yv_minus = yv - errorMinus;
329 var yv_plus = yv + errorPlus;
330 points[j].y_top = DygraphLayout._calcYNormal(axis, yv_minus, logscale);
331 points[j].y_bottom = DygraphLayout._calcYNormal(axis, yv_plus, logscale);
332 }
333 }
334 }
335 };
336
337 DygraphLayout.prototype._evaluateAnnotations = function() {
338 // Add the annotations to the point to which they belong.
339 // Make a map from (setName, xval) to annotation for quick lookups.
340 var i;
341 var annotations = {};
342 for (i = 0; i < this.annotations.length; i++) {
343 var a = this.annotations[i];
344 annotations[a.xval + "," + a.series] = a;
345 }
346
347 this.annotated_points = [];
348
349 // Exit the function early if there are no annotations.
350 if (!this.annotations || !this.annotations.length) {
351 return;
352 }
353
354 // TODO(antrob): loop through annotations not points.
355 for (var setIdx = 0; setIdx < this.points.length; setIdx++) {
356 var points = this.points[setIdx];
357 for (i = 0; i < points.length; i++) {
358 var p = points[i];
359 var k = p.xval + "," + p.name;
360 if (k in annotations) {
361 p.annotation = annotations[k];
362 this.annotated_points.push(p);
363 }
364 }
365 }
366 };
367
368 /**
369 * Convenience function to remove all the data sets from a graph
370 */
371 DygraphLayout.prototype.removeAllDatasets = function() {
372 delete this.datasets;
373 delete this.setNames;
374 delete this.setPointsLengths;
375 delete this.setPointsOffsets;
376 this.datasets = [];
377 this.setNames = [];
378 this.setPointsLengths = [];
379 this.setPointsOffsets = [];
380 };
381
382 /**
383 * Return a copy of the point at the indicated index, with its yval unstacked.
384 * @param int index of point in layout_.points
385 */
386 DygraphLayout.prototype.unstackPointAtIndex = function(setIdx, row) {
387 var point = this.points[setIdx][row];
388 // If the point is missing, no unstacking is necessary
389 if (!Dygraph.isValidPoint(point)) {
390 return point;
391 }
392
393 // Clone the point since we modify it
394 var unstackedPoint = {};
395 for (var pt in point) {
396 unstackedPoint[pt] = point[pt];
397 }
398
399 if (!this.attr_("stackedGraph")) {
400 return unstackedPoint;
401 }
402
403 // The unstacked yval is equal to the current yval minus the yval of the
404 // next point at the same xval.
405 // We need to iterate over setIdx just in case some series have invalid values
406 // at current row
407 for(setIdx++; setIdx < this.points.length; setIdx++) {
408 var nextPoint = this.points[setIdx][row];
409 if (nextPoint.xval == point.xval && // should always be true?
410 Dygraph.isValidPoint(nextPoint)) {
411 unstackedPoint.yval -= nextPoint.yval;
412 break; // stop at first valid point
413 }
414 }
415
416 return unstackedPoint;
417 };