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[dygraphs.git] / dygraph-layout.js
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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/**
13 * Creates a new DygraphLayout object.
14 *
15 * This class contains all the data to be charted.
16 * It uses data coordinates, but also records the chart range (in data
17 * coordinates) and hence is able to calculate percentage positions ('In this
18 * view, Point A lies 25% down the x-axis.')
19 *
20 * Two things that it does not do are:
21 * 1. Record pixel coordinates for anything.
22 * 2. (oddly) determine anything about the layout of chart elements.
23 *
24 * The naming is a vestige of Dygraph's original PlotKit roots.
25 *
26 * @constructor
27 */
28DygraphLayout = function(dygraph) {
29 this.dygraph_ = dygraph;
30 this.datasets = new Array();
31 this.annotations = new Array();
32 this.yAxes_ = null;
33
34 // TODO(danvk): it's odd that xTicks_ and yTicks_ are inputs, but xticks and
35 // yticks are outputs. Clean this up.
36 this.xTicks_ = null;
37 this.yTicks_ = null;
38};
39
40DygraphLayout.prototype.attr_ = function(name) {
41 return this.dygraph_.attr_(name);
42};
43
44DygraphLayout.prototype.addDataset = function(setname, set_xy) {
45 this.datasets[setname] = set_xy;
46};
47
48DygraphLayout.prototype.getPlotArea = function() {
49 return this.computePlotArea_();
50}
51
52// Compute the box which the chart should be drawn in. This is the canvas's
53// box, less space needed for axis and chart labels.
54DygraphLayout.prototype.computePlotArea_ = function() {
55 var area = {
56 // TODO(danvk): per-axis setting.
57 x: 0,
58 y: 0
59 };
60 if (this.attr_('drawYAxis')) {
61 area.x = this.attr_('yAxisLabelWidth') + 2 * this.attr_('axisTickSize');
62 }
63
64 area.w = this.dygraph_.width_ - area.x - this.attr_('rightGap');
65 area.h = this.dygraph_.height_;
66 if (this.attr_('drawXAxis')) {
67 if (this.attr_('xAxisHeight')) {
68 area.h -= this.attr_('xAxisHeight');
69 } else {
70 area.h -= this.attr_('axisLabelFontSize') + 2 * this.attr_('axisTickSize');
71 }
72 }
73
74 // Shrink the drawing area to accomodate additional y-axes.
75 if (this.dygraph_.numAxes() == 2) {
76 // TODO(danvk): per-axis setting.
77 area.w -= (this.attr_('yAxisLabelWidth') + 2 * this.attr_('axisTickSize'));
78 } else if (this.dygraph_.numAxes() > 2) {
79 this.dygraph_.error("Only two y-axes are supported at this time. (Trying " +
80 "to use " + this.dygraph_.numAxes() + ")");
81 }
82
83 // Add space for chart labels: title, xlabel and ylabel.
84 if (this.attr_('title')) {
85 area.h -= this.attr_('titleHeight');
86 area.y += this.attr_('titleHeight');
87 }
88 if (this.attr_('xlabel')) {
89 area.h -= this.attr_('xLabelHeight');
90 }
91 if (this.attr_('ylabel')) {
92 // It would make sense to shift the chart here to make room for the y-axis
93 // label, but the default yAxisLabelWidth is large enough that this results
94 // in overly-padded charts. The y-axis label should fit fine. If it
95 // doesn't, the yAxisLabelWidth option can be increased.
96 }
97
98 // Add space for range selector, if needed.
99 if (this.attr_('showRangeSelector')) {
100 area.h -= this.attr_('rangeSelectorHeight') + 4;
101 }
102
103 return area;
104};
105
106DygraphLayout.prototype.setAnnotations = function(ann) {
107 // The Dygraph object's annotations aren't parsed. We parse them here and
108 // save a copy. If there is no parser, then the user must be using raw format.
109 this.annotations = [];
110 var parse = this.attr_('xValueParser') || function(x) { return x; };
111 for (var i = 0; i < ann.length; i++) {
112 var a = {};
113 if (!ann[i].xval && !ann[i].x) {
114 this.dygraph_.error("Annotations must have an 'x' property");
115 return;
116 }
117 if (ann[i].icon &&
118 !(ann[i].hasOwnProperty('width') &&
119 ann[i].hasOwnProperty('height'))) {
120 this.dygraph_.error("Must set width and height when setting " +
121 "annotation.icon property");
122 return;
123 }
124 Dygraph.update(a, ann[i]);
125 if (!a.xval) a.xval = parse(a.x);
126 this.annotations.push(a);
127 }
128};
129
130DygraphLayout.prototype.setXTicks = function(xTicks) {
131 this.xTicks_ = xTicks;
132};
133
134// TODO(danvk): add this to the Dygraph object's API or move it into Layout.
135DygraphLayout.prototype.setYAxes = function (yAxes) {
136 this.yAxes_ = yAxes;
137};
138
139DygraphLayout.prototype.setDateWindow = function(dateWindow) {
140 this.dateWindow_ = dateWindow;
141};
142
143DygraphLayout.prototype.evaluate = function() {
144 this._evaluateLimits();
145 this._evaluateLineCharts();
146 this._evaluateLineTicks();
147 this._evaluateAnnotations();
148};
149
150DygraphLayout.prototype._evaluateLimits = function() {
151 this.minxval = this.maxxval = null;
152 if (this.dateWindow_) {
153 this.minxval = this.dateWindow_[0];
154 this.maxxval = this.dateWindow_[1];
155 } else {
156 for (var name in this.datasets) {
157 if (!this.datasets.hasOwnProperty(name)) continue;
158 var series = this.datasets[name];
159 if (series.length > 1) {
160 var x1 = series[0][0];
161 if (!this.minxval || x1 < this.minxval) this.minxval = x1;
162
163 var x2 = series[series.length - 1][0];
164 if (!this.maxxval || x2 > this.maxxval) this.maxxval = x2;
165 }
166 }
167 }
168 this.xrange = this.maxxval - this.minxval;
169 this.xscale = (this.xrange != 0 ? 1/this.xrange : 1.0);
170
171 for (var i = 0; i < this.yAxes_.length; i++) {
172 var axis = this.yAxes_[i];
173 axis.minyval = axis.computedValueRange[0];
174 axis.maxyval = axis.computedValueRange[1];
175 axis.yrange = axis.maxyval - axis.minyval;
176 axis.yscale = (axis.yrange != 0 ? 1.0 / axis.yrange : 1.0);
177
178 if (axis.g.attr_("logscale")) {
179 axis.ylogrange = Dygraph.log10(axis.maxyval) - Dygraph.log10(axis.minyval);
180 axis.ylogscale = (axis.ylogrange != 0 ? 1.0 / axis.ylogrange : 1.0);
181 if (!isFinite(axis.ylogrange) || isNaN(axis.ylogrange)) {
182 axis.g.error('axis ' + i + ' of graph at ' + axis.g +
183 ' can\'t be displayed in log scale for range [' +
184 axis.minyval + ' - ' + axis.maxyval + ']');
185 }
186 }
187 }
188};
189
190DygraphLayout._calcYNormal = function(axis, value) {
191 if (axis.logscale) {
192 return 1.0 - ((Dygraph.log10(value) - Dygraph.log10(axis.minyval)) * axis.ylogscale);
193 } else {
194 return 1.0 - ((value - axis.minyval) * axis.yscale);
195 }
196};
197
198DygraphLayout.prototype._evaluateLineCharts = function() {
199 // add all the rects
200 this.points = new Array();
201 // An array to keep track of how many points will be drawn for each set.
202 // This will allow for the canvas renderer to not have to check every point
203 // for every data set since the points are added in order of the sets in
204 // datasets.
205 this.setPointsLengths = new Array();
206
207 for (var setName in this.datasets) {
208 if (!this.datasets.hasOwnProperty(setName)) continue;
209
210 var dataset = this.datasets[setName];
211 var axis = this.dygraph_.axisPropertiesForSeries(setName);
212
213 var setPointsLength = 0;
214
215 for (var j = 0; j < dataset.length; j++) {
216 var item = dataset[j];
217 var xValue = parseFloat(dataset[j][0]);
218 var yValue = parseFloat(dataset[j][1]);
219
220 // Range from 0-1 where 0 represents left and 1 represents right.
221 var xNormal = (xValue - this.minxval) * this.xscale;
222 // Range from 0-1 where 0 represents top and 1 represents bottom
223 var yNormal = DygraphLayout._calcYNormal(axis, yValue);
224
225 var point = {
226 // TODO(danvk): here
227 x: xNormal,
228 y: yNormal,
229 xval: xValue,
230 yval: yValue,
231 name: setName
232 };
233 this.points.push(point);
234 setPointsLength += 1;
235 }
236 this.setPointsLengths.push(setPointsLength);
237 }
238};
239
240DygraphLayout.prototype._evaluateLineTicks = function() {
241 this.xticks = new Array();
242 for (var i = 0; i < this.xTicks_.length; i++) {
243 var tick = this.xTicks_[i];
244 var label = tick.label;
245 var pos = this.xscale * (tick.v - this.minxval);
246 if ((pos >= 0.0) && (pos <= 1.0)) {
247 this.xticks.push([pos, label]);
248 }
249 }
250
251 this.yticks = new Array();
252 for (var i = 0; i < this.yAxes_.length; i++ ) {
253 var axis = this.yAxes_[i];
254 for (var j = 0; j < axis.ticks.length; j++) {
255 var tick = axis.ticks[j];
256 var label = tick.label;
257 var pos = this.dygraph_.toPercentYCoord(tick.v, i);
258 if ((pos >= 0.0) && (pos <= 1.0)) {
259 this.yticks.push([i, pos, label]);
260 }
261 }
262 }
263};
264
265
266/**
267 * Behaves the same way as PlotKit.Layout, but also copies the errors
268 * @private
269 */
270DygraphLayout.prototype.evaluateWithError = function() {
271 this.evaluate();
272 if (!(this.attr_('errorBars') || this.attr_('customBars'))) return;
273
274 // Copy over the error terms
275 var i = 0; // index in this.points
276 for (var setName in this.datasets) {
277 if (!this.datasets.hasOwnProperty(setName)) continue;
278 var j = 0;
279 var dataset = this.datasets[setName];
280 var axis = this.dygraph_.axisPropertiesForSeries(setName);
281 for (var j = 0; j < dataset.length; j++, i++) {
282 var item = dataset[j];
283 var xv = parseFloat(item[0]);
284 var yv = parseFloat(item[1]);
285
286 if (xv == this.points[i].xval &&
287 yv == this.points[i].yval) {
288 var errorMinus = parseFloat(item[2]);
289 var errorPlus = parseFloat(item[3]);
290
291 var yv_minus = yv - errorMinus;
292 var yv_plus = yv + errorPlus;
293 this.points[i].y_top = DygraphLayout._calcYNormal(axis, yv_minus);
294 this.points[i].y_bottom = DygraphLayout._calcYNormal(axis, yv_plus);
295 }
296 }
297 }
298};
299
300DygraphLayout.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 annotations = {};
304 for (var i = 0; i < this.annotations.length; i++) {
305 var a = this.annotations[i];
306 annotations[a.xval + "," + a.series] = a;
307 }
308
309 this.annotated_points = [];
310
311 // Exit the function early if there are no annotations.
312 if (!this.annotations || !this.annotations.length) {
313 return;
314 }
315
316 // TODO(antrob): loop through annotations not points.
317 for (var i = 0; i < this.points.length; i++) {
318 var p = this.points[i];
319 var k = p.xval + "," + p.name;
320 if (k in annotations) {
321 p.annotation = annotations[k];
322 this.annotated_points.push(p);
323 }
324 }
325};
326
327/**
328 * Convenience function to remove all the data sets from a graph
329 */
330DygraphLayout.prototype.removeAllDatasets = function() {
331 delete this.datasets;
332 this.datasets = new Array();
333};
334
335/**
336 * Return a copy of the point at the indicated index, with its yval unstacked.
337 * @param int index of point in layout_.points
338 */
339DygraphLayout.prototype.unstackPointAtIndex = function(idx) {
340 var point = this.points[idx];
341
342 // Clone the point since we modify it
343 var unstackedPoint = {};
344 for (var i in point) {
345 unstackedPoint[i] = point[i];
346 }
347
348 if (!this.attr_("stackedGraph")) {
349 return unstackedPoint;
350 }
351
352 // The unstacked yval is equal to the current yval minus the yval of the
353 // next point at the same xval.
354 for (var i = idx+1; i < this.points.length; i++) {
355 if (this.points[i].xval == point.xval) {
356 unstackedPoint.yval -= this.points[i].yval;
357 break;
358 }
359 }
360
361 return unstackedPoint;
362}