fix disappearing annotations bug
[dygraphs.git] / dygraph-tickers.js
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1// Copyright 2011 Google Inc. All Rights Reserved.
2// MIT-licensed (http://opensource.org/licenses/MIT)
3
4/**
5 * @fileoverview Description of this file.
6 * @author danvk@google.com (Dan Vanderkam)
7 *
8 * A ticker is a function with the following interface:
9 *
10 * function(a, b, pixels, options_view, dygraph, forced_values);
11 * -> [ { v: tick1_v, label: tick1_label[, label_v: label_v1] },
12 * { v: tick2_v, label: tick2_label[, label_v: label_v2] },
13 * ...
14 * ]
15 *
16 * The returned value is called a "tick list".
17 *
18 * Arguments
19 * ---------
20 *
21 * [a, b] is the range of the axis for which ticks are being generated. For a
22 * numeric axis, these will simply be numbers. For a date axis, these will be
23 * millis since epoch (convertable to Date objects using "new Date(a)" and "new
24 * Date(b)").
25 *
26 * opts provides access to chart- and axis-specific options. It can be used to
27 * access number/date formatting code/options, check for a log scale, etc.
28 *
29 * pixels is the length of the axis in pixels. opts('pixelsPerLabel') is the
30 * minimum amount of space to be allotted to each label. For instance, if
31 * pixels=400 and opts('pixelsPerLabel')=40 then the ticker should return
32 * between zero and ten (400/40) ticks.
33 *
34 * dygraph is the Dygraph object for which an axis is being constructed.
35 *
36 * forced_values is used for secondary y-axes. The tick positions are typically
37 * set by the primary y-axis, so the secondary y-axis has no choice in where to
38 * put these. It simply has to generate labels for these data values.
39 *
40 * Tick lists
41 * ----------
42 * Typically a tick will have both a grid/tick line and a label at one end of
43 * that line (at the bottom for an x-axis, at left or right for the y-axis).
44 *
45 * A tick may be missing one of these two components:
46 * - If "label_v" is specified instead of "v", then there will be no tick or
47 * gridline, just a label.
48 * - Similarly, if "label" is not specified, then there will be a gridline
49 * without a label.
50 *
51 * This flexibility is useful in a few situations:
52 * - For log scales, some of the tick lines may be too close to all have labels.
53 * - For date scales where years are being displayed, it is desirable to display
54 * tick marks at the beginnings of years but labels (e.g. "2006") in the
55 * middle of the years.
56 */
57
58Dygraph.numericTicks = function(a, b, pixels, opts, dygraph, vals) {
59 var pixels_per_tick = opts('pixelsPerLabel');
60 var ticks = [];
61 if (vals) {
62 for (var i = 0; i < vals.length; i++) {
63 ticks.push({v: vals[i]});
64 }
65 } else {
66 // TODO(danvk): factor this log-scale block out into a separate function.
67 if (opts("logscale")) {
68 var nTicks = Math.floor(pixels / pixels_per_tick);
69 var minIdx = Dygraph.binarySearch(a, Dygraph.PREFERRED_LOG_TICK_VALUES, 1);
70 var maxIdx = Dygraph.binarySearch(b, Dygraph.PREFERRED_LOG_TICK_VALUES, -1);
71 if (minIdx == -1) {
72 minIdx = 0;
73 }
74 if (maxIdx == -1) {
75 maxIdx = Dygraph.PREFERRED_LOG_TICK_VALUES.length - 1;
76 }
77 // Count the number of tick values would appear, if we can get at least
78 // nTicks / 4 accept them.
79 var lastDisplayed = null;
80 if (maxIdx - minIdx >= nTicks / 4) {
81 for (var idx = maxIdx; idx >= minIdx; idx--) {
82 var tickValue = Dygraph.PREFERRED_LOG_TICK_VALUES[idx];
83 var pixel_coord = Math.log(tickValue / a) / Math.log(b / a) * pixels;
84 var tick = { v: tickValue };
85 if (lastDisplayed == null) {
86 lastDisplayed = {
87 tickValue : tickValue,
88 pixel_coord : pixel_coord
89 };
90 } else {
91 if (Math.abs(pixel_coord - lastDisplayed.pixel_coord) >= pixels_per_tick) {
92 lastDisplayed = {
93 tickValue : tickValue,
94 pixel_coord : pixel_coord
95 };
96 } else {
97 tick.label = "";
98 }
99 }
100 ticks.push(tick);
101 }
102 // Since we went in backwards order.
103 ticks.reverse();
104 }
105 }
106
107 // ticks.length won't be 0 if the log scale function finds values to insert.
108 if (ticks.length == 0) {
109 // Basic idea:
110 // Try labels every 1, 2, 5, 10, 20, 50, 100, etc.
111 // Calculate the resulting tick spacing (i.e. this.height_ / nTicks).
112 // The first spacing greater than pixelsPerYLabel is what we use.
113 // TODO(danvk): version that works on a log scale.
114 var kmg2 = opts("labelsKMG2");
115 if (kmg2) {
116 var mults = [1, 2, 4, 8];
117 } else {
118 var mults = [1, 2, 5];
119 }
120 var scale, low_val, high_val, nTicks;
121 for (var i = -10; i < 50; i++) {
122 if (kmg2) {
123 var base_scale = Math.pow(16, i);
124 } else {
125 var base_scale = Math.pow(10, i);
126 }
127 for (var j = 0; j < mults.length; j++) {
128 scale = base_scale * mults[j];
129 low_val = Math.floor(a / scale) * scale;
130 high_val = Math.ceil(b / scale) * scale;
131 nTicks = Math.abs(high_val - low_val) / scale;
132 var spacing = pixels / nTicks;
133 // wish I could break out of both loops at once...
134 if (spacing > pixels_per_tick) break;
135 }
136 if (spacing > pixels_per_tick) break;
137 }
138
139 // Construct the set of ticks.
140 // Allow reverse y-axis if it's explicitly requested.
141 if (low_val > high_val) scale *= -1;
142 for (var i = 0; i < nTicks; i++) {
143 var tickV = low_val + i * scale;
144 ticks.push( {v: tickV} );
145 }
146 }
147 }
148
149 // Add formatted labels to the ticks.
150 var k;
151 var k_labels = [];
152 if (opts("labelsKMB")) {
153 k = 1000;
154 k_labels = [ "K", "M", "B", "T" ];
155 }
156 if (opts("labelsKMG2")) {
157 if (k) self.warn("Setting both labelsKMB and labelsKMG2. Pick one!");
158 k = 1024;
159 k_labels = [ "k", "M", "G", "T" ];
160 }
161
162 var formatter = opts('axisLabelFormatter');
163
164 // Add labels to the ticks.
165 for (var i = 0; i < ticks.length; i++) {
166 if (ticks[i].label !== undefined) continue; // Use current label.
167 var tickV = ticks[i].v;
168 var absTickV = Math.abs(tickV);
169 // TODO(danvk): set granularity to something appropriate here.
170 var label = formatter(tickV, 0, opts, dygraph);
171 if (k_labels.length > 0) {
172 // TODO(danvk): should this be integrated into the axisLabelFormatter?
173 // Round up to an appropriate unit.
174 var n = k*k*k*k;
175 for (var j = 3; j >= 0; j--, n /= k) {
176 if (absTickV >= n) {
177 label = Dygraph.round_(tickV / n, opts('digitsAfterDecimal')) +
178 k_labels[j];
179 break;
180 }
181 }
182 }
183 ticks[i].label = label;
184 }
185
186 return ticks;
187};
188
189
190Dygraph.dateTicker = function(a, b, pixels, opts, dygraph, vals) {
191 var pixels_per_tick = opts('pixelsPerLabel');
192 var chosen = -1;
193 for (var i = 0; i < Dygraph.NUM_GRANULARITIES; i++) {
194 var num_ticks = Dygraph.numDateTicks(a, b, i);
195 if (pixels / num_ticks >= pixels_per_tick) {
196 chosen = i;
197 break;
198 }
199 }
200
201 if (chosen >= 0) {
202 return Dygraph.getDateAxis(a, b, chosen, opts, dygraph);
203 } else {
204 // this can happen if self.width_ is zero.
205 return [];
206 }
207};
208
209// Time granularity enumeration
210Dygraph.SECONDLY = 0;
211Dygraph.TWO_SECONDLY = 1;
212Dygraph.FIVE_SECONDLY = 2;
213Dygraph.TEN_SECONDLY = 3;
214Dygraph.THIRTY_SECONDLY = 4;
215Dygraph.MINUTELY = 5;
216Dygraph.TWO_MINUTELY = 6;
217Dygraph.FIVE_MINUTELY = 7;
218Dygraph.TEN_MINUTELY = 8;
219Dygraph.THIRTY_MINUTELY = 9;
220Dygraph.HOURLY = 10;
221Dygraph.TWO_HOURLY = 11;
222Dygraph.SIX_HOURLY = 12;
223Dygraph.DAILY = 13;
224Dygraph.WEEKLY = 14;
225Dygraph.MONTHLY = 15;
226Dygraph.QUARTERLY = 16;
227Dygraph.BIANNUAL = 17;
228Dygraph.ANNUAL = 18;
229Dygraph.DECADAL = 19;
230Dygraph.CENTENNIAL = 20;
231Dygraph.NUM_GRANULARITIES = 21;
232
233Dygraph.SHORT_SPACINGS = [];
234Dygraph.SHORT_SPACINGS[Dygraph.SECONDLY] = 1000 * 1;
235Dygraph.SHORT_SPACINGS[Dygraph.TWO_SECONDLY] = 1000 * 2;
236Dygraph.SHORT_SPACINGS[Dygraph.FIVE_SECONDLY] = 1000 * 5;
237Dygraph.SHORT_SPACINGS[Dygraph.TEN_SECONDLY] = 1000 * 10;
238Dygraph.SHORT_SPACINGS[Dygraph.THIRTY_SECONDLY] = 1000 * 30;
239Dygraph.SHORT_SPACINGS[Dygraph.MINUTELY] = 1000 * 60;
240Dygraph.SHORT_SPACINGS[Dygraph.TWO_MINUTELY] = 1000 * 60 * 2;
241Dygraph.SHORT_SPACINGS[Dygraph.FIVE_MINUTELY] = 1000 * 60 * 5;
242Dygraph.SHORT_SPACINGS[Dygraph.TEN_MINUTELY] = 1000 * 60 * 10;
243Dygraph.SHORT_SPACINGS[Dygraph.THIRTY_MINUTELY] = 1000 * 60 * 30;
244Dygraph.SHORT_SPACINGS[Dygraph.HOURLY] = 1000 * 3600;
245Dygraph.SHORT_SPACINGS[Dygraph.TWO_HOURLY] = 1000 * 3600 * 2;
246Dygraph.SHORT_SPACINGS[Dygraph.SIX_HOURLY] = 1000 * 3600 * 6;
247Dygraph.SHORT_SPACINGS[Dygraph.DAILY] = 1000 * 86400;
248Dygraph.SHORT_SPACINGS[Dygraph.WEEKLY] = 1000 * 604800;
249
250/**
251 * @private
252 * This is a list of human-friendly values at which to show tick marks on a log
253 * scale. It is k * 10^n, where k=1..9 and n=-39..+39, so:
254 * ..., 1, 2, 3, 4, 5, ..., 9, 10, 20, 30, ..., 90, 100, 200, 300, ...
255 * NOTE: this assumes that Dygraph.LOG_SCALE = 10.
256 */
257Dygraph.PREFERRED_LOG_TICK_VALUES = function() {
258 var vals = [];
259 for (var power = -39; power <= 39; power++) {
260 var range = Math.pow(10, power);
261 for (var mult = 1; mult <= 9; mult++) {
262 var val = range * mult;
263 vals.push(val);
264 }
265 }
266 return vals;
267}();
268
269Dygraph.numDateTicks = function(start_time, end_time, granularity) {
270 if (granularity < Dygraph.MONTHLY) {
271 // Generate one tick mark for every fixed interval of time.
272 var spacing = Dygraph.SHORT_SPACINGS[granularity];
273 return Math.floor(0.5 + 1.0 * (end_time - start_time) / spacing);
274 } else {
275 var year_mod = 1; // e.g. to only print one point every 10 years.
276 var num_months = 12;
277 if (granularity == Dygraph.QUARTERLY) num_months = 3;
278 if (granularity == Dygraph.BIANNUAL) num_months = 2;
279 if (granularity == Dygraph.ANNUAL) num_months = 1;
280 if (granularity == Dygraph.DECADAL) { num_months = 1; year_mod = 10; }
281 if (granularity == Dygraph.CENTENNIAL) { num_months = 1; year_mod = 100; }
282
283 var msInYear = 365.2524 * 24 * 3600 * 1000;
284 var num_years = 1.0 * (end_time - start_time) / msInYear;
285 return Math.floor(0.5 + 1.0 * num_years * num_months / year_mod);
286 }
287};
288
289Dygraph.getDateAxis = function(start_time, end_time, granularity, opts, dg) {
290 var formatter = opts("axisLabelFormatter");
291 var ticks = [];
292 if (granularity < Dygraph.MONTHLY) {
293 // Generate one tick mark for every fixed interval of time.
294 var spacing = Dygraph.SHORT_SPACINGS[granularity];
295 var format = '%d%b'; // e.g. "1Jan"
296
297 // Find a time less than start_time which occurs on a "nice" time boundary
298 // for this granularity.
299 var g = spacing / 1000;
300 var d = new Date(start_time);
301 if (g <= 60) { // seconds
302 var x = d.getSeconds(); d.setSeconds(x - x % g);
303 } else {
304 d.setSeconds(0);
305 g /= 60;
306 if (g <= 60) { // minutes
307 var x = d.getMinutes(); d.setMinutes(x - x % g);
308 } else {
309 d.setMinutes(0);
310 g /= 60;
311
312 if (g <= 24) { // days
313 var x = d.getHours(); d.setHours(x - x % g);
314 } else {
315 d.setHours(0);
316 g /= 24;
317
318 if (g == 7) { // one week
319 d.setDate(d.getDate() - d.getDay());
320 }
321 }
322 }
323 }
324 start_time = d.getTime();
325
326 for (var t = start_time; t <= end_time; t += spacing) {
327 ticks.push({ v:t,
328 label: formatter(new Date(t), granularity, opts, dg)
329 });
330 }
331 } else {
332 // Display a tick mark on the first of a set of months of each year.
333 // Years get a tick mark iff y % year_mod == 0. This is useful for
334 // displaying a tick mark once every 10 years, say, on long time scales.
335 var months;
336 var year_mod = 1; // e.g. to only print one point every 10 years.
337
338 if (granularity == Dygraph.MONTHLY) {
339 months = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ];
340 } else if (granularity == Dygraph.QUARTERLY) {
341 months = [ 0, 3, 6, 9 ];
342 } else if (granularity == Dygraph.BIANNUAL) {
343 months = [ 0, 6 ];
344 } else if (granularity == Dygraph.ANNUAL) {
345 months = [ 0 ];
346 } else if (granularity == Dygraph.DECADAL) {
347 months = [ 0 ];
348 year_mod = 10;
349 } else if (granularity == Dygraph.CENTENNIAL) {
350 months = [ 0 ];
351 year_mod = 100;
352 } else {
353 Dygraph.warn("Span of dates is too long");
354 }
355
356 var start_year = new Date(start_time).getFullYear();
357 var end_year = new Date(end_time).getFullYear();
358 var zeropad = Dygraph.zeropad;
359 for (var i = start_year; i <= end_year; i++) {
360 if (i % year_mod != 0) continue;
361 for (var j = 0; j < months.length; j++) {
362 var date_str = i + "/" + zeropad(1 + months[j]) + "/01";
363 var t = Dygraph.dateStrToMillis(date_str);
364 if (t < start_time || t > end_time) continue;
365 ticks.push({ v:t,
366 label: formatter(new Date(t), granularity, opts, dg)
367 });
368 }
369 }
370 }
371
372 return ticks;
373};
374
375// These are set here so that this file can be included after dygraph.js.
376Dygraph.DEFAULT_ATTRS.axes.x.ticker = Dygraph.dateTicker;
377Dygraph.DEFAULT_ATTRS.axes.y.ticker = Dygraph.numericTicks;
378Dygraph.DEFAULT_ATTRS.axes.y2.ticker = Dygraph.numericTicks;