Fix Issue 279: Strange animations when zooming animations are enabled and double...
[dygraphs.git] / dygraph-tickers.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 Description of this file.
9 * @author danvk@google.com (Dan Vanderkam)
10 *
11 * A ticker is a function with the following interface:
12 *
13 * function(a, b, pixels, options_view, dygraph, forced_values);
14 * -> [ { v: tick1_v, label: tick1_label[, label_v: label_v1] },
15 * { v: tick2_v, label: tick2_label[, label_v: label_v2] },
16 * ...
17 * ]
18 *
19 * The returned value is called a "tick list".
20 *
21 * Arguments
22 * ---------
23 *
24 * [a, b] is the range of the axis for which ticks are being generated. For a
25 * numeric axis, these will simply be numbers. For a date axis, these will be
26 * millis since epoch (convertable to Date objects using "new Date(a)" and "new
27 * Date(b)").
28 *
29 * opts provides access to chart- and axis-specific options. It can be used to
30 * access number/date formatting code/options, check for a log scale, etc.
31 *
32 * pixels is the length of the axis in pixels. opts('pixelsPerLabel') is the
33 * minimum amount of space to be allotted to each label. For instance, if
34 * pixels=400 and opts('pixelsPerLabel')=40 then the ticker should return
35 * between zero and ten (400/40) ticks.
36 *
37 * dygraph is the Dygraph object for which an axis is being constructed.
38 *
39 * forced_values is used for secondary y-axes. The tick positions are typically
40 * set by the primary y-axis, so the secondary y-axis has no choice in where to
41 * put these. It simply has to generate labels for these data values.
42 *
43 * Tick lists
44 * ----------
45 * Typically a tick will have both a grid/tick line and a label at one end of
46 * that line (at the bottom for an x-axis, at left or right for the y-axis).
47 *
48 * A tick may be missing one of these two components:
49 * - If "label_v" is specified instead of "v", then there will be no tick or
50 * gridline, just a label.
51 * - Similarly, if "label" is not specified, then there will be a gridline
52 * without a label.
53 *
54 * This flexibility is useful in a few situations:
55 * - For log scales, some of the tick lines may be too close to all have labels.
56 * - For date scales where years are being displayed, it is desirable to display
57 * tick marks at the beginnings of years but labels (e.g. "2006") in the
58 * middle of the years.
59 */
60
61/*jshint globalstrict: true */
62/*global Dygraph:false */
63"use strict";
64
65Dygraph.numericLinearTicks = function(a, b, pixels, opts, dygraph, vals) {
66 var nonLogscaleOpts = function(opt) {
67 if (opt === 'logscale') return false;
68 return opts(opt);
69 };
70 return Dygraph.numericTicks(a, b, pixels, nonLogscaleOpts, dygraph, vals);
71};
72
73Dygraph.numericTicks = function(a, b, pixels, opts, dygraph, vals) {
74 var pixels_per_tick = opts('pixelsPerLabel');
75 var ticks = [];
76 var i, j, tickV, nTicks;
77 if (vals) {
78 for (i = 0; i < vals.length; i++) {
79 ticks.push({v: vals[i]});
80 }
81 } else {
82 // TODO(danvk): factor this log-scale block out into a separate function.
83 if (opts("logscale")) {
84 nTicks = Math.floor(pixels / pixels_per_tick);
85 var minIdx = Dygraph.binarySearch(a, Dygraph.PREFERRED_LOG_TICK_VALUES, 1);
86 var maxIdx = Dygraph.binarySearch(b, Dygraph.PREFERRED_LOG_TICK_VALUES, -1);
87 if (minIdx == -1) {
88 minIdx = 0;
89 }
90 if (maxIdx == -1) {
91 maxIdx = Dygraph.PREFERRED_LOG_TICK_VALUES.length - 1;
92 }
93 // Count the number of tick values would appear, if we can get at least
94 // nTicks / 4 accept them.
95 var lastDisplayed = null;
96 if (maxIdx - minIdx >= nTicks / 4) {
97 for (var idx = maxIdx; idx >= minIdx; idx--) {
98 var tickValue = Dygraph.PREFERRED_LOG_TICK_VALUES[idx];
99 var pixel_coord = Math.log(tickValue / a) / Math.log(b / a) * pixels;
100 var tick = { v: tickValue };
101 if (lastDisplayed === null) {
102 lastDisplayed = {
103 tickValue : tickValue,
104 pixel_coord : pixel_coord
105 };
106 } else {
107 if (Math.abs(pixel_coord - lastDisplayed.pixel_coord) >= pixels_per_tick) {
108 lastDisplayed = {
109 tickValue : tickValue,
110 pixel_coord : pixel_coord
111 };
112 } else {
113 tick.label = "";
114 }
115 }
116 ticks.push(tick);
117 }
118 // Since we went in backwards order.
119 ticks.reverse();
120 }
121 }
122
123 // ticks.length won't be 0 if the log scale function finds values to insert.
124 if (ticks.length === 0) {
125 // Basic idea:
126 // Try labels every 1, 2, 5, 10, 20, 50, 100, etc.
127 // Calculate the resulting tick spacing (i.e. this.height_ / nTicks).
128 // The first spacing greater than pixelsPerYLabel is what we use.
129 // TODO(danvk): version that works on a log scale.
130 var kmg2 = opts("labelsKMG2");
131 var mults;
132 if (kmg2) {
133 mults = [1, 2, 4, 8];
134 } else {
135 mults = [1, 2, 5];
136 }
137 var scale, low_val, high_val;
138 for (i = -10; i < 50; i++) {
139 var base_scale;
140 if (kmg2) {
141 base_scale = Math.pow(16, i);
142 } else {
143 base_scale = Math.pow(10, i);
144 }
145 var spacing = 0;
146 for (j = 0; j < mults.length; j++) {
147 scale = base_scale * mults[j];
148 low_val = Math.floor(a / scale) * scale;
149 high_val = Math.ceil(b / scale) * scale;
150 nTicks = Math.abs(high_val - low_val) / scale;
151 spacing = pixels / nTicks;
152 // wish I could break out of both loops at once...
153 if (spacing > pixels_per_tick) break;
154 }
155 if (spacing > pixels_per_tick) break;
156 }
157
158 // Construct the set of ticks.
159 // Allow reverse y-axis if it's explicitly requested.
160 if (low_val > high_val) scale *= -1;
161 for (i = 0; i < nTicks; i++) {
162 tickV = low_val + i * scale;
163 ticks.push( {v: tickV} );
164 }
165 }
166 }
167
168 // Add formatted labels to the ticks.
169 var k;
170 var k_labels = [];
171 if (opts("labelsKMB")) {
172 k = 1000;
173 k_labels = [ "K", "M", "B", "T", "Q" ];
174 }
175 if (opts("labelsKMG2")) {
176 if (k) Dygraph.warn("Setting both labelsKMB and labelsKMG2. Pick one!");
177 k = 1024;
178 k_labels = [ "k", "M", "G", "T", "P", "E" ];
179 }
180
181 var formatter = opts('axisLabelFormatter');
182
183 // Add labels to the ticks.
184 for (i = 0; i < ticks.length; i++) {
185 if (ticks[i].label !== undefined) continue; // Use current label.
186 tickV = ticks[i].v;
187 var absTickV = Math.abs(tickV);
188 // TODO(danvk): set granularity to something appropriate here.
189 var label = formatter(tickV, 0, opts, dygraph);
190 if (k_labels.length > 0) {
191 // TODO(danvk): should this be integrated into the axisLabelFormatter?
192 // Round up to an appropriate unit.
193 var n = Math.pow(k, k_labels.length);
194 for (j = k_labels.length - 1; j >= 0; j--, n /= k) {
195 if (absTickV >= n) {
196 label = Dygraph.round_(tickV / n, opts('digitsAfterDecimal')) +
197 k_labels[j];
198 break;
199 }
200 }
201 }
202 ticks[i].label = label;
203 }
204
205 return ticks;
206};
207
208
209Dygraph.dateTicker = function(a, b, pixels, opts, dygraph, vals) {
210 var chosen = Dygraph.pickDateTickGranularity(a, b, pixels, opts);
211
212 if (chosen >= 0) {
213 return Dygraph.getDateAxis(a, b, chosen, opts, dygraph);
214 } else {
215 // this can happen if self.width_ is zero.
216 return [];
217 }
218};
219
220// Time granularity enumeration
221Dygraph.SECONDLY = 0;
222Dygraph.TWO_SECONDLY = 1;
223Dygraph.FIVE_SECONDLY = 2;
224Dygraph.TEN_SECONDLY = 3;
225Dygraph.THIRTY_SECONDLY = 4;
226Dygraph.MINUTELY = 5;
227Dygraph.TWO_MINUTELY = 6;
228Dygraph.FIVE_MINUTELY = 7;
229Dygraph.TEN_MINUTELY = 8;
230Dygraph.THIRTY_MINUTELY = 9;
231Dygraph.HOURLY = 10;
232Dygraph.TWO_HOURLY = 11;
233Dygraph.SIX_HOURLY = 12;
234Dygraph.DAILY = 13;
235Dygraph.WEEKLY = 14;
236Dygraph.MONTHLY = 15;
237Dygraph.QUARTERLY = 16;
238Dygraph.BIANNUAL = 17;
239Dygraph.ANNUAL = 18;
240Dygraph.DECADAL = 19;
241Dygraph.CENTENNIAL = 20;
242Dygraph.NUM_GRANULARITIES = 21;
243
244Dygraph.SHORT_SPACINGS = [];
245Dygraph.SHORT_SPACINGS[Dygraph.SECONDLY] = 1000 * 1;
246Dygraph.SHORT_SPACINGS[Dygraph.TWO_SECONDLY] = 1000 * 2;
247Dygraph.SHORT_SPACINGS[Dygraph.FIVE_SECONDLY] = 1000 * 5;
248Dygraph.SHORT_SPACINGS[Dygraph.TEN_SECONDLY] = 1000 * 10;
249Dygraph.SHORT_SPACINGS[Dygraph.THIRTY_SECONDLY] = 1000 * 30;
250Dygraph.SHORT_SPACINGS[Dygraph.MINUTELY] = 1000 * 60;
251Dygraph.SHORT_SPACINGS[Dygraph.TWO_MINUTELY] = 1000 * 60 * 2;
252Dygraph.SHORT_SPACINGS[Dygraph.FIVE_MINUTELY] = 1000 * 60 * 5;
253Dygraph.SHORT_SPACINGS[Dygraph.TEN_MINUTELY] = 1000 * 60 * 10;
254Dygraph.SHORT_SPACINGS[Dygraph.THIRTY_MINUTELY] = 1000 * 60 * 30;
255Dygraph.SHORT_SPACINGS[Dygraph.HOURLY] = 1000 * 3600;
256Dygraph.SHORT_SPACINGS[Dygraph.TWO_HOURLY] = 1000 * 3600 * 2;
257Dygraph.SHORT_SPACINGS[Dygraph.SIX_HOURLY] = 1000 * 3600 * 6;
258Dygraph.SHORT_SPACINGS[Dygraph.DAILY] = 1000 * 86400;
259Dygraph.SHORT_SPACINGS[Dygraph.WEEKLY] = 1000 * 604800;
260
261/**
262 * @private
263 * This is a list of human-friendly values at which to show tick marks on a log
264 * scale. It is k * 10^n, where k=1..9 and n=-39..+39, so:
265 * ..., 1, 2, 3, 4, 5, ..., 9, 10, 20, 30, ..., 90, 100, 200, 300, ...
266 * NOTE: this assumes that Dygraph.LOG_SCALE = 10.
267 */
268Dygraph.PREFERRED_LOG_TICK_VALUES = function() {
269 var vals = [];
270 for (var power = -39; power <= 39; power++) {
271 var range = Math.pow(10, power);
272 for (var mult = 1; mult <= 9; mult++) {
273 var val = range * mult;
274 vals.push(val);
275 }
276 }
277 return vals;
278}();
279
280/**
281 * Determine the correct granularity of ticks on a date axis.
282 *
283 * @param {Number} a Left edge of the chart (ms)
284 * @param {Number} b Right edge of the chart (ms)
285 * @param {Number} pixels Size of the chart in the relevant dimension (width).
286 * @param {Function} opts Function mapping from option name -> value.
287 * @return {Number} The appropriate axis granularity for this chart. See the
288 * enumeration of possible values in dygraph-tickers.js.
289 */
290Dygraph.pickDateTickGranularity = function(a, b, pixels, opts) {
291 var pixels_per_tick = opts('pixelsPerLabel');
292 for (var i = 0; i < Dygraph.NUM_GRANULARITIES; i++) {
293 var num_ticks = Dygraph.numDateTicks(a, b, i);
294 if (pixels / num_ticks >= pixels_per_tick) {
295 return i;
296 }
297 }
298 return -1;
299};
300
301Dygraph.numDateTicks = function(start_time, end_time, granularity) {
302 if (granularity < Dygraph.MONTHLY) {
303 // Generate one tick mark for every fixed interval of time.
304 var spacing = Dygraph.SHORT_SPACINGS[granularity];
305 return Math.floor(0.5 + 1.0 * (end_time - start_time) / spacing);
306 } else {
307 var year_mod = 1; // e.g. to only print one point every 10 years.
308 var num_months = 12;
309 if (granularity == Dygraph.QUARTERLY) num_months = 3;
310 if (granularity == Dygraph.BIANNUAL) num_months = 2;
311 if (granularity == Dygraph.ANNUAL) num_months = 1;
312 if (granularity == Dygraph.DECADAL) { num_months = 1; year_mod = 10; }
313 if (granularity == Dygraph.CENTENNIAL) { num_months = 1; year_mod = 100; }
314
315 var msInYear = 365.2524 * 24 * 3600 * 1000;
316 var num_years = 1.0 * (end_time - start_time) / msInYear;
317 return Math.floor(0.5 + 1.0 * num_years * num_months / year_mod);
318 }
319};
320
321Dygraph.getDateAxis = function(start_time, end_time, granularity, opts, dg) {
322 var formatter = opts("axisLabelFormatter");
323 var ticks = [];
324 var t;
325
326 if (granularity < Dygraph.MONTHLY) {
327 // Generate one tick mark for every fixed interval of time.
328 var spacing = Dygraph.SHORT_SPACINGS[granularity];
329
330 // Find a time less than start_time which occurs on a "nice" time boundary
331 // for this granularity.
332 var g = spacing / 1000;
333 var d = new Date(start_time);
334 var x;
335 if (g <= 60) { // seconds
336 x = d.getSeconds(); d.setSeconds(x - x % g);
337 } else {
338 d.setSeconds(0);
339 g /= 60;
340 if (g <= 60) { // minutes
341 x = d.getMinutes(); d.setMinutes(x - x % g);
342 } else {
343 d.setMinutes(0);
344 g /= 60;
345
346 if (g <= 24) { // days
347 x = d.getHours(); d.setHours(x - x % g);
348 } else {
349 d.setHours(0);
350 g /= 24;
351
352 if (g == 7) { // one week
353 d.setDate(d.getDate() - d.getDay());
354 }
355 }
356 }
357 }
358 start_time = d.getTime();
359
360 for (t = start_time; t <= end_time; t += spacing) {
361 ticks.push({ v:t,
362 label: formatter(new Date(t), granularity, opts, dg)
363 });
364 }
365 } else {
366 // Display a tick mark on the first of a set of months of each year.
367 // Years get a tick mark iff y % year_mod == 0. This is useful for
368 // displaying a tick mark once every 10 years, say, on long time scales.
369 var months;
370 var year_mod = 1; // e.g. to only print one point every 10 years.
371
372 if (granularity == Dygraph.MONTHLY) {
373 months = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ];
374 } else if (granularity == Dygraph.QUARTERLY) {
375 months = [ 0, 3, 6, 9 ];
376 } else if (granularity == Dygraph.BIANNUAL) {
377 months = [ 0, 6 ];
378 } else if (granularity == Dygraph.ANNUAL) {
379 months = [ 0 ];
380 } else if (granularity == Dygraph.DECADAL) {
381 months = [ 0 ];
382 year_mod = 10;
383 } else if (granularity == Dygraph.CENTENNIAL) {
384 months = [ 0 ];
385 year_mod = 100;
386 } else {
387 Dygraph.warn("Span of dates is too long");
388 }
389
390 var start_year = new Date(start_time).getFullYear();
391 var end_year = new Date(end_time).getFullYear();
392 var zeropad = Dygraph.zeropad;
393 for (var i = start_year; i <= end_year; i++) {
394 if (i % year_mod !== 0) continue;
395 for (var j = 0; j < months.length; j++) {
396 var date_str = i + "/" + zeropad(1 + months[j]) + "/01";
397 t = Dygraph.dateStrToMillis(date_str);
398 if (t < start_time || t > end_time) continue;
399 ticks.push({ v:t,
400 label: formatter(new Date(t), granularity, opts, dg)
401 });
402 }
403 }
404 }
405
406 return ticks;
407};
408
409// These are set here so that this file can be included after dygraph.js.
410Dygraph.DEFAULT_ATTRS.axes.x.ticker = Dygraph.dateTicker;
411Dygraph.DEFAULT_ATTRS.axes.y.ticker = Dygraph.numericTicks;
412Dygraph.DEFAULT_ATTRS.axes.y2.ticker = Dygraph.numericTicks;