3 * Copyright 2011 Dan Vanderkam (danvdk@gmail.com)
4 * MIT-licensed (http://opensource.org/licenses/MIT)
8 * @fileoverview Description of this file.
9 * @author danvk@google.com (Dan Vanderkam)
11 * A ticker is a function with the following interface:
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] },
19 * The returned value is called a "tick list".
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
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.
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.
37 * dygraph is the Dygraph object for which an axis is being constructed.
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.
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).
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
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.
62 /*global Dygraph:false */
66 /** @typedef {Array.<{v:number, label:string, label_v:(string|undefined)}>} */
67 Dygraph
.TickList
= undefined
; // the ' = undefined' keeps jshint happy.
69 /** @typedef {function(
76 * ): Dygraph.TickList}
78 Dygraph
.Ticker
= undefined
; // the ' = undefined' keeps jshint happy.
80 /** @type {Dygraph.Ticker} */
81 Dygraph
.numericLinearTicks
= function(a
, b
, pixels
, opts
, dygraph
, vals
) {
82 var nonLogscaleOpts
= function(opt
) {
83 if (opt
=== 'logscale') return false;
86 return Dygraph
.numericTicks(a
, b
, pixels
, nonLogscaleOpts
, dygraph
, vals
);
89 /** @type {Dygraph.Ticker} */
90 Dygraph
.numericTicks
= function(a
, b
, pixels
, opts
, dygraph
, vals
) {
91 var pixels_per_tick
= /** @type{number} */(opts('pixelsPerLabel'));
93 var i
, j
, tickV
, nTicks
;
95 for (i
= 0; i
< vals
.length
; i
++) {
96 ticks
.push({v
: vals
[i
]});
99 // TODO(danvk): factor this log-scale block out into a separate function.
100 if (opts("logscale")) {
101 nTicks
= Math
.floor(pixels
/ pixels_per_tick
);
102 var minIdx
= Dygraph
.binarySearch(a
, Dygraph
.PREFERRED_LOG_TICK_VALUES
, 1);
103 var maxIdx
= Dygraph
.binarySearch(b
, Dygraph
.PREFERRED_LOG_TICK_VALUES
, -1);
108 maxIdx
= Dygraph
.PREFERRED_LOG_TICK_VALUES
.length
- 1;
110 // Count the number of tick values would appear, if we can get at least
111 // nTicks / 4 accept them
.
112 var lastDisplayed
= null;
113 if (maxIdx
- minIdx
>= nTicks
/ 4) {
114 for (var idx
= maxIdx
; idx
>= minIdx
; idx
--) {
115 var tickValue
= Dygraph
.PREFERRED_LOG_TICK_VALUES
[idx
];
116 var pixel_coord
= Math
.log(tickValue
/ a) / Math
.log(b
/ a
) * pixels
;
117 var tick
= { v
: tickValue
};
118 if (lastDisplayed
=== null) {
120 tickValue
: tickValue
,
121 pixel_coord
: pixel_coord
124 if (Math
.abs(pixel_coord
- lastDisplayed
.pixel_coord
) >= pixels_per_tick
) {
126 tickValue
: tickValue
,
127 pixel_coord
: pixel_coord
135 // Since we went in backwards order.
140 // ticks.length won't be 0 if the log scale function finds values to insert.
141 if (ticks
.length
=== 0) {
143 // Try labels every 1, 2, 5, 10, 20, 50, 100, etc.
144 // Calculate the resulting tick spacing (i.e. this.height_ / nTicks
).
145 // The first spacing greater than pixelsPerYLabel is what we use.
146 // TODO(danvk): version that works on a log scale.
147 var kmg2
= opts("labelsKMG2");
150 mults
= [1, 2, 4, 8, 16, 32, 64, 128, 256];
153 mults
= [1, 2, 5, 10, 20, 50, 100];
157 // Get the maximum number of permitted ticks based on the
158 // graph's pixel size and pixels_per_tick setting.
159 var max_ticks
= Math
.ceil(pixels
/ pixels_per_tick
);
161 // Now calculate the data unit equivalent of this tick spacing.
162 // Use abs() since graphs may have a reversed Y axis.
163 var units_per_tick
= Math
.abs(b
- a
) / max_ticks
;
165 // Based on this, get a starting scale which is the largest
166 // integer power of the chosen base (10 or 16) that still remains
167 // below the requested pixels_per_tick spacing.
168 var base_power
= Math
.floor(Math
.log(units_per_tick
) / Math
.log(base
));
169 var base_scale
= Math
.pow(base
, base_power
);
171 // Now try multiples of the starting scale until we find one
172 // that results in tick marks spaced sufficiently far apart.
173 // The "mults" array should cover the range 1 .. base^2 to
174 // adjust for rounding and edge effects.
175 var scale
, low_val
, high_val
, spacing
;
176 for (j
= 0; j
< mults
.length
; j
++) {
177 scale
= base_scale
* mults
[j
];
178 low_val
= Math
.floor(a
/ scale
) * scale
;
179 high_val
= Math
.ceil(b
/ scale
) * scale
;
180 nTicks
= Math
.abs(high_val
- low_val
) / scale
;
181 spacing
= pixels
/ nTicks
;
182 if (spacing
> pixels_per_tick
) break;
185 // Construct the set of ticks.
186 // Allow reverse y-axis if it's explicitly requested.
187 if (low_val
> high_val
) scale
*= -1;
188 for (i
= 0; i
<= nTicks
; i
++) {
189 tickV
= low_val
+ i
* scale
;
190 ticks
.push( {v
: tickV
} );
195 var formatter
= /**@type{AxisLabelFormatter}*/(opts('axisLabelFormatter'));
197 // Add labels to the ticks.
198 for (i
= 0; i
< ticks
.length
; i
++) {
199 if (ticks
[i
].label
!== undefined
) continue; // Use current label.
200 // TODO(danvk): set granularity to something appropriate here.
201 ticks
[i
].label
= formatter(ticks
[i
].v
, 0, opts
, dygraph
);
208 /** @type {Dygraph.Ticker} */
209 Dygraph
.dateTicker
= function(a
, b
, pixels
, opts
, dygraph
, vals
) {
210 var chosen
= Dygraph
.pickDateTickGranularity(a
, b
, pixels
, opts
);
213 return Dygraph
.getDateAxis(a
, b
, chosen
, opts
, dygraph
);
215 // this can happen if self.width_ is zero.
220 // Time granularity enumeration
221 // TODO(danvk): make this an @enum
222 Dygraph
.SECONDLY
= 0;
223 Dygraph
.TWO_SECONDLY
= 1;
224 Dygraph
.FIVE_SECONDLY
= 2;
225 Dygraph
.TEN_SECONDLY
= 3;
226 Dygraph
.THIRTY_SECONDLY
= 4;
227 Dygraph
.MINUTELY
= 5;
228 Dygraph
.TWO_MINUTELY
= 6;
229 Dygraph
.FIVE_MINUTELY
= 7;
230 Dygraph
.TEN_MINUTELY
= 8;
231 Dygraph
.THIRTY_MINUTELY
= 9;
233 Dygraph
.TWO_HOURLY
= 11;
234 Dygraph
.SIX_HOURLY
= 12;
237 Dygraph
.MONTHLY
= 15;
238 Dygraph
.QUARTERLY
= 16;
239 Dygraph
.BIANNUAL
= 17;
241 Dygraph
.DECADAL
= 19;
242 Dygraph
.CENTENNIAL
= 20;
243 Dygraph
.NUM_GRANULARITIES
= 21;
245 // Date components enumeration (in the order of the arguments in Date)
246 // TODO: make this an @enum
247 Dygraph
.DATEFIELD_Y
= 0;
248 Dygraph
.DATEFIELD_M
= 1;
249 Dygraph
.DATEFIELD_D
= 2;
250 Dygraph
.DATEFIELD_HH
= 3;
251 Dygraph
.DATEFIELD_MM
= 4;
252 Dygraph
.DATEFIELD_SS
= 5;
253 Dygraph
.DATEFIELD_MS
= 6;
254 Dygraph
.NUM_DATEFIELDS
= 7;
257 /** @type {Array.<{datefield:number, step:number, spacing:number}>} */
258 Dygraph
.TICK_PLACEMENT
= [];
259 Dygraph
.TICK_PLACEMENT
[Dygraph
.SECONDLY
] = {datefield
: Dygraph
.DATEFIELD_SS
, step
: 1, spacing
: 1000 * 1};
260 Dygraph
.TICK_PLACEMENT
[Dygraph
.TWO_SECONDLY
] = {datefield
: Dygraph
.DATEFIELD_SS
, step
: 2, spacing
: 1000 * 2};
261 Dygraph
.TICK_PLACEMENT
[Dygraph
.FIVE_SECONDLY
] = {datefield
: Dygraph
.DATEFIELD_SS
, step
: 5, spacing
: 1000 * 5};
262 Dygraph
.TICK_PLACEMENT
[Dygraph
.TEN_SECONDLY
] = {datefield
: Dygraph
.DATEFIELD_SS
, step
: 10, spacing
: 1000 * 10};
263 Dygraph
.TICK_PLACEMENT
[Dygraph
.THIRTY_SECONDLY
] = {datefield
: Dygraph
.DATEFIELD_SS
, step
: 30, spacing
: 1000 * 30};
264 Dygraph
.TICK_PLACEMENT
[Dygraph
.MINUTELY
] = {datefield
: Dygraph
.DATEFIELD_MM
, step
: 1, spacing
: 1000 * 60};
265 Dygraph
.TICK_PLACEMENT
[Dygraph
.TWO_MINUTELY
] = {datefield
: Dygraph
.DATEFIELD_MM
, step
: 2, spacing
: 1000 * 60 * 2};
266 Dygraph
.TICK_PLACEMENT
[Dygraph
.FIVE_MINUTELY
] = {datefield
: Dygraph
.DATEFIELD_MM
, step
: 5, spacing
: 1000 * 60 * 5};
267 Dygraph
.TICK_PLACEMENT
[Dygraph
.TEN_MINUTELY
] = {datefield
: Dygraph
.DATEFIELD_MM
, step
: 10, spacing
: 1000 * 60 * 10};
268 Dygraph
.TICK_PLACEMENT
[Dygraph
.THIRTY_MINUTELY
] = {datefield
: Dygraph
.DATEFIELD_MM
, step
: 30, spacing
: 1000 * 60 * 30};
269 Dygraph
.TICK_PLACEMENT
[Dygraph
.HOURLY
] = {datefield
: Dygraph
.DATEFIELD_HH
, step
: 1, spacing
: 1000 * 3600};
270 Dygraph
.TICK_PLACEMENT
[Dygraph
.TWO_HOURLY
] = {datefield
: Dygraph
.DATEFIELD_HH
, step
: 2, spacing
: 1000 * 3600 * 2};
271 Dygraph
.TICK_PLACEMENT
[Dygraph
.SIX_HOURLY
] = {datefield
: Dygraph
.DATEFIELD_HH
, step
: 6, spacing
: 1000 * 3600 * 6};
272 Dygraph
.TICK_PLACEMENT
[Dygraph
.DAILY
] = {datefield
: Dygraph
.DATEFIELD_D
, step
: 1, spacing
: 1000 * 86400};
273 Dygraph
.TICK_PLACEMENT
[Dygraph
.WEEKLY
] = {datefield
: Dygraph
.DATEFIELD_D
, step
: 7, spacing
: 1000 * 604800};
274 Dygraph
.TICK_PLACEMENT
[Dygraph
.MONTHLY
] = {datefield
: Dygraph
.DATEFIELD_M
, step
: 1, spacing
: 1000 * 7200 * 365.2524}; // 1e3 * 60 * 60 * 24 * 365.2524 / 12
275 Dygraph
.TICK_PLACEMENT
[Dygraph
.QUARTERLY
] = {datefield
: Dygraph
.DATEFIELD_M
, step
: 3, spacing
: 1000 * 21600 * 365.2524}; // 1e3 * 60 * 60 * 24 * 365.2524 / 4
276 Dygraph
.TICK_PLACEMENT
[Dygraph
.BIANNUAL
] = {datefield
: Dygraph
.DATEFIELD_M
, step
: 6, spacing
: 1000 * 43200 * 365.2524}; // 1e3 * 60 * 60 * 24 * 365.2524 / 2
277 Dygraph
.TICK_PLACEMENT
[Dygraph
.ANNUAL
] = {datefield
: Dygraph
.DATEFIELD_Y
, step
: 1, spacing
: 1000 * 86400 * 365.2524}; // 1e3 * 60 * 60 * 24 * 365.2524 * 1
278 Dygraph
.TICK_PLACEMENT
[Dygraph
.DECADAL
] = {datefield
: Dygraph
.DATEFIELD_Y
, step
: 10, spacing
: 1000 * 864000 * 365.2524}; // 1e3 * 60 * 60 * 24 * 365.2524 * 10
279 Dygraph
.TICK_PLACEMENT
[Dygraph
.CENTENNIAL
] = {datefield
: Dygraph
.DATEFIELD_Y
, step
: 100, spacing
: 1000 * 8640000 * 365.2524}; // 1e3 * 60 * 60 * 24 * 365.2524 * 100
283 * This is a list of human-friendly values at which to show tick marks on a log
284 * scale. It is k * 10^n, where k=1..9 and n=-39..+39, so:
285 * ..., 1, 2, 3, 4, 5, ..., 9, 10, 20, 30, ..., 90, 100, 200, 300, ...
286 * NOTE: this assumes that Dygraph.LOG_SCALE = 10.
287 * @type {Array.<number>}
289 Dygraph
.PREFERRED_LOG_TICK_VALUES
= (function() {
291 for (var power
= -39; power
<= 39; power
++) {
292 var range
= Math
.pow(10, power
);
293 for (var mult
= 1; mult
<= 9; mult
++) {
294 var val
= range
* mult
;
302 * Determine the correct granularity of ticks on a date axis.
304 * @param {number} a Left edge of the chart (ms)
305 * @param {number} b Right edge of the chart (ms)
306 * @param {number} pixels Size of the chart in the relevant dimension (width).
307 * @param {function(string):*} opts Function mapping from option name -> value.
308 * @return {number} The appropriate axis granularity for this chart. See the
309 * enumeration of possible values in dygraph-tickers.js.
311 Dygraph
.pickDateTickGranularity
= function(a
, b
, pixels
, opts
) {
312 var pixels_per_tick
= /** @type{number} */(opts('pixelsPerLabel'));
313 for (var i
= 0; i
< Dygraph
.NUM_GRANULARITIES
; i
++) {
314 var num_ticks
= Dygraph
.numDateTicks(a
, b
, i
);
315 if (pixels
/ num_ticks
>= pixels_per_tick
) {
323 * Compute the number of ticks on a date axis for a given granularity.
324 * @param {number} start_time
325 * @param {number} end_time
326 * @param {number} granularity (one of the granularities enumerated above)
327 * @return {number} (Approximate) number of ticks that would result.
329 Dygraph
.numDateTicks
= function(start_time
, end_time
, granularity
) {
330 var spacing
= Dygraph
.TICK_PLACEMENT
[granularity
].spacing
;
331 return Math
.round(1.0 * (end_time
- start_time
) / spacing
);
335 * Compute the positions and labels of ticks on a date axis for a given granularity.
336 * @param {number} start_time
337 * @param {number} end_time
338 * @param {number} granularity (one of the granularities enumerated above)
339 * @param {function(string):*} opts Function mapping from option name -> value.
340 * @param {Dygraph=} dg
341 * @return {!Dygraph.TickList}
343 Dygraph
.getDateAxis
= function(start_time
, end_time
, granularity
, opts
, dg
) {
344 var formatter
= /** @type{AxisLabelFormatter} */(
345 opts("axisLabelFormatter"));
346 var utc
= opts("labelsUTC");
347 var accessors
= utc
? Dygraph
.DateAccessorsUTC
: Dygraph
.DateAccessorsLocal
;
349 var datefield
= Dygraph
.TICK_PLACEMENT
[granularity
].datefield
;
350 var step
= Dygraph
.TICK_PLACEMENT
[granularity
].step
;
351 var spacing
= Dygraph
.TICK_PLACEMENT
[granularity
].spacing
;
353 // Choose a nice tick position before the initial instant.
354 // Currently, this code deals properly with the existent daily granularities:
355 // DAILY (with step of 1) and WEEKLY (with step of 7 but specially handled).
356 // Other daily granularities (say TWO_DAILY) should also be handled specially
357 // by setting the start_date_offset to 0.
358 var start_date
= new Date(start_time
);
360 date_array
[Dygraph
.DATEFIELD_Y
] = accessors
.getFullYear(start_date
);
361 date_array
[Dygraph
.DATEFIELD_M
] = accessors
.getMonth(start_date
);
362 date_array
[Dygraph
.DATEFIELD_D
] = accessors
.getDate(start_date
);
363 date_array
[Dygraph
.DATEFIELD_HH
] = accessors
.getHours(start_date
);
364 date_array
[Dygraph
.DATEFIELD_MM
] = accessors
.getMinutes(start_date
);
365 date_array
[Dygraph
.DATEFIELD_SS
] = accessors
.getSeconds(start_date
);
366 date_array
[Dygraph
.DATEFIELD_MS
] = accessors
.getMilliseconds(start_date
);
368 var start_date_offset
= date_array
[datefield
] % step
;
369 if (granularity
== Dygraph
.WEEKLY
) {
370 // This will put the ticks on Sundays.
371 start_date_offset
= accessors
.getDay(start_date
);
374 date_array
[datefield
] -= start_date_offset
;
375 for (var df
= datefield
+ 1; df
< Dygraph
.NUM_DATEFIELDS
; df
++) {
376 // The minimum value is 1 for the day of month, and 0 for all other fields.
377 date_array
[df
] = (df
=== Dygraph
.DATEFIELD_D
) ? 1 : 0;
380 // Generate the ticks.
381 // For granularities not coarser than HOURLY we use the fact that:
382 // the number of milliseconds between ticks is constant
383 // and equal to the defined spacing.
384 // Otherwise we rely on the 'roll over' property of the Date functions:
385 // when some date field is set to a value outside of its logical range,
386 // the excess 'rolls over' the next (more significant) field.
387 // However, when using local time with DST transitions,
388 // there are dates that do not represent any time value at all
389 // (those in the hour skipped at the 'spring forward'),
390 // and the JavaScript engines usually return an equivalent value.
391 // Hence we have to check that the date is properly increased at each step,
392 // returning a date at a nice tick position.
394 var tick_date
= accessors
.makeDate
.apply(null, date_array
);
395 var tick_time
= tick_date
.getTime();
396 if (granularity
<= Dygraph
.HOURLY
) {
397 if (tick_time
< start_time
) {
398 tick_time
+= spacing
;
399 tick_date
= new Date(tick_time
);
401 while (tick_time
<= end_time
) {
402 ticks
.push({ v
: tick_time
,
403 label
: formatter(tick_date
, granularity
, opts
, dg
)
405 tick_time
+= spacing
;
406 tick_date
= new Date(tick_time
);
409 if (tick_time
< start_time
) {
410 date_array
[datefield
] += step
;
411 tick_date
= accessors
.makeDate
.apply(null, date_array
);
412 tick_time
= tick_date
.getTime();
414 while (tick_time
<= end_time
) {
415 if (granularity
>= Dygraph
.DAILY
||
416 accessors
.getHours(tick_date
) % step
=== 0) {
417 ticks
.push({ v
: tick_time
,
418 label
: formatter(tick_date
, granularity
, opts
, dg
)
421 date_array
[datefield
] += step
;
422 tick_date
= accessors
.makeDate
.apply(null, date_array
);
423 tick_time
= tick_date
.getTime();
429 // These are set here so that this file can be included after dygraph.js
432 Dygraph
.DEFAULT_ATTRS
&&
433 Dygraph
.DEFAULT_ATTRS
['axes'] &&
434 Dygraph
.DEFAULT_ATTRS
['axes']['x'] &&
435 Dygraph
.DEFAULT_ATTRS
['axes']['y'] &&
436 Dygraph
.DEFAULT_ATTRS
['axes']['y2']) {
437 Dygraph
.DEFAULT_ATTRS
['axes']['x']['ticker'] = Dygraph
.dateTicker
;
438 Dygraph
.DEFAULT_ATTRS
['axes']['y']['ticker'] = Dygraph
.numericTicks
;
439 Dygraph
.DEFAULT_ATTRS
['axes']['y2']['ticker'] = Dygraph
.numericTicks
;