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.
63 Dygraph
.numericTicks
= function(a
, b
, pixels
, opts
, dygraph
, vals
) {
64 var pixels_per_tick
= opts('pixelsPerLabel');
67 for (var i
= 0; i
< vals
.length
; i
++) {
68 ticks
.push({v
: vals
[i
]});
71 // TODO(danvk): factor this log-scale block out into a separate function.
72 if (opts("logscale")) {
73 var nTicks
= Math
.floor(pixels
/ pixels_per_tick
);
74 var minIdx
= Dygraph
.binarySearch(a
, Dygraph
.PREFERRED_LOG_TICK_VALUES
, 1);
75 var maxIdx
= Dygraph
.binarySearch(b
, Dygraph
.PREFERRED_LOG_TICK_VALUES
, -1);
80 maxIdx
= Dygraph
.PREFERRED_LOG_TICK_VALUES
.length
- 1;
82 // Count the number of tick values would appear, if we can get at least
83 // nTicks / 4 accept them
.
84 var lastDisplayed
= null;
85 if (maxIdx
- minIdx
>= nTicks
/ 4) {
86 for (var idx
= maxIdx
; idx
>= minIdx
; idx
--) {
87 var tickValue
= Dygraph
.PREFERRED_LOG_TICK_VALUES
[idx
];
88 var pixel_coord
= Math
.log(tickValue
/ a) / Math
.log(b
/ a
) * pixels
;
89 var tick
= { v
: tickValue
};
90 if (lastDisplayed
== null) {
92 tickValue
: tickValue
,
93 pixel_coord
: pixel_coord
96 if (Math
.abs(pixel_coord
- lastDisplayed
.pixel_coord
) >= pixels_per_tick
) {
98 tickValue
: tickValue
,
99 pixel_coord
: pixel_coord
107 // Since we went in backwards order.
112 // ticks.length won't be 0 if the log scale function finds values to insert.
113 if (ticks
.length
== 0) {
115 // Try labels every 1, 2, 5, 10, 20, 50, 100, etc.
116 // Calculate the resulting tick spacing (i.e. this.height_ / nTicks
).
117 // The first spacing greater than pixelsPerYLabel is what we use.
118 // TODO(danvk): version that works on a log scale.
119 var kmg2
= opts("labelsKMG2");
121 var mults
= [1, 2, 4, 8];
123 var mults
= [1, 2, 5];
125 var scale
, low_val
, high_val
, nTicks
;
126 for (var i
= -10; i
< 50; i
++) {
128 var base_scale
= Math
.pow(16, i
);
130 var base_scale
= Math
.pow(10, i
);
132 for (var j
= 0; j
< mults
.length
; j
++) {
133 scale
= base_scale
* mults
[j
];
134 low_val
= Math
.floor(a
/ scale
) * scale
;
135 high_val
= Math
.ceil(b
/ scale
) * scale
;
136 nTicks
= Math
.abs(high_val
- low_val
) / scale
;
137 var spacing
= pixels
/ nTicks
;
138 // wish I could break out of both loops at once...
139 if (spacing
> pixels_per_tick
) break;
141 if (spacing
> pixels_per_tick
) break;
144 // Construct the set of ticks.
145 // Allow reverse y-axis if it's explicitly requested.
146 if (low_val
> high_val
) scale
*= -1;
147 for (var i
= 0; i
< nTicks
; i
++) {
148 var tickV
= low_val
+ i
* scale
;
149 ticks
.push( {v
: tickV
} );
154 // Add formatted labels to the ticks.
157 if (opts("labelsKMB")) {
159 k_labels
= [ "K", "M", "B", "T" ];
161 if (opts("labelsKMG2")) {
162 if (k
) self
.warn("Setting both labelsKMB and labelsKMG2. Pick one!");
164 k_labels
= [ "k", "M", "G", "T" ];
167 var formatter
= opts('axisLabelFormatter');
169 // Add labels to the ticks.
170 for (var i
= 0; i
< ticks
.length
; i
++) {
171 if (ticks
[i
].label
!== undefined
) continue; // Use current label.
172 var tickV
= ticks
[i
].v
;
173 var absTickV
= Math
.abs(tickV
);
174 // TODO(danvk): set granularity to something appropriate here.
175 var label
= formatter(tickV
, 0, opts
, dygraph
);
176 if (k_labels
.length
> 0) {
177 // TODO(danvk): should this be integrated into the axisLabelFormatter?
178 // Round up to an appropriate unit.
180 for (var j
= 3; j
>= 0; j
--, n
/= k
) {
182 label
= Dygraph
.round_(tickV
/ n
, opts('digitsAfterDecimal')) +
188 ticks
[i
].label
= label
;
195 Dygraph
.dateTicker
= function(a
, b
, pixels
, opts
, dygraph
, vals
) {
196 var pixels_per_tick
= opts('pixelsPerLabel');
198 for (var i
= 0; i
< Dygraph
.NUM_GRANULARITIES
; i
++) {
199 var num_ticks
= Dygraph
.numDateTicks(a
, b
, i
);
200 if (pixels
/ num_ticks
>= pixels_per_tick
) {
207 return Dygraph
.getDateAxis(a
, b
, chosen
, opts
, dygraph
);
209 // this can happen if self.width_ is zero.
214 // Time granularity enumeration
215 Dygraph
.SECONDLY
= 0;
216 Dygraph
.TWO_SECONDLY
= 1;
217 Dygraph
.FIVE_SECONDLY
= 2;
218 Dygraph
.TEN_SECONDLY
= 3;
219 Dygraph
.THIRTY_SECONDLY
= 4;
220 Dygraph
.MINUTELY
= 5;
221 Dygraph
.TWO_MINUTELY
= 6;
222 Dygraph
.FIVE_MINUTELY
= 7;
223 Dygraph
.TEN_MINUTELY
= 8;
224 Dygraph
.THIRTY_MINUTELY
= 9;
226 Dygraph
.TWO_HOURLY
= 11;
227 Dygraph
.SIX_HOURLY
= 12;
230 Dygraph
.MONTHLY
= 15;
231 Dygraph
.QUARTERLY
= 16;
232 Dygraph
.BIANNUAL
= 17;
234 Dygraph
.DECADAL
= 19;
235 Dygraph
.CENTENNIAL
= 20;
236 Dygraph
.NUM_GRANULARITIES
= 21;
238 Dygraph
.SHORT_SPACINGS
= [];
239 Dygraph
.SHORT_SPACINGS
[Dygraph
.SECONDLY
] = 1000 * 1;
240 Dygraph
.SHORT_SPACINGS
[Dygraph
.TWO_SECONDLY
] = 1000 * 2;
241 Dygraph
.SHORT_SPACINGS
[Dygraph
.FIVE_SECONDLY
] = 1000 * 5;
242 Dygraph
.SHORT_SPACINGS
[Dygraph
.TEN_SECONDLY
] = 1000 * 10;
243 Dygraph
.SHORT_SPACINGS
[Dygraph
.THIRTY_SECONDLY
] = 1000 * 30;
244 Dygraph
.SHORT_SPACINGS
[Dygraph
.MINUTELY
] = 1000 * 60;
245 Dygraph
.SHORT_SPACINGS
[Dygraph
.TWO_MINUTELY
] = 1000 * 60 * 2;
246 Dygraph
.SHORT_SPACINGS
[Dygraph
.FIVE_MINUTELY
] = 1000 * 60 * 5;
247 Dygraph
.SHORT_SPACINGS
[Dygraph
.TEN_MINUTELY
] = 1000 * 60 * 10;
248 Dygraph
.SHORT_SPACINGS
[Dygraph
.THIRTY_MINUTELY
] = 1000 * 60 * 30;
249 Dygraph
.SHORT_SPACINGS
[Dygraph
.HOURLY
] = 1000 * 3600;
250 Dygraph
.SHORT_SPACINGS
[Dygraph
.TWO_HOURLY
] = 1000 * 3600 * 2;
251 Dygraph
.SHORT_SPACINGS
[Dygraph
.SIX_HOURLY
] = 1000 * 3600 * 6;
252 Dygraph
.SHORT_SPACINGS
[Dygraph
.DAILY
] = 1000 * 86400;
253 Dygraph
.SHORT_SPACINGS
[Dygraph
.WEEKLY
] = 1000 * 604800;
257 * This is a list of human-friendly values at which to show tick marks on a log
258 * scale. It is k * 10^n, where k=1..9 and n=-39..+39, so:
259 * ..., 1, 2, 3, 4, 5, ..., 9, 10, 20, 30, ..., 90, 100, 200, 300, ...
260 * NOTE: this assumes that Dygraph.LOG_SCALE = 10.
262 Dygraph
.PREFERRED_LOG_TICK_VALUES
= function() {
264 for (var power
= -39; power
<= 39; power
++) {
265 var range
= Math
.pow(10, power
);
266 for (var mult
= 1; mult
<= 9; mult
++) {
267 var val
= range
* mult
;
274 Dygraph
.numDateTicks
= function(start_time
, end_time
, granularity
) {
275 if (granularity
< Dygraph
.MONTHLY
) {
276 // Generate one tick mark for every fixed interval of time.
277 var spacing
= Dygraph
.SHORT_SPACINGS
[granularity
];
278 return Math
.floor(0.5 + 1.0 * (end_time
- start_time
) / spacing
);
280 var year_mod
= 1; // e.g. to only print one point every 10 years.
282 if (granularity
== Dygraph
.QUARTERLY
) num_months
= 3;
283 if (granularity
== Dygraph
.BIANNUAL
) num_months
= 2;
284 if (granularity
== Dygraph
.ANNUAL
) num_months
= 1;
285 if (granularity
== Dygraph
.DECADAL
) { num_months
= 1; year_mod
= 10; }
286 if (granularity
== Dygraph
.CENTENNIAL
) { num_months
= 1; year_mod
= 100; }
288 var msInYear
= 365.2524 * 24 * 3600 * 1000;
289 var num_years
= 1.0 * (end_time
- start_time
) / msInYear
;
290 return Math
.floor(0.5 + 1.0 * num_years
* num_months
/ year_mod
);
294 Dygraph
.getDateAxis
= function(start_time
, end_time
, granularity
, opts
, dg
) {
295 var formatter
= opts("axisLabelFormatter");
297 if (granularity
< Dygraph
.MONTHLY
) {
298 // Generate one tick mark for every fixed interval of time.
299 var spacing
= Dygraph
.SHORT_SPACINGS
[granularity
];
300 var format
= '%d%b'; // e.g. "1Jan"
302 // Find a time less than start_time which occurs on a "nice" time boundary
303 // for this granularity.
304 var g
= spacing
/ 1000;
305 var d
= new Date(start_time
);
306 if (g
<= 60) { // seconds
307 var x
= d
.getSeconds(); d
.setSeconds(x
- x
% g
);
311 if (g
<= 60) { // minutes
312 var x
= d
.getMinutes(); d
.setMinutes(x
- x
% g
);
317 if (g
<= 24) { // days
318 var x
= d
.getHours(); d
.setHours(x
- x
% g
);
323 if (g
== 7) { // one week
324 d
.setDate(d
.getDate() - d
.getDay());
329 start_time
= d
.getTime();
331 for (var t
= start_time
; t
<= end_time
; t
+= spacing
) {
333 label
: formatter(new Date(t
), granularity
, opts
, dg
)
337 // Display a tick mark on the first of a set of months of each year.
338 // Years get a tick mark iff y % year_mod == 0. This is useful for
339 // displaying a tick mark once every 10 years, say, on long time scales.
341 var year_mod
= 1; // e.g. to only print one point every 10 years.
343 if (granularity
== Dygraph
.MONTHLY
) {
344 months
= [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ];
345 } else if (granularity
== Dygraph
.QUARTERLY
) {
346 months
= [ 0, 3, 6, 9 ];
347 } else if (granularity
== Dygraph
.BIANNUAL
) {
349 } else if (granularity
== Dygraph
.ANNUAL
) {
351 } else if (granularity
== Dygraph
.DECADAL
) {
354 } else if (granularity
== Dygraph
.CENTENNIAL
) {
358 Dygraph
.warn("Span of dates is too long");
361 var start_year
= new Date(start_time
).getFullYear();
362 var end_year
= new Date(end_time
).getFullYear();
363 var zeropad
= Dygraph
.zeropad
;
364 for (var i
= start_year
; i
<= end_year
; i
++) {
365 if (i
% year_mod
!= 0) continue;
366 for (var j
= 0; j
< months
.length
; j
++) {
367 var date_str
= i
+ "/" + zeropad(1 + months[j]) + "/01";
368 var t
= Dygraph
.dateStrToMillis(date_str
);
369 if (t
< start_time
|| t
> end_time
) continue;
371 label
: formatter(new Date(t
), granularity
, opts
, dg
)
380 // These are set here so that this file can be included after dygraph.js.
381 Dygraph
.DEFAULT_ATTRS
.axes
.x
.ticker
= Dygraph
.dateTicker
;
382 Dygraph
.DEFAULT_ATTRS
.axes
.y
.ticker
= Dygraph
.numericTicks
;
383 Dygraph
.DEFAULT_ATTRS
.axes
.y2
.ticker
= Dygraph
.numericTicks
;