1 // Copyright 2011 Google Inc. All Rights Reserved.
4 * @fileoverview Description of this file.
5 * @author danvk@google.com (Dan Vanderkam)
7 * A ticker is a function with the following interface:
9 * function(a, b, pixels, options_view, dygraph, forced_values);
10 * -> [ { v: tick1_v, label: tick1_label[, label_v: label_v1] },
11 * { v: tick2_v, label: tick2_label[, label_v: label_v2] },
15 * The returned value is called a "tick list".
20 * [a, b] is the range of the axis for which ticks are being generated. For a
21 * numeric axis, these will simply be numbers. For a date axis, these will be
22 * millis since epoch (convertable to Date objects using "new Date(a)" and "new
25 * opts provides access to chart- and axis-specific options. It can be used to
26 * access number/date formatting code/options, check for a log scale, etc.
28 * pixels is the length of the axis in pixels. opts('pixelsPerLabel') is the
29 * minimum amount of space to be allotted to each label. For instance, if
30 * pixels=400 and opts('pixelsPerLabel')=40 then the ticker should return
31 * between zero and ten (400/40) ticks.
33 * dygraph is the Dygraph object for which an axis is being constructed.
35 * forced_values is used for secondary y-axes. The tick positions are typically
36 * set by the primary y-axis, so the secondary y-axis has no choice in where to
37 * put these. It simply has to generate labels for these data values.
41 * Typically a tick will have both a grid/tick line and a label at one end of
42 * that line (at the bottom for an x-axis, at left or right for the y-axis).
44 * A tick may be missing one of these two components:
45 * - If "label_v" is specified instead of "v", then there will be no tick or
46 * gridline, just a label.
47 * - Similarly, if "label" is not specified, then there will be a gridline
50 * This flexibility is useful in a few situations:
51 * - For log scales, some of the tick lines may be too close to all have labels.
52 * - For date scales where years are being displayed, it is desirable to display
53 * tick marks at the beginnings of years but labels (e.g. "2006") in the
54 * middle of the years.
57 Dygraph
.numericTicks
= function(a
, b
, pixels
, opts
, dygraph
, vals
) {
58 var pixels_per_tick
= opts('pixelsPerLabel');
61 for (var i
= 0; i
< vals
.length
; i
++) {
62 ticks
.push({v
: vals
[i
]});
65 // TODO(danvk): factor this log-scale block out into a separate function.
66 if (opts("logscale")) {
67 var nTicks
= Math
.floor(pixels
/ pixels_per_tick
);
68 var minIdx
= Dygraph
.binarySearch(a
, Dygraph
.PREFERRED_LOG_TICK_VALUES
, 1);
69 var maxIdx
= Dygraph
.binarySearch(b
, Dygraph
.PREFERRED_LOG_TICK_VALUES
, -1);
74 maxIdx
= Dygraph
.PREFERRED_LOG_TICK_VALUES
.length
- 1;
76 // Count the number of tick values would appear, if we can get at least
77 // nTicks / 4 accept them
.
78 var lastDisplayed
= null;
79 if (maxIdx
- minIdx
>= nTicks
/ 4) {
80 for (var idx
= maxIdx
; idx
>= minIdx
; idx
--) {
81 var tickValue
= Dygraph
.PREFERRED_LOG_TICK_VALUES
[idx
];
82 var pixel_coord
= Math
.log(tickValue
/ a) / Math
.log(b
/ a
) * pixels
;
83 var tick
= { v
: tickValue
};
84 if (lastDisplayed
== null) {
86 tickValue
: tickValue
,
87 pixel_coord
: pixel_coord
90 if (Math
.abs(pixel_coord
- lastDisplayed
.pixel_coord
) >= pixels_per_tick
) {
92 tickValue
: tickValue
,
93 pixel_coord
: pixel_coord
101 // Since we went in backwards order.
106 // ticks.length won't be 0 if the log scale function finds values to insert.
107 if (ticks
.length
== 0) {
109 // Try labels every 1, 2, 5, 10, 20, 50, 100, etc.
110 // Calculate the resulting tick spacing (i.e. this.height_ / nTicks
).
111 // The first spacing greater than pixelsPerYLabel is what we use.
112 // TODO(danvk): version that works on a log scale.
113 var kmg2
= opts("labelsKMG2");
115 var mults
= [1, 2, 4, 8];
117 var mults
= [1, 2, 5];
119 var scale
, low_val
, high_val
, nTicks
;
120 for (var i
= -10; i
< 50; i
++) {
122 var base_scale
= Math
.pow(16, i
);
124 var base_scale
= Math
.pow(10, i
);
126 for (var j
= 0; j
< mults
.length
; j
++) {
127 scale
= base_scale
* mults
[j
];
128 low_val
= Math
.floor(a
/ scale
) * scale
;
129 high_val
= Math
.ceil(b
/ scale
) * scale
;
130 nTicks
= Math
.abs(high_val
- low_val
) / scale
;
131 var spacing
= pixels
/ nTicks
;
132 // wish I could break out of both loops at once...
133 if (spacing
> pixels_per_tick
) break;
135 if (spacing
> pixels_per_tick
) break;
138 // Construct the set of ticks.
139 // Allow reverse y-axis if it's explicitly requested.
140 if (low_val
> high_val
) scale
*= -1;
141 for (var i
= 0; i
< nTicks
; i
++) {
142 var tickV
= low_val
+ i
* scale
;
143 ticks
.push( {v
: tickV
} );
148 // Add formatted labels to the ticks.
151 if (opts("labelsKMB")) {
153 k_labels
= [ "K", "M", "B", "T" ];
155 if (opts("labelsKMG2")) {
156 if (k
) self
.warn("Setting both labelsKMB and labelsKMG2. Pick one!");
158 k_labels
= [ "k", "M", "G", "T" ];
161 var formatter
= opts('axisLabelFormatter');
163 // Add labels to the ticks.
164 for (var i
= 0; i
< ticks
.length
; i
++) {
165 if (ticks
[i
].label
!== undefined
) continue; // Use current label.
166 var tickV
= ticks
[i
].v
;
167 var absTickV
= Math
.abs(tickV
);
168 // TODO(danvk): set granularity to something appropriate here.
169 var label
= formatter(tickV
, 0, opts
, dygraph
);
170 if (k_labels
.length
> 0) {
171 // TODO(danvk): should this be integrated into the axisLabelFormatter?
172 // Round up to an appropriate unit.
174 for (var j
= 3; j
>= 0; j
--, n
/= k
) {
176 label
= Dygraph
.round_(tickV
/ n
, opts('digitsAfterDecimal')) +
182 ticks
[i
].label
= label
;
189 Dygraph
.dateTicker
= function(a
, b
, pixels
, opts
, dygraph
, vals
) {
190 var pixels_per_tick
= opts('pixelsPerLabel');
192 for (var i
= 0; i
< Dygraph
.NUM_GRANULARITIES
; i
++) {
193 var num_ticks
= Dygraph
.numDateTicks(a
, b
, i
);
194 if (pixels
/ num_ticks
>= pixels_per_tick
) {
201 return Dygraph
.getDateAxis(a
, b
, chosen
, opts
, dygraph
);
203 // this can happen if self.width_ is zero.
208 // Time granularity enumeration
209 Dygraph
.SECONDLY
= 0;
210 Dygraph
.TWO_SECONDLY
= 1;
211 Dygraph
.FIVE_SECONDLY
= 2;
212 Dygraph
.TEN_SECONDLY
= 3;
213 Dygraph
.THIRTY_SECONDLY
= 4;
214 Dygraph
.MINUTELY
= 5;
215 Dygraph
.TWO_MINUTELY
= 6;
216 Dygraph
.FIVE_MINUTELY
= 7;
217 Dygraph
.TEN_MINUTELY
= 8;
218 Dygraph
.THIRTY_MINUTELY
= 9;
220 Dygraph
.TWO_HOURLY
= 11;
221 Dygraph
.SIX_HOURLY
= 12;
224 Dygraph
.MONTHLY
= 15;
225 Dygraph
.QUARTERLY
= 16;
226 Dygraph
.BIANNUAL
= 17;
228 Dygraph
.DECADAL
= 19;
229 Dygraph
.CENTENNIAL
= 20;
230 Dygraph
.NUM_GRANULARITIES
= 21;
232 Dygraph
.SHORT_SPACINGS
= [];
233 Dygraph
.SHORT_SPACINGS
[Dygraph
.SECONDLY
] = 1000 * 1;
234 Dygraph
.SHORT_SPACINGS
[Dygraph
.TWO_SECONDLY
] = 1000 * 2;
235 Dygraph
.SHORT_SPACINGS
[Dygraph
.FIVE_SECONDLY
] = 1000 * 5;
236 Dygraph
.SHORT_SPACINGS
[Dygraph
.TEN_SECONDLY
] = 1000 * 10;
237 Dygraph
.SHORT_SPACINGS
[Dygraph
.THIRTY_SECONDLY
] = 1000 * 30;
238 Dygraph
.SHORT_SPACINGS
[Dygraph
.MINUTELY
] = 1000 * 60;
239 Dygraph
.SHORT_SPACINGS
[Dygraph
.TWO_MINUTELY
] = 1000 * 60 * 2;
240 Dygraph
.SHORT_SPACINGS
[Dygraph
.FIVE_MINUTELY
] = 1000 * 60 * 5;
241 Dygraph
.SHORT_SPACINGS
[Dygraph
.TEN_MINUTELY
] = 1000 * 60 * 10;
242 Dygraph
.SHORT_SPACINGS
[Dygraph
.THIRTY_MINUTELY
] = 1000 * 60 * 30;
243 Dygraph
.SHORT_SPACINGS
[Dygraph
.HOURLY
] = 1000 * 3600;
244 Dygraph
.SHORT_SPACINGS
[Dygraph
.TWO_HOURLY
] = 1000 * 3600 * 2;
245 Dygraph
.SHORT_SPACINGS
[Dygraph
.SIX_HOURLY
] = 1000 * 3600 * 6;
246 Dygraph
.SHORT_SPACINGS
[Dygraph
.DAILY
] = 1000 * 86400;
247 Dygraph
.SHORT_SPACINGS
[Dygraph
.WEEKLY
] = 1000 * 604800;
251 * This is a list of human-friendly values at which to show tick marks on a log
252 * scale. It is k * 10^n, where k=1..9 and n=-39..+39, so:
253 * ..., 1, 2, 3, 4, 5, ..., 9, 10, 20, 30, ..., 90, 100, 200, 300, ...
254 * NOTE: this assumes that Dygraph.LOG_SCALE = 10.
256 Dygraph
.PREFERRED_LOG_TICK_VALUES
= function() {
258 for (var power
= -39; power
<= 39; power
++) {
259 var range
= Math
.pow(10, power
);
260 for (var mult
= 1; mult
<= 9; mult
++) {
261 var val
= range
* mult
;
268 Dygraph
.numDateTicks
= function(start_time
, end_time
, granularity
) {
269 if (granularity
< Dygraph
.MONTHLY
) {
270 // Generate one tick mark for every fixed interval of time.
271 var spacing
= Dygraph
.SHORT_SPACINGS
[granularity
];
272 return Math
.floor(0.5 + 1.0 * (end_time
- start_time
) / spacing
);
274 var year_mod
= 1; // e.g. to only print one point every 10 years.
276 if (granularity
== Dygraph
.QUARTERLY
) num_months
= 3;
277 if (granularity
== Dygraph
.BIANNUAL
) num_months
= 2;
278 if (granularity
== Dygraph
.ANNUAL
) num_months
= 1;
279 if (granularity
== Dygraph
.DECADAL
) { num_months
= 1; year_mod
= 10; }
280 if (granularity
== Dygraph
.CENTENNIAL
) { num_months
= 1; year_mod
= 100; }
282 var msInYear
= 365.2524 * 24 * 3600 * 1000;
283 var num_years
= 1.0 * (end_time
- start_time
) / msInYear
;
284 return Math
.floor(0.5 + 1.0 * num_years
* num_months
/ year_mod
);
288 Dygraph
.getDateAxis
= function(start_time
, end_time
, granularity
, opts
, dg
) {
289 var formatter
= opts("axisLabelFormatter");
291 if (granularity
< Dygraph
.MONTHLY
) {
292 // Generate one tick mark for every fixed interval of time.
293 var spacing
= Dygraph
.SHORT_SPACINGS
[granularity
];
294 var format
= '%d%b'; // e.g. "1Jan"
296 // Find a time less than start_time which occurs on a "nice" time boundary
297 // for this granularity.
298 var g
= spacing
/ 1000;
299 var d
= new Date(start_time
);
300 if (g
<= 60) { // seconds
301 var x
= d
.getSeconds(); d
.setSeconds(x
- x
% g
);
305 if (g
<= 60) { // minutes
306 var x
= d
.getMinutes(); d
.setMinutes(x
- x
% g
);
311 if (g
<= 24) { // days
312 var x
= d
.getHours(); d
.setHours(x
- x
% g
);
317 if (g
== 7) { // one week
318 d
.setDate(d
.getDate() - d
.getDay());
323 start_time
= d
.getTime();
325 for (var t
= start_time
; t
<= end_time
; t
+= spacing
) {
327 label
: formatter(new Date(t
), granularity
, opts
, dg
)
331 // Display a tick mark on the first of a set of months of each year.
332 // Years get a tick mark iff y % year_mod == 0. This is useful for
333 // displaying a tick mark once every 10 years, say, on long time scales.
335 var year_mod
= 1; // e.g. to only print one point every 10 years.
337 if (granularity
== Dygraph
.MONTHLY
) {
338 months
= [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ];
339 } else if (granularity
== Dygraph
.QUARTERLY
) {
340 months
= [ 0, 3, 6, 9 ];
341 } else if (granularity
== Dygraph
.BIANNUAL
) {
343 } else if (granularity
== Dygraph
.ANNUAL
) {
345 } else if (granularity
== Dygraph
.DECADAL
) {
348 } else if (granularity
== Dygraph
.CENTENNIAL
) {
352 Dygraph
.warn("Span of dates is too long");
355 var start_year
= new Date(start_time
).getFullYear();
356 var end_year
= new Date(end_time
).getFullYear();
357 var zeropad
= Dygraph
.zeropad
;
358 for (var i
= start_year
; i
<= end_year
; i
++) {
359 if (i
% year_mod
!= 0) continue;
360 for (var j
= 0; j
< months
.length
; j
++) {
361 var date_str
= i
+ "/" + zeropad(1 + months[j]) + "/01";
362 var t
= Dygraph
.dateStrToMillis(date_str
);
363 if (t
< start_time
|| t
> end_time
) continue;
365 label
: formatter(new Date(t
), granularity
, opts
, dg
)
374 // These are set here so that this file can be included after dygraph.js.
375 Dygraph
.DEFAULT_ATTRS
.axes
.x
.ticker
= Dygraph
.dateTicker
;
376 Dygraph
.DEFAULT_ATTRS
.axes
.y
.ticker
= Dygraph
.numericTicks
;
377 Dygraph
.DEFAULT_ATTRS
.axes
.y2
.ticker
= Dygraph
.numericTicks
;