dygraphs
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dygraphs is a fast, flexible open source JavaScript charting library.
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JavaScript
/**
* @license
* Copyright 2011 Dan Vanderkam (danvdk@gmail.com)
* MIT-licenced: https://opensource.org/licenses/MIT
*/
/**
* @fileoverview Description of this file.
* @author danvk@google.com (Dan Vanderkam)
*/
/*
* A ticker is a function with the following interface:
*
* function(a, b, pixels, options_view, dygraph, forced_values);
* -> [ { v: tick1_v, label: tick1_label[, label_v: label_v1] },
* { v: tick2_v, label: tick2_label[, label_v: label_v2] },
* ...
* ]
*
* The returned value is called a "tick list".
*
* Arguments
* ---------
*
* [a, b] is the range of the axis for which ticks are being generated. For a
* numeric axis, these will simply be numbers. For a date axis, these will be
* millis since epoch (convertable to Date objects using "new Date(a)" and "new
* Date(b)").
*
* opts provides access to chart- and axis-specific options. It can be used to
* access number/date formatting code/options, check for a log scale, etc.
*
* pixels is the length of the axis in pixels. opts('pixelsPerLabel') is the
* minimum amount of space to be allotted to each label. For instance, if
* pixels=400 and opts('pixelsPerLabel')=40 then the ticker should return
* between zero and ten (400/40) ticks.
*
* dygraph is the Dygraph object for which an axis is being constructed.
*
* forced_values is used for secondary y-axes. The tick positions are typically
* set by the primary y-axis, so the secondary y-axis has no choice in where to
* put these. It simply has to generate labels for these data values.
*
* Tick lists
* ----------
* Typically a tick will have both a grid/tick line and a label at one end of
* that line (at the bottom for an x-axis, at left or right for the y-axis).
*
* A tick may be missing one of these two components:
* - If "label_v" is specified instead of "v", then there will be no tick or
* gridline, just a label.
* - Similarly, if "label" is not specified, then there will be a gridline
* without a label.
*
* This flexibility is useful in a few situations:
* - For log scales, some of the tick lines may be too close to all have labels.
* - For date scales where years are being displayed, it is desirable to display
* tick marks at the beginnings of years but labels (e.g. "2006") in the
* middle of the years.
*/
/*jshint sub:true */
/*global Dygraph:false */
"use strict";
import * as utils from './dygraph-utils';
/** @typedef {Array.<{v:number, label:string, label_v:(string|undefined)}>} */
var TickList = undefined; // the ' = undefined' keeps jshint happy.
/** @typedef {function(
* number,
* number,
* number,
* function(string):*,
* Dygraph=,
* Array.<number>=
* ): TickList}
*/
var Ticker = undefined; // the ' = undefined' keeps jshint happy.
/** @type {Ticker} */
export var numericLinearTicks = function(a, b, pixels, opts, dygraph, vals) {
var nonLogscaleOpts = function(opt) {
if (opt === 'logscale') return false;
return opts(opt);
};
return numericTicks(a, b, pixels, nonLogscaleOpts, dygraph, vals);
};
/** @type {Ticker} */
export var numericTicks = function(a, b, pixels, opts, dygraph, vals) {
var pixels_per_tick = /** @type{number} */(opts('pixelsPerLabel'));
var ticks = [];
var i, j, tickV, nTicks;
if (vals) {
for (i = 0; i < vals.length; i++) {
ticks.push({v: vals[i]});
}
} else {
// TODO(danvk): factor this log-scale block out into a separate function.
if (opts("logscale")) {
nTicks = Math.floor(pixels / pixels_per_tick);
var minIdx = utils.binarySearch(a, PREFERRED_LOG_TICK_VALUES, 1);
var maxIdx = utils.binarySearch(b, PREFERRED_LOG_TICK_VALUES, -1);
if (minIdx == -1) {
minIdx = 0;
}
if (maxIdx == -1) {
maxIdx = PREFERRED_LOG_TICK_VALUES.length - 1;
}
// Count the number of tick values would appear, if we can get at least
// nTicks / 4 accept them.
var lastDisplayed = null;
if (maxIdx - minIdx >= nTicks / 4) {
for (var idx = maxIdx; idx >= minIdx; idx--) {
var tickValue = PREFERRED_LOG_TICK_VALUES[idx];
var pixel_coord = Math.log(tickValue / a) / Math.log(b / a) * pixels;
var tick = { v: tickValue };
if (lastDisplayed === null) {
lastDisplayed = {
tickValue : tickValue,
pixel_coord : pixel_coord
};
} else {
if (Math.abs(pixel_coord - lastDisplayed.pixel_coord) >= pixels_per_tick) {
lastDisplayed = {
tickValue : tickValue,
pixel_coord : pixel_coord
};
} else {
tick.label = "";
}
}
ticks.push(tick);
}
// Since we went in backwards order.
ticks.reverse();
}
}
// ticks.length won't be 0 if the log scale function finds values to insert.
if (ticks.length === 0) {
// Basic idea:
// Try labels every 1, 2, 5, 10, 20, 50, 100, etc.
// Calculate the resulting tick spacing (i.e. this.height_ / nTicks).
// The first spacing greater than pixelsPerYLabel is what we use.
// TODO(danvk): version that works on a log scale.
var kmg2 = opts("labelsKMG2");
var mults, base;
if (kmg2) {
mults = [1, 2, 4, 8, 16, 32, 64, 128, 256];
base = 16;
} else {
mults = [1, 2, 5, 10, 20, 50, 100];
base = 10;
}
// Get the maximum number of permitted ticks based on the
// graph's pixel size and pixels_per_tick setting.
var max_ticks = Math.ceil(pixels / pixels_per_tick);
// Now calculate the data unit equivalent of this tick spacing.
// Use abs() since graphs may have a reversed Y axis.
var units_per_tick = Math.abs(b - a) / max_ticks;
// Based on this, get a starting scale which is the largest
// integer power of the chosen base (10 or 16) that still remains
// below the requested pixels_per_tick spacing.
var base_power = Math.floor(Math.log(units_per_tick) / Math.log(base));
var base_scale = Math.pow(base, base_power);
// Now try multiples of the starting scale until we find one
// that results in tick marks spaced sufficiently far apart.
// The "mults" array should cover the range 1 .. base^2 to
// adjust for rounding and edge effects.
var scale, low_val, high_val, spacing;
for (j = 0; j < mults.length; j++) {
scale = base_scale * mults[j];
low_val = Math.floor(a / scale) * scale;
high_val = Math.ceil(b / scale) * scale;
nTicks = Math.abs(high_val - low_val) / scale;
spacing = pixels / nTicks;
if (spacing > pixels_per_tick) break;
}
// Construct the set of ticks.
// Allow reverse y-axis if it's explicitly requested.
if (low_val > high_val) scale *= -1;
for (i = 0; i <= nTicks; i++) {
tickV = low_val + i * scale;
ticks.push( {v: tickV} );
}
}
}
var formatter = /**@type{AxisLabelFormatter}*/(opts('axisLabelFormatter'));
// Add labels to the ticks.
for (i = 0; i < ticks.length; i++) {
if (ticks[i].label !== undefined) continue; // Use current label.
// TODO(danvk): set granularity to something appropriate here.
ticks[i].label = formatter.call(dygraph, ticks[i].v, 0, opts, dygraph);
}
return ticks;
};
/** @type {Ticker} */
export var dateTicker = function(a, b, pixels, opts, dygraph, vals) {
var chosen = pickDateTickGranularity(a, b, pixels, opts);
if (chosen >= 0) {
return getDateAxis(a, b, chosen, opts, dygraph);
} else {
// this can happen if self.width_ is zero.
return [];
}
};
// Time granularity enumeration
export var Granularity = {
MILLISECONDLY: 0,
TWO_MILLISECONDLY: 1,
FIVE_MILLISECONDLY: 2,
TEN_MILLISECONDLY: 3,
FIFTY_MILLISECONDLY: 4,
HUNDRED_MILLISECONDLY: 5,
FIVE_HUNDRED_MILLISECONDLY: 6,
SECONDLY: 7,
TWO_SECONDLY: 8,
FIVE_SECONDLY: 9,
TEN_SECONDLY: 10,
THIRTY_SECONDLY: 11,
MINUTELY: 12,
TWO_MINUTELY: 13,
FIVE_MINUTELY: 14,
TEN_MINUTELY: 15,
THIRTY_MINUTELY: 16,
HOURLY: 17,
TWO_HOURLY: 18,
SIX_HOURLY: 19,
DAILY: 20,
TWO_DAILY: 21,
WEEKLY: 22,
MONTHLY: 23,
QUARTERLY: 24,
BIANNUAL: 25,
ANNUAL: 26,
DECADAL: 27,
CENTENNIAL: 28,
NUM_GRANULARITIES: 29
}
// Date components enumeration (in the order of the arguments in Date)
// TODO: make this an @enum
var DateField = {
DATEFIELD_Y: 0,
DATEFIELD_M: 1,
DATEFIELD_D: 2,
DATEFIELD_HH: 3,
DATEFIELD_MM: 4,
DATEFIELD_SS: 5,
DATEFIELD_MS: 6,
NUM_DATEFIELDS: 7
};
/**
* The value of datefield will start at an even multiple of "step", i.e.
* if datefield=SS and step=5 then the first tick will be on a multiple of 5s.
*
* For granularities <= HOURLY, ticks are generated every `spacing` ms.
*
* At coarser granularities, ticks are generated by incrementing `datefield` by
* `step`. In this case, the `spacing` value is only used to estimate the
* number of ticks. It should roughly correspond to the spacing between
* adjacent ticks.
*
* @type {Array.<{datefield:number, step:number, spacing:number}>}
*/
var TICK_PLACEMENT = [];
TICK_PLACEMENT[Granularity.MILLISECONDLY] = {datefield: DateField.DATEFIELD_MS, step: 1, spacing: 1};
TICK_PLACEMENT[Granularity.TWO_MILLISECONDLY] = {datefield: DateField.DATEFIELD_MS, step: 2, spacing: 2};
TICK_PLACEMENT[Granularity.FIVE_MILLISECONDLY] = {datefield: DateField.DATEFIELD_MS, step: 5, spacing: 5};
TICK_PLACEMENT[Granularity.TEN_MILLISECONDLY] = {datefield: DateField.DATEFIELD_MS, step: 10, spacing: 10};
TICK_PLACEMENT[Granularity.FIFTY_MILLISECONDLY] = {datefield: DateField.DATEFIELD_MS, step: 50, spacing: 50};
TICK_PLACEMENT[Granularity.HUNDRED_MILLISECONDLY] = {datefield: DateField.DATEFIELD_MS, step: 100, spacing: 100};
TICK_PLACEMENT[Granularity.FIVE_HUNDRED_MILLISECONDLY] = {datefield: DateField.DATEFIELD_MS, step: 500, spacing: 500};
TICK_PLACEMENT[Granularity.SECONDLY] = {datefield: DateField.DATEFIELD_SS, step: 1, spacing: 1000 * 1};
TICK_PLACEMENT[Granularity.TWO_SECONDLY] = {datefield: DateField.DATEFIELD_SS, step: 2, spacing: 1000 * 2};
TICK_PLACEMENT[Granularity.FIVE_SECONDLY] = {datefield: DateField.DATEFIELD_SS, step: 5, spacing: 1000 * 5};
TICK_PLACEMENT[Granularity.TEN_SECONDLY] = {datefield: DateField.DATEFIELD_SS, step: 10, spacing: 1000 * 10};
TICK_PLACEMENT[Granularity.THIRTY_SECONDLY] = {datefield: DateField.DATEFIELD_SS, step: 30, spacing: 1000 * 30};
TICK_PLACEMENT[Granularity.MINUTELY] = {datefield: DateField.DATEFIELD_MM, step: 1, spacing: 1000 * 60};
TICK_PLACEMENT[Granularity.TWO_MINUTELY] = {datefield: DateField.DATEFIELD_MM, step: 2, spacing: 1000 * 60 * 2};
TICK_PLACEMENT[Granularity.FIVE_MINUTELY] = {datefield: DateField.DATEFIELD_MM, step: 5, spacing: 1000 * 60 * 5};
TICK_PLACEMENT[Granularity.TEN_MINUTELY] = {datefield: DateField.DATEFIELD_MM, step: 10, spacing: 1000 * 60 * 10};
TICK_PLACEMENT[Granularity.THIRTY_MINUTELY] = {datefield: DateField.DATEFIELD_MM, step: 30, spacing: 1000 * 60 * 30};
TICK_PLACEMENT[Granularity.HOURLY] = {datefield: DateField.DATEFIELD_HH, step: 1, spacing: 1000 * 3600};
TICK_PLACEMENT[Granularity.TWO_HOURLY] = {datefield: DateField.DATEFIELD_HH, step: 2, spacing: 1000 * 3600 * 2};
TICK_PLACEMENT[Granularity.SIX_HOURLY] = {datefield: DateField.DATEFIELD_HH, step: 6, spacing: 1000 * 3600 * 6};
TICK_PLACEMENT[Granularity.DAILY] = {datefield: DateField.DATEFIELD_D, step: 1, spacing: 1000 * 86400};
TICK_PLACEMENT[Granularity.TWO_DAILY] = {datefield: DateField.DATEFIELD_D, step: 2, spacing: 1000 * 86400 * 2};
TICK_PLACEMENT[Granularity.WEEKLY] = {datefield: DateField.DATEFIELD_D, step: 7, spacing: 1000 * 604800};
TICK_PLACEMENT[Granularity.MONTHLY] = {datefield: DateField.DATEFIELD_M, step: 1, spacing: 1000 * 7200 * 365.2425}; // 1e3 * 60 * 60 * 24 * 365.2425 / 12
TICK_PLACEMENT[Granularity.QUARTERLY] = {datefield: DateField.DATEFIELD_M, step: 3, spacing: 1000 * 21600 * 365.2425}; // 1e3 * 60 * 60 * 24 * 365.2425 / 4
TICK_PLACEMENT[Granularity.BIANNUAL] = {datefield: DateField.DATEFIELD_M, step: 6, spacing: 1000 * 43200 * 365.2425}; // 1e3 * 60 * 60 * 24 * 365.2425 / 2
TICK_PLACEMENT[Granularity.ANNUAL] = {datefield: DateField.DATEFIELD_Y, step: 1, spacing: 1000 * 86400 * 365.2425}; // 1e3 * 60 * 60 * 24 * 365.2425 * 1
TICK_PLACEMENT[Granularity.DECADAL] = {datefield: DateField.DATEFIELD_Y, step: 10, spacing: 1000 * 864000 * 365.2425}; // 1e3 * 60 * 60 * 24 * 365.2425 * 10
TICK_PLACEMENT[Granularity.CENTENNIAL] = {datefield: DateField.DATEFIELD_Y, step: 100, spacing: 1000 * 8640000 * 365.2425}; // 1e3 * 60 * 60 * 24 * 365.2425 * 100
/**
* This is a list of human-friendly values at which to show tick marks on a log
* scale. It is k * 10^n, where k=1..9 and n=-39..+39, so:
* ..., 1, 2, 3, 4, 5, ..., 9, 10, 20, 30, ..., 90, 100, 200, 300, ...
* NOTE: this assumes that utils.LOG_SCALE = 10.
* @type {Array.<number>}
*/
var PREFERRED_LOG_TICK_VALUES = (function() {
var vals = [];
for (var power = -39; power <= 39; power++) {
var range = Math.pow(10, power);
for (var mult = 1; mult <= 9; mult++) {
var val = range * mult;
vals.push(val);
}
}
return vals;
})();
/**
* Determine the correct granularity of ticks on a date axis.
*
* @param {number} a Left edge of the chart (ms)
* @param {number} b Right edge of the chart (ms)
* @param {number} pixels Size of the chart in the relevant dimension (width).
* @param {function(string):*} opts Function mapping from option name -> value.
* @return {number} The appropriate axis granularity for this chart. See the
* enumeration of possible values in dygraph-tickers.js.
*/
export var pickDateTickGranularity = function(a, b, pixels, opts) {
var pixels_per_tick = /** @type{number} */(opts('pixelsPerLabel'));
for (var i = 0; i < Granularity.NUM_GRANULARITIES; i++) {
var num_ticks = numDateTicks(a, b, i);
if (pixels / num_ticks >= pixels_per_tick) {
return i;
}
}
return -1;
};
/**
* Compute the number of ticks on a date axis for a given granularity.
* @param {number} start_time
* @param {number} end_time
* @param {number} granularity (one of the granularities enumerated above)
* @return {number} (Approximate) number of ticks that would result.
*/
var numDateTicks = function(start_time, end_time, granularity) {
var spacing = TICK_PLACEMENT[granularity].spacing;
return Math.round(1.0 * (end_time - start_time) / spacing);
};
/**
* Compute the positions and labels of ticks on a date axis for a given granularity.
* @param {number} start_time
* @param {number} end_time
* @param {number} granularity (one of the granularities enumerated above)
* @param {function(string):*} opts Function mapping from option name -> value.
* @param {Dygraph=} dg
* @return {!TickList}
*/
export var getDateAxis = function(start_time, end_time, granularity, opts, dg) {
var formatter = /** @type{AxisLabelFormatter} */(
opts("axisLabelFormatter"));
var utc = opts("labelsUTC");
var accessors = utc ? utils.DateAccessorsUTC : utils.DateAccessorsLocal;
var datefield = TICK_PLACEMENT[granularity].datefield;
var step = TICK_PLACEMENT[granularity].step;
var spacing = TICK_PLACEMENT[granularity].spacing;
// Choose a nice tick position before the initial instant.
// Currently, this code deals properly with the existent daily granularities:
// DAILY (with step of 1) and WEEKLY (with step of 7 but specially handled).
// Other daily granularities (say TWO_DAILY) should also be handled specially
// by setting the start_date_offset to 0.
var start_date = new Date(start_time);
var date_array = [];
date_array[DateField.DATEFIELD_Y] = accessors.getFullYear(start_date);
date_array[DateField.DATEFIELD_M] = accessors.getMonth(start_date);
date_array[DateField.DATEFIELD_D] = accessors.getDate(start_date);
date_array[DateField.DATEFIELD_HH] = accessors.getHours(start_date);
date_array[DateField.DATEFIELD_MM] = accessors.getMinutes(start_date);
date_array[DateField.DATEFIELD_SS] = accessors.getSeconds(start_date);
date_array[DateField.DATEFIELD_MS] = accessors.getMilliseconds(start_date);
var start_date_offset = date_array[datefield] % step;
if (granularity == Granularity.WEEKLY) {
// This will put the ticks on Sundays.
start_date_offset = accessors.getDay(start_date);
}
date_array[datefield] -= start_date_offset;
for (var df = datefield + 1; df < DateField.NUM_DATEFIELDS; df++) {
// The minimum value is 1 for the day of month, and 0 for all other fields.
date_array[df] = (df === DateField.DATEFIELD_D) ? 1 : 0;
}
// Generate the ticks.
// For granularities not coarser than HOURLY we use the fact that:
// the number of milliseconds between ticks is constant
// and equal to the defined spacing.
// Otherwise we rely on the 'roll over' property of the Date functions:
// when some date field is set to a value outside of its logical range,
// the excess 'rolls over' the next (more significant) field.
// However, when using local time with DST transitions,
// there are dates that do not represent any time value at all
// (those in the hour skipped at the 'spring forward'),
// and the JavaScript engines usually return an equivalent value.
// Hence we have to check that the date is properly increased at each step,
// returning a date at a nice tick position.
var ticks = [];
var tick_date = accessors.makeDate.apply(null, date_array);
var tick_time = tick_date.getTime();
if (granularity <= Granularity.HOURLY) {
if (tick_time < start_time) {
tick_time += spacing;
tick_date = new Date(tick_time);
}
while (tick_time <= end_time) {
ticks.push({ v: tick_time,
label: formatter.call(dg, tick_date, granularity, opts, dg)
});
tick_time += spacing;
tick_date = new Date(tick_time);
}
} else {
if (tick_time < start_time) {
date_array[datefield] += step;
tick_date = accessors.makeDate.apply(null, date_array);
tick_time = tick_date.getTime();
}
while (tick_time <= end_time) {
if (granularity >= Granularity.DAILY ||
accessors.getHours(tick_date) % step === 0) {
ticks.push({ v: tick_time,
label: formatter.call(dg, tick_date, granularity, opts, dg)
});
}
date_array[datefield] += step;
tick_date = accessors.makeDate.apply(null, date_array);
tick_time = tick_date.getTime();
}
}
return ticks;
};