dygraphs

<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"> <style> .KEYW {color: #933;} .COMM {color: #bbb; font-style: italic;} .NUMB {color: #393;} .STRN {color: #393;} .REGX {color: #339;} .line {border-right: 1px dotted #666; color: #666; font-style: normal;} </style></head><body><pre> 1 /** 2 * @license 3 * Copyright 2011 Dan Vanderkam (danvdk@gmail.com) 4 * MIT-licenced: https://opensource.org/licenses/MIT 5 */ 6 7 /** 8 * @fileoverview Description of this file. 9 * @author danvk@google.com (Dan Vanderkam) 10 */ 11 12 /* 13 * A ticker is a function with the following interface: 14 * 15 * function(a, b, pixels, options_view, dygraph, forced_values); 16 * -> [ { v: tick1_v, label: tick1_label[, label_v: label_v1] }, 17 * { v: tick2_v, label: tick2_label[, label_v: label_v2] }, 18 * ... 19 * ] 20 * 21 * The returned value is called a "tick list". 22 * 23 * Arguments 24 * --------- 25 * 26 * [a, b] is the range of the axis for which ticks are being generated. For a 27 * numeric axis, these will simply be numbers. For a date axis, these will be 28 * millis since epoch (convertable to Date objects using "new Date(a)" and "new 29 * Date(b)"). 30 * 31 * opts provides access to chart- and axis-specific options. It can be used to 32 * access number/date formatting code/options, check for a log scale, etc. 33 * 34 * pixels is the length of the axis in pixels. opts('pixelsPerLabel') is the 35 * minimum amount of space to be allotted to each label. For instance, if 36 * pixels=400 and opts('pixelsPerLabel')=40 then the ticker should return 37 * between zero and ten (400/40) ticks. 38 * 39 * dygraph is the Dygraph object for which an axis is being constructed. 40 * 41 * forced_values is used for secondary y-axes. The tick positions are typically 42 * set by the primary y-axis, so the secondary y-axis has no choice in where to 43 * put these. It simply has to generate labels for these data values. 44 * 45 * Tick lists 46 * ---------- 47 * Typically a tick will have both a grid/tick line and a label at one end of 48 * that line (at the bottom for an x-axis, at left or right for the y-axis). 49 * 50 * A tick may be missing one of these two components: 51 * - If "label_v" is specified instead of "v", then there will be no tick or 52 * gridline, just a label. 53 * - Similarly, if "label" is not specified, then there will be a gridline 54 * without a label. 55 * 56 * This flexibility is useful in a few situations: 57 * - For log scales, some of the tick lines may be too close to all have labels. 58 * - For date scales where years are being displayed, it is desirable to display 59 * tick marks at the beginnings of years but labels (e.g. "2006") in the 60 * middle of the years. 61 */ 62 63 /*jshint sub:true */ 64 /*global Dygraph:false */ 65 "use strict"; 66 67 import * as utils from './dygraph-utils'; 68 69 /** @typedef {Array.<{v:number, label:string, label_v:(string|undefined)}>} */ 70 var TickList = undefined; // the ' = undefined' keeps jshint happy. 71 72 /** @typedef {function( 73 * number, 74 * number, 75 * number, 76 * function(string):*, 77 * Dygraph=, 78 * Array.<number>= 79 * ): TickList} 80 */ 81 var Ticker = undefined; // the ' = undefined' keeps jshint happy. 82 83 /** @type {Ticker} */ 84 export var numericLinearTicks = function(a, b, pixels, opts, dygraph, vals) { 85 var nonLogscaleOpts = function(opt) { 86 if (opt === 'logscale') return false; 87 return opts(opt); 88 }; 89 return numericTicks(a, b, pixels, nonLogscaleOpts, dygraph, vals); 90 }; 91 92 /** @type {Ticker} */ 93 export var numericTicks = function(a, b, pixels, opts, dygraph, vals) { 94 var pixels_per_tick = /** @type{number} */(opts('pixelsPerLabel')); 95 var ticks = []; 96 var i, j, tickV, nTicks; 97 if (vals) { 98 for (i = 0; i < vals.length; i++) { 99 ticks.push({v: vals[i]}); 100 } 101 } else { 102 // TODO(danvk): factor this log-scale block out into a separate function. 103 if (opts("logscale")) { 104 nTicks = Math.floor(pixels / pixels_per_tick); 105 var minIdx = utils.binarySearch(a, PREFERRED_LOG_TICK_VALUES, 1); 106 var maxIdx = utils.binarySearch(b, PREFERRED_LOG_TICK_VALUES, -1); 107 if (minIdx == -1) { 108 minIdx = 0; 109 } 110 if (maxIdx == -1) { 111 maxIdx = PREFERRED_LOG_TICK_VALUES.length - 1; 112 } 113 // Count the number of tick values would appear, if we can get at least 114 // nTicks / 4 accept them. 115 var lastDisplayed = null; 116 if (maxIdx - minIdx >= nTicks / 4) { 117 for (var idx = maxIdx; idx >= minIdx; idx--) { 118 var tickValue = PREFERRED_LOG_TICK_VALUES[idx]; 119 var pixel_coord = Math.log(tickValue / a) / Math.log(b / a) * pixels; 120 var tick = { v: tickValue }; 121 if (lastDisplayed === null) { 122 lastDisplayed = { 123 tickValue : tickValue, 124 pixel_coord : pixel_coord 125 }; 126 } else { 127 if (Math.abs(pixel_coord - lastDisplayed.pixel_coord) >= pixels_per_tick) { 128 lastDisplayed = { 129 tickValue : tickValue, 130 pixel_coord : pixel_coord 131 }; 132 } else { 133 tick.label = ""; 134 } 135 } 136 ticks.push(tick); 137 } 138 // Since we went in backwards order. 139 ticks.reverse(); 140 } 141 } 142 143 // ticks.length won't be 0 if the log scale function finds values to insert. 144 if (ticks.length === 0) { 145 // Basic idea: 146 // Try labels every 1, 2, 5, 10, 20, 50, 100, etc. 147 // Calculate the resulting tick spacing (i.e. this.height_ / nTicks). 148 // The first spacing greater than pixelsPerYLabel is what we use. 149 // TODO(danvk): version that works on a log scale. 150 var kmg2 = opts("labelsKMG2"); 151 var mults, base; 152 if (kmg2) { 153 mults = [1, 2, 4, 8, 16, 32, 64, 128, 256]; 154 base = 16; 155 } else { 156 mults = [1, 2, 5, 10, 20, 50, 100]; 157 base = 10; 158 } 159 160 // Get the maximum number of permitted ticks based on the 161 // graph's pixel size and pixels_per_tick setting. 162 var max_ticks = Math.ceil(pixels / pixels_per_tick); 163 164 // Now calculate the data unit equivalent of this tick spacing. 165 // Use abs() since graphs may have a reversed Y axis. 166 var units_per_tick = Math.abs(b - a) / max_ticks; 167 168 // Based on this, get a starting scale which is the largest 169 // integer power of the chosen base (10 or 16) that still remains 170 // below the requested pixels_per_tick spacing. 171 var base_power = Math.floor(Math.log(units_per_tick) / Math.log(base)); 172 var base_scale = Math.pow(base, base_power); 173 174 // Now try multiples of the starting scale until we find one 175 // that results in tick marks spaced sufficiently far apart. 176 // The "mults" array should cover the range 1 .. base^2 to 177 // adjust for rounding and edge effects. 178 var scale, low_val, high_val, spacing; 179 for (j = 0; j < mults.length; j++) { 180 scale = base_scale * mults[j]; 181 low_val = Math.floor(a / scale) * scale; 182 high_val = Math.ceil(b / scale) * scale; 183 nTicks = Math.abs(high_val - low_val) / scale; 184 spacing = pixels / nTicks; 185 if (spacing > pixels_per_tick) break; 186 } 187 188 // Construct the set of ticks. 189 // Allow reverse y-axis if it's explicitly requested. 190 if (low_val > high_val) scale *= -1; 191 for (i = 0; i <= nTicks; i++) { 192 tickV = low_val + i * scale; 193 ticks.push( {v: tickV} ); 194 } 195 } 196 } 197 198 var formatter = /**@type{AxisLabelFormatter}*/(opts('axisLabelFormatter')); 199 200 // Add labels to the ticks. 201 for (i = 0; i < ticks.length; i++) { 202 if (ticks[i].label !== undefined) continue; // Use current label. 203 // TODO(danvk): set granularity to something appropriate here. 204 ticks[i].label = formatter.call(dygraph, ticks[i].v, 0, opts, dygraph); 205 } 206 207 return ticks; 208 }; 209 210 /** @type {Ticker} */ 211 export var dateTicker = function(a, b, pixels, opts, dygraph, vals) { 212 var chosen = pickDateTickGranularity(a, b, pixels, opts); 213 214 if (chosen >= 0) { 215 return getDateAxis(a, b, chosen, opts, dygraph); 216 } else<sp