3 * Copyright 2013 David Eberlein (david.eberlein@ch.sauter-bc.com)
4 * MIT-licensed (http://opensource.org/licenses/MIT)
8 * @fileoverview This file contains the managment of data handlers
9 * @author David Eberlein (david.eberlein@ch.sauter-bc.com)
11 * The idea is to define a common, generic data format that works for all data
12 * structures supported by dygraphs. To make this possible, the DataHandler
13 * interface is introduced. This makes it possible, that dygraph itself can work
14 * with the same logic for every data type independent of the actual format and
15 * the DataHandler takes care of the data format specific jobs.
16 * DataHandlers are implemented for all data types supported by Dygraphs and
17 * return Dygraphs compliant formats.
18 * By default the correct DataHandler is chosen based on the options set.
19 * Optionally the user may use his own DataHandler (similar to the plugin
23 * The unified data format returend by each handler is defined as so:
24 * series[n][point] = [x,y,(extras)]
26 * This format contains the common basis that is needed to draw a simple line
27 * series extended by optional extras for more complex graphing types. It
28 * contains a primitive x value as first array entry, a primitive y value as
29 * second array entry and an optional extras object for additional data needed.
31 * x must always be a number.
32 * y must always be a number, NaN of type number or null.
33 * extras is optional and must be interpreted by the DataHandler. It may be of
36 * In practice this might look something like this:
38 * errorBar / customBar: [x, yVal, [yTopVariance, yBottomVariance] ]
41 /*global Dygraph:false */
42 /*global DygraphLayout:false */
48 * The data handler is responsible for all data specific operations. All of the
49 * series data it receives and returns is always in the unified data format.
50 * Initially the unified data is created by the extractSeries method
53 var DygraphDataHandler
= function () {
56 var handler
= DygraphDataHandler
;
59 * X-value array index constant for unified data samples.
66 * Y-value array index constant for unified data samples.
73 * Extras-value array index constant for unified data samples.
80 * Extracts one series from the raw data (a 2D array) into an array of the
81 * unified data format.
82 * This is where undesirable points (i.e. negative values on log scales and
83 * missing values through which we wish to connect lines) are dropped.
84 * TODO(danvk): the "missing values" bit above doesn't seem right.
86 * @param {!Array.<Array>} rawData The raw data passed into dygraphs where
87 * rawData[i] = [x,ySeries1,...,ySeriesN].
88 * @param {!number} seriesIndex Index of the series to extract. All other
89 * series should be ignored.
90 * @param {!DygraphOptions} options Dygraph options.
91 * @return {Array.<[!number,?number,?]>} The series in the unified data format
92 * where series[i] = [x,y,{extras}].
94 handler
.prototype.extractSeries
= function(rawData
, seriesIndex
, options
) {
98 * Converts a series to a Point array. The resulting point array must be
99 * returned in increasing order of idx property.
101 * @param {!Array.<[!number,?number,?]>} series The series in the unified
102 * data format where series[i] = [x,y,{extras}].
103 * @param {!string} setName Name of the series.
104 * @param {!number} boundaryIdStart Index offset of the first point, equal to the
105 * number of skipped points left of the date window minimum (if any).
106 * @return {!Array.<Dygraph.PointType>} List of points for this series.
108 handler
.prototype.seriesToPoints
= function(series
, setName
, boundaryIdStart
) {
109 // TODO(bhs): these loops are a hot-spot for high-point-count charts. In
111 // on chrome+linux, they are 6 times more expensive than iterating through
113 // points and drawing the lines. The brunt of the cost comes from allocating
114 // the |point| structures.
116 for ( var i
= 0; i
< series
.length
; ++i
) {
117 var item
= series
[i
];
119 var yval
= yraw
=== null ? null : handler
.parseFloat(yraw
);
123 xval
: handler
.parseFloat(item
[0]),
125 name
: setName
, // TODO(danvk): is this really necessary?
126 idx
: i
+ boundaryIdStart
,
127 canvasx
: NaN
, // add these so we do not alter the structure later, which slows Chrome
132 this.onPointsCreated_(series
, points
);
137 * Callback called for each series after the series points have been generated
138 * which will later be used by the plotters to draw the graph.
139 * Here data may be added to the seriesPoints which is needed by the plotters.
140 * The indexes of series and points are in sync meaning the original data
141 * sample for series[i] is points[i].
143 * @param {!Array.<[!number,?number,?]>} series The series in the unified
144 * data format where series[i] = [x,y,{extras}].
145 * @param {!Array.<Dygraph.PointType>} points The corresponding points passed
149 handler
.prototype.onPointsCreated_
= function(series
, points
) {
153 * Calculates the rolling average of a data set.
155 * @param {!Array.<[!number,?number,?]>} series The series in the unified
156 * data format where series[i] = [x,y,{extras}].
157 * @param {!number} rollPeriod The number of points over which to average the data
158 * @param {!DygraphOptions} options The dygraph options.
159 * @return {!Array.<[!number,?number,?]>} the rolled series.
161 handler
.prototype.rollingAverage
= function(series
, rollPeriod
, options
) {
165 * Computes the range of the data series (including confidence intervals).
167 * @param {!Array.<[!number,?number,?]>} series The series in the unified
168 * data format where series[i] = [x, y, {extras}].
169 * @param {!Array.<number>} dateWindow The x-value range to display with
170 * the format: [min, max].
171 * @param {!DygraphOptions} options The dygraph options.
172 * @return {Array.<number>} The low and high extremes of the series in the
173 * given window with the format: [low, high].
175 handler
.prototype.getExtremeYValues
= function(series
, dateWindow
, options
) {
179 * Callback called for each series after the layouting data has been
180 * calculated before the series is drawn. Here normalized positioning data
181 * should be calculated for the extras of each point.
183 * @param {!Array.<Dygraph.PointType>} points The points passed to
185 * @param {!Object} axis The axis on which the series will be plotted.
186 * @param {!boolean} logscale Weather or not to use a logscale.
188 handler
.prototype.onLineEvaluated
= function(points
, axis
, logscale
) {
192 * Optimized replacement for parseFloat, which was way too slow when almost
193 * all values were type number, with few edge cases, none of which were strings.
194 * @param {?number} val
198 handler
.parseFloat
= function(val
) {
199 // parseFloat(null) is NaN
204 // Assume it's a number or NaN. If it's something else, I'll be shocked.
208 export default DygraphDataHandler
;