};
DygraphLayout.prototype._evaluateLineCharts = function() {
- // add all the rects
- this.points = [];
// An array to keep track of how many points will be drawn for each set.
// This will allow for the canvas renderer to not have to check every point
// for every data set since the points are added in order of the sets in
this.setPointsOffsets = [];
var connectSeparated = this.attr_('connectSeparatedPoints');
- for (var setIdx = 0; setIdx < this.datasets.length; ++setIdx) {
+ // TODO(bhs): these loops are a hot-spot for high-point-count charts. In fact,
+ // on chrome+linux, they are 6 times more expensive than iterating through the
+ // points and drawing the lines. The brunt of the cost comes from allocating
+ // the |point| structures.
+ var i = 0;
+ var setIdx;
+
+ // Preallocating the size of points reduces reallocations, and therefore,
+ // calls to collect garbage.
+ var totalPoints = 0;
+ for (setIdx = 0; setIdx < this.datasets.length; ++setIdx) {
+ totalPoints += this.datasets[setIdx].length;
+ }
+ this.points = new Array(totalPoints);
+
+ for (setIdx = 0; setIdx < this.datasets.length; ++setIdx) {
+ this.setPointsOffsets.push(i);
var dataset = this.datasets[setIdx];
var setName = this.setNames[setIdx];
var axis = this.dygraph_.axisPropertiesForSeries(setName);
- this.setPointsOffsets.push(this.points.length);
- var setPointsLength = 0;
-
for (var j = 0; j < dataset.length; j++) {
var item = dataset[j];
- var xValue = parseFloat(item[0]);
- var yValue = parseFloat(item[1]);
+ var xValue = DygraphLayout.parseFloat_(item[0]);
+ var yValue = DygraphLayout.parseFloat_(item[1]);
// Range from 0-1 where 0 represents left and 1 represents right.
var xNormal = (xValue - this.minxval) * this.xscale;
// Range from 0-1 where 0 represents top and 1 represents bottom
var yNormal = DygraphLayout._calcYNormal(axis, yValue);
- var point = {
+ if (connectSeparated && item[1] === null) {
+ yValue = null;
+ }
+ this.points[i] = {
// TODO(danvk): here
x: xNormal,
y: yNormal,
yval: yValue,
name: setName
};
- if (connectSeparated && item[1] === null) {
- point.yval = null;
- }
- this.points.push(point);
- setPointsLength += 1;
+ i++;
}
- this.setPointsLengths.push(setPointsLength);
+ this.setPointsLengths.push(i - this.setPointsOffsets[setIdx]);
}
};
+/**
+ * Optimized replacement for parseFloat, which was way too slow when almost
+ * all values were type number, with few edge cases, none of which were strings.
+ */
+DygraphLayout.parseFloat_ = function(val) {
+ // parseFloat(null) is NaN
+ if (val === null) {
+ return NaN;
+ }
+
+ // Assume it's a number or NaN. If it's something else, I'll be shocked.
+ return val;
+}
+
DygraphLayout.prototype._evaluateLineTicks = function() {
var i, tick, label, pos;
this.xticks = [];
var axis = this.dygraph_.axisPropertiesForSeries(setName);
for (j = 0; j < dataset.length; j++, i++) {
var item = dataset[j];
- var xv = parseFloat(item[0]);
- var yv = parseFloat(item[1]);
+ var xv = DygraphLayout.parseFloat_(item[0]);
+ var yv = DygraphLayout.parseFloat_(item[1]);
if (xv == this.points[i].xval &&
yv == this.points[i].yval) {
- var errorMinus = parseFloat(item[2]);
- var errorPlus = parseFloat(item[3]);
+ var errorMinus = DygraphLayout.parseFloat_(item[2]);
+ var errorPlus = DygraphLayout.parseFloat_(item[3]);
var yv_minus = yv - errorMinus;
var yv_plus = yv + errorPlus;