bhs performance enhancement base. This hits biggest bang for the buck.

[dygraphs.git] / dygraph-layout.js

diff --git a/dygraph-layout.js b/dygraph-layout.js
index 328da81..e55f62b 100644 (file)
--- a/dygraph-layout.js
+++ b/dygraph-layout.js
@@ -32,6 +32,7 @@
 var DygraphLayout = function(dygraph) {
   this.dygraph_ = dygraph;
   this.datasets = [];
+  this.setNames = [];
   this.annotations = [];
   this.yAxes_ = null;
 
@@ -46,7 +47,8 @@ DygraphLayout.prototype.attr_ = function(name) {
 };
 
 DygraphLayout.prototype.addDataset = function(setname, set_xy) {
-  this.datasets[setname] = set_xy;
+  this.datasets.push(set_xy);
+  this.setNames.push(setname);
 };
 
 DygraphLayout.prototype.getPlotArea = function() {
@@ -162,9 +164,8 @@ DygraphLayout.prototype._evaluateLimits = function() {
     this.minxval = this.dateWindow_[0];
     this.maxxval = this.dateWindow_[1];
   } else {
-    for (var name in this.datasets) {
-      if (!this.datasets.hasOwnProperty(name)) continue;
-      var series = this.datasets[name];
+    for (var setIdx = 0; setIdx < this.datasets.length; ++setIdx) {
+      var series = this.datasets[setIdx];
       if (series.length > 1) {
         var x1 = series[0][0];
         if (!this.minxval || x1 < this.minxval) this.minxval = x1;
@@ -205,33 +206,45 @@ DygraphLayout._calcYNormal = function(axis, value) {
 };
 
 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
   // datasets.
   this.setPointsLengths = [];
+  this.setPointsOffsets = [];
+
+  var connectSeparated = this.attr_('connectSeparatedPoints');
+  // 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 totalPoints = 0;
+  for (var setIdx = 0; setIdx < this.datasets.length; ++setIdx) {
+    totalPoints += this.datasets[setIdx].length;
+  }
+  this.points = new Array(totalPoints);
 
-  for (var setName in this.datasets) {
-    if (!this.datasets.hasOwnProperty(setName)) continue;
-
-    var dataset = this.datasets[setName];
+  for (var 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);
 
-    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 = item[0];
+      var yValue = 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,
@@ -239,10 +252,9 @@ DygraphLayout.prototype._evaluateLineCharts = function() {
         yval: yValue,
         name: setName
       };
-      this.points.push(point);
-      setPointsLength += 1;
+      i++;
     }
-    this.setPointsLengths.push(setPointsLength);
+    this.setPointsLengths.push(i - this.setPointsOffsets[setIdx]);
   }
 };
 
@@ -283,20 +295,20 @@ DygraphLayout.prototype.evaluateWithError = function() {
 
   // Copy over the error terms
   var i = 0;  // index in this.points
-  for (var setName in this.datasets) {
-    if (!this.datasets.hasOwnProperty(setName)) continue;
+  for (var setIdx = 0; setIdx < this.datasets.length; ++setIdx) {
     var j = 0;
-    var dataset = this.datasets[setName];
+    var dataset = this.datasets[setIdx];
+    var setName = this.setNames[setIdx];
     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 = item[0];
+      var yv = 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 = item[2];
+        var errorPlus = item[3];
 
         var yv_minus = yv - errorMinus;
         var yv_plus = yv + errorPlus;
@@ -340,7 +352,13 @@ DygraphLayout.prototype._evaluateAnnotations = function() {
  */
 DygraphLayout.prototype.removeAllDatasets = function() {
   delete this.datasets;
+  delete this.setNames;
+  delete this.setPointsLengths;
+  delete this.setPointsOffsets;
   this.datasets = [];
+  this.setNames = [];
+  this.setPointsLengths = [];
+  this.setPointsOffsets = [];
 };
 
 /**
@@ -349,6 +367,10 @@ DygraphLayout.prototype.removeAllDatasets = function() {
  */
 DygraphLayout.prototype.unstackPointAtIndex = function(idx) {
   var point = this.points[idx];
+  // If the point is missing, no unstacking is necessary
+  if (!point.yval) {
+    return point;
+  }
 
   // Clone the point since we modify it
   var unstackedPoint = {};
@@ -363,7 +385,7 @@ DygraphLayout.prototype.unstackPointAtIndex = function(idx) {
   // The unstacked yval is equal to the current yval minus the yval of the
   // next point at the same xval.
   for (var i = idx+1; i < this.points.length; i++) {
-    if (this.points[i].xval == point.xval) {
+    if ((this.points[i].xval == point.xval) && this.points[i].yval) {
       unstackedPoint.yval -= this.points[i].yval;
       break;
     }