From 0f20de1c01823dd14dadff582c264a05605ee67b Mon Sep 17 00:00:00 2001
From: Dan Vanderkam <dan@dygraphs.com>
Date: Wed, 18 Jul 2012 10:01:02 -0500
Subject: [PATCH 1/1] faster, a few tests failing

---
 dygraph-canvas.js | 54 +++++++++++++++++++++++++++++++++++++++---------------
 dygraph-utils.js  |  1 +
 phantom-driver.js |  2 +-
 3 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/dygraph-canvas.js b/dygraph-canvas.js
index 3d4b880..887c6ff 100644
--- a/dygraph-canvas.js
+++ b/dygraph-canvas.js
@@ -235,10 +235,12 @@ DygraphCanvasRenderer._getIteratorPredicate = function(connectSeparatedPoints) {
   return connectSeparatedPoints
       ? DygraphCanvasRenderer._predicateThatSkipsEmptyPoints
       : null;
-}
+};
 
 DygraphCanvasRenderer._predicateThatSkipsEmptyPoints =
-  function(array, idx) { return array[idx].yval !== null; }
+    function(array, idx) {
+  return array[idx].yval !== null;
+};
 
 /**
  *
@@ -304,8 +306,16 @@ DygraphCanvasRenderer.prototype._drawSeries = function(
   ctx.strokeStyle = color;
   ctx.lineWidth = strokeWidth;
 
-  while (iter.hasNext) {
-    point = iter.next();
+  for (var i = iter.start_; i < iter.end_; i++) {
+    // while (iter.hasNext) {
+    point = iter.array_[i];
+    if (iter.predicate_) {
+      while (i < iter.end_ && !iter.predicate_(iter.array_, i)) {
+        i++;
+      }
+      if (i == iter.end_) break;
+    }
+
     if (point.canvasy === null || point.canvasy != point.canvasy) {
       if (stepPlot && prevCanvasX !== null) {
         // Draw a horizontal line to the start of the missing data
@@ -314,19 +324,33 @@ DygraphCanvasRenderer.prototype._drawSeries = function(
       }
       prevCanvasX = prevCanvasY = null;
     } else {
-      nextCanvasY = iter.hasNext ? iter.peek.canvasy : null;
-      // TODO: we calculate isNullOrNaN for this point, and the next, and then,
-      // when we iterate, test for isNullOrNaN again. Why bother?
-      var isNextCanvasYNullOrNaN = nextCanvasY === null || nextCanvasY != nextCanvasY;
-      isIsolated = (!prevCanvasX && isNextCanvasYNullOrNaN);
-      if (drawGapPoints) {
-        // Also consider a point to be "isolated" if it's adjacent to a
-        // null point, excluding the graph edges.
-        if ((!first && !prevCanvasX) ||
-            (iter.hasNext && isNextCanvasYNullOrNaN)) {
-          isIsolated = true;
+      isIsolated = false;
+      if (drawGapPoints || !prevCanvasX) {
+        // nextCanvasY = iter.hasNext ? iter.peek.canvasy : null;
+        // var next_i = i + 1;
+        // while (next_i < iter.end_ && (!iter.predicate_ || !iter.predicate_(iter.array_, next_i))) {
+        //   next_i++;
+        // }
+        iter.nextIdx_ = i;
+        var peek = iter.next();
+        nextCanvasY = peek ? peek.canvasy : null;
+        // nextCanvasY = next_i < iter.end_ ? iter.array_[next_i].canvasy : null;
+
+        // TODO: we calculate isNullOrNaN for this point, and the next, and then,
+        // when we iterate, test for isNullOrNaN again. Why bother?
+        var isNextCanvasYNullOrNaN = nextCanvasY === null ||
+            nextCanvasY != nextCanvasY;
+        isIsolated = (!prevCanvasX && isNextCanvasYNullOrNaN);
+        if (drawGapPoints) {
+          // Also consider a point to be "isolated" if it's adjacent to a
+          // null point, excluding the graph edges.
+          if ((!first && !prevCanvasX) ||
+              (iter.hasNext && isNextCanvasYNullOrNaN)) {
+            isIsolated = true;
+          }
         }
       }
+
       if (prevCanvasX !== null) {
         if (strokeWidth) {
           if (stepPlot) {
diff --git a/dygraph-utils.js b/dygraph-utils.js
index 7aeca8d..d3a31d5 100644
--- a/dygraph-utils.js
+++ b/dygraph-utils.js
@@ -686,6 +686,7 @@ Dygraph.Iterator = function(array, start, length, predicate) {
   length = length || array.length;
   this.hasNext = true; // Use to identify if there's another element.
   this.peek = null; // Use for look-ahead
+  this.start_ = start;
   this.array_ = array;
   this.predicate_ = predicate;
   this.end_ = Math.min(array.length, start + length);
diff --git a/phantom-driver.js b/phantom-driver.js
index 009c634..6e4c18e 100644
--- a/phantom-driver.js
+++ b/phantom-driver.js
@@ -80,7 +80,7 @@ page.open(url, function(status) {
     for (var test in caseResults) {
       if (caseResults[test] !== true) {
         num_failing++;
-        failures.push(testCase + '.' + test + ' failed');
+        failures.push(testCase + '.' + test);
       } else {
         // console.log(testCase + '.' + test + ' passed');
         num_passing++;
-- 
2.7.4