From ecf9b464f6a10e3b99f22132ec300e2f83584aaf Mon Sep 17 00:00:00 2001
From: Dan Vanderkam <danvk@google.com>
Date: Tue, 19 Jul 2011 17:36:05 -0400
Subject: [PATCH] drop pixel skipping optimization w/ annotations, too

---
 dygraph-canvas.js |  4 +++-
 dygraph-layout.js | 16 ++++++++--------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/dygraph-canvas.js b/dygraph-canvas.js
index 4606dfb..04c53b8 100644
--- a/dygraph-canvas.js
+++ b/dygraph-canvas.js
@@ -786,7 +786,9 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
             prevX = point.canvasx;
             prevY = point.canvasy;
           } else {
-            // TODO(danvk): figure out why this conditional is necessary.
+            // TODO(antrob): skip over points that lie on a line that is already
+            // going to be drawn. There is no need to have more than 2
+            // consecutive points that are collinear.
             if (strokeWidth) {
               ctx.beginPath();
               ctx.strokeStyle = color;
diff --git a/dygraph-layout.js b/dygraph-layout.js
index 266e3d0..4f8656e 100644
--- a/dygraph-layout.js
+++ b/dygraph-layout.js
@@ -141,14 +141,17 @@ DygraphLayout.prototype._evaluateLineCharts = function() {
     var prevYPx = NaN;
     var currXPx = NaN;
     var currYPx = NaN;
-    
-    var errorBars = this.attr_("errorBars") || this.attr_("customBars");
+
+    // Ignore the pixel skipping optimization if there are error bars.
+    var skip_opt = (this.attr_("errorBars") ||
+                    this.attr_("customBars") ||
+                    this.annotations.length > 0);
 
     for (var j = 0; j < dataset.length; j++) {
       var item = dataset[j];
       var xValue = parseFloat(dataset[j][0]);
       var yValue = parseFloat(dataset[j][1]);
-      
+
       // Range from 0-1 where 0 represents top and 1 represents bottom
       var xNormal = (xValue - this.minxval) * this.xscale;
       // Range from 0-1 where 0 represents left and 1 represents right.
@@ -158,17 +161,14 @@ DygraphLayout.prototype._evaluateLineCharts = function() {
       } else {
         yNormal = 1.0 - ((yValue - axis.minyval) * axis.yscale);
       }
-      
+
       // Current pixel coordinates that the data point would fill.
       currXPx = Math.round(xNormal * graphWidth);
       currYPx = Math.round(yNormal * graphHeight);
 
       // Skip over pushing points that lie on the same pixel.
-      // Ignore this optimization if there are error bars.
       // TODO(antrob): optimize this for graphs with error bars.
-      if (prevXPx != currXPx || prevYPx != currYPx || errorBars) {
-        // TODO(antrob): skip over points that lie on a line that is already going to be drawn.
-        // There is no need to have more than 2 consecutive points that are collinear.
+      if (skip_opt || prevXPx != currXPx || prevYPx != currYPx) {
         var point = {
           // TODO(danvk): here
           x: xNormal,
-- 
2.7.4