From 4f70731dfb7104e297b1f0481cb6a15260d283ae Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@7thposition.com>
Date: Sat, 31 May 2014 03:23:31 -0400
Subject: [PATCH] Only render oneway markers that actually appear in the
 viewport (motorways and rivers used to fill the DOM tree with a lot of crap!)

---
 js/id/svg.js | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/js/id/svg.js b/js/id/svg.js
index fc848e5de..3bba099bf 100644
--- a/js/id/svg.js
+++ b/js/id/svg.js
@@ -43,6 +43,7 @@ iD.svg = {
                 i = 0,
                 offset = dt,
                 segments = [],
+                viewport = iD.geo.Extent(projection.clipExtent()),
                 coordinates = graph.childNodes(entity).map(function(n) {
                     return n.loc;
                 });
@@ -61,9 +62,10 @@ iD.svg = {
                     b = [x, y];
 
                     if (a) {
-                        var span = iD.geo.euclideanDistance(a, b) - offset;
+                        var extent = iD.geo.Extent(a).extend(b),
+                            span = iD.geo.euclideanDistance(a, b) - offset;
 
-                        if (span >= 0) {
+                        if (extent.intersects(viewport) && span >= 0) {
                             var angle = Math.atan2(b[1] - a[1], b[0] - a[0]),
                                 dx = dt * Math.cos(angle),
                                 dy = dt * Math.sin(angle),