From 2f11e74ba1f91e53e4f00b83f1655534a1ca2dc3 Mon Sep 17 00:00:00 2001
From: Tom MacWright <tom@macwright.org>
Date: Thu, 6 Dec 2012 10:27:26 -0500
Subject: [PATCH] Support other subdomains, tiger2012 tiles

---
 css/app.css                  |  4 ++++
 js/id/renderer/background.js | 18 +++++++++++++-----
 js/id/ui/layerswitcher.js    | 29 +++++++++++++++++------------
 3 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/css/app.css b/css/app.css
index b263dd5ad..dad9a0905 100644
--- a/css/app.css
+++ b/css/app.css
@@ -122,6 +122,10 @@ div.layerswitcher-control div.opacity-options {
     width:45px;
 }
 
+div.layerswitcher-control a.layer {
+    display:block;
+}
+
 div.layerswitcher-control a.opacity {
     background:#000;
     display:inline-block;
diff --git a/js/id/renderer/background.js b/js/id/renderer/background.js
index c42182058..7cac286e8 100644
--- a/js/id/renderer/background.js
+++ b/js/id/renderer/background.js
@@ -1,7 +1,8 @@
 iD.Background = function() {
     var tile = d3.geo.tile(),
         scaleExtent = [0, 20],
-        projection, source;
+        projection,
+        source;
 
     // derive the tiles onscreen, remove those offscreen and position tiles
     // correctly for the currentstate of `projection`
@@ -16,6 +17,7 @@ iD.Background = function() {
                 projection.scale() / 2 - projection.translate()[0],
                 projection.scale() / 2 - projection.translate()[1]];
 
+        tiles.forEach(function(t) { t.push(source(t)); });
         var image = this
             .selectAll("image")
             .data(tiles, function(d) { return d; });
@@ -23,7 +25,7 @@ iD.Background = function() {
         image.exit().remove();
 
         image.enter().append("image")
-            .attr("xlink:href", source);
+            .attr("xlink:href", function(d) { return d[3]; });
 
         image.attr('transform', function(d) {
             return 'translate(' +
@@ -64,7 +66,7 @@ iD.Background = function() {
 iD.BackgroundSource = {};
 
 // derive the url of a 'quadkey' style tile from a coordinate object
-iD.BackgroundSource.template = function(template) {
+iD.BackgroundSource.template = function(template, subdomains) {
     return function(coord) {
         var u = '';
         for (var zoom = coord[2]; zoom > 0; zoom--) {
@@ -75,7 +77,8 @@ iD.BackgroundSource.template = function(template) {
             u += byte.toString();
         }
         // distribute requests against multiple domains
-        var t = coord[2] % 5;
+        var t = subdomains ?
+            subdomains[coord[2] % subdomains.length] : '';
         return template
             .replace('{t}', t)
             .replace('{u}', u)
@@ -86,4 +89,9 @@ iD.BackgroundSource.template = function(template) {
 };
 
 iD.BackgroundSource.Bing = iD.BackgroundSource.template(
-    'http://ecn.t{t}.tiles.virtualearth.net/tiles/a{u}.jpeg?g=587&mkt=en-gb&n=z');
+    'http://ecn.t{t}.tiles.virtualearth.net/tiles/a{u}.jpeg?g=587&mkt=en-gb&n=z',
+    [1, 2, 3, 4]);
+
+iD.BackgroundSource.Tiger2012 = iD.BackgroundSource.template(
+    'http://{t}.tile.openstreetmap.us/tiger2012_roads_expanded/{z}/{x}/{y}.png',
+    ['a', 'b', 'c']);
diff --git a/js/id/ui/layerswitcher.js b/js/id/ui/layerswitcher.js
index 9f8609bd5..9a68963e2 100644
--- a/js/id/ui/layerswitcher.js
+++ b/js/id/ui/layerswitcher.js
@@ -1,11 +1,13 @@
 iD.layerswitcher = function(map) {
-    var event = d3.dispatch('cancel', 'save');
-    var sources = [{
-        name: 'Bing',
-        source: iD.BackgroundSource.Bing
-    }];
-
-    var opacities = [1, 0.5, 0];
+    var event = d3.dispatch('cancel', 'save'),
+        sources = [{
+            name: 'Bing',
+            source: iD.BackgroundSource.Bing
+        }, {
+            name: 'TIGER 2012',
+            source: iD.BackgroundSource.Tiger2012
+        }],
+        opacities = [1, 0.5, 0];
 
     function layerswitcher(selection) {
         selection
@@ -16,7 +18,7 @@ iD.layerswitcher = function(map) {
         var content = selection
             .append('div').attr('class', 'content');
 
-        var opa = content.append('div')
+        opa = content.append('div')
             .attr('class', 'opacity-options')
             .selectAll('a.opacity')
             .data(opacities)
@@ -31,14 +33,17 @@ iD.layerswitcher = function(map) {
                     .style('opacity', d);
             });
 
-        var s = content.selectAll('a.layer')
-            .data(sources);
-
-        s.enter()
+        content.selectAll('a.layer')
+            .data(sources)
+            .enter()
             .append('a')
             .attr('class', 'layer')
             .text(function(d) {
                 return d.name;
+            })
+            .on('click', function(d) {
+                map.background.source(d.source);
+                map.redraw();
             });
     }