Allow the beginning node of a way be an intersection with another way.

This needs to be ported to drawway and addarea. Fixes #137

js/id/actions/modes.js

@@ -75,6 +75,24 @@ iD.modes.AddRoad = {
             });
         });
 
+        // http://josm.openstreetmap.de/browser/josm/trunk/src/org/openstreetmap/josm/actions/mapmode/ImproveWayAccuracyAction.java#L431
+        // https://github.com/systemed/potlatch2/blob/master/net/systemeD/halcyon/connection/Way.as#L215
+        var map = this.map;
+        function dist(a, b) {
+            return Math.sqrt(Math.pow(a[0] - b[0], 2) + Math.pow(a[1] - b[1], 2));
+        }
+        function chooseIndex(way, point) {
+            var projNodes = way.nodes.map(function(n) {
+                return map.projection([n.lon, n.lat]);
+            });
+            for (var i = 0, changes = []; i < projNodes.length - 1; i++) {
+                changes[i] =
+                    (dist(projNodes[i], point) + dist(point, projNodes[i + 1])) /
+                    dist(projNodes[i], projNodes[i + 1]);
+            }
+            return _.indexOf(changes, _.min(changes));
+        }
+
         function addRoad() {
             var t = d3.select(d3.event.target),
                 node,
@@ -83,6 +101,14 @@ iD.modes.AddRoad = {
             // connect a way to an existing way
             if (t.data() && t.data()[0] && t.data()[0].type === 'node') {
                 node = t.data()[0];
+            // snap into an existing way
+            } else if (t.data() && t.data()[0] && t.data()[0].type === 'way') {
+                var index = chooseIndex(t.data()[0], d3.mouse(surface.node()));
+                node = iD.modes._node(this.map.projection.invert(
+                    d3.mouse(surface.node())));
+                var connectedWay = this.map.history.graph().entity(t.data()[0].id);
+                connectedWay.nodes.splice(1, 0, node.id);
+                this.map.perform(iD.actions.addWayNode(connectedWay, node));
             } else {
                 node = iD.modes._node(this.map.projection.invert(
                     d3.mouse(surface.node())));

js/id/renderer/map.js

@@ -75,7 +75,6 @@ iD.Map = function(elem, connection) {
         class_stroke = iD.Style.styleClasses('stroke'),
         class_fill = iD.Style.styleClasses('stroke'),
         class_area = iD.Style.styleClasses('area'),
-        class_marker = iD.Style.styleClasses('marker'),
         class_casing = iD.Style.styleClasses('casing'),
         // For one-way roads, find the length of a triangle
         alength = (function() {
@@ -237,9 +236,9 @@ iD.Map = function(elem, connection) {
         // Determine the lengths of oneway paths
         var lengths = {};
         var oneways = strokes
-        .filter(function(d, i) {
+        .filter(function(d) {
             return d.tags.oneway && d.tags.oneway === 'yes';
-        }).each(function(d, i) {
+        }).each(function(d) {
             lengths[d.id] = Math.floor(this.getTotalLength() / alength);
         }).data();
 
@@ -248,7 +247,7 @@ iD.Map = function(elem, connection) {
         uses.exit().remove();
         uses.enter().append('path');
         uses
-            .attr('id', function(d, i) { return 'shadow-' + d.id; })
+            .attr('id', function(d) { return 'shadow-' + d.id; })
             .attr('d', function(d) { return d._line; });
 
         var labels = text_g.selectAll('text')
@@ -264,7 +263,7 @@ iD.Map = function(elem, connection) {
         text_g.selectAll('.textpath')
             .attr('letter-spacing', alength * 2)
             .attr('xlink:href', function(d, i) { return '#shadow-' + d.id; })
-            .text(function(d, i) {
+            .text(function(d) {
                 return (new Array(Math.floor(lengths[d.id] / 2))).join('►');
             });
     }
@@ -386,7 +385,7 @@ iD.Map = function(elem, connection) {
     }).on('remove', function(d) {
         map.perform(iD.actions.remove(d));
         hideInspector();
-    }).on('close', function(d) {
+    }).on('close', function() {
         deselectClick();
         hideInspector();
     });

js/id/renderer/tiles.js

@@ -25,7 +25,9 @@ iD.Tiles = function(selection, projection) {
             .translate(projection.translate())();
 
         var image = selection
-            .attr("transform", function(d) { return "scale(" + tiles.scale + ")translate(" + tiles.translate + ")"; })
+            .attr("transform", function() {
+                return "scale(" + tiles.scale + ")translate(" + tiles.translate + ")";
+            })
             .selectAll("image")
             .data(tiles, function(d) { return d; });
 

js/id/ui/inspector.js

@@ -46,7 +46,7 @@ iD.Inspector = function() {
                     event.close(entity);
                 });
 
-            var head = selection.append('div')
+            selection.append('div')
                 .attr('class', 'head').call(drawhead);
 
             var table = selection

js/id/ui/loading.js

@@ -2,7 +2,7 @@ iD.loading = function(message) {
     var loading = d3.select('div.loading');
     if (loading.empty()) loading = d3.select(document.body)
         .append('div').attr('class', 'loading shaded');
-    var modal = loading.append('div')
+    loading.append('div')
         .attr('class', 'modal loading-pane')
         .text(message || '');