Enable scaling the selection via hotkeys

modules/actions/index.js

@@ -30,6 +30,7 @@ export { actionRestrictTurn } from './restrict_turn';
 export { actionReverse } from './reverse';
 export { actionRevert } from './revert';
 export { actionRotate } from './rotate';
+export { actionScale } from './scale';
 export { actionSplit } from './split';
 export { actionStraightenNodes } from './straighten_nodes';
 export { actionStraightenWay } from './straighten_way';

modules/actions/scale.js

@@ -0,0 +1,24 @@
+import { utilGetAllNodes } from '../util';
+
+export function actionScale(ids, pivotLoc, scaleFactor, projection) {
+    return function(graph) {
+        return graph.update(function(graph) {
+            let point, radial;
+
+            utilGetAllNodes(ids, graph).forEach(function(node) {
+
+                point = projection(node.loc);
+                radial = [
+                    point[0] - pivotLoc[0],
+                    point[1] - pivotLoc[1]
+                ];
+                point = [
+                    pivotLoc[0] + (scaleFactor * radial[0]),
+                    pivotLoc[1] + (scaleFactor * radial[1])
+                ];
+
+                graph = graph.replace(node.move(projection.invert(point)));
+            });
+        });
+    };
+}