forcegraph: keyboard zoom using + -

lib/forcegraph.js

@@ -469,6 +469,21 @@ define(["d3"], function (d3) {
       }
     }
 
+    function keyboardZoom(z) {
+      return function () {
+        var e = d3.event
+
+        if (e.altKey || e.ctrlKey || e.metaKey)
+          return
+
+        if (e.keyCode === 43)
+            animatePanzoom(z.translate(), z.scale() * 1.41)
+
+        if (e.keyCode === 45)
+            animatePanzoom(z.translate(), z.scale() / 1.41)
+      }
+    }
+
     el = document.createElement("div")
     el.classList.add("graph")
     self.div = el
@@ -479,10 +494,11 @@ define(["d3"], function (d3) {
                      .translate([sidebar.getWidth(), 0])
 
     canvas = d3.select(el)
-               .call(zoomBehavior)
                .append("canvas")
-               .attr("pointer-events", "all")
+               .attr("tabindex", 1)
                .on("click", onClick)
+               .on("keypress", keyboardZoom(zoomBehavior))
+               .call(zoomBehavior)
                .call(draggableNode)
                .node()