Define rangeBand in context of rangePoints.

Previously, the rangeBand was zero when rangePoints was used. Now it returns the
size of the step between points. Fixes #584.

d3.js

@@ -6762,7 +6762,7 @@ d3 = function() {
       if (arguments.length < 2) padding = 0;
       var start = x[0], stop = x[1], step = (stop - start) / (Math.max(1, domain.length - 1) + padding);
       range = steps(domain.length < 2 ? (start + stop) / 2 : start + step * padding / 2, step);
-      rangeBand = 0;
+      rangeBand = Math.abs(step);
       ranger = {
         t: "rangePoints",
         a: arguments

src/scale/ordinal.js

@@ -42,7 +42,7 @@ function d3_scale_ordinal(domain, ranger) {
         stop = x[1],
         step = (stop - start) / (Math.max(1, domain.length - 1) + padding);
     range = steps(domain.length < 2 ? (start + stop) / 2 : start + step * padding / 2, step);
-    rangeBand = 0;
+    rangeBand = Math.abs(step);
     ranger = {t: "rangePoints", a: arguments};
     return scale;
   };

test/scale/ordinal-test.js

@@ -109,29 +109,29 @@ suite.addBatch({
       "computes discrete points in a continuous range": function(ordinal) {
         var x = ordinal().domain(["a", "b", "c"]).rangePoints([0, 120]);
         assert.deepEqual(x.range(), [0, 60, 120]);
-        assert.equal(x.rangeBand(), 0);
+        assert.equal(x.rangeBand(), 60);
         var x = ordinal().domain(["a", "b", "c"]).rangePoints([0, 120], 1);
         assert.deepEqual(x.range(), [20, 60, 100]);
-        assert.equal(x.rangeBand(), 0);
+        assert.equal(x.rangeBand(), 40);
         var x = ordinal().domain(["a", "b", "c"]).rangePoints([0, 120], 2);
         assert.deepEqual(x.range(), [30, 60, 90]);
-        assert.equal(x.rangeBand(), 0);
+        assert.equal(x.rangeBand(), 30);
       },
       "correctly handles singleton domains": function(ordinal) {
         var x = ordinal().domain(["a"]).rangePoints([0, 120]);
         assert.deepEqual(x.range(), [60]);
-        assert.equal(x.rangeBand(), 0);
+        assert.equal(x.rangeBand(), 120);
       },
       "can be set to a descending range": function(ordinal) {
         var x = ordinal().domain(["a", "b", "c"]).rangePoints([120, 0]);
         assert.deepEqual(x.range(), [120, 60,0]);
-        assert.equal(x.rangeBand(), 0);
+        assert.equal(x.rangeBand(), 60);
         var x = ordinal().domain(["a", "b", "c"]).rangePoints([120, 0], 1);
         assert.deepEqual(x.range(), [100, 60, 20]);
-        assert.equal(x.rangeBand(), 0);
+        assert.equal(x.rangeBand(), 40);
         var x = ordinal().domain(["a", "b", "c"]).rangePoints([120, 0], 2);
         assert.deepEqual(x.range(), [90, 60, 30]);
-        assert.equal(x.rangeBand(), 0);
+        assert.equal(x.rangeBand(), 30);
       }
     },
 
@@ -244,14 +244,14 @@ suite.addBatch({
         x.rangePoints([1, 2]);
         assert.inDelta(x(0), 1, 1e-6);
         assert.inDelta(x(1), 2, 1e-6);
-        assert.inDelta(x.rangeBand(), 0, 1e-6);
+        assert.inDelta(x.rangeBand(), 1, 1e-6);
         assert.inDelta(y(0), 1/11, 1e-6);
         assert.inDelta(y(1), 6/11, 1e-6);
         assert.inDelta(y.rangeBand(), 4/11, 1e-6);
         y.rangeBands([0, 1]);
         assert.inDelta(x(0), 1, 1e-6);
         assert.inDelta(x(1), 2, 1e-6);
-        assert.inDelta(x.rangeBand(), 0, 1e-6);
+        assert.inDelta(x.rangeBand(), 1, 1e-6);
         assert.inDelta(y(0), 0, 1e-6);
         assert.inDelta(y(1), 1/2, 1e-6);
         assert.inDelta(y.rangeBand(), 1/2, 1e-6);